Bovine repro

Question 1

Where are GnRH, FSH, LH, oestrogen and progesterone produced from? What do they act on?

Answer 1

GnRH: hypothalamus, acts on pituitary to produce FSH and LH
FSH and LH: anterior pituitary, FSH acts on follicles, LH acts on egg
Oestrogen: follicle
Progesterone: corpus luteum

Question 2

Stages of follicle growth? What does growth of follicles depend on?

Answer 2

Initiation of follicle growth -> recruitment -> selection and dominance -> ovulation
Primoridal follicles -> primary follicles -> secondary follicles (antrum formation)
Atresia of follicles along the way
Preantral follicle growth for 3 months - GF dependent, gonadotropin influenced
Antral follicle growth for 2 oestrus cycles - gonadotropin dependent, GF influenced

Question 3

Stages of the bovine oestrus cycle?

Answer 3

Day 0: ovulation - follicle releases oocyte for fertilisation, collapsed follicle develops into CL
Day 6: CL is mature, secretes progesterone
Day 16: luteolysis
Oestrus -> metoestrus -> dioestrus -> protestrus
Follicles continue developing in waves through dioestrusbut hormones prevent ovulation

Question 4

How big is a dominant follicle?

Answer 4

> 9mm

Question 5

Hormone levels after calving? When does the first follicle wave emerge postpartum for dairy and beef cows? Does the first dominant follicle ovulate/what does it depend on? How long until first oestrus? Nature of first ovulation?

Answer 5

Low progesterone and oestrogen
Resumption of FSH surges increases within 3-5d, at 7-10d intervals
Emergence of first follicle wave: 5-10d post partum
First post partum follicle wave -> first dominant follicle
Ovulates if sufficient E2 from DF for LH/FSH surge
Capacity for E2 secretion depends on DF size, LH pulse frequency (nutrition, health), IGF-I bioavailability (nutrition)
First oestrus: 2-3 weeks in dairy unless ill/NEB, 3w-3m in beef as increased inhibition
Nature of 1st ovulation: silent

Question 6

What regulates the LH pulse frequency post partum?

Answer 6

Declining NEB
BCS at calving
DMI
Disease state
Suckling and calf presence (beef)

Question 7

What does success of AI depend on?

Answer 7

Use of proven/fertile sires

Reliable oestrus detection

Question 8

Best time to inseminate cows?

Answer 8

In oestrus not dioestrus!

12h before ovulation?

Question 9

Duration of cow signs of heat?

Answer 9

Coming into oestrus: 6-24h (mucus discharge, swelling of vulva, holding milk, bawling, restless, mounts other cows)
Standing oestrus: 6-18h (all above plus stands to be mounted)
Going out of oestrus: 12-24h (same as coming into)

Question 10

Signs of a cow in oestrus?

Answer 10

Sniffing vulva
Chin resting
Licking
Bunting
Mounting head to head
Standing to be mounted (only 50% of cows will do)

Question 11

Methods of oestrus detection of cows?

Answer 11

Visual observation
Paint/chalk/kamar - not all animals show standing heat
Record keeping - start looking 18d after last oestrus
Teaser bull
Chin balls
Milk progesterone
Activity meters - pedometers

Question 12

What must be done to increase pregnancy rates with AI routine?

Answer 12

Tweezers not fingers
Thaw at 37 degrees for 40 seconds
Keep warm
Chilling once thawed is bad
Dry thoroughly

Question 13

Early embryonic development stages?

Answer 13

Fertilisation -> zygote -> 2-cell -> 4-cell -> 8-cell -> morula -> blastocyst

Question 14

Which hormone is crucial for embryo growth?

Answer 14

Progesterone

Question 15

What controls calving?

Answer 15

ACTH from calf pituitary -> cortisol from calf adrenal gland -> increased prostaglandin and reduced progesterone from placentomes
Infusion causes premature labour
Ablation causes prolonged pregnancy

Question 16

How is submission rate calculated?

Answer 16

No. animals served/No. eligible/3 week cycle

First service submission rate: eligible = all animals after earliest service date who have not yet been served
All services submission rate = all animals after earliest service date who are not yet pregnant

Question 17

What is ‘pregnancy rate’? What is ‘preg rate’?

Answer 17

Pregnancy rate: % pregnant of those served

Preg rate: number pregnant/number eligible to be served/3 weeks

Question 18

When does ovulation occur in cows?

Answer 18

24h after heat

Question 19

Timeline of physiological events to calf between ovulation and calving? When can embryo transfer be done? When does failure of inseminsation occur cumulatively?

Answer 19

24h after heat, day 0: ovulation (2% failure)
Day 2: fertilisation (15% failure)
Day 4: entry into uterus (16-32 cells)
Day 6-7: ET can be carried out
Day 8-13: maternal recognition of pregnancy (45% failure)
Day 21-23: interdigitation and expansion
Day 23: heart begins beating
Day 28: amnion remains spherical
Weeks 5-6: distension of uterus (50% failure)
Weeks 6-7: Sexual differentiation of foetus
Weeks 8-9: genital tubercle migration

Question 20

Length of normal bovine oestrus cycle? Type of breeder? Type of ovulation? Which ovary ovulates?

Answer 20

18-24 days
Non seasonal
Spontaneous ovulation
Right ovary has 60% of ovulations

Question 21

What happens during regeneration of the endometrium post-calving?

Answer 21

Septal mass = early evidence of necrosis of septum
Sloughing of necrotic septal mass 5d post partum, fully sloughed by 10-15 days, leaves vascular stubs
Smooth surface of stratum compact by 19d post partum
Normal by 25d+

Question 22

Why are retained foetal membranes a problem?

Answer 22

Delays involution of uterus

Reduces milk yield

Question 23

Problems with uterine infections?

Answer 23

Damages the uterus
Suppresses hypothalamic GnRH and pituitary LH secretion
Localised effects on ovarian function

Question 24

Main uterine infection pathogens?

Answer 24

E.coli
Trueperella pyogenes
Dichelobacter nodosus
Fusobacterium necrophorum
(BoHV4)

Question 25

Risk factors for uterine bacterial infection?

Answer 25

Dystocia Abortion Twins RFM ``` Reduced DMI in dry period NEB after calving Milk fever/vitamin D Vit E/selenium Vitamin A Iodine ```

Question 26

Definition and grades of metritis?

Answer 26

= Inflammation of the uterus caused by bacterial infection, with a reddish-brown (purulent), soul smelling uterine exudate detectable in the vagina, within 21d after parturition Grade 1: enlarged uterus and purulent uterine discharge but no pyrexia/illness Grade 2: 'puerperal metritis' - overt systemic illness (decreased milk yield, fever >39.5C, reduced appetite) Grade 3: 'toxaemic metritis' - signs of toxaemia (cold extremities, dullness)

Question 27

Definition, diagnosis and treatment of pyometra in cows? Cause?

Answer 27

= Intrauterine accumulation of pus in the presence of a CL and a closed cervix Mixed bacterial infection, similar to endometritis Diagnosis: no signs of heat, enlarged uterus, CL, US for pus Treatment: PGF

Question 28

Definition of clinical endometritis?

Answer 28

= Inflammation of the endometrium, with a purulent uterine discharge detectable in vagina 21 days or more post partum (usually caused by bacterial infection)

Question 29

Uterine discharge scoring?

Answer 29

``` 0 = clear or translucent 1 = flecks of white or off-white pus 2 = <50ml exudate containing <50% white or off-white material 3 = >50ml exudate containing purulent material, usually white or yellow but occasionally bloody ```

Question 30

Average calving-conception?

Answer 30

80 days

Question 31

What factors increase the calving-conception time in order from worst first?

Answer 31

``` Drop in social status Caesarean Bad calving Lameness Endometritis RFM Dystocia Mastitis Milk fever Low BCS ```

Question 32

Sub clinical endometritis? What is it? % affected? Risks?

Answer 32

``` Inflammation of the endometrium, usually caused by bacterial infection Increased PMN in cytology Not necessarily any bacteria cultured 5-50% of cows in herd affected Risks: NEG/ketosis, metritis ```

Question 33

Cystic ovarian disease: Clinical signs? What do follicular cysts look like and do? What do luteal cysts look like? When most common?

Answer 33

``` Anoestrus -> nymphomania Follicular cysts: - fluid filled - internal diameter >25mm - thin wall <3mm, - ovulates within 10 days - secrete oestradiol for first half of cyst lifespan - other follicles cannot develop during oestrogen phase - prolonged oestradiol inhibits LH surge - turnover of persistent follicles does occur but rarely do they luteinise - repeated waves of anovulatory follicles Luteal cysts: - luteinised follicular cyst - >25mm external diameter - thick wall >3mm (indicates progesterone production) - fluid filled lacuna - duration 10 days Most common <60 DIM ```

Question 34

Factors associated with cystic ovarian disease?

Answer 34

``` High milk production NEB and ketosis - raised NEFAs Twinning and periparturient problems Genetic predisposition Higher parity Excess BCS at drying off ```

Question 35

Diagnosis of cystic ovarian disease?

Answer 35

Palpation/ultrasound - degree of uncertainty | Milk progesterone

Question 36

First stage labour in cows - what is it? how long can it takes? signs?

Answer 36

= dilation of cervix May take 3-6h Separates herself Appetite decreases May frequently alternate between lying and standing Thick string of mucus often seen hanging from vulva Towards end, bouts of abdominal straining occur more frequently, usually every 2-3 mins - pushed uterine contents against cervix, giving more stimulation to dilate

Question 37

Second stage of labour in cows - What is it? What happens?

Answer 37

= delivery of calf Begins with appearance of membranes (water bag) at vulva May last several hours Water bag ruptures with sudden rush of fluid Cervix dilates with further pressure from calf Powerful reflex and voluntary contractions of abdominal muscles and diaphragm (straining) expels the calf

Question 38

Third stage of labour - What is it? How quick should happen?

Answer 38

Expulsion of placenta Usually happens within few hours RFM if not expelled within 12 hours after delivery of calf?

Question 39

What are ideal calving facilities?

Answer 39

``` Individual pen 12 x 12ft+ - like to calve alone Easy to clean out between calvings Gate +/- quick release headlock -to easily catch cow for examination/assistance ofcavling Milking facility Well bedded and dry Good access to food and water Good lighting Well ventilated Quiet ```

Question 40

When to intervene with a calving? Problem if intervene too early?

Answer 40

If intervene too early when cow in first stage labour, can prevent full dilatation of cervix Only intervene if: - no progress after 1h of water bag showing - showed signs of first stage labour but has not progressed to second stage after 6h (possible twisted uterus) - appears in extreme discomfort - significant bleeding from vulva

Question 41

Most common causes of dystocia?

Answer 41

Malpresentation Foeto-maternal oversize - large calf, fat dam, young/poorly grown dam, dead emphysematous calf Congenital abnormality - Schistoma reflexus, spina bifida, hydrocephalus Hydrops allantois Schmallenberg virus Primary inertia - hypocalcaemia

Question 42

Diagnosis of dystocia?

Answer 42

History - age, parity, breed, previous problems, how long straining, attempts by farmer, water bag broken? Cow attitude, BCS, behaviour General examination e.g. if recumbent and not bright/bloated Obstetrical examination - vulva slackened, vaginal exam, rectal exam

Question 43

What to pay attention to during vaginal examination for dystocia?

Answer 43

``` Lesions (tears) or haemorrhage Position of uterus and calf Relaxation and dilatation of vulva, vagina, cervix Signs of life from calf Possibility of extraction Position of umbilical cord ```

Question 44

What to do if dystocia confirmed?

Answer 44

``` Restrain Clean Lubricate Identify 3 Rs: reposition, repulsion, rotation Extract! ```

Question 45

Aids to help delivering calf with dystocia?

Answer 45

Position cow downhill or uphill Best lube = J-lube Pump warm water and lube into uterus - fill her up, makes space Sink plunger for repulsion Epidural anaesthesia Clenbuterol - relaxes uterus but she won't help in delivery, increases uterine blood perfusion Phone colleague if no progress in 20 mins or need help e.g. lots of bleeding, twisted uterus, breech, needs caesarean Ropes/chains - above fetlock has higher risk of leg fracture, below fetlock has higher risk of slipping off, double loop has minimal chance of leg fracture or slipping off

Question 46

How to decide if calf in anterior presentation can be delivered per vaginum?

Answer 46

Head should be easily lifted into pelvis and remain there without flopping back into uterus - C section if not Forelimbs crossing over = insufficient room for calving per vaginum as cow's pelvis is putting pressure on humeri and width of shoulders is too large Should be able to easily bring calf up so fetlocks are a hands breadth out of vulva - means shoulder is within pelvic canal, failure to achieve means too big for extraction per vaginum Should be able to easily slide hand between foetal cranium and maternal sacrum - c section if not

Question 47

How to decide if calf in posterior presentation can be delivered per vaginum? What to check?

Answer 47

Assess space by sliding hand over tail head 2 people should be able to exteriorise limbs to point where hocks are past vulva - failure = rules out per vaginum Check position of umbilical cord - if round hock will break cord as pull calf and may die/drown before out - advise farm of risk, can do c section or calve and take risk

Question 48

When is an episiotomy done? What must be done prior? How done?

Answer 48

Uncommonly used in cattle - almost totally reserved for heifers In HF heifers, 5-10% may need Narrow vestibule and vulva - vulva not fully slackened and dilated but cervix dilated and calf entering pelvic canal Try manually stretching vulval lips with arms for 20mins before resorting to episiotomy Perineum area contamination risk high - requires antibiotics Caudal epidural anaesthesia Cut at 10-11 O'clock or 1-2 O'clock position Controlled cut, rather than tear vulva during traction Make incision when calf's head passing through vulva Sutures - interrupted deep dissolvable, interrupted or continuous skin sutures

Question 49

Complications of episiotomy?

Answer 49

Wound infection and breakdown Distorted vulva conformation - pneumo-vaginum, uro-vaginum (poor conception rates) Weak point to muscles which may affect ability to calve naturally in future If cut at 12 O'clock - rectovaginal fistula

Question 50

Embryotomy of calf? Drugs needed? When are full and partial embryotomies done?

Answer 50

Must have sufficient space Caudal epidural anaesthesia Clenbuterol Sufficient lubrication Full embryotomy: - large dead calf - abnormal calf (foetal monster) Partial embryotomy: - hip locked (euthanasia if still alive, cut off trunk as close to vulva as poss, pass wire to split pelvis, reps one hindquarter and remove other) - head back, unable to correct and dead calf (remove head using passing method) - leg back, unable to correct and calf dead (remove leg with passing method, must ensure elbow shoulder and scapula removed or no narrowing will be achieved)

Question 51

Passing method of placing wire for embryotomy?

Answer 51

Pass wire by hand around area of calf needing removal Where appropriate attach curved snare director or another form of weight Thread wire through each side of embryotome, tighten, check wire in correct place by palpation before sawing

Question 52

Cleat method of placing wire for embryotomy?

Answer 52

Place obstetric chain on limb Thread wire through embryotome Place the loop of wire in between the cleats on the leg Advance embryotome laterally up limb to just past top of scapula/anterior aspect of greater trochanter Unhook wire from between cleats, pass obstetric chain through loop, to allow wire to be tightened up the medial aspect of the limb to lie in axilla or between hindlimbs Check position of wire before sawing

Question 53

How to remove head and trunk for embryotomy?

Answer 53

For head: - cut as far caudal along neck as poss - embryotome placed lateral or ventral - avoid cutting cervix or vaginal wall For thorax/trunk - using obstetric hook advance the trunk - remove as much of trunk as possible by using passing method of wire placement - pull/cut out any parts of GIT interfering with ability to feel remnants of foetus - remove rest of trunk if necessary or leave hind quarters - split pelvis using passing method - extract one hindlimb at a time Check for twin Check for damage to uterus, cervix, vagina Remove foetal membranes if possible Anti-inflammatories and antibiotics advised

Question 54

Complications of embryotomy/foetotomy?

Answer 54

Uterine/cervical/vaginal tears - from sharp bone edges or incorrect rough handling of embryotome RFM Metritis Adhesions

Question 55

When do most uterine torsions occur? Risk factors? Which way do most twist?

Answer 55

``` Most occur at onset of parturition Risk factors: - poor rumen fill - space in abdomen - hilly land - process of standing up/laying down Majority are anti-clockwise (when stood behind cow) 90->360 degrees ```

Question 56

Signs of uterine torsions at calving? Examination findings?

Answer 56

Appear to start calving but don't progress No straining as Ferguson's reflex not stimulated May just see slightly raised tail Dry cow off colour/down/toxic Vaginal exam - arm 'corkscrews', may just feel 'lip' in front of cervix, may not be able to feel cervix or calf Rectal exam - palpation of torsion

Question 57

Correction methods for uterine torsion?

Answer 57

'Swing' calf with coordinated allotment of abdomen to flip calf and uterine horn back into correct position - must be able to reach and firmly grasp calf by hand/rope Twist legs of calf and uterus may twist too Roll cow - majority of cows require cow to be rolled from left lateral onto back and into right lateral, if calf can be reached grasp leg firmly or place calving rope and hold firmly while cow rolled, if calf can't be reached can place plank across abdomen and weighed down to apply pressure to abdomen while rolled C section - if unable to untwist uterus

Question 58

Complications of uterine torsions?

Answer 58

If high degree of torsion -> blood supply occluded -> friable tissue -> dead emphysematous calf and toxic cow if not noticed early

Question 59

Indications for C section?

Answer 59

Foetal oversize/foeto-maternal disproportion Irreducible uterine torsion Insufficient cervical dilatation Foetal malpresentation if unable to reposition Abnormal calf where embryotomy not feasible Dead/emphysematous calf where embryotomy not feasible Constricted vagina and vestibule where massage has not relieved constriction Elective: double muscled breeds, embryo transfer calves (wait for 1st stage labour)

Question 60

C section of cow - Anaesthesia? Sedation? Pre-op meds? Position?

Answer 60

Anaesthesia - caudal epidural (block Ferguson's reflex), paravertebral nerve block Sedation - avoid unless unsafe without, xylazine will cross placenta and decrease viability, clenbuterol must be used as uterine tone increased but exterioristation of uterus may still be difficult Pre-op meds: - Tocolytic (clenbuterol) - NSAID - antibiotic - calcium if appropriate Position - standing or right lateral (either way, must stay that way)

Question 61

C section of cow - method?

Answer 61

Left flank approach Clip and sterile prep flank Incise from 1 hands breadth below transverse processes, approx length from tip of finger to point of elbow - angled or vertical Locate uterine horn containing calf and exteriorise Incise uterus - normal presentation: incise greater curvature from point of hock to tip of toe - breech: incise greater curvature from carpus to tip of toe - avoid cutting placentomes - ligate any bleeding caruncles Remove calf - locate umbilical cord and ensure not torsed, prevent early rupture and rupture too close to body wall on extraction - extend incision if needed carefully Check for twins Remove foetal membranes Suture uterus - 2 layers, inverted, absorbable, round bodied needle, monofilament Clean off contamination from uterus, rumen and remove blood clots from abdomen Close muscle and peritoneum in 2 layers, and skin Apply antibiotics to muscle layers - shown to reduce risk of wound infection Post op meds - oxytocin, calcium if needed

Question 62

How to alter C section method if emphysematous calf?

Answer 62

Paramedian incision Very low flank incision Sedation/drop - large epidural, xylazine, xylazine and ketamine

Question 63

C section complications? Signs? Treatment?

Answer 63

Haemorrage: post op check may show cow off colour, tachycardia/murmur, pallor - re-open, locate site of bleeding and ligate Peritonitis: off colour, pyrexia - re-open, identify any site of leakage, flush abdomen with sterile fluid, if palpable on rectal exam 7d post-op then poor prognosis Localised adhesions RFM Metritis Wound infections/seroma/breakdown/emphysema Poor fertility due to: delayed uterine involution, RFM, endometritis, salpingitis, adhesions, abortion

Question 64

Factor affecting uterine prolapse in cows post partum? Survival? Effect on production?

Answer 64

Hypocalcaemia 2 week survival 80% (better if live calf) 50 day increase in calving-conception

Question 65

Replacement technique for uterine prolapse of cow?

Answer 65

Standing or sternal with hindlimb extended out behind her Caudal epidural +/- clenbuterol Protective cover under uterus Removed foetal membranes and clean off contamination Apply lube and gradually feed back in - avoid using finger tips as may rupture uterus, feed in sections starting close to vulva or every from horn yips Once replaced, ensure horn tips fully everted by using a bottle to extend the reach of your arm, or fill uterus with water Give oxytocin, NSAIDs, antibiotics, calcium Buhner's suture?

Question 66

What are the main factors affecting cyclicality of cows?

Answer 66

Lameness Low BCS High yield

Question 67

Risk factors for milk fever?

Answer 67

Difficult calving RFM Endometritis Subclinical low Ca

Question 68

Effect of post partum mastitis, BCS loss and lameness on oestrus and luteal activity etc?

Answer 68

Mastitis: - first CL and first oestrus are later - smaller follicles - reduced fertility - take longer to ovulate if synchronised Increased BCS loss: - increased days to first ovulation after calving - lower first service pregnancy rate Lameness: - first CL and first oestrus are later - lower intensity of oestrus - reduced oestrus behaviours - don't respond as well to a progesterone synchronisation regime

Question 69

Effect of milk yield on oestrus signs?

Answer 69

Shorter duration of being mounted (e.g. 6h) Lower incidence of standing oestrus Shorter duration of standing More silent heats

Question 70

What does oestradiol production by first dominant follicle depend on 1-21d after calving?

Answer 70

IGF-1

Question 71

Define abortion in cows?

Answer 71

Calving that occurs before 270d gestation | Must be reported (due to Brucella risk)

Question 72

Measures to monitor for Brucellosis in cows?

Answer 72

All abortions to be reported Monthly routine bulk milk sampling APHA decides if individual case to be testing Stat testing = dam's blood + vaginal swab + milk

Question 73

Which infectious agents causing bovine abortion have vaccines?

Answer 73

Lepto BHV1 BVDv Brucella

Question 74

How much does a replacement animal cost following a culled cow?

Answer 74

£1500-2000

Question 75

Definition of primary abortive agents?

Answer 75

Destroys integrity of foeti-maternal unit E.g. placentitis due to hypoxia Allows opportunistic pathogens to invade placenta and foetus Alters microbiological profile within pregnant uterus

Question 76

What primary infectious abortive agents are there in cows?

Answer 76

``` Brucella abortus BVDv Leptospirosis borgpetersensii (commensal in repro tract) Neospora BHV1 Parainfluenza 3 Bacillus licheniformis Fungi ```

Question 77

Define secondary (opportunistic) abortive agents of cows?

Answer 77

Usually associated with chorionitis/amnionitis Placental steroidogenesis abolished (progesterone) Associated inflammatory cascade and prostaglandins causes: - luteolysis - relaxation of cervix - foetus expelled

Question 78

What secondary abortive agents of cows are there?

Answer 78

``` Gram +ve: - T pyogenes - Listeria monocytogenes - Staph aureus - B-haemolytic Strep Gram -ve: - E.coli - Fusobacterium necrophorum - Histophilus somnis - Leptospirosis borgpetersensii - Pseudomona aeruginosa - Salmonella dublin/typhimurium Others: - Mycoplasma bovigenitalium - Yersinia pseudotuberculosis - Ureaplasma divers ```

Question 79

What are the 3 possible routes of infection of bovine abortive agents?

Answer 79

Resident flora of reproduction tract during pregnancy - at time of service in cattle e.g. Ureaplasma diversum Transplacental (contaminate amnion) - Bacillus licheniformis in cattle, Chlamydophila abortus in ewes Haematogenous - viruses e.g. BVDv, BHV-1

Question 80

What foetal lesions are associated with transpacental infection of abortive agents in cows?

Answer 80

Ureaplasma diversum -> conjunctivitis, bronchopneumonia, peri-bronchiolar cuffing T progenies -> bronchopneumonia

Question 81

What foetal lesions are associated with haematogenous infection of BHV-1 in cows?

Answer 81

Peri-bronchiolar mononuclear inflammatory cell infiltration and vasculitis Centrolobular necrosis of liver

Question 82

Foetal lesions associated with iodine deficiency?

Answer 82

Thyroid hyperplasia (foetal weight in kg/2to3 = expected weight of thyroid in g)

Question 83

Foetal lesions associated with selenium/vitamin E deficiency?

Answer 83

Cell membrane protein associated with removal of oxidation products Myocardial degeneration Mixed inflammatory cell infiltration with some mineralisation - chorionitis

Question 84

What foetal lesions are associated with haematogenous infection of BVDv in cows?

Answer 84

Pale liver without autolysis Fatal focal myocarditis with mononuclear inflammatory cell infiltration Radio-opaque lines Cerebellar hypoplasia

Question 85

Formula to relate foetal tibial length to gestational age?

Answer 85

If tibial length <58mm, days = 68 + (1.7xL) If tibial length 58-163mm, days = 114 + (0.91xL) If tibial length >160mm, days = 105 + L

Question 86

Approximate timing of bovine abortions?

Answer 86

BVD, Salmonella, T progenies, M tuberculosis - any time Trichomonas - 2-4 months Neospora - 4-6 months Campylobacter - 4-8 months Mycotic, lepto, listeria, IBR, IPV - 4-9 months Bacillus/Chlamydia - 5-9 months Brucella - 6-8 months

Question 87

Foetal immunity - when does T cell recognition of self occur? When are antibodies produced?

Answer 87

``` T cell recognition of self: 90-120 days The more complex the antigenic stimulus, the later in gestation Abs are produced - BDVv after day 140 - Salmonella dublin after day 165 - Fungi after day 200 ```

Question 88

IBR - Agent? Signs? Diagnosis? Prevention?

Answer 88

``` BHV-1 Unusual to have resp and retro symptoms Latent carriers - trigeminal ganglion Recrudescence - stress Serology - ELISA Swabs - IF Vaccines - protection in face of outbreak (into-nasal, marker vaccine) ```

Question 89

Neospora caninum - What is it? Phylum? Definitive host? When does it cause abortion? Transmission? Outcome?

Answer 89

Intracellular parasite Definitive host - canidae Phylum = Apicomplexa Dogs: bradyzoite ingestion -> oocysts in faeces, transplacental transmission -> puppies may have disease (neonatal paresis), Ab response Most commonly diagnosed cause of abortion Usually 4-6 month gestation May cause early embryonic death - manifests clinically as infertility (rare) Congenitally infected heifers most at risk of abortion in first gestation Cows infected by oocysts ingestion (exogenous) -> abortion or PI calf born Recrudesence of infection in cow -> transplacental (endogenous) -> abortion of PI calf born 10%: Abortion 80%: Birth of clinically normal PI calf 10%: Birth of clinically normal uninfected calf but may be weak 95% of calves born to infected dams are themselves infected Endemic abortion pattern: - annual abortion rate >3% - endogenous transpacental transmission - very efficient, common route Epidemic abortion pattern: - abortion storm >10% of at risk cows abort over a 12 week period - associated with exogenous transplacental transmission

Question 90

Diagnosis of Neospora in cows?

Answer 90

Maternal serology (ELISA) fluctuates though reproductive cycle - nothing at 12-18mo (little use screening young stock) - use increasing levels as evidence of recrudescence - test in second half of pregnancy - eliminate other causes Test calf at birth - indicates dam infected if calf +ve PM of dead foetus - brain histopath, non suppurative encaphalitis

Question 91

Control of Neospora?

Answer 91

Keep dogs away from cattle feed and water and don't allow to eat placentas Identify positive cows - serology of whole herd Cull seropositive animals and offspring - often not practical as high prevalence so expensive Breed to beef and do not keep or sell as replacement heifers Use sexed semen to get more heifers from uninfected animals Embryo transfer to negative recipients PI cows are immune to further challenge but may recrudesce Causes 35% of abortions in UK

Question 92

BVD - Type of virus? Incubation period? When are Abs present? Genotypes? Biotypes? What happens if infection during pregnancy?

Answer 92

Pestivirus Incubation period 5-7d Abs present 14-21d after initial infection Genotype I - mildly/moderately pathogenic, most common type in N Europe Genotype II - virulent type, problem in N America, severe diarrhoea and moderately mortality rates (30%) 2 biotypes within each genotype: - non cytopathic: rarely causes clinical disease (unless genotype II) but crosses foeti-maternal barrier - cytopathic: associated with mucosal disease in PI animals Infection during pregnancy of non cytopathic: - First trimester (0-95d): foetal resorption or abortion - 95-120d: immunotolerance (PI) - 120-285d: seropositive foetus +/- congenital lesions, abortion may occur due to placentitis

Question 93

Consequences of BVD?

Answer 93

Lowered pregnancy rates - reproduction tract epithelia and follicles affected Abortion - compromised foeti-maternal barrier allows secondary bacterial infection (placentitis and foetal pathology) PI calves Congenital abnormalities - cerebellar hypoplasia, microphthalmia, cataracts Mucosal disease - PI animals then infected with cytopathic biotype

Question 94

Problems with BVD PI calves?

Answer 94

Don't recognise virus as foreign as infection occurs before immune system development Ab negative, Ag positive (serum for Ab, heparin for Ag) Susceptible to MD if encounter secondary infection with cytopathic virus (don't mount an immune response) - usually via mutation of resident strain Often poor-doers as BVD is immunosuppressive - but can make to adulthood and produce PI calves

Question 95

Clinical signs of BVD mucosal disease?

Answer 95

Ulceration of mucosal (particularly tongue, soft palate, gingiva and oesophagus) Ill thrift Diarrhoea +/- Concurrent respiratory disease (immune suppression)

Question 96

Diagnosis of BVD?

Answer 96

Seroconvert over 3 weeks Bulk milk Abs (quarterly) - vaccination will render useless Detect PI in blood from 1mo (<30do MDA interferes) Ear notch tissue test when tagged Check test (5 bloods per group_ Bulk tank PCR detection limit one in 300 Probably 50% dairy herds are but tank BVD Ab+ve (70% in UK cattle)

Question 97

Leptospirosis - Main 2 types in UK cattle? Where do the bacteria go? Transmission?

Answer 97

L interrogans serovar Hardjo (type hard-prajitno) L borgpetersensii serovar Hardjo (type hardjo-bovis) Bacteria can reside in kidneys Excreted for months-years via urine Survive long periods in water Spread by contact with skin, mucous membranes or orally 75% of adult UK cattle have been exposed to L hardjo

Question 98

Clinical signs of Leptospirosis in cattle?

Answer 98

Often unapparent and cow in latent state Persistent infection of reproduction tract - infertility, shedding in discharges Abortions, still births, weak calves in acute infections RFM

Question 99

Diagnosis of Leptospirosis in cattle?

Answer 99

Bulk milk Ab testing gauges level of infection in herd Serology by MAT Identification of leptospires from aborted tissue, blood or urine by IF or PCR

Question 100

Treatment, risk factors and control methods for leptospirosis in cattle?

Answer 100

Antibiotics - prolonged course of dihydrostreptomycin or oxytetracycline Early treatment aids prognosis in preventing latent carrier status Risk factors/control: - buying in stock - screen or avoid - running a bull with cows - use AI - co-grazing with sheep - don't - watercourses - fence off Vaccinate - all breeding stock and replacement heifers from 4mo, annually Difficult to eradicate because of latent infection

Question 101

Salmonella - Most common serovar associated with bovine abortion? Sources? Control?

Answer 101

S.Dublin Sources: faeces, feed, fomites Shedding increased by stress e.g. around calving Can vaccinate 2 months pre-calving plus youngstock Treat sick Hygiene!

Question 102

Trichomonas foetus - Clinical signs? Infection route?

Answer 102

``` Confined to repro tract of cow and bull Spread by natural service - less common now due to AI Clinical signs: - occasionally abortion - more commonly poor pregnancy rates - pyometra and endometritis ```

Question 103

Why has vaccination not eradicated BVD?

Answer 103

<20% of Ab +ve herds have PI milking Half primary vaccine course given at incorrect time 24% given vaccine at correct time relative to service 20% given wrong dose or route 1/3 doses kept open longer than one month 1/3 farmers never refer to data sheet Buy trojan horses ie cows with PI on board

Question 104

PME for abortion cases?

Answer 104

``` Crown-rump length - gestational age Thyroid gland weight Fractures/haemorrhages Fluid compartment-itis Placentitis Liver rupture meningeal haemorrhage/oedema ```

Question 105

What samples to use for abortion case?

Answer 105

``` Placentome or placenta Spleen -> BVD PCR Liver - IBR and bacteriology Stomach contents - bacteria e.g. Salmonella, Campy Kidney - Lepto Brain - Neoplasia Left ventricle Thyroid Eyelid - Ureaplasma, fungal hyphae in hair follicles Tired dam serology ```

Question 106

Formulae for thyroid weight and foetal age using CRL?

Answer 106

Thyroid weight (g) = foetal weight (kg)/2to3 Foetal age 1st trimester (days) = (CRL(mm)+87.8)/2.74 Foetal age 2nd and 3rd trimester (days) = (CRL(mm)+297.1)/4.70

Question 107

Antibodies in blood or milk for abortion investigation?

Answer 107

Ab following natural infection is long lasting for BVD, BHV1 and L Hardjo Ab levels following inactivated vaccination can be low and short lived for BVD and BHV1 Single samples - exposure or vaccination? Use paired sera for current infection Bulk milk BVD/Lepto/IBR/Neo BVD Ag PCR on bulk tank if <300 cows If +ve: do a first lactation (homebred) screen (pooled)

Question 108

Diagnosis and treatment of Campylobacter foetus? Control?

Answer 108

Preputial washing of bulls and culture - phosphate buffered saline warmed, prevent faecal contamination Vaginal mucus collection of cows for culture/ELISA - select 12 females most recently identified as problem, detects IgA, only 50% of infected will produce positive result, 50% of positives become negative within 6 months, from 7 weeks to 10 months PI Low Se - 30% in bulls, lower in cows Treatment: systemic streptomycin, sheath lavage with pen/strep Control: - use AI for at least 2 seasons or longer - separate infected from non infected herds - autogenous vaccine of unknown efficacy - cull older bulls - treat younger bulls

Question 109

Equation for the genetic variation in a population?

Answer 109

Vp = Vg + Ve

Question 110

What is the heritability for: body conformation, udder conformation, milk fat/protein %, growth rate, milk yield, BCS, BHBA, reproduction traits?

Answer 110

``` Body conformation, udder conformation, milk fat/protein %: 0.6 Growth rate, milk yield: 0.35 BCS: 0.3 BHBA: 0.08-0.4 Reproduction traits: <0.1 ```

Question 111

What does pleiotropy mean?

Answer 111

Genes affecting more than one trait

Question 112

What positive and negative genetic correlations are there in relation to dairy cows?

Answer 112

``` Negative: - milk/fat% - milk/protein% - milk/fertility - milk/BCS - BHBA/reproduction traits Positive: - milk/fat yield - milk/protein yield - milk/mastitis - SCC/mastitis - BCS/repro - lameness/milk yield ```

Question 113

What are breeding values?

Answer 113

Refers to the additive genetic merit of an animal Double the expected deviation in progeny performance from the population mean Predicted from animal's own performance, parents' performance and progeny performance Also heritability of trait important and comparisons between contemporary groups Number and type of records and heritability affects accuracy of predictions Positive, negative or zero

Question 114

What is Bovine Leucocyte Adhesion Deficiency? Clinical signs? Testing?

Answer 114

Autosomal recessive Single point mutation (adenine to guanine) causes aspartic acid to glycine substitution Impaired expression of the beta-2 intern (CD11a,b,c/CCD18) of the leukocyte adhesion molecule of neutrophils Fewer neutrophils get into tissue to fight infection Produced and seen in higher numbers in circulation Clinical signs: - ulcers on oral mucosa - gingivitis/periodontitis - chronic pneumonia - recurrent/chronic diarrhoea Die fue to infection <1yo No treatment effective All bulls from major AI companies tested (PCR)

Question 115

What is Complex Vertebral Malformation (CVM)?

Answer 115

Autosomal recessive Misshapen, fused vertebrae around cervico-thoracic junction Symmetrical arthrogryposis of the limbs 50% have cardiac abnormalities Semi-lethal Mis-sense mutation n Golgi resident nucleotide-sugar transporter Abnormal protein glycosylation of chondroitin sulphate Bulls from major AI companies tested (PCR)

Question 116

What is Holstein haplotype for cholesterol deficiency (HCD)?

Answer 116

Heterozygous animals have reduced choleterol Homozygous animals have no cholesterol and survive only few months Causal mutation not found

Question 117

Genomic evaluation - when useful?

Answer 117

Better than using parent averages - important for selection of young bulls GEBVs Can be useful or natural mating More accurate in future - more animals genotyped, high density chips

Question 118

What should a Bull Breeding Soundness examinations (BBSE) detect? What should a fertile bull achieve?

Answer 118

To detect bulls whose fertility is sub-optimal and avoid using them A fertile bull should get: - 90% of 50 normal, cycling, disease free females pregnant within 9 weeks - 60% should become pregnant within the first 3 weeks of the breeding period

Question 119

How long does it take for a sperm to develop from a germ cell and be present in the ejaculate? How cool must the tested be for normal spermatogenesis?

Answer 119

61 days | 2-6 degrees cooler than body temperature

Question 120

What does a Bull Breeding Soundness examinations (BBSE) involve?

Answer 120

1. General clinical exam - BCS, locomotion and gait, conformation, ocular conditions 2. Repro tract exam - scrotal circumference, testicles, accessory sex glands, prepuce and penis 3. Semen evaluation - gross motility, linear progressive motility, morphology, WBCs

Question 121

What accessory sex glands do bulls have?

Answer 121

Bulbourethral gland Prostate Seminal vesicles Ampullae

Question 122

``` Which methods os semen collection are best for assessment of: Libido and mating Penile abnormality Volume and concentration of ejaculate Sperm motility Sperm morphology Health and safety Time Reliability ```

Answer 122

Libido and mating - internal artificial vagina Penile abnormality - artificial vagina Volume and concentration of ejaculate - artificial vagina Sperm motility - artificial vagina and electro-ejaculation Sperm morphology - all Health and safety - electro-ejaculation, trans-rectal ampullarf massage Time - electro-ejaculation Reliability - electro-ejaculation

Question 123

What is the rule of thumb for libido testing of a bull when put with a cow on heat?

Answer 123

Should serve her definitely within 20 mins and ideally within 10 mins

Question 124

Treatment options for a penile haematoma (broken penis)?

Answer 124

Cull Medical treatment: - most successful when swelling <15cm - sexual rest for 2 months - cold hosing for 4 days followed by warm hosing and massage for 3 weeks - antibiotics to stop abscess formation and NSAIDs Surgical treatment: - removal of blood clot and suturing of tunica albuginea where possible - followed by medical treatment

Question 125

Penile Fibropapilloma in bulls - Cause? Which bulls affected? Significance? Treatment?

Answer 125

Bovine papilloma virus Most common in young bulls May disappear over time but can take a while and may interfere with serving So surgical removal may be indicated - can be done standing under pudendal nerve block

Question 126

What are the main venereal diseases of bulls?

Answer 126

Campylobacter foetus venerealis Tritrichomonas foetus (rare in UK) BHV 1

Question 127

Clinical signs of Campylobacter foetus venerealis (and C foetus foetus)? Immunity? Treatment?

Answer 127

Endometritis after service Failure to conceive Embryonic death Abortion (usually 4-5 months) Cows develop immunity after a few months and can get pregnant again but may shed for up to 1 year Bulls don't develop immunity Young bulls (<4yo) can sometimes be treated with Streptomycin Rare in dairy herds using AI (still common in beef cattle) Important to test bulls

Question 128

Infectious Pustular Vulvovaginitis/Balanoposthitis - Cause? Spread? Incubation period? Clinical signs? Diagnosis? Treatment?

Answer 128

BHV-1 Strain is genetically distinct from the cause of IBR Venereal spread by carrier animals Uncommon in UK 1-3 days incubation period Mucopurulent vaginal discharge Inflammation of vaginal and vulvar mucosa with pustules which become ulcers Painful swelling of penis and prepuce Diagnosis: PCR or FAT on swabs, or paired serology No specific treatment - will get better without

Question 129

Category 1 animal by products?

Answer 129

= highest risk All SRM/bodies containing SRM (unless removed and disposed of separately)/bodies of animals suspected or confirmed as TSE positive/sludge or by products collected from waste water drain screenings in ruminant slaughterhouses and other premises in which SRM is removed Animal material (sludge) or animal by-products collected during the treatment of waste water Animals killed in the context of TSE eradication measures Wild animals when suspected of being infected with diseases communicable to humans or animals Pproducts derived from animals treated with substances prohibited under EC legislation or containing residues of environmental contaminants SRM Carcases, blood and all parts (including hide / skin) from animals which do not prove negative for a TSE following testing. All parts (including hides / skins and blood) of TSE sampled carcases disposed of prior to test results being obtained. • Products suspected of containing EC prohibited non-medicinal treatments or illegal substances, such as elevated dioxin or heavy metal contaminants, if such residues exceed the permitted levels (but does NOT include products containing residues of permitted veterinary drugs). • Bodies of wild game animals suspected of being affected by disease communicable to humans or animals, such as foot and mouth disease or tuberculosis. • Any animal material that comes into contact with SRM after it has been removed from the carcase. • Whole bodies of cattle, sheep, goats, water buffalo and bison either rejected at ante-mortem inspection, or found dead on arrival, or found dead in the lairage (unless SRM has been removed at the point of disposal).

Question 130

What environmental and contagious mastitis pathogens are there?

Answer 130

``` Environmental: - E.coli - Klebsiella - Strep uberis Contagious: - Strep uberis - Strep agalactiae - Strep dysgalactiae - Staph aureus, - Coagulase Negative Staphs - Mycoplasma ```

Question 131

Grades of clinical mastitis? What if subclinical?

Answer 131

Grade 1 - mild changes in milk Grade 2A - acute, changes in milk, hot painful udder Grade 2C - chronic, changes in milk, hard lumpy udder Grade 3 - changes in milk and udder, cow sick (e.g. gangrenous mastitis) Subclinical - no visible clinical signs, but changes in SCC, milk quality, milk yield

Question 132

Effect of a higher SCC on milk quality?

Answer 132

Bacterial enzymes spoils protein (less casein, more Igs) and fat Reduces storage time

Question 133

What does the teat skin have to prevent colonisation with bacteria? Problems with teat skin predisposing to mastitis? Prevention methods?

Answer 133

``` Has: - stratified squamous epithelium - bacteriostatic fatty acids Problems: - bruising, chapping, trauma, teat lesions - milking machine vacuum, pulsation, liners, over milking Prevention: - post milking teat dip emollients - prompt treatment of teat lesions - good milking machine function ```

Question 134

How does the teat canal prevent colonisation of bacteria? Problems? Prevention?

Answer 134

Keratin lining traps bacteria and continuously sloughing Keratin plug forms seal over teat end when cow is dried off Open during and after milking Teat sphincter muscle acts as barrier but takes 20-30 mins to close Teat canal damage due to: - milking machines causing hyperkeratosis due to excessive vacuums, faulty pulsations, liner types and teat shape - trauma - teat lesions - teat cannula Prevention: - genetics - milking machine function - loafing time post milking (30 mins) - teat sealants at drying off

Question 135

What antimicrobial substances are inside the udder/in the milk? What do they do?

Answer 135

Resident leucocytes Lactoperoxidase - bacteriostatic agent Lysozyme - bactericidal protein Lactoferrin - iron chelating protein produced by epithelial cells and leucocytes, highest in dry period, inhibits growth of bugs requiring iron e.g. E.coli Complement - produced by hepatocytes, aid in opsonisation of bacteria, attract phagocytes

Question 136

What is somatic cell count?

Answer 136

Number of cells per ml of milk Mainly macrophages, neutrophils and T lymphocytes For: - phagocytosis and killing of invading pathogens - trigger acquired immune system by release of pro-inflammatory mediators and Ag presentation

Question 137

What is the most important cell in the acquired immune system for mastitis? How do they get there?

Answer 137

Neutrophils Respond to release of pro inflammatory cytokines Adhere to and migrate along endothelial cell surface towards site of infection Migrate through tissue to infection site Phagocytosis

Question 138

Role of B lymphocytes in mastitis?

Answer 138

``` Circulate through lymphatic system Exposed to Ags in tissue fluids Initial response: produce IgM, IgG1 Repeated exposure: produce IgG2 Abs IgG2 Abs circulate and enter inflamed udder - aid opsonisation of pathogens by neutrophils Present Ag to T lymphocytes ```

Question 139

Roles of T lymphocytes in mastitis?

Answer 139

T helper cells - produce cytokines following Ag recognition stimulates immune response T cytotoxic cells - eliminate host cells invaded by pathogens

Question 140

Which types of antibodies are important for mastitis? What do they do?

Answer 140

IgG2 most important IgM fixates complement for opsonisation of pathogens, agglutination of pathogens and neutralisation of toxins IgA agglutination of bacteria and neutralisation of toxins IgG1 opsonisation of bacteria?

Question 141

What can currently be selected for genetically to reduce risk of mastitis?

Answer 141

Low SCC Udder conformation Yield Would be better to use clinical mastitis incidence as selection criteria by farm records are poor

Question 142

What stages of lactation are risk periods for acquiring infection in udder? Why?

Answer 142

Dry period - high risk of acquiring new infections despite antibiotic tubes - cessation of milking -> increased intra-mammary pressure and widening of teat canal - bacteria not flushed out - no teat dipping - only 50% of cows have adequate keratin plug by 10 days post calving - WBC function reduced Clinical disease usually seen in first 6 weeks after calving

Question 143

Why is the WBC function reduced in the early dry period and peri-parturient cow?

Answer 143

Early dry period: - neutrophils present in high numbers in secretions but full of fat and cellular debris so function impaired Peri-parturient cow: - increasing levels of IgG1 for colostrogenesis may interfere with neutrophil capacity to deal with pathogens - neutrophil recruitment and phagocytic ability is reduced: high levels of cortisol, oestradiol and progesterone? Nutrition? - macrophages have reduced phagocytic function

Question 144

What nutritional problems can be risk factors for mastitis?

Answer 144

NEB - leucocytes have impaired activity, lower number Vitamin E and selenium - deficiency results in slow migration and weaker activity of leucoytes SARA - reduced appetite -> reduced DMI -> NEB, and also diarrhoea -> poor cow hygiene Hypocalcaemia - weaken teat sphincter mechanism

Question 145

Startvac?

Answer 145

Protects against Staph aureus, coliforms and coagulase-negative staphylococci Reduce incidence of sub-clinical mastitis Reduces incidence and severity of the clinical mastitis Recent UK trial – not yet published Good if having problems with grade 3 per-acute toxic mastitis

Question 146

UBAC?

Answer 146

Strep uberis vaccine | Authorised but not available yet

Question 147

Role of milking machine vacuum and pulsator liner? How does it work?

Answer 147

Negative pressure outside teat to remove milk Controlled by a regulator Continuous vacuum would stop circulation in teat Applied intermittently via pulsator liner opening and closing to allow teat to rest and circulation restored - 60/min Vacuum on:off = 2:1 Vacuum is off when liner is closed (milk flow stops and teat rests) Vacuum is on when liner opens (milk flows out)

Question 148

Milking cluster unit labelling photo

Answer 148

Claw piece collects milk

Question 149

What damage can the milking machine cause to teats to allow bacteria to colonise? How?

Answer 149

Blue, oedematous, petechiations or chapped teats: - worn/hard liners - inadequate rest phase in pulsators (set too fast) -> poor circulation - excess vacuum - inadequate emollient in post milking teat dip Teat end sphincter hyperkeratosis: - excess vacuum - fluctuating vacuums - over milking (no ACR/ACR set too high) - faulty liners - poor pre-milking teat preparation

Question 150

Transfer of infection via milking machine?

Answer 150

Contamination of liners - transfer on teat skin Wet milking - milk flushed upwards into teat canal carrying pathogens with it (inadequate vacuums, fluctuating vacuums, blocked air bleed)

Question 151

How to test the milking machine?

Answer 151

Examine clusters - blocked air bleeds, cleanliness of liners, wear of liners, holes in tibing Vacuum - note gauge level, watch while milking and observe for fluctuations (should be between 42-48kpa) Liners slipping 0 hear shh sound = inadequate vacuum Watch cows - paddling/kicking = over milking/faulty vacuum or pulsators/excess vacuum/hard liners Teat score (min 20% of herd) Ask wash up routine Ask when serviced

Question 152

Why is fore-milking important?

Answer 152

Legal requirement Early detection of mastitis Stimulation of milk let down reflex

Question 153

Methods of premilking teat prep?

Answer 153

``` None Wipe with common udder cloth Disinfectant wipe - one per cow Wash (+disinfection) +/- dry (if wash must always dry) Spray or dip cup with disinfectant Foaming products ```

Question 154

What disinfectants can be used for premilking teat prep? What to make sure?

Answer 154

Chlorhexidine 0.35-0.5% Iodophors 0.1-0.5% Chlorine dioxide (active in presence of faeces) Hypochlorite (bleach, 4%) Make sure correct concentration and contact time (30s-2m)

Question 155

What is the milk ejection reflex?

Answer 155

Teat stimulation causes afferent neural inpusts, terminating in paraventricular nucleus of hypothalamus Oxytocin released from posterior pituitary Leads to contraction of myoepithelial cells in mammary gland

Question 156

Post milking teat dip constituents?

Answer 156

``` Disinfectants: - Iodine - Chlorhexidine - Lactic acid - Chlorine dioxide - Ammonium compounds Emollients (lanolin, glycerine, sorbitol) for skin condition Dye? Sticking agents ```

Question 157

Role of loafing time post milking?

Answer 157

Allow closure of test sphincter post milking Prevent environmental infections 30 mins Clean area

Question 158

Milking order?

Answer 158

1. heifers 2. fresh calvers 3. high yielders 4. low yielders 5. high cell count cows 6. mastitis cows

Question 159

Parlour wash routine?

Answer 159

Clean milk out and remove bacteria deposited Cold rinse once daily Hot wash once daily (85-90C, 10-12L per unit) Rinse with hypochlorite Acid and alkali washed Staph aureus builds up if not hot enough

Question 160

Diagnosis of teat infections?

Answer 160

Age (teat warts in younger animals) One or several Painful? pseudo cowpox usually not painful, Bovine herpes mammilitis is very painful

Question 161

Teat warts? Agent? Transmission? Problems? Treatment?

Answer 161

``` Bovine papillomatosis Bovine papilloma virus Young animals Flies may be involved in transmission Harbour bacteria predisposing to mastitis, poor liner attachment leading to teat end impacts and difficult milking, pain can make milking/calf suckling difficult Most self cure given time Can try removal by ligation, surgery, cryosurgery Severe cases - autogenous vaccine ```

Question 162

Pseudocowpox? Agent? Signs? Problems? Treatment?

Answer 162

``` Parapox virus Circular or horseshoe shaped scabs Not particularly painful Spreads through herd and can recurrence months later Treated by thorough PMTD ```

Question 163

Bovine herpes mammilitis? Agent? Signs? Immunity? Preventing spread?

Answer 163

``` Bovine herpes virus 2 Uncommon Very painful vesicle -> ulcer - often whole teat Slow healing (weeks) Life long immunity Milk affected cows last to reduce spread Acyclovir? ```

Question 164

Cowpox of cow teats - what virus? Transmission? Signs?

Answer 164

``` Orthopox virus Transmitted by cats Painful vesicles, ulcers, scabs Weeks to heal Very painful ```

Question 165

Black spot of teats? What is it? Treatment?

Answer 165

Common Damage to teat end e.g. teat end eversion from excess vacuum plus secondary infection with Fusobacterium necrophorum -> necrotic craters? Topical antibiotics, teat cannula Check milking machine

Question 166

Udder or teat impetigo? Signs? Agent? Control?

Answer 166

Pustular lesions of teat and udder skin Usually Staph aureus Can spread to milkers Controlled by PMTD, antiseptic udder creams

Question 167

Photosensitisation of teats?

Answer 167

Can occur as part of generalised photosensitisation disorder in which non pigmented skin only affected Lateral aspects of teats and unpigmented skin General supported treatment Remove from light NSAIDs, sunblocks

Question 168

Chapped teats? Causes? Treatment?

Answer 168

Painful Worn teat liners, poor teat skin care, calf suckling Emollients, teat cannula to rest

Question 169

3 fold rule for teat dips?

Answer 169

Pre-milking to remove organisms from teat skin that may enter udder via teat during milking - environmental mastitis pathogens Post-milking to kill bacteria on teat after milking and protect from new infection from environment - contagious mastitis pathogens and teat skin pathogens Condition teat skin to withstand disinfectants and milking machine

Question 170

Teat pea? What is it? How to remove?

Answer 170

Pedunculated granuloma attached o wall of teat canal - blocks flow of milk Removal by Hudsons spiral inserted by rotating up teat canal then jerk upwards to tear granuloma off - granuloma then milked out Mosquito forceps up canal to tear off Must give prophylactic antibiotics to precent mastitis Sedate, cannulate, open up teat wall, suture

Question 171

Teat stenosis and blind teats? When seen? Treatment?

Answer 171

Teat stenosis usually sequelae to trauma Treated by local anaesthesia, sedation, insert small teat knife and rotate Rest teat with teat cannula and IM antibiotics for 3-5 days Prognosis guarded as scar tissue may reform Blind teats heifers no milk in teat then leave as cannot open If milk in teat then lesions is in canal and treat as above

Question 172

Treatment for cut teats?

Answer 172

Sedate cow in crush - e.g. low dose xylazine Lift hind leg as for foot trimming Can also sedate and cast cow Clean wounds thoroughly Superficial (skin only or old) - do not suture, can use tape and/or glue Other wounds - local anaesthetic (teat lumen block or ring block around base of teat), clean and debride, suture with simple interrupted and swaged on needle 3 metric OR staple OR glue Prognosis guarded Always give prophylactic antibiotics Teat cannula to allow milk to drain during milking Bandage? Op-site spray and Leukopor tape

Question 173

Supernumerary teats - What to do?

Answer 173

Ideally removed in heifers at time of disbudding Restrain dog sitting with HL hobbled; you stand on rope...can’t kick you! <2mo: can be removed without anaesthetic and using sharp scissors in animals Older animals: local anaesthetic and scissors or emasculators

Question 174

What % of cubicle area must be loafing for Red Tractor? How many cubicles? Feed space requirement for milking and dry cows? Water supply space per cow? How much do cows drink at a time? Lunge space needed for normal rising behaviour? How much dung do cows produce per day?

Answer 174

``` 120% of cubicle area must be loafing Good practice is 5% more cubicles than cows (FAWC and Red Tractor only require 1/cow) Milking cow feed space: 60cm/cow Dry cow feed space: 90cm/cow Water supply: Ad lib, 10cm/cow, 1m squared/60 cows, 10% of herd drink simultaneously Cows drink 15-20L/min 0.7-1m lunge space (30 movements) 50kg dung/day ```

Question 175

5 freedoms?

Answer 175

``` Freedom from hunger and thirst Freedom from discomfort Freedom from pain, injury and disease Freedom to express normal behaviour Freedom from fear and distress ```

Question 176

How much light per day is good for maximum feed intake and milk production?

Answer 176

16-18 hours/day | Yield increased by 2L compared to natural photoperiod

Question 177

Pros and cons of loose straw housing? Space requirement?

Answer 177

Comfortable - reduced lameness? Hygiene - wet warm straw -> bacterial stew -> increased environmental mastitis risk 1.3m squared/1000 milk production 70% bed, 30% loafing Totally clean out every 2 weeks

Question 178

Ideal cubicle design?

Answer 178

Slight upward incline kerb-front Dung passed over kerb with minus deposited on cubicle rear (mastitis) Concrete base Top layer - mattress/mar/sand Brisket barrier/board to aid cow position Head rail may aid cow position

Question 179

Basic cubicle measurements?

Answer 179

Length 2.3-2.4m Height of “head rail” 1.4m Width 1.15-1.20m Kerb height 10cm (remember to account for mat/mattress etc) 2-3% slope from front to kerb (= 5” fall) Lying length 1.7 m - must permit 0.7-1m lunge space Diagonal from head rail to kerb 2.2m

Question 180

Cow comfort quotient? What is an acceptable level? How to calculate?

Answer 180

<50% is poor >80% is acceptable = number of cows lying correctly interacting with cubicles/number of cows interacting at all with cubicle x 100

Question 181

What does it mean about cubicles if: - cow reversed into cubicle? - cow standing with hind feet in passage and forefeet in cubicle? - cow lying diagonally in cubicles? - dog sitting?

Answer 181

Cow reversed into cubicle = too high a kerb as cows dislike reversing down a steep step, prefer to reverse upwards and descend forwards Cow standing with hind feet in passage = head rail too near kerb, causing cows to bang head when rising so learn to nor lie in it Cow lying diagonally in cubicles = cubicle too wide Dog sitting = can't lunge

Question 182

What does it suggest about cubicles if: - hock lesions? - callus/hair loss along spine? - callus/hair loss on neck?

Answer 182

Hock lesions - may indicate insufficient substrate/bedding or cubicle too short, or poor quality shaving (splinters) Callus/hair loss along spine - ma indicate insufficient lower rail height Callus/hair loss on neck - may indicate low feed barrier

Question 183

Consequences of poor cubicle use?

Answer 183

Half in half out posture -> excessive standing on hind feet -> solar ulcers Feet increasingly stood in slurry -> heel horn erosion (slurry heel) Dung, urine and milk deposited onto cubicle and udder on feet -> increased risk of environmental mastitis and high SCC

Question 184

What beds and substrates can be used for cubicles? How much substrate?

Answer 184

Concrete only with light scattering of substrate = unacceptable, will cause pressure sores and pain Rubber mats with substrate - cheap Mattresses - foam covered with stretched membrane, gel filled, water filled Substrate = 3kg straw/cubicle/day or sawdust/shavings Sand - hygienic, requires daily raking and repositioning to avoid waste Deep straw - comfortable but increased risk of Strep uberis Paper 'ash' - cheap, may harden when wet

Question 185

Types of grooving for housing flooring?

Answer 185

Grooving improves grip Parallel grooves: 40mm apart, each groove 10mm wide and 6-10mm deep Squares or diamonds

Question 186

Building design - Placement of cubicles/passages etc?

Answer 186

2 rows of cubicles per feed barrier (4’ wide cubicle = 2’ /cow feed space) 2.4m (8’) Passage (P) through every 20 cubicles as well as at ends (useful area for troughs but needs extra width; 3.6m) No dead ends (avoid trapping subordinate cows) 3m (10’) passage between cubicles and a 4.3m feed passage

Question 187

Slats and slurry? Placement and sizing?

Answer 187

Useful every 25m along track of auto scrapers to reduce pooled slurry in front of scraper Width of slat: 14-16cm Spacing between slats: 35-40mm For smaller cattle breeds or heifers the spacing should be reduced

Question 188

How big should the roof slots be for housing?

Answer 188

0.75in

Question 189

What is 'green bedding'?

Answer 189

``` Recycled manure solids “RMS” Slurry pressed to remove water (above 34% dry matter) then re-used, as bedding Used fresh and not composted (that is also an option) Initial high capital cost (£50,000) Then low ongoing bedding costs Key seems to be ventilation Can have mastitis problems Allowed in cubicles in UK ```

Question 190

What is Multiplex PCR?

Answer 190

11 pathogens and Staph penicillinase gene (Bla Z) Mycoplasma or yeast not included in all versions Preservative so no overgrowth of contaminants Semi-quantitative More expensive than traditional bacteriology Monitors for mastitis

Question 191

Targets for: - number of clinical cases of mastitis per 100 cows/year? - % of herd affected (annual incidence)? - % recurrence rate (repeat cases)? - milking cow tube usage per 100 cows/year? - SCC?

Answer 191

``` <30 clinical cases/100 cows/year <20% of herd affected <10% recurrence rate <140 milking cow tubes/100 cows/year <145,000cells/ml SCC (top 1/4 of herd's level) ```

Question 192

Top 3 most common mastitis bacteria cultured?

Answer 192

Strep uberis E.coli Staph aureus

Question 193

How is the milk price typically affected in pence/L by SCC?

Answer 193

``` 225-250,000: -0.25 251-300,000: -1.75 301-400,000: -6.0 401,000+: -20.0 Milk exceeding 250,000 will be excluded from the supermarket supply until under 250,000 for 3 months ```

Question 194

Effect of herd size on SCC?

Answer 194

Larger herd -> lower SCC

Question 195

How to interpret an individual cell count?

Answer 195

<100,000cells/ml - no infection likely 100-200 - likely one infected quarter with minor pathogen >200 - infected quarter with major pathogen

Question 196

Which contagious pathogens can be responsible for a herd high cell count problem?

Answer 196

Staph aureus Strep uberis Strep agalactiae Strep dysgalactiae

Question 197

California Mastitis Test - when positive?

Answer 197

>300,000 from any quarter

Question 198

What to do for a chronic high cell count cow?

Answer 198

Identify pathogen Treat during lactation according to C+S Extended courses of intramammary therapy for Staph aureus and Strep uberis - e.g. cloxacillin for 6 days Systemic - tylosin, penethamate Mini blitz - all high cell count cows together as group Dry off and treat - better bacteriological cure rate, dry cow intramammary antibiotics and systemic antibiotic Cull chronically infected, older cows

Question 199

What is Bactoscan? Causes for a high number?

Answer 199

Actual count of bacterial numbers in milk Causes for a high number: - poor plant cleaning - high levels of mastitis - poor housing hygiene - poor premilking teat prep Also could take a milk sample from the bulk tank for bulk milk bacteriology to indicate where problem is Carried out by milk processor company (NML) Hygienic quality of the milk Measured weekly - can get daily

Question 200

How is milk price in pence/L affected by Bactoscan results?

Answer 200

``` 0-30,000/ml: -0.25 21-50: -1.25 50-75: -1.25 75-100: -2.0 100-250: -4.0 250+: -8.0 Milk exceeding 50,000 will be excluded from the supermarket supply until <50,000 for 3 months ```

Question 201

What does Bulk Tank bacteriology involve?

Answer 201

Total bacterial count Cell count LPC thermoduric count and pseudomonas (assess cleanliness of plant) Coliform count (assess environmental contamination, indicate standard of pre-milking teat prep) Total Staphylococcal count (CNS and Staph aureus) Identify other pathogenic bacteria (strep uberis, Strep dysgalactiae, Strep agalactiae)

Question 202

Problems with individual cow bacteriology?

Answer 202

Contaminated samples intermittent shedding e.g. Staph aureus Antibiotic treatment -> no growth

Question 203

Method of sample collection for individual cow bacteriology?

Answer 203

Wear gloves Clean and disinfect and dry teat Discard 10-15ml of foremilk Clean each teat end and orifice for 15-20s with a cotton wool swab which has been sealed in 70% alcohol Sample close teats then far away ones to avoid contamination Keep sample container as close as possible to horizontal, don't overfill and do not touch its rim Teat dip afterwards

Question 204

Milk bacteriology interpretation?

Answer 204

Pure growth of bacteria - causal, good collection technique Major pathogen + minor pathogen - major pathogen causal More than one major pathogen - mixed aetiology More than 3 bacteria present - contaminated? Repeat No growth - intermittently shed or had antibiotics: repeat

Question 205

Factual cost figures of mastitis: - Doubling of SCC above 50,000cells/ml results in what kg/day milk loss? - Mild case? - Severe case? - Fatal case? - How many cases per 100 cows per year?

Answer 205

``` Doubling of SCC above 50,000cells/ml results in 0.4kg/day milk loss for heifers and 0.6kg/day loss for older cows Mild case: £169 Severe case: £400 Fatal case: £1709 45-65 cases/100 cows/year ```

Question 206

5 point plan for mastitis control?

Answer 206

1. Post milking teat disinfection 2. Dry cow therapy 3. Prompt treatment of clinical cases 4. Cull chronic cases 5. Maintain and use milking machine properly Good for contagious, insufficient for environmental

Question 207

Methods to prevent mastitis from contagious pathogens? Treatment of specific pathogens?

Answer 207

``` Prevent spread during milking - post milking teat disinfection - properly functioning milking machine - milking order/disinfect cluster Strep agalactiae and Strep dysgalactiae: - prompt and effective treatment during lactation (penicillin sensitive) - dry cow therapy Staph aureus: - treat for longer periods - C+S as 35-40% penicillin resistance - if near end of lactation: dry off early, dry cow antibiotics +/- systemic - if during lactation: extended therapy, 5-8d intramammary antibiotics, systemic - cull chronically infected cows ```

Question 208

Methods to prevent mastitis from the main environmental pathogens and where are their sources?

Answer 208

``` E.coli and Strep uberis: - source: faeces, bedding - picked up in dry period and early lactation - housing hygiene and comfort especially dry period, calving and early lactation - pre milking teat disinfection - loafing times - dry cow management (nutrition, dry cow therapy selection, consider teat sealants) E.coli: - startvac vaccine Strep uberis: - can be persistent infections - parlour hygiene measures ```

Question 209

Parlour routine important for mastitis action plan?

Answer 209

1. Wear gloves 2. Milking order/management of high cell count cows 3. Fore-milking 4. Pre-milking teat disinfection 5. Ensure good milking machine function 6. Post-milking teat dipping 7. Post-milking loafing time 8. Maintain good teat condition

Question 210

PCR vs culture for mastitis?

Answer 210

92% PCR vs 70% bacterial culture 30% no growth in culture PCR: - dead or alive - ok to have had antibiotics - Set up for the common pathogens' DNA and beta-lactamase gene (so won't find other bugs) Culture: - negative samples due to undetected Staph aureus are rare - bacteria must be alive - no antibiotics for at least 7d prior to culture - must be shedding on day of sampling (luck!)

Question 211

Hygiene scoring of cows?

Answer 211

``` 3 main areas to look at: - below hock - upper leg and flank - udder <25% scores 3 or 3 ```

Question 212

Which types of mastitis are now advocated as not to be treated for?

Answer 212

Mild cases due to gram negative organisms

Question 213

Which antibiotics are used most commonly for mastitis?

Answer 213

1. Tetracyclines 2. Beta-lactams 3. Aminoglycosides 4. Trimethoprim/sulphonamides

Question 214

When are acute enterobacteriacae infections postpartum (mastitis) acquired?

Answer 214

50% of clinical cases in first 100 days acquired during dry period

Question 215

What requirement is needed by Tesco since Jan 2017 for CIA dry cow therapy?

Answer 215

C+S showing an animal with a high SCC at the end go lactation and at the first recording of the next lactation are infected with an organism that is only sensitive to Cefquinome If acute mastitis after calving, need data to indicate it is only antibiotic available in a dry cow tube which the organism is senstive Similar for Red Tractor since June 2018

Question 216

What is selective dry cow therapy?

Answer 216

= Teat sealant only to some cows - Also in combination with antibiotic tubes - 4 g of suspension containing 65% bismuth subnitrate - Orbeseal (Zoetis) @ £1.50+/tube to farmer - Boviseal (Bimeda), - Ubroseal (Boehringer Ingelheim) - Noroseal (Norbrook), Cepralock (MSD) + Povidone iodine

Question 217

How does Orbeseal work?

Answer 217

Remains as a paste within the base of the teat cistern and teat canal until stripped out at calving Remain in situ for the entire length of the dry period, even in dry periods of up to 100 days

Question 218

How to select for selective dry cow therapy?

Answer 218

Cows not treated with a sealant get 50% more mastitis Bacteriology - expensive and Staph intermittently shed SCC - <200,000 cells/ml in cows, <125,000 cells/ml in 1st lactation heifers AND no clinical case in this lactation CMT before drying off if SCC not recently Check teat ends Start with 25% of legible cows and gain confidence If not sterile, cows will get sick (and could die) a few days after infusion Test cow day before drying off with California mastitis test to ensure not become infected since last recording

Question 219

Teat sealant problems?

Answer 219

Black spots in cheese: - Bismuth subnitrate + hydrogen sulphide from maturing cheese = bismuth sulphide - Farmer trained to apply sealant and not massage the udder - Removal of sealant residues by centrifuging milk Risk of infection if not instilled in a “surgically” sterile fashion Newer “me too” products have limited clinical efficacy data prior to authorisation

Question 220

What is classed as blanket dry cow treatment by ARLA?

Answer 220

If not selecting at least 10% for no treatment

Question 221

Protocol for intra-mammary tube application?

Answer 221

``` Do after milking and cleaning of parlour Clean gloves, washed between cows Pre-dip and allow kill time of 30s+ Loads of surgical spirit and cotton wool Clean teat ends until no more comes off Get new cotton wool and repeat Post dip - some repeat dip daily Barrier external teat sealant? Loafing for 30 mins Re-check daily Feed restriction to reduce milk production Dry cow management - do not neglect ```

Question 222

What affects the duration of intra-mammary dry cow tubes?

Answer 222

Type of antibiotic Salt of antibiotic Particle size - micronisation delays dissolution and absorption esp Cloxacillin and Ampicillin Base - oils, emulsions etc

Question 223

What intra-mammary dry cow tubes are there?

Answer 223

``` Target Staph then broaden out: Cloxacillin only (as benzathine salt) Cloxacillin + Ampicillin (as trihydrate) For E.coli: Penicillin (as procaine salt) Penicillin + Framycetin + Penethamate Cefalonium Cefquinome ```

Question 224

What is the milk withdrawal time for ampicillin and cloxacillin after injection? Withdrawal time after calving? Meat?

Answer 224

Milk withdrawal after calving: usually 96 hour post calving, some down to 24 hours Meat withhold 10-30 days (most 28 days) Ampicillin: 7 days Cloxacillin: 49 days

Question 225

Causes of mastitis treatment failure?

Answer 225

Antibiotic resistance Bacterial dormancy L-forms - naked so insensitive to beta lactams Biofilms Reduced host response - steroids, stress Reduced phagocytosis (novobiocin) Re-infections - from uncleared udder infections, from teat canal infections, from external sources Antibiotics don't reach site of infection in adequate concentrations due to too low dose, too long dose interval or too short treatment period Pharmacokinetic limitations: - absorption, disposition, elimination - sequestration due to ionisation (pH trap) - diffusion barriers in intramammary treatment (oedema, blocked ducts, abscesses, fibrosis) - poor delivery of AB across blood/milk barrier in parenteral treatment - binding of AB to milk or serum protein - intracellular parasitism

Question 226

Where to target antimicrobial therapy for mastitis caused by: - Strep agalactiae - Other Strep - Staph aureus - Coagulase negative Staph - T pyogenes - Coliforms

Answer 226

Strep agalactiae: milk/ducts +++ Other Strep: milk/ducts +++ udder tissue + Staph aureus: udder tissues +++ milk/ducts + Coagulase negative Staph: milk/ducts +++ T pyogenes: cow +++ udder tissue ++ Coliforms: cow +++ milk/ducts +

Question 227

Which antibiotics are good at reaching mastitis infection via the teat?

Answer 227

``` Macrolides Phenicols Fluoroqunilones Penethamate Aminopenicillins Novobiocin Trimethoprim (Limited: sulphonamides, cephalosporins, tetracyclines, penicillin G) (Poor: streptomycin, framycetin, neomycin) ```

Question 228

What are the therapeutic strategies during lactation for mastitis antibiotics?

Answer 228

12 hours intervals for 3 consecutive milking Every 24h for 3 occasions - Multiject, UBRO yellow Every 24h for 8 occasions - Pirsue Every 48h for 3 occasions - Orbenin LA Once - Pathocef, Tetra Delta Extended course Pulse therapy - course + withhold + course + withhold etc Blitz = whole herd treated (Strep agalactiae only) Mini blitz = whole group treated

Question 229

Which antibiotics are good at reaching mastitis infection via the blood?

Answer 229

Macrolides Phenicol Tetracyclines IV Fluoroquinolones Trimethoprim (Limited: sulphonamides, penicillins, cefaquinome) (Poor: ceftiofur, streptomycin, framycetin, neomycin)

Question 230

Which licensed intramammary/systemic antibiotic combinations are there for mastitis?

Answer 230

Cobactan Synulox Combiclav

Question 231

Non antibiotic treatments for mastitis?

Answer 231

``` Oxytocin daily for 1 week: £3.50/day Vitamin E/selenium Copper? Be careful Zinc - teat keratin Startvac vaccine (E.coli and Staph aureus inactivated) ```

Question 232

When to use Startvac and UBAC vaccines?

Answer 232

Startvac: 45 days precalving, 10 days precalving, 52 days post calving UBAC (lipoteichoic acid from biofilm adhesion component of Strep uberis): 8 weeks precalving, 3 weeks precalving, 2 weeks post calving

Question 233

NSAID options for mastitis? Milk withhold times?

Answer 233

(Flunixin meglamine: 12-48 hour milk withhold) Ketoprofen: nil milk withhold Tolfenamic acid: discard 1st milking Meloxicam: 5 days milk withhold Carprofen: nil milk withhold Aspirin: not for use in animals producing milk for human consumption

Question 234

What to do with mastitis if: 1. Young, first case of mastitis this lactation, high SCC previous month? 2. End of lactation, high SCC? 3. Old and 3rd case this lactation, chronic high SCC? 4. Young, first case, low SCC previous month?

Answer 234

1. Intramammary treatment +/- systemic 2. Dry off and treat with dry cow therapy +/- systemic 3. Cull 4. No treatment - watchful waiting

Question 235

Cabergoline for mastitis?

Answer 235

D2 dopamine receptor agonist, inhibition of prolactin secretion To aid in abrupt drying off by reducing milk production to reduce milk leakage, the risk of new intramammary infections during the dry period and discomfort Cows shown to lie down longer day after treatment than if not treated

Question 236

Pegbovigrastim (Imrestor) for mastitis?

Answer 236

= Immune stimulant Cytokine bovine granulocyte colony stimulating factor (bG-CSF) 7 days prior to calving and on day of calving Restores normal neutrophil function to cattle during periparturient period Significantly fewer cases of clinical mastitis Reduces susceptibility to clinical mastitis infections

Question 237

Finishing beef animals: - growth rate? - age at slaughter? - slaughter weight? - killing out %? - store animal growth?

Answer 237

``` Growth rate: 1-1.4kg Slaughter: 18-24mo Slaughter weight: 600-800kg Killing out: 55% Store animals: restrict growth to 0.8kg/day in winter, then compensatory growth at turn out to grass ```

Question 238

Beef suckler herds' KPI aims?: - what is the most sensitive measure of cow performance and what is the aim? - barren rate? - calves born? - calf mortality? - claves weaned? - weaned calf kg/cow kg - time to first service and CR?

Answer 238

``` Calving spread (days from first to last calf born): aim 9 weeks with conception rate 65% (aim 60-80%) so 65% of calves born in first 3 weeks - ie higher conception rate = higher % born in first month Barren rate: 3-4% Calves born: 95% Calf mortality: <3-4% Calves weaned: 93-95% Weaned calf (kg/cow kg): 50% First oestrus 35 days: CR 20% Third oestrus 6-80 days: CR 80% ```

Question 239

What is the single most important factor influencing the profitability go suckled calf production?

Answer 239

Fertility

Question 240

How much are beef calves worth? Why is a tight calving herd better?

Answer 240

£2/kg LW Early born calves are heavier Herd with 15 week calving spread: first calf is 1kg x 105 days heavier = 105kg heavier than last born calf Late born calves more likely to die Lower culling rate as cows more fertile -> high conception rate - high % of cows calve in first month - so high % of cows have a long rest before service (aim 6-8 weeks rest) - so high % of cows get pregnant at first service to calve early in season next year - so 7-9 calves in a profitable life time

Question 241

What is a major cause of disease in suckler calves?

Answer 241

Neonatal diarrhoea Rotavirus, coronavirus, crypto etc Oro-faecal route Pathogen multiplier effect

Question 242

How long should a bull be put with beef cows?

Answer 242

9-12 weeks only

Question 243

Is Spring or autumn beef calving better? Target condition scores?

Answer 243

``` Autumn calving - problems with fertility as cows likely in poorest condition when come to service before spring turn out Winter calving is disaster - poorest growth rates in calves, cows served in poorest condition Cows should be gaining weight at service Autumn calving: - BCS 3 in autumn when calving - BCS 2.5 in Nov/Dec when serving BCS 1.5 in Mar/Ar when turnout - BCS 2.5 in June when weaned Spring calving: - BCS 3 in autumn when weaning - BCS 2.5 in Feb when calving - BCS 2 in Apr/May when serving - BCS 3 in Aug when weaning ```

Question 244

Which beef cows need supplementary feeding at mating? Effect of early and late weaning?

Answer 244

Autumn calves only - must continue until 6 weeks after end of mating period Early weaning if thin (1mo early) = gain of 0.5-1 CS = 50kg Late weaning if fat

Question 245

Main 2 problems with beef heifers?

Answer 245

``` Require extra food for growth (+10%) Bad calving (dystocia) ```

Question 246

Beef heifer management: - age at calving? - when to calve in relation to rest of herd? - service period? - prevention of dystocia? - when to wean calves?

Answer 246

``` Age at calving: 2yo Calve 21-28d before rest of herd to give long rest period 6 week service period Bull selection to avoid dystocia Wean one month early to allow to grow ```

Question 247

How to achieve a tight calving pattern?

Answer 247

Cull late calves and replace with heifers calving at start of calving period Split herd into spring and autumn calving herds: - correct feeding and use of target BCSs - early weaning of heifers and thin cows - good heifer management

Question 248

Desirable traits of a suckler cow?

Answer 248

Fertility and ease of calving Adequate milk yield for good calf growth (reflected by weaning, 200d, weight) Conformation and offspring carcass quality Cow size and maintenance requirements Ability to lay down fat stores in summer Hardy - utilise poor forages

Question 249

What pure and cross bred suckler cows are there? What are they good for?

Answer 249

Pure bred British for early maturing, small and high fat %: Hereford, Aberdeen Angus, Welsh Black Pure bred continental for late maturing, bigger, leaner carcasses: Charolais, Limousin Crosses for hybrid vigour (fertility +16%, calf growth +1.5%, calf mortality -3.5%, 3 way cross fertility +23%): - Dairy cross - very milky but poor conformation - Beef cross - higher carcass quality

Question 250

Desirable traits in beef terminal sire?

Answer 250

``` Carcass quality - size and conformation Good growth rate of cross bred calves: - high weaning (200d) weight: reflection of dam milk supply - high 400d weight: sire effect Ease of calving - short gestation length ```

Question 251

Generic programme example for synchronisation of beef cows for AI?

Answer 251

Day 0: Inject GnRH to synchronise follicular waves Insert PRID for 8 days Day 8: Inject PG and remove PRID 56-72h AI (GnRH at service or 24h previously) Cows not pregnant after first service: Re-insert PRID 14d after service and tail paint Remove PRID after 7 days Serve to observed heats (2-3 days later)

Question 252

Which Campylobacter species affect beef cows? What do they cause? Risk?

Answer 252

``` C jejuni - faecal commensal - GI disease in humans from meat - can cause abortion in cattle C fetus fetus - faecal commensal - can cause abortion in sheep and cattle C fetus venerealis - genital infection - early embryonic death (empty cows at PD, repeat bullers, vulval discharge, post service endometritis) - bulls often lifelong carriers (lives in epithelial crypts) - cows immune after 12mo - risk is purchased infected bulls/cows and hired bulls - minimise risk by buying virgin bulls ```

Question 253

Difference between contagious pathogens and environmental pathogens causing mastitis?

Answer 253

Contagious: - obligate parasites (must live on cow to survive) - on udder and teat skin, intra-mammary, tonsils, vagina - main source of infection is other infected cows - spread from cow to cow during milk via clusters, milker's hands, communal teat cloths etc Environmental: - live in slurry, bedding, soil, feed and water - infection when teats come into contact with contaminated material between milking times and during milking

Question 254

Staph aureus mastitis: Characteristics of agent? Transmission? Pathogenesis? Shedding pattern? Which grades of mastitis may be seen?

Answer 254

Gram positive cocci Coagulase positive On blood agar, white colonies with a ring of haemolysis Most common contagious pathogen Transmission: - spread in milking parlour via clusters, hands, udder cloths - spread amongst heifers pre-calving by teat sucking - fly spread Pathogenesis: - Able to persist intraceullarly in udder so difficult for cows to clear the infection - Damages the duct system -> deep pockets of infection in secretory tissue -> abscesses (sometimes can palpate if big) - Often responsible fo recurrent persistent chronic infections/persistently high cell counts Intermittent shedding All grades occur Grade 3 = gangrenous mastitis

Question 255

Virulence factors of Staph aureus for mastitis?

Answer 255

Haemolysins: damage tissue and cells aiding intracellular colonisation Protein A in cell wall: binds antibody and prevents recognition by neutrophils Clumping Factor A: adherence of pathogens to gland tissue Pseudocapsule: surrounding bacteria preventing phagocytosis Alpha toxin: produced in large amounts particularly in gangrenous mastitis Ability to survive intracellular killing: can even multiply within phagocytes Survive in keratin of teat canal B lactamase: makes some of them resistant to penicillin Exotoxins: damage udder tissue stimulating fibrosis/ abscessation udder

Question 256

Clinical signs of grade 3 (gangrenous) mastitis caused by Staph aureus?

Answer 256

Usually newly calved cow (periparturient immunosuppression) Peracute toxaemic sick cow (massive release of a toxin) Gangrene of udder tissue, udder cold and blue, then necrotic, then sloughs Milk often dark red and bloody

Question 257

Control of different types of mastitis?

Answer 257

Staph aureus mastitis: - prevent introduction of new infection: check cell count history and examine udder when buying in cows - reduce existing infections by treating cases, culling chronic cases, dry cow therapy - prevent spread within herd: milking parlour routine (wear gloves, no common udder wipes, early detection and treatment, post milking teat disinfection, milk mastitic cows and high SCC cows last, maintained milking machine correctly) Streptococcus agalactiae: - good parlour hygiene - responds well to antibiotics Mycoplasma: - lack a cell wall so non-responsive to beta-lactams - in vitro sensitivity to several antibiotics but poor success so cull affected cows - don't feed milk to calves -> pneumonia/otitis - control similar to Staph aureus (milking order, disinfect clusters) E.coli: - improve housing hygiene (infection common in dry period and early lactation) - pre-milking teat prep - loafing times post milking - appropriate dry cow therapy - vaccination "Startvac" Strep uberis: - housing hygiene (infection common during dry period and early lactation) - prevent muddy fields/tracks - pre-milking teat prep - milking order - cull chronic cases - dry cow therapy

Question 258

Streptococcus agalactiae mastitis: Features of agent? When seen? Which grades seen? Control?

Answer 258

Gram positive cocci Non haemolytic Very small pin prick colonies Udder is infection reservoir Disease often seen when failure of parlour hygiene or introduced by bought in animal Usually subclinical (high SCC) and grade 1-2 mastitis So not usually systemically ill Not associated with persistent infections Streptococcus dysgalactiae: - check teat conditions - check for milking machine pulsator or vacuum problems - check use of emollients in teat dips (need to be good quality) - responds well to penicillin

Question 259

Streptococcus dysgalactiae: Features of agent? Sources of infection? When seen?

Answer 259

Gram positive cocci Small pin point colonies on Edwards Medium Partial, alpha haemolysis Udder and teat skin are source of infection, particularly when skin damages Cows and heifers licking each other's teats are important Also part of summer mastitis complex Can cause persistent infections

Question 260

Mycoplasma mastitis: Which species? Other problems caused? Clinical signs? Spread? Pathogenesis?

Answer 260

``` Less common than the others M. bovis and M. californicum M. bovis also: - infertility - metritis - otitis media - arthritis - keratoconjunctivitis - pneumonia Often produce marked milk drop and swollen quarter although cow not systemically ill Highly contagious in parlour, aerosol spread and haematogenous Pathogenesis: - LPS on outer surface -> stimulates host immunity -> alveolar epithelium degenerates -> massive leucocyte outpouring -> abscesses, alveolar hypertrophy, fibroplasia around ducts -> destroyed quarter Subclinical infection -> reduced yield, high SCC, secrete lots of Mycoplasma in milk Shed for months and maybe life Difficult to culture - special medium ```

Question 261

Coagulase negative Staphylococci mastitis: When seen? How bad? Treatment?

Answer 261

Minor pathogen? Problem in herds where good control of other pathogens Heifers infected before calving Mild disease: high somatic cell counts Query the significance in a sample as may be teat skin contaminant Repeat sampling or pure culture or number cases in herd may confirm importance Often regarded as the cause IF no other pathogens found Spontaneous cure common Treat with antibiotics: usually respond well to penicillin

Question 262

E.coli mastitis: features of agent? Source of infection? When at higher risk? Grades?

Answer 262

Blood agar forms creamy white colonies Haemolytic and non haemolytic Gram negative rods Source of infection is bovine faeces Udder adapted strains? May infect before clinical signs Housed cattle more at risk Problem with housing hygiene: wet, dirty, poorly ventilated, wet muddy fields Outbreaks as a result of build up of infection over housing period Clinical cases often seen in early lactation: often acquired during dry period and peri-parturiently (calving cow + open teats + dirty calving area = mastitis risk) Not commonly associated with subclinical mastitis and raised cell counts < 15% become chronically infected Grade 3 common

Question 263

Pathogenesis of E.coli mastitis?

Answer 263

Contamination of teat end is followed by invasion of teat canal Proliferates rapidly producing LPS endotoxin damages vascular and secretory tissue Clinical outcome of the infection will depend on the quantity and speed of neutrophil influx: inadequate or too slow -> cow will develop endotoxaemia which is often fatal

Question 264

Clinical signs of grade 3 E.coli mastitis?

Answer 264

= common Very sick cow Endotoxaemic shock (usually post calving peri-parturient immunosuppression) Udder variable: can be cold or hot, hard or soft, Milk varies from clots to blood Important differential for downer cow post calving

Question 265

Strep uberis mastitis: features of agent? Strains? Where is higher risk? Grades?

Answer 265

Non haemolytic Brown colonies on Edwards medium Environmental but also cow adapted strains in tonsils, genital tract and rumen, so also contagious At least 250 strains Straw yard housing, straw bedded cubicles, muddy fields at the end of summer Can see all grades at all stages of lactation, rarely parachute grade 3 Persistent subclinical infection is common (high cell count cows) Recurrent clinical cases

Question 266

Pathogenesis/virulence of Streptococcus uberis causing mastitis? How does it persist in the udder?

Answer 266

Able to hide in mammary epithelial cells and avoid detection by immune system SUAM (step uberis adhesion molecule) adhere to mammary epithelial cells Hyaluronic acid capsule may act as protective shell preventing attachment of antibodies or the neutrophils Even after phagocytosis some strains can resist killing by neutrophils May inhibit PMN ability to produce pseudopodia

Question 267

Risk factors for mastitis caused by: Klebsiella, Bacillus cereus/licheniformis, Pseudomonas and yeasts? Other factors?

Answer 267

``` Klebsiella: - sawdust bedding and dirty parlour wash water - often acute mastitis appear v similar to E coli infections Bacillus cereus and licheniformis: - environmental brewers grains, dirty parlour wash water - often acute mastitis Pseudomonas: - sawdust bedding - dirty parlour wash water - poor hygiene when inserting tubes - often acute difficult to treat Yeasts (Candida spp): - sporadic wet mouldy bedding - teats washed before milking but not dried - poor hygiene ```

Question 268

Summer mastitis: Which cows affected? Aetiology? Spread? Clinical signs?

Answer 268

Typically affects dry cows and heifers outside in summer in fields But also seen occasionally in steers and bulls and can occur in housed cows in winter Mixed infections with Trueperella pyogenes, Peptococcus indolicus, Strep dysgalactiae, Bacteriodes melaninogenicus, Fusiformus necrophorum Spread by Hydrotea irritans (sheep head fly) Clinical signs: - classically hot, hard, swollen, very painful udder with a thick purulent secretion - may be lame and systemically ill - mild cases do occur and are only noticed as cow calved down with blind teat end or with a mild case of mastitis from which T. Pyogenes is cultured

Question 269

Which pathogens cause metritis and endometritis in cows? Features of each?

Answer 269

E. coli: - particularly prevalent in first week post partum - uterine pathogen adapted strains - virulence factors related to adhesion - opens way for T pyogenes - role of LPS (=bacterial endotoxin) Trueperella pyogenes: - opportunistic pathogen - toxins: pyolysin (PLO) and cholesterol dependent cytolysin - epithelial cells have a protective role against PLO - adhesion factors (FimA) mediate binding between T pyogenes and endometrial cells - important role in development of endometritis Fusobacterium necrophorum: - opportunistic pathogen - leukotoxin: toxic to leucocytes, macrophages and epithelial cells - adhesion factors - necrotic disease conditions Prevotella: - gram negative anaerobes Bovine herpesvirus 4: - enveloped DNA virus - tropic for endometrial cells - rapid cytopathic effect

Question 270

Cervicitis/vaginitis: Causes?

Answer 270

Injuries due to dystocia Mixed infections: Mycoplasma bovigenitalium, Ureaplasma spp., Haemophilus somnus Trueperella pyogenes PVD syndrome (purulent vaginal discharge)

Question 271

Viral vaginitis: aetiology? Spread? What does it cause?

Answer 271

Infectious bovine rhinotracheitis virus Bovine herpesvirus I type 2 Spread through infected bulls Abortions

Question 272

Why does Brucella abortus cause abortion? How long are cows infected for?

Answer 272

Abortion due to purulent placentitis Necrosis of cotyledons Remain infected for life

Question 273

Which protozoa are part of the Apicomplexa phylum? What do they all have/do?

Answer 273

Neospora, Toxoplasma, Babesia, Eimeria, Plasmodium Sexual and asexual reproduction Locomotion by gliding Characteristic apical complex - involved in host cell invasion

Question 274

Life cycle of Neospora caninum?

Answer 274

Tachyzoite: - rapidly dividing form - intracellular - preference for monocytes/macrophages but will invade any cell type - crescent shaped Bradyzoite - slowly replicating form - forms intracellular cyst surrounded by cyst wall - preference for neurological tissues Can differentiate into eachother Oocysts - the result of sexual reproduction - only found in faeces of definitive hosts (dogs) - unsporulated when passed - sporulated oocyct contains 2 sporocysts, each with 4 sporozoites 1. Dogs scavenge infected bovine tissues (bradyzoites) 2. Enteric sexual cycle in dog, syngamy with macro and microgametes to form a zygote, exreted as an oocyst 3. Oocysts excreted in dog faeces contaminate food and water and are ingested by cattle Exogenous transplacental transmission: - pregnant cows ingest oocysts - tachyzoites cross placenta and infect foetus -> abortion or PI Endogenous transplacental transmission: - recrudescence of a persistent infection - slow growing bradyzoites persist within tissue cysts in neural tissue - during pregnancy, bradyzoites differentiate into rapidly dividing tachyzoites - tachyzoites cross placenta and infect foetus -> abortion or PI

Question 275

Treatment for suppurative mastitis producing pus?

Answer 275

Surgical drainage and antibiotics e.g. pen/strep

Question 276

Most likely cause of mastitis in a 150 cow herd with 75 cases of mastitis over a year, average SCC of 110,000 and on day of visit one animal is suffering from clinical mastitis?

Answer 276

E coli

Question 277

Most likely cause of mastitis in a 500 cow herd with 10% incidence rate of mastitis, with average SCC 300,000, and on day of visit 20 animals were suffering with mastitis?

Answer 277

Staph aureus

Question 278

How to abort a mismating of cows? Mated 8-10 weeks previously.

Answer 278

``` IM cloprostenol (prostaglandin) Need careful aseptic precautions when administering ```

Question 279

What to do for cow not seen bulling with CL and dominant follicle, on organic farm? What if not organic for cost-benefit?

Answer 279

Kamar Not organic - IM cloprostenol (as long as no tone of uterus, if tone then wait and observe for season and do fertility check next time if no season)

Question 280

Cow calving but can feel head, 2 forelimbs and also a hindlimb by head: What is it? What should you fo?

Answer 280

Schistomomus reflexus Embryotomy or caesarian section (after tried repelling hindlimbs)