Bovine Reproduction Flashcards

Question

What are the indications for using OvSynch?

Answer 1

- Poor heat detection - Not practicing continuous detection of heat - Simple reproductive program - Treatment of anoestrus.

Answer 2

Short-term protocols Two types: 7 day CO-Synch + CIDR GnRH day 0, PG day 7. AI and GnRH at the same time day 9: Ones that aren't in heat --> Ovulate with GnRH 24 hours later at the end 5 day CO-Sync + CIDR Inject GnRH, 5 days later inject PG. Day 7 do AI and GnRH at the same time. Heifers: follicle may be too small/luteolysis may not occur. Give 2 injections of prostaglandin 24 hours apart to make sure luteolysis occurs.

Answer 3

Role: Synchronise return to oestrus after 1st or 2nd AI Timing: Implemented following AI without knowledge of pregnancy status Inseminate and synchronise those who did not get pregnant after the first insemination. Pregnant ones are dropped out of the system 2 Strategies: 1. Resync without early preg testing: Oestradial benzoate/EB: Relies on oestrus detection to ID those who need to be inseminated W/o EB: CDRI, GnRH, PG: No visible oestrus to show, relies on TAI (AI) 2. Early Preg Testing & Resync Allows non-pregnant cows to be ID'd and treated with PG --> Insemination on detection or fixed (Or both)

Answer 4

1. Conception Rate: (No. of inseminations with pregnancy x 100)/No. of Inseminations Range: 30-60% 2. Pregnancy Rate: (No. of cows in herd selected that are pregnant x 100)/Total no. of cows selected 3. In-calf rate: Percentage of animals that are diagnosed as pregnant after a specific duration E.g. 6 week in calf rate: The % of cows that are diagnosed as pregnant in first 6 weeks of the breeding period. Non-Return date: Percentage of cows that are not detected in oestrus after insemination Dis: Assumed to be pregnant (Imprecise) Role: Positive correlation with conception rate, Used by semen semen suppliers assess conception rates of different bull/AI Technicians where pregnancy data is not available.

Answer 5

Adv: - Genetic Progress (Production increase) --> Genetic selection for desirable traits. EBV to select sires - Disease control: Venereal diseases can be eliminated - Wider sire choice - Safety (bulls) - Increased record keeping Dis: - Expensive (Beef > Dairy) - Increased management for optimum condition of cows - Decreased Repro performance in some circumstances e.g. poor quality semen/handling/technique/detection - Skills required - Increased undesirable traits (Dystocia)

Answer 6

Equipment: - AI guns & sheaths - Semen (In straws) - Lubricant - Gloves - Forceps, scissors - Thawing container Method: Wipe the vulva clean, enter insemination gun through the vulva and press arm down in the rectum to open the vulvar lips. Follow progress of the gun with your hand in the rectum and work gum through the cervix. Use index finger at the front of the cervix to feel the gun passing through. Do not want to progress too deep into the uterus. Only protruding from the front of the cervix. Deposit semen slowly into the body of the uterus. (less chance of pregnancy in horn) remove gun smoothly while arm is still inserted in the rectum.

Answer 7

Method: Artificial vagina (preferred), electroejaculation, artificial breeding mount (Steers > Cows) Frequency: 3x per week total, up to 2x day Amount: 4ml/ejaculate Licensed: Free from physical defects and normal conformation Must be free of: EBL (Enzootic bovine lucosis), IBR (Infectious bovine rhintoracheitis), Johne's, tuberculosis, trichomonas, Lepto, BVDV, Q-Fever, Brucellosis, Ephemeral fever, Camplyobacteriosis Unlicensed: Quality & Disease status not gurranteed

Answer 8

- Frozen semen: Most commonly used 1 step or 2 step method 2 step method: Dilute semen in extender: Glucose, fractose, egg yolk, sodium chloride/citrate. --> Stabilise cell membranes with no glycerol. Sit in fluid for several hours to cool to 4 degrees. Then add glycerol fraction to the extender, cyroprotectant and helps the semen survive freezing. Glycerol pushes water out of the cell, so there is no crystals of ice when frozen. Then package into straws: a) Vapour method: Straws 4cm abovet liquid nitrogen for 7-10 minutes. Then plunged into liquid nitrogen b) Computerised freezing: Controlled freezing rate. Straws transferred to liquid nitrogen tank for storage/distribution. 1 step: Same but Dilute in extender with glycerol initially. Better freeze with 2 step method. - Liquid semen: Semen is diluted in various liquid extenders and distributed for use. Dilute in caprogen extender. Enables lower doses and maintains fertility for 72 hours. Packaging: - Plastic straws: 2 sizes --> 1/4mL of 1/2 mL - Amploules/Pellets: No longer used for bovine semen

Answer 9

Acronym: FP DIS SHT 1. Fertility of cows Factors affecting cow fertility: - Cycle status - Calving to AI interval - Milk-protein concentration - BCS/Weight --> nutrition - Stress - Synchronisation of treatment & equipment (e.g. inaccurate dose) - Breed - Age/parity - Disease, lameness - suckling 2. Poor Records - Insemination of incorrect cows, unable to assess performance + pregnancy loss during synchronisation treatment. 3. Dose For optimum fertility: 5 to 10 x 10^6 live sperm per insemination required. 30% of sperm should be alive post thawing, with 30% of live sperm progressively motile at least. --> There is an optimal dose with sperm and if it is below this it is less likely to cause pregnancy. Past the optimal dose the pregnancy rate plateaus, even though there is more sperm: No more pregnancy rate --> Thus want to have the optimal dose. 4. Insemination Technique Effects pregnancy rate due to technician error: - Contaminated gun (faeces) - Wrong location: not in body of the uterus - Inseminating contralateral follicle to the preovulatory follicle - Excess trauma to tract - Poor thawing Assess: - Different technicians within the herd and analyse pregnancy rates achieved by diff technicians: At least 50 inseminations are needed for each technician to detect differences. 5. Storage 6. Sire --> Sire effects due to: Variation in semen quality, longevity, ability to survive freezing and thawing & unknown factors --> Straws from some bulls may require higher dose to compensate for lower fertility. 7. Handling/Thawing Time between removal from nitrogen tank and AI: should be 15 minutes Equipment/Site of thawing should be clean, dry, sheltered, warm Thawing: Place in water bath 32-38 degrees for 30-50 seconds. Straws should be separated and dried with a paper towel. 8. Timing: Timing of insemination post heat. 4-14 hours after the onset of oestrus is the ideal time. Just below ovulation: Pregnancy rate is lower. Too early: A lot of sperm die by the time the animal ovulates Too late: Oocyte is waiting, oocyte fertility wanes as it is waiting too long for the sperm. Less quality. - Ideally if oestrus onset is known, AI 4 to 14 hours post heat. Issues: - Unable to determine oestrus onset, unable to AI at optimum time (too many cows) - If in heat/detected in oestrus: Inseminate as unknown what stage of oestrus cow is at - If oestrus is detected infrequently, then Ai once daily. - AM-PM rule: Two stages of AI: AM oestrus --> PM insemination. Recent work suggests that AI once daily is sufficient.

Answer 10

Freemartinism is the sterile female of a male-female twin pair. Pathogenesis: - Vascular connections form between placenta of developing twins - Co-mingling of blood supply --> Each Foetus becomes a Blood chimaera (both share blood cells/DNA) *If prior to sexual differentiation ( Hypoplasia of cranial vagina, uterus, uterine tubes. Testosterone: Varying degress of masculinisation: Large clitoris, increased anogenital distance.

Answer 11

External signs: - Tuft of hair from ventral vulva labia, hypoplastic mammary teats resembling those seen in normal males - Prominent clitoris - Increase anogenital distance Internal - Short blind ending vagina: shorter in freemartin heifers than adults. - Hypoplastic reproductive tract: Cervix absent, uterus hard to find, ovaries vary in size + sometimes seminal vesicles can be palpated. Diagnose: - PCR (EDTA): detection of Y alleles indicates blood sharing with male twin during gestation Karyotyping: presence of Y Chromosome Serum AMH: High levels of AMH expected in male/freemartin calves Management: Cull at birth.

Answer 12

Presence of an anovulatory follicular structure that persists on one or more ovaries. > 2.5cm in diameter. Hosts: 10% of dairy cows Major cause of infertility and increased calving-conception rates Pathogenesis: Inadequate LH surge via refractory nature to GnRH: Growth of anovulatory follicles. --> Increasing oestradiol normally stimulates a GnRH surge thus stimulating a surge of LH from the pituitary, leading to ovulation. A lack of responsiveness of the GnRH surge centre = inadequate preovulatory LH surge.

Answer 13

CS: - Anoestrous - Nymphomania: Persistent oestrus - Infertility - Erratic oestrus - Sterility hump: Chronic, relaxation of pelvic ligament due to increased oestrogen Cows show frequent behavioural oestrus. Outcomes: 1. Persist: For extended period (10-70 days) and remain dominant over other follicular structures 2. Turn-over: regress and replaced by a new follicular structure that forms a new cyst 3. Self-correction: Regress and replaced by a new ovulating follicular structure (20% of cows)

Answer 14

- History of infertility/anoestrous - Palpation of follicle: > 2.5cm - Classification as a follicular cyst or luteal cyst - Behavioural signs Treatment: - No treatment: Spontaneous recovery - Remove stressors - Manual rupture/aspiration --> Risk of adhesions - Induction of luteolysis if lutenisation has occured --> PGF2 alpha - Induction of LH surge to induce ovulation/lutenisation - Progesterone treatment to restore hypothalamic pituitary sensitivity to oestrodiol - Combination therapy (OvSynch, P4 treatment + induction of ovulation)

Answer 15

1. Follicular Path: Thin walled, P4 low, secrete oestradiol --> Occurs post partum (15-45 days) transition from anoestrus to oestrus 2. Luteal Thick walled, P4 high via lutenisation of thecal and granulosa cells, presence of CL Dx: Difficult to differentiate via palpation, use ultrasonography.

Answer 16

Refers to the failure of cows to enter oestrus or to be detected in oestrous 10-30% may have a CL Timing: Normal during early post partum Most commonly 20 to 40 days. --> Undernourished cows, cows that have higher genetic merit for milk production, higher incidence of retained foteal membranes/uterine discharge may take longer to resume cyclicity. 30 days after uterus is involuting, if the first cycle is missed: 2-3 cycles before the opportunity to get pregnant is missed. Prevalence: 15-30% seasonal calving cows Reduces repro performance, delays calving-conception, increased culling rate

Answer 17

Anovulatory anoestrous: Absence of oestrous behaviour & failure to ovulate --> CL is not present Ovaries are small Ovulatory Anoestrus: Absence of oestrous behaviour but animal has ovulated. --> 10-30% may have CL

Answer 18

- GnRH & LH secretion are reduced during anoestrous via increased oestrogen receptors (Negative feedback) If the animal is not physiologically ready for oestrus: The oestrogen produced by follicles feeds back to the hypothalamus oestrodiol receptors and suppresses GnRH Ovary is functioning separately to the brain. Closer to ovulation: Negative feed back sensitivity decreases. Greater ovarian stimulation, more oestradiol, decreased sensitivity of the hypothalamus --> eventually LH surge. Other factors such as nutrition, suckling, metabolic factors interact with neurones that influence GnRH neurones, suppressing GnRH secretion.

Answer 19

Cause of anoestrus in cows 1. Ovarian Quiescence Principle cause: Negative energy balance - Nutrition: Low BCS. --> Nutritional deficiency: Deficiency of micronutrients e.g. P - Nutritional excess prepartum: Over feeding - Lactation: Negative energy balance delaying cyclicity - Suckling: Neural effect to suppress GnRH secretion. Physiological association between calf and cow. - Disease. Ovarian tumours, Cystic ovarian disease, abnormal gonad can cause - Age (pre-puberty)

Answer 20

1. Behavioural Anoestrus: Silent Heat, Nervous disposition, Extreme environment, Housing (Slats, concretes), Disease (lameness, ill) 2. Prolonged luteal function: Ovulated but progesterone remains high. - Prolonged disorders - Pyometra - Pregnancy - Early embryonic loss: Delay in return to oestrus 3. Failure to detect oestrus: - Inadequate heat detection - High production of milk - Early postpartum

Answer 21

- Monitor oestrus: Over 3-4 weeks Those not detected: Anoestrus/non-cycler Can observe or use of aids for detection of oestrus: Tail paint, rump mounted, pressure activated devices

Answer 22

Dairy: - Optimise body condition score - Optimise diet/transitional diet and dry matter intake - Calve heifers before main herd begins calving to give them more time to recover before mating starts. - Delay mating e.g. split calving/year round calving. To bring back their condition/recover. Beef cows: - Maximise nutrition - Agistment/ supplementary feeding Molasses/Dry licks. Source of protein/urea to maintain BCS. - Mineral supplementation: e.g. P during lactation - Spike feeding: Supplemental source of nutrition prior to calving/mating - Early weaning: Preserve condition and increase conception at next mating. Wean when cows condition score falls below 2.5. - Restrictive suckling: twice daily or prevent for 48 hours after removing CIDR/Cue-Mate

Answer 23

- Select for shorter post partum anoestrus intervals - Select bulls based on EBV for fertility - Genotype for environment to reduce impact of environmental stressors - Select heifers with an earlier age of puberty, select heifers that got in calf earliest in the mating period. - Achieve critical mating/calving weights.

Answer 24

- P4 > 7 days: decreased sensitvity/receptors for oestrogen negative feedback. Thus increase in GnRH and decrease incidence of short cycles High hypothalamic sensitivity to oestrogen occurs with an increase expression of oestradiol receptors in the hypothalamus. Treatment with P4 devices, decreases the expression of these oestradial receptors, thus reducing the sensitivity of the hypothalamus to oestrogen negative feedback, allowing for increased secretion of GnRH. - PG: Not required post P4 removal if in anovulatory anoestrus, as they will not have a functional CL. - eCG: At the end of a P4 treatment can improve pregnancy rates - Ov-Synch: If initial GnRH injection does not work but no P4 pre-treatment - Biostimulation: Exposure to bull may reduce post-partum anoestrus interval.

Answer 25

The interval between calving and breeding has significant effect on pregnancy rate Optimal: 60-80 days following calving to conceive. Need to give cows enough rest at start of breeding season before mating. Due to: Negative energy balance Later calving and shorter calving to breeding intervals are associated with reduced fertility. Optimise calving to breeding interval: - Sync oestrus - Selective culling/replacement of late cows - Late calving bred later in the year alternatively. Split-calving dairy herds for cows that fail to conceive within a restricted mating period.

Answer 26

Time after calving during which no insemination occurs even if in heat. 30-60 days with 40-50 days best for most herds. Short period < 30 days: - Lower conception rate, only minimal extra pregnancies - increase in 100 day in calf rate but lower 200 day not in calf rate --> More opportunities to get pregnant. - Increased semen use/cost Long Period > 60 days - Higher conception rates - Reduced semen use - reduce 100 day in calf rate and increase 200 day not in calf rate More pregnant at the end of the breeding period. --> Unnecessary delay in becoming pregnant Increasing the average days in milk for the herd. *high producing cows: Can afford for them to take longer to get pregnant. Greater lactation persistence may enable longer VWP. Lower producing herd: Shorter VWPs

Answer 27

Improved detection = increase no. of cows submitted for AI & pregnant within 6 weeks at the start of mating increasing

Answer 28

Significant loss of BCS can reduce reproductive performance - Increase intervals from calving to first ovulation - Decrease conception rates - Increase embryonic loss rates - Produce less milk Likelihood of Pregnancy at Day 40: Loss of BCS: 25% Maintained BCS: 38% Gained BCS: 84% Optimal BCS targets for dairy cows: 1-8 scale At calving: < 15% of cows below 4.5 < 15% of cows above 5.5 At mating: Average decrease <0.6 <15% of cows lose >1 BCS since calving Maintain or gain BCS from the start of mating At drying off: Herd average BCS 4.5-5.5 < 15% of cows below BCS 4.5 Optimal BCS - Beef: Calving > 3 Mating: > 2.5, rising plane DAIRY COWS: TOO THIN: - produce less milk - longer post partum anoestrus - less likely to get pregnant TOO FAT: - Reduced feed intake - Don't produce more milk - Increased metabolic problems

Answer 29

Heifer liveweight effects: - Reproductive performance of maiden heifers/first calf heifers - Lifetime milk production - Calve easier and stay in herd longer Target body weights at calving: - Hostein-Freisian: calve heifers at 85% of their adult mature liveweight - Jersey: 83% Need to grow at the correct weight and speed = increased calving rate Target bodyweights for heifers at mating: - British breeds: 65% of adult mature weight Dairy heifers: 55% of adult LW at time of mating Bos indicus & continental breeds: 70% of adult mature weight Critical Mating Weights - Beef: Defined as weight at which 85% of heifers fall pregnant over 45 days. This is the weight at puberty as it reflects the weight at which most heifers for a breed will be cycling, and have high chance of pregnancy. Achieve: - Weigh regularly post-wean - Supplementary feed to attain grwoth targets - Parasite control at weaning and drench again 3-4 weeks prior to joining - Ensure heifers are cycling in unison before mating. - Maximise no. of heifers at critical mating weight 2-3 cycles before joining.

Answer 30

Weight at puberty varies between individual animals so selection of earlier onset is okay. --> more chance to recover before calving --> more cows get pregnant earlier --> Try to control age of puberty to get more animals cycling by breeding time Variation Reduced by: - Controlling birth month - Shortening duration of mating - Supplementary feed for prepuberty heifers - Breeding selection

Answer 31

- Aim for heifers to reach critical mating weight at the start of joining - Mate more heifers than will needed to allow good selection from pregnant animals. Mate 25% excess - Include lighter weighing heifers when mating --> early maturing animals - Preg tet --> Select all heifers that got in calf earliest in the mating period - Select on foetal aging and temperament. - Avoid excess hybrid vigour --> produce calf that is too big for the heifer --> Dystocia

Answer 32

It is assigned in heifers 6-8 weeks prior to mating to assess no. of heifers likely pubertal/cycling Reproductive tract scores are from 1-5. RTS score of 1 = infantile reproductive tract RTS score of 5 = Pubertal, CL preset Normal: >50% to have a reproductive tract score (RTS) of 4/5 Adv: Preg. rates increase with high RTS Dis: Labour and skill required to assess bodyweight.

Answer 33

ABV: Dairy (australian breeding value for dairy cows) As ABV increases, genetic merit increased fertility. Sires ABV rated based on the fertility of their daughters 1. Daughter Fertility ABV: Calculated by measuring the repro. performance of each sires daughters. The Daughter Fertility ABV average is 100. Cows with 100 ABV: Industry average 6 week in-calf rate. Cows with 105: 6 week in calf rate 5% above the current industry average. 103: 3% greater than average for fertility. 2. Calving Ease ABV: Average is 100. Bulls with Calving Ease ABV above 100 have fewer assisted calvings than bulls that are below ABV. --> Manage nutrition as well to manage calving ease. 3. Gestation length ABV: Indication of a bull's influence on the number of days from conception to bird. Average is 0. To reduce gestation length, select bulls with gestation length ABV of less than 0.

Answer 34

Instead of selecting for individual traits, you can select for indices that weight multiple different traits. To make a balanced selection decision BPI: Balanced performance Index For: - Production, health HWI: Health Weighted Index For: - Fertility, mastitis resistance, feed saved, longevity TWI: Type Weighted Index For: Overall type and mammary system *Selecting for High daughter fertility ABV + High BPI sires can positively influence herd fertility Cross-breeding: - Can improve fertility/ Holstein herds are more susceptible to inbreeding, negative effect on fertility over time/

Answer 35

1. Days to Calving EBVs: Estimates genetic differences of fertility. Expressed as number of days from the start of the joining period until subsequent calving. Lower days to calving EBV is more favourable, as quicker return to oestrus after calving and early conception. Avg = 0, Select for < 0 2. Scortal Size EBV's. - Estimate of scrotal circumference at 400 days of age. Larger scrotal size EBV more favourable: earlier age of puberty in heifers. Also have favourable relationship with days to calving. Bulls with larger Scrotal Size have daughters with shorter days to calving.

Answer 36

Insufficient replacement heifers and inadequate culling of aged cows can increase number of sub fertile cows in a herd. These are carry over cows Carry over cows: Reduce repro. performance & milk yield. Fail to conceive, are heavier condition and low milk yield Cull cows: > 10 year beef cows, 1st calf heifers that fail to produce in the 1st year, sub-fertile cows.

Answer 37

Bull management - Bulls should BSE tested, vaccinated for vibriosis, negative for BVDV, not used on other farms to prevent venereal diseases, not overfed Parasite control Adquate BCS, target weights Select bulls with appropriate EBVs/ABVs, low risk of dystocia Bull Power: Aim for 2.5-4% bulls per 100 cows 1 bull/30 heifers When synchronising oestrus without AI: Increase bull power Dairy herds: bull power can be based on how many pregnant in a herd. *Maximum 2 bulls/100 cows for intensively managed southern herds Maximum 4 bulls/100 cows for extensive grazing Minimum 2 bulls/100 cows or per herd. avoid single sire mating as if the bull fails it may be too late when realised. Increased risk of reduced calving %

Answer 38

Southern Beef Short Breeding Period of 9 weeks is Ideal. Goals: 65-70% of calves born in the first 3 weeks, 20% in second 3 weeks, 10% in the third 3 weeks To achieve ideal calving distribution: - Maximum 60 days for bulls to run with cows (3 cycles) Min: 45 days Correction required: when > 20% cows conceive in the third oestrus cycle. Longer Breeding Period (12-15 weeks) Dis: - Hard to maintain 365d ay calving interval - Hard to achieve critical mating weight at nominated mating date for heifers that conceive later - Wider spread of calf weights delays weaning & issues with calf marking and husbandry procedures - Unnecessary Increase of high quality pasture and decrease availability for growing stock - Increased Heifer culling and disrupted herd age structure - Increased cost of supervision for calving heifers Adv: Decreases NICR (Not in calf rate) Split Calving: Goals: 1st Cycle (3 week): 51-61% 2nd cycle: 77-94% 3rd cycle: 94-100%

Answer 39

Northern Beef: Green Date Timing: Calve 6 weeks before reliable chance of seasonal break in beef herds to match available feed with increasing age. - Usually after the green date - The green date is the number of days after the 1st October to achieve a 70% chance of receiving 50 mms of rain over a 3 day period. Adv: Calving in Dec-Jan had the highest % of pregnancy <4m *Calving earlier than the green date enables good quality feed to be available for calves when they are older and matches a cows nutrients demand.

Answer 40

Autumn Calving: Calve: Late Feb --> Calve before April as it will rain: moisture + Grass will grow. Increase in feed availability and good quality pasture Mate: Late April Wean: Mid July --> Pasture curve in August Spring Calving Calve: Aug Starting to warm and get growth Mate: Late Sep Wean: Late Dec --> Miss Pasture Curve -> requires silage

Answer 41

- Seasonal or controlled mating - Segregated breeder management - Continuous mating (joining)

Answer 42

Only allowed to breed during selected weeks/months of the year to control pregnancy/calving Adv: - Supplementation reduced due to few/no dry season lactations - Lactation matched with best pastures available - Critical mating weight improved - Selection of bull/heifer increased opportunities - Preg diagnosis for early/late calvers - Even weaner mix. Targeted weaner management - Mustering reduced as fewer weaning rounds - Reduced calf loss (no mustering during calving) Dis: - Risk of suboptimal pasture availability when mating commences. Variable and harsh conditions of N. Aus. - Must segregate stock & control bulls. - If poor bull control, must foetal age & remove late calvers - > 70% mature breeders within 12 month inter-calving interval required for controlled mating to be successful

Answer 43

Continuous: Spread calving throughout the year, usually in extensive North Aus pastures with lock stocking rates Adv: More calves are born Dis: Spread of calving is wider Segregated Animals are grouped based on stage of gestation and body condition to allow personal intervention. E.g. Maiden heifers, 1st calvers, mature cows Gestation (<5m,5m) Adv: Expenditure is where need, Avoid high mortalities

Answer 44

- Regional effects on reproduction - BCS at Pregnancy diagnosis muster - P deficiency - Time of previous calving period - Seasonal pasture quality - Seasonal environmental conditions - Mustering within 2 months of calving/incomplete musters - Cow hip height - Cow age: 1st lactation vs older cows - Cow reproductive history: Cows that did not lactate in previous year - Presence of infectious diseases: Vibriosis, pestivirus, wild dogs.

Answer 45

Effects of High Milk Production: - Decreased repro performance - Increase number of service/conception - Increased calving-conception internval - Decreased duration of heat Cause of declining fertility - Decrease Oocyte viability - Reduction in fertilisation rates - Less favourable environment for early embryonic development - Lower concentrations of some repro. hormones e.g. P4 - Reduced embryonic growth rates - Increase in early embryonic loss - Placental insufficiency - Increase in interoestrus intervals, delayed return to oestrus after AI of some cows (phantom cows) - Increase in dry matter intake and increase in metabolic rate - Increase in negative energy balance - Increase in concentrate feeding - Higher prevalence of anoestrus cows and longer post partrum to first ovulation intervals.

Answer 46

Phantom cows are cows that are inseminated but fail to return to oestrus within 24 days of AI. But are diagnosed as non-pregnant. Due to early embryonic loss.

Answer 47

1. Genetics - ABV: Daughter fertility. Slow progress in preventing and heritability is low. - Cross breeding: may reduce milk yield. 2. Nutrition - Optimise BCS, reduce loss during lactation - Decrease depth/duration of negative energy balance - Maximise dry matter intakes - Optimise transition period: Well balanced diet 3. Heat Detection - Improve practices or consider fixed time AI to bypass detection 4. Health and Welfare - Decrease dystocia - Hygienic calving - Manage uterine infections - Optimise neonatal health - Optimise nutrition/stress

Answer 48

The thermoneutral zone: 23-27 degrees Above this temperature the body actively regulates Cows need to offload excess heat, cows ability to lose heat decreases as temperature increases Increase in internal core temperature has effects on physiological processes, rumen function and oocyte quality/embryo viability Dairy cows: More susceptible due to high feed intake and milk production Heat Load: Heat produced internally by metabolic processes + Heat gained from the external environment - heat lost to the external enviro Heat Loss: a) at 30 degrees: Radiation, convection, conduction b) at 40 degrees: Breath & Sweat evaporation Humidity Thresholds: - Stress: 68-71% - Mild-moderate: 72-79% - Moderate-Severe: 80-89 Severe: 90-99

Answer 49

1. Fertility - 6 week/100 day in calf rates decrease - Not in calf rates increased - Length and intensity of heats decreased - Conception rates decreased - Risk of embryo death increased - Calf birth weight and viability reduced 2. Feed Intake/Nutrition - 20-30% more maintenance energy needed to compensate for effort to keep cool - Decreased Dry matter intake by 10-20% - Decreased rumination/cud chewing - Decreased ability to digest/absorb 3. Milk Production - Drop by 10-25%, 40% in extreme - Milk protein percentage decreased by 0.2-0.4% - Milk fat percentage is more variable, severely decreased with ruminal acidosis - Increase risk of mastitis due to increase SCC/Sediments in milk. 4. Cow Health: - Decreased rumen buffering, decreased saliva - Decrease Rumen pH - Increased Ruminal acidosis/ketosis - Risk of laminitis increased - Immunosuprresion - Risk of mastitis increased

Answer 50

- Breed heifers in warm months, less prone to heat stress. - Fixed time AI if detection is poor - Cool down cows - Cheaper semen in heat as pregnancy rates will be lower - Heat detection improved - AI to reduce infertility - Nutrition optimised - Genetic improvement: Tropically adapted, thermotolerant breeds - ET Transfer

Answer 51

1. Undernutrition: - Delays onset of puberty = Decrease in percentage of Heifers cycling at mating - Delay first ovulation post calving, decreases pregnancy rates - BCS loss due to early lactation - Delayed uterine involution - Increased embryonic loss - Decrease concentrations of IGF-I: IGF-I increases the effects of LH on ovary. Thus low IGF-I reduces the effectiveness of LH 2. Dietary Protein: - Rumen degradable nitrogen diets: Higher plasma concentrations ofblood urea nitrogen: Decrease conception rates, and change uterine pH, Increase intrauterine concentrations and alter hormone concentrations - High protein: Variable: dairy based cows have superior conception. - Avoid: Excess protein in mixed rations, sudden changes of protein during breeding. Dietary imbalance: Reduced fiber --> Alteration in rumen function --> Reduce rumen pH --> Reduce fertility 3. Vitamins and Minerals Involved in repro: P, Se/Vit. E. Cu, Mn, Co, Vit. A, Zn Deficiency: - Decreased activity of rumen micro-organisms and decreased digestibility - Decreased integrity of reproductive cells --> Anti-oxidant effects - Altered enzymes: Alters energy, protein and hormone synthesis - Decreased conception - Increased embryonic loss/abortion - Increased post portum anoestrous intervals - Decreased dry matter intake or digestibility - Retained placental - Increased perinatal mortalities

Answer 52

- Disruption of normal endocrinology of pregnancy - Foetal death or stress

Answer 53

1. Maternal Illness e.g. Hypoxia, Endotoxemia, High Fever 2. Placentitis - Release of PGF2 alpha, foetal death, foetal stress: Premature delivery. Effects on foetus depends on: - Organism - Maternal Immunity - Placental pathology - Time of infection

Answer 54

First trimester: - Early embryonic death - Regular or irregular return to oestrus - Apparent infertility, abortion Second trimester: - Abortion, mummification, prolonged gestation, retained placenta Third Trimester: - Abortion, mummification, stillbirth, weak neonates, autolysed foetus, dystocia, retained placenta, serologically positive foetus

Answer 55

This is Bovine Herpes -1/Infectious Bovine Rhinotracheitis virus. Subtypes: - BHV-1.2 a causes abortions. - BHV -1.2b is less pathogenic and does not cause abortion Transmission: Direct contact with URT, conjunctiva or genital mucous membranes Latency: Persistent carriers Clincial signs: - Abortion (> 5 months. Can occur 2-3 weeks post infection) - Temporarily infertility - Balanosposthitis (inflam of glans penis + prepuce) - Enteritis - Encephalitis - Respiratory disease - Infectious pustular vulvovaginitis Diagnose:L - FAT - Virus isolation - Serology (Poor) - Histopathology: Multifocal necrosis with intranuclear inclusions Control: - Natural exposure - Vaccination: Not available for BHV 1.2a - Safe semen - Biosecurity - Eradication

Answer 56

Transmission: Inhalation, ingestion, transplacental, venereal Depends on: - Viral strain and stage of gestation infection Signs: - Reduced repro performance - Increased calf morbidity & mortality - Decreased weaner/yearling growth rates/health. - Mucosal disease - Increased respiratory & diarrhoea in calves

Answer 57

Tests on foetus: Retest for positive viral A tests to rule out transient infection Tests on foetus: - ELISA (Ag) - BVDV ab (Pericardial fluid) - Virus isolation or PCR - Developmental defects - Histopathology: Lesions in organs characterised by mononuclear cell infiltration & lesions of skin, lymphoid, cerebellar, ocular. Tests on Herd: Persistently Infected (PI) animals have a nil/weak Ab reaction but positive for Ag. Sample Size: 8-12 animals from varied ae groups OR 5% of larger groups - PCR: - Virus Isolation - Antibody ELISA: Ear notch -> take sample from the front of the ear. Colostrum Ab doesn't interfere, retest PI 3 weeks later to confirm. - Immunohistochemistry - Viral Neutralisation teset - Bulk Milk Testing: Tests for change or outbreak of seroprevalence via sample. *The higher the sample to positive ratio (S/P), the more antibodies are present in the bulk sample. Thus higher the prevalence of seropositive cows in the herd. S/P >1: Active/recurrent PI exposure S/P > 0.75-1.0: relatively recent exposure S/P: 0.25-0.75: Random/historic exposure S/P: <0.25: naive herd, likely BVDV free - AGID: Indication of seroprevalence and if infection is recent - +1 - +2: Exposed to BVDV > 12 months ago - > + 3: Recent infection, last 3-9 months False neg: PI's, Post-vaccination

Answer 58

- Vaccination: Not useful in peak as foetal loss is 10-27 days PI with abortion at <50 days after 2x doses To control sources of introduction investigate: - Determine % of the herd at risk (Serology) - Assess risk of exposure - Autovaccination - Remove PI's - Biosecurity Control of Introduction: 1. Minimise risk of introduction - Closed herd - Test and quarantine all introduced cattle - Vaccinate travelling cattle - Avoid over fence contact 2. Minimise virus transmission - Avoid mixing cattle - Detect and remove PI's - Reduce BVDV transfer via fomites 3. Utilise AI: - Registered semen/embryos - Use BVDV-free media - Test ET donors/recipients

Answer 59

Transmission: - Via bites from culicoides - Contaminated semen Strains: Aus strains cause little disease Clinical signs: - Cattle: no CS - Sheep: Only naive show CS - Early: Resorption, mummification, abortion Infection 75-100 days: Still born, cerebral malformation

Answer 60

Source: Culicoides Introduced via: - Movement of naive cattle to endemic - Movement of vectors - Prolonged drought: Wet conditions favours the vector and naive cows infected CS: - Abortion, still births - 76-104 days: Hydrocephaly - 105-174 days: Arthrogryposis - Dystocia Diagnose: - History - Histopathology Control: Vaccination & natural exposure

Answer 61

Bacterial cause of abortion Most common in 2nd half of gestation Route: Ingestion, AI, venereal, contaminated milk machines CS: Cows: Abortion: 2nd half of gestation. Stillbirths, weak calves, retained placenta, metritis Bulls: Orchitis, epididymitis, seminal vesiculitis Pathology: Chronic placentitis: Cotyledons and intercotyledonary areas affected Diagnosis: - Culture: Abomasal fluid, foetal lung, placenta, milk, uterine fluids Serology: Rose-Bengal test, CFT, SAT Control: *Vaccination: 1. Strain 19: Live vaccine, persistent titres. Vax heifers at 3-6 months - RB-51: RB-51, Live vaccine no persistent titres. Vax heifers at 4-12 mths. - Control movement - Quarantined infected - Regular test and slaughter - Ring test (bull milk) - Repeated blood sampling

Answer 62

Cause: Poorly fermented silage CS: - Sporadic abortion in 3rd trimester - Retained placenta - Autolysed foetus - Asymptomatic OR metritis and fever. Diagnosis: - Pinpoint white to yellow foci may be present in the liver - Culture gram stain (Gram positive coccobacilli) - Immunohistochemistry Treatment and prevention: - Dam: Systemic antibiotics (Penicillin) - Avoid feeding poor quality feed

Answer 63

Strains: Most common in cow - L. Hardjo, L. pomona, L. grippotyphosa Transmission: Contact with MM/Skin CS: - Late term abortions or at any stage - Systemic signs: Pyrexia, haemolytic anaemia, mastitis, hepatorenal disease, photosensitisation Diagnose: - Dark field microscopy - FAT - PCR: Urine - Serology: Herd test - Histopathology: Silver stains - Culture; urine --> hard TreatmentL - Antibiotics: Oxytetracycline, ceftifur, tilmicosin, penicillin, amoxicilin Control: Vaccination

Answer 64

Transmission: Venereal, contaminated sperm, AI equipment Hosts: 1. Males: asymptomatic carriers 2. Females: Immune following infection CS: - History of outside exposure - Irregular return to oestrus - Increased calving conception intervals - Low fertility - Long oestrus intervals - Abortion: 4-7 months Diagnose: - Preputial wash/scare. - PCR 3 x 1 week apart - Vaginal mucous: Culture (Early in infection), ELISA - Aborted foetal samples - Virgin heifer test mating Control: - Vaccination - Breeding: AI rather than nature breeding - Segregate: By repro. status: Not pregnant, < 5 mths, > 5mths - Avoid borrowed or stray bulls Treatment: Vaccination, Oxytetracycline, Erythromycin, Dihydrostreptomycin

Answer 65

Protozoal cause of abortion. Transmission: Venereal, contaminated sperm, AI equipment Hosts: 1. Males: Asymptomatic carriers 2. Females: immune following infection <15 months CS: - History of outside exposure - Increased calving conception intervals - Long oestrus intervals - Irregular return to oestrus - Post coital pyometra - Infertility from early embryonic death - Abortion <5 months occasionally Diagnose: - Preputial wash/scrape: PCR: 3x tests- 1 week apart - Vaginal mucus: Wet prep & culture - Aborted foetal samples - Virgin heifer test mating - IFT Control: - AI- - Segregation! Not pregnant, <5m, >5m, aborted (cull?) - Closed herd - Test & cull positives - Virgin bulls - Avoid borrowed or stay bulls - ↓ length of breed season - Only breed <5yr bulls Treatment: No approved therapy & vaccine poor. Nitroimidazole off-label - cull

Answer 66

Transmission: Ingestion of sporulated oocysts, intra-uterine infection CS: Dam: - Abortion: 2nd trimester - Premature, weak, still born - Asymptomatic Calves: - 95% born normal - No CS > 2 months of age - PI calves - Proprioceptive defects, ataxia - Exopthalmus and eye asymmetry - Hydrocephalus, spinal stenosis Diagnose: - Histopathology - Serology (positive titres show exposure, not causality) - Indirect FAT/ELISA: Foetal fluids - PCR (ag) - Immunohistochemistry: Foetal tissues Control: - Serology on adults/new borns to select for non-carrier replacements - Test calves at 6 months to eliminate PI - Control dogs/carcasses - Embryo transfer for valuable infected cows. - Test & cull infected - Vaccination: Not in AUS

Answer 67

Toxoplasmosis: Ingestion of oocysts Path: Cotyledons have multiple white areas of focal necrosis/calcification Dx: FAT, histopathology, serology Control: Reduce cat population & contamination of feed Theileria Exotic species: African T Australian: T. Oreintalis CS: Lethargy, anorexia, lagging, abort Control: - Tick Control - Avoid Stress/movement - Avoid moving naive cattle to endemic - Quarantine intros for 30 days

Answer 68

Route: Inhalation/ingestion leading to haematogenous spread to foetus. CS: - Late abortion (6-8 months) - neumonia Pathogenesis: Placental insufficiency, intrauterine growth retardation Pathology: - Chronic diffuse placentitis - Intercotyledonary thickening - Cotyledon necrosis Diagnose: Smears, culture, serology Control: Good ventilation, avoid mouldy feed

Answer 69

Rotation usually 180-270 degrees. In direction of non-gravid horn Predisposing factors: - Large foetus - Multiparous cow - Large, elliptical abdomen CS: - Abdominal discomfort - Increase pulse/respiration rate - Delayed cervical dilation - Rectal palpation: Broad ligament pulled tight over the uterus Treatment: < 90 degees: rotate foetus into normal position < 90 - 270 degrees: Rotate or roll - 360 degrees: Roll or C section (Preferred due to closed cervix) 1. Manual Rotation: Method: Animal is standing, twist via forehead or proximal region of a limb in the opp. direction to the torsion. 2. Rod Detorsion: Method: Loop chains on proximal limb, preferably on the distal presenting radius or tibia. Thread through loop of rod --> use of screwdriver & chain wrapped around the detorsion rod in direction of rotation (avoid tissue) 3. Detorsion by rolling: - Used when Torsion up to 360 degrees, cervix is closed and ceasarean undesirable Method: Cast cow on side of torsion direction, place plank on paralumbar fossa region & stand on it Tie front + hind legs together. Pull legs up over the recumbent cow.

Answer 70

Risk factors: large calf, pluri-parous, Bos indicus, overweight, low BCS Host: Beef > Dairy cows or super-ovulated cows Timing: Late gestation OR post partum or during oestrus (Inceased oestrogen) Aetiology: - Progressive: Repeated partial prolapse and return when lying down vs standing - Swelling, trauma or dryin mucosa --> Straining and enlargement --> permanent prolapse - High E2 level may cause softening of peri-vaginal region/ligaments - Involvement of the cervix/bladder Treatment: Often recurs, should cull Surgery: - Initial rectal exam to check if pregnant --> lignocaine epidural --> Clean mass/vulva - Reduce mass via hyperosmosis and replace once small enough - Place retention stitch (Buhner's stitch (loop/knot pattern), shoelace pattern, Minchev procedure/Johnson, Transvaginal cervicopexy). OR pins/buttons but remove close to parturition.

Answer 71

1. Prolapsed Rectum 2. Cystic vestibular land: Becomes occluded and distends. 3. Uterine prolapse

Answer 72

Death of a foetus, in the absence of air and bacterial contamination. Cervix remains closed, no bacterial colonisation of the uterus. - Resorption of fluid, dehydration of the foetus & tight adherence of uterus to foetus Cuases: Viral infection e.g. BVD Clinical signs: - Anoestrus damn, uterus tight with firm contents & lack of fluid, sunken eyes of foetus, absent fremitys, no placentomes Treatment: - Cull if ecnomic - C-section - Luteolysis (PGF2a) --> Recheck for delivery or expulsion Prognosis: Good if expelled without complication Prognosis is lowered the larger the foetus is

Answer 73

Death of a foetus with dilated cervix & bacterial invasion Clinical signs: - No fremitus or placentomes - Absent fluctuation of uternine contents - Putrefaction of foetus: Gas, variable fluid content, brown/smelly discharge, bone fragments on ultrasound/palpation Treatment: - Cull as future fertility poor - Carcass condemnation --> Slaughter and ethics - C-section: Ventral midline to avoid contamination - PGF2alpha: may fail due to poor cervix dilation.contractions.

Answer 74

Abnormal/rapid increase in allantoic fluid post mid gestation + abnormal placenta. Reduced number of placentomes Adventitious placentation: specks next to normal cotyledons. Severe: Multiple random islets of cotyledonary tissue around a normal cotyledon. CS: - Bilateral, symmetrical abdominal distension - Anorexia (compressed rumen) - Increase in HR, RR --> Recumbency and death - Rectal palpation: Tight/enlarged uterus. Difficult to palpate foetus Treatment: - Gradual fluid removal: Lateral catheter with fluids - Induced parturition Prognosis: Future fertility is poor, survival is poor

Answer 75

More gradual onset CS Signs: - Abnormal foetus: Defective swallowing, renal tissue abnormality - Palpable foetus/placentomes - Pear-Shaped abdomen

Answer 76

1. Primary: Independent of initiating disease 2. Secondary: Induced by primary disease that exacerbates negative energy balance Predisopsin factors: - Twins - First calf heifers - GIT Parasite - Over conditioned beef cows with sudden reduction in feed. OR late gestation pasture quality/quantity is low - Early autumn calving --> Inadequate nutrition Consequences: Fatty liver infiltration --> Reduced hepatic gluconeogenesis --> Increased ketogenesis Clinical signs: - Ketonuria - Appetite reduced - Lethargy - Ruminal atong - Recumbent - Aggressive/stumbling fat beef cows Treatment: - Bolus IV glucose or dextrose - Glucocorticoid admin --> parturition - Glucogenic subs e.g. glycerol - Treat concurrent disorders Prevent: Nutrition Prognosis Good if ambulating, eating, has quality feed If inappetent/recumbent: Poor prognosis. Die

Answer 77

Timing: <24 hours following parturition Pathogenesis: - Decrease in uterine tone e.g. hypocalcaemia, twinning, large foetus, hydrops - Can cause inversion of the uterus. - Inverted uterus enters the pelvic cavity --> Stimulates abdominal contractions --> Uterine prolapse Prognosis: 70-80% success, majority are fertile Treatment: Emergency - No movement, cover uterus if recumbent, provide water, correct hypocalcaemia + epidural - Recumbent: Sternal recumbency, extend hind legs with stifles down to prevent straining. Faciing downhiill. - Standing: Restrain and elevate uterus to level of vulva - Uterus: Elevate in supporting dish (+ wrap in bag). Clean with antiseptic/saline to reduce oedema, leave placenta attached as removal traumatises caruncles. Repair significant lacerations with inverting pattern - Replacement: Apply cranial force at uterine base by vulva with mittens - Invert: Once replaced, invert with base of an empty wine bottle by pressuring cranially of each uterine horn end. Post-operation: - Administrate IM oxytocin, early return to ambulation reduces risk of re-prolapse. Uterine Amputation: If extensive trauma has occurred/uncontrollable haemorhage. Incise uterine wall, avoid caruncles. Ligate large uterine arteries and veins. Transect broad ligament.

Answer 78

Location: Through rupture/tear in floor of the vagina Differential diagnosis: Eversion of the bladder through the urethra Treatment: Epidural, clean, replace, suture laceration Systemic antibiotics.

Answer 79

Cause: Relaxation of pelvic ligaments --> Ventral displacement of sacrum when cow is mounted Timing: Uncommon, peripartruient No treatment

Answer 80

Barriers to infection: - Vulva, vestibular sphincter, cervix At calving, the uterus is contaminated by variety of pathogenic/non-pathogenic organisms. Timing: <4 weeks from calving to be cleared Predisposing factors: Impaired neutrophil function via reduced DMI during the dry period/poor hygiene at calving --> Uterine inflammatory disease post partum Prevention: - Optimise transition diet/ DMI post partum - Adequate Se/Vit. E - Good hygiene at calving/dystocia - Prevent hypocalcaemia

Answer 81

1. Antibiotics - Oxytetracycline commonly use Adv: Maintains activity within debris and anaerobic uterine environment Dis: Irritant: Can cause inflam of the endometrium 2. Intrauterine Antiseptics - Little evidence to justify usage, may induce inflammation e.g. Alcohol, chlorhex, Iotagen 3. Hormones: - Oxytocin: Ineffective > 48-72 hours post calving Use within first 24 hours following relief of dystocia to promote uterine contraction - Oestrogen: Ineffective - PGF2a: No benefit in early post partum period. Pyometra: Drug of choice --> Cervical relaxation and uterine drainage. - Progestins: Contraindicated in uterine inflam disease as they reduce neutrophil function in uterus --> exacerbate infection

Answer 82

Inflammation of all layers of the uterus e.g. mucosa, submucosa, muscularis, serosa Risk Factors: - Retained foetal membranes and factors predisposing - Reduced feed intake Main pathogens: E. coli, A. Pyogens, Pepto-streptococci CS: - Within the first week post calving: Large, atonic fluid filled uterus, fever, depression, anorexia, recumbency, decreased milk yield Red brown water, foul vaginal discharge Treatment: - Systemic: Ceftiofour sodium or procaine penicillin, ampicillin - Intrauterine treatment: Oxytetracycline --> controversial whether beneficial Supportive: NSAIDs, Fluids, Ca/energy supp Avoid: Intrauterine manipulation to decrease bacteraemia, endotoxaemia and trauma (e.g. oestrogen, PG)

Answer 83

Inflammation of the endometrium & no deeper than stratus spongiosum Main pathogens: A. Pyogens, F. Necrophorum, Gram: Anaerobes Risk Factors: Hypocalcaemia, Postpartum negative energy balance, Retained foetal membranes/RFM, Dystocia, Twins, Metritis, Ketosis, LDA Pathogenesis: - Infection stimulates immune response which is compromised by post partum neutrophil influence - Immune response suppresses GnRH and LH secretion: Decreased ovulation - If cows do ovulate: the CL produces less progesterone and luteolytyic mechanism is impaired via redirection of Prostaglandins from the F to E series. - Ovulating oocytes have reduced development, embyronic development will be affected by hostile uterine enviro. - Thus accumulation of neutrophils and bacteria in uterus --> Extended anoestrus/luteal phases * Bacterial products and endogenous inflam. mediators affect embryo development + disrupt pregnancy --> Local vascular exchange mechanisms may allow for transfer of mediators from the uterus to ovaries/udde. Decreases fertility. Consequences: - Low repro performance - Increased calving conception interval - Increased culling

Answer 84

Diagnose: - External Inspection: Pus discharge - Palpation of cervix: Cervix > 7.5cm diameter. Uterus unequal+ large fluid horns - Purulent material in vagina: 21-28 days PP, Vaginoscopy, manual exam or metricheck - Evaluation of serum markers: Hepatoglobulin, a1-acid glycoprotein - Endometrial biopsy: Negative affect on subsequent fertility Treatment: - Intrautrin Ab: -28 days post partum: Cepharin No milk withholding period PGF2alpha: Variable, some benefit when CL present but no useful <28 days post partum

Answer 85

No visible cervix discharge but cytological evidence of inflam Timing: 35-60D Lactation Associated: ↓ Preg rate, delayed conception, ↑ % of failed conception Dx: Saline lavage, cytobrush, ultrasound (Less effective) Tx: Cephapirin IU or PGF2a

Answer 86

Exist in cases where there is a vaginal exudate in absence of endometrial inflammation Risk factors: - Obstetric complications - Uperperal metritis Treatment: Cephapirin

Answer 87

Accumulation of purulent exudate within the uterus with functional CL. Systemic signs absent Pathogenesis: - High conc. P4 post-ovulation suppresses defence mechanisms - Failure of PGF2alpha release from uterus in presence of uterine inflam: Persistent CL Diagnose: - rectal palpation: Fluid filled uterus, horns equal, lack membrane slip/placentomes/foetus - Ultrasound: Hyperechoic fluid within uterus Treatment: PGF2a to induce luteolysis & drainage Recurrence occurs 9-13% Refractory cases: - Assess vagina via speculum - Assess uterus for presence of remnant foetal parts, intrauterine adhesions (Ultrasound) - therapeutic flushes of the uterus until the flow is clear --> With Foley catheter and sterile saline solution

Answer 88

12 hours post partum: retention of placenta for approx 6.8 days Normal uterine involution: - Placental detachment: 3-6 hours - Cotyledon proteolysis: 3 days - Caruncle necrosis: 7 days - Caruncle sloughing: 15 days - Collagen breakdown via collagenase - Epithelial cover of endothelium: 26-30 days Pathophysiology: - There is prepartum inhibition of cotyledon proteolysis and neutrophil function - Ischaemic retained placenta post bird = metabolically stressed placenta with release of inflam. mediators and local immunosuppression - Bacterial colonisation compounds impact Potential causes: 1. Uterine atony 2. Oedeoma of chorionic villi (Dystocia) 3. Cellular dysfunction/necrosis (infection) 4. Decreased innate/humoural immunity 5. Oxidative damage via insufficient antioxidants 6. decreased pre partum BCS = decreased a-tocopherol conc., increased NEFA and BHBA conc. 7. Incomplete extracellular matrix by collagenase related to steroid hormone imbalance

Answer 89

Diagnose: When >10% prevalence or increase in individual herds --> Investigate Treatment: Aim: Early detachment to decrease occurence of metritis, decreased milk yield and reduce negative impact on repro performance Experimental: infusion of collagenase into umbilical arteries, 85% effective within 36 hours. - Physical removal: NOT recommended as risk of iatrogenic contamination, residual placental tissues can remain and traumatise the uterus - Hormonal: E2 and oxytocin not effective in placental separation - Intrauterine therapy: Antiseptics can exacerbate inflammation Oxytetracycline can reduce incident of fever BUT in milk residues for 144 hours Tetrayclines inhibit matrix proteineases, may PROLONG RFM Systemic Ab: Recommended if pyrexia, ceftiofur decreases metritis. No witholding period but expensive. Procaine peniclin: Cheap but milk residues.

Answer 90

Mucous character 0 - clear or translucent 1 - clear or translucent with flecks of white pus 2 - <50mL containing < 50% white/cream pus 3- >50mL containing >50% white/cream/bloody bus Mucous odour 0 - no unpleasant odour 3 - Fetid odour

Answer 91

- Preserve the life of the damn e.g. late pregnant cows with metabolic diseases such as pregnancy toxaemia - Reduce dystocia by reducing birth weight in heifers - Mismated animals - Scheduled C-section - Close observation for detection and correction of dystocia - Historical use: Sync lactation, increase milk yield, decrease culling in seasonal herds and improve lifetime production - Prevent excessive udder odeama - Seasonal herds: Once late committed to a lifetime of late calving

Answer 92

Suitable Selection: - Age 3-8 years that are not replacements - BCS 4.5-5.5/8 - 6-13 weeks before expected calving - Healthy - Dried off for >7 weeks - Avoid mammary gland infection/mastitis Trends/Ethics: - Banned in NZ - Phased out in AU unless dispensation ranted for exceptional circumstances. - AVA opposes if not therapeutic

Answer 93

- Low birth weight and weaning weight in beef herds - Calf mortality <2 week from due date, welfare - Public attitude - Increased incidence of retained foetal membranes and thus low repro performance - Metritis, hypocalcaemia, dystocia - Treatment with corticosteroids have side effects: mastitis, photosensitisation - Increased calf morbidity/mortality

Answer 94

- Exam pre-AI for uterine infection/treat - Oestrus sync protocols - Treatment of non-cycling cows - Nutrition optimised to max health - All other methods to improve fertility: Cross-breeding, genetics, culling, heat detection

Answer 95

- Ensure labour is sufficient - Ensure human treatment of calves - Preg check all presented - Assess alternatives - <1month from calving - Screen out unsuitable - Ensure adequate dry period & management to prevent hypocalcaemia

Answer 96

1. Corticosteroids: help decrease placental P4 production a) Short Acting: Dexamethasone Efficiency: 80-90% Parturition: 24-72 hours Timing: Close to calving with milk present b) Long acting: Timing: >7 months gestation + no udder distension. Often in cows not conceived to AI but to herd bull. Aim: Decrease cull rate, increase lifetime production Drug: Dexmethasone trimethy acetate Parturition: 4-26 Days, Post-infection: Monitor for 20 minutes for anaphylactic reactions Dis: Decreased milk production and increased RFM. *Variability in time to calving after treatment can be reduced by administering PGF2 alpha about 8-12 days after. BUT calf mortality and incidence of RFM incrased. 2. PGF2alpha - Help remove CL P4 production Timing: Last 2 weeks gestation Parturition: 24-72 hours Dis: Increase RFM

Answer 97

- Animals induced in good health - Up to 150 days: PF2 alpha to induce abortion - Greater than 150 days: Combination of PG and dexmethasone. Abortion in 3-9 days. - Oestrogen: Treatmenet within 2-3 days ovulation disrupts oviductal transport of embryo. Cause luteolysis up to about 150 with high doses - Intrauterine infusion of an irritant chemical e.g. iodine

Answer 98

Research project where data was collected from commercial dairy herds in Australia. Aim: Understand reproductive performance & major related factors in dairy cows. Benchmark reproductive performance of dairy cows in Aus.

Answer 99

Seasonal/split herds: - 6 week in-calf rate: % of cows pregnant after 6 weeks of mating > 60% - Not in calf rate: % of cows not pregnant at the end of the mating period < 8% Year round calving herds: 100 day in calf rate % of cows pregnant by 100 days after calving > 60% 200 day not-in-calf rate % of cows not pregnant by 200 days after calving 7% (<13%)

Answer 100

Split/seasonal: 3 week submission rate: % of cows receiving at least one insemination in the first 3 weeks of mating > 85% Conception rate: % inseminations that resulted in a positive pregnancy test > 50% Year round: 80 day submission rate: % of cows that received at least one insemination or mating by 80 days after calving >73% Conception rate: % of inseminations that resulted in a positive pregnancy test >50%

Answer 101

Cows need to calve at least 6 weeks, and heifers up to 9 weeks before mating start date 88% of the whole herd calved by week 6 First calves have 75% calved by week 3, 92% by week 6

Answer 102

Addresses: Current position, realistic improvements, what areas need improving Consists of: 1. Overall herd performance 2. Drivers of in-calf rates --> SR and conception % 3. Key indicators of improvement 3. Summary page

Answer 103

1. Volume 2. Colour No discolouration or blood, pus, urine discolouration 3. Consistency Affected by: Semen production, collection and method (electroejaculation = dilute semen) Scale: 0 - clear 1- Cloudy < 200 2- Milky 200-500 3- Thick milk 500-1000 4- Creamy 1000-1500 5- Thick creamy 1500 + 4. Smell: e.g. Urine contamination 5. pH: Normal pH of bull is 6.2-7.4. Decreases overtime due to build of lactic acid

Answer 104

- Mass Activity: Small drop of semen on pre-warned slide with no cover slip --> Use: reserved for ruminant semen as highly concentrated --> Calculate: Concentration & motility Scale: 0 - No swirl 1 - Very slow swiel 2- Slow swirl 3- Moderate Swirl 4- Fast swirl 5- Very fast swirl - Individual motility a) Total motility: % of sperm moving in any direction b) Progressive motility: % of sperm moving progressively across the field of view (moving actively forward), assess different parts of the slide Results: Tick -> 60%, Q -> 30-59%, X - <30% c) Speed of movement Method: Dilute sample (warm isotonic) and place on drop on a pre-warmed slide with a coverslip or dip wooden applicator in semen & dilutant. - Morphology Determining the % of normal vs abnormal sperm whilst immotile Methods: a) Wet prep: Drop of semen on slide with coverslip --> Phase contrast or DIC microscope b) Eosin-nigrosin stain: Mix small semen drop with large stain drop --> place on slide near frosted edge and use blood smear method to spread. --> bright field microscope Major defects: Proximal cytoplasmic droplets pyriform heads, folded/coiled tails, mid piece defects, maldeveloped, craters Result: Tick > 70%, Q - 50-60%, X - <50% - Foreign cell smear: Smear made from raw semen directly or from a pellet of semen after centrifuging Cells seen: Sperm, neutrophils, lymphpcytes, epithelial cells, spermatogenic cells Smegma contamination: WBC's High no. of neutrophils from sheath ejaculation may be normal, but high numbers if penis is exteriorised/washed is worrying. 3. Concentration Results: Tick - > 200, Q - >200, X - < 200 Methods: - Haemocytometer Step 1: Dilute sperm in saline/phosphate buffered glutaraldehyde --> Preserved sperm Step 2: mix well, load an aliquot on eac side of the haemocytometer Step 3: Count no. of sperm heads within counting area (25 squares) boarded by 3x lines, if too many sperm, count sperm in 5 corner/middle squares and multiple by 5 ONLY count sperm heads in contact with upper/left border and NOT lower/right border Step 4: Calculate concentration taking in dilution factor = Count in 25 squares x 10,000 x Dilution Factor (AKA 1:100 factor = x 100) Other ways of measuring sperm concentration: - Nucelocounter - Photometer (Spermacute) - CASA: Computer assisted semen analysis

Answer 105

- Fertile: Can naturally impregnate 60-90% of 50 normal, cycling females within 3-9 weeks respectively - Sub-fertile: Achieve natural pregnancies at a lower rate OR only achieve via AI, not naturally - Infertile: Cannot achieve pregnancy - Serving capacity: Counting no. of successful services in 20 months --> Not ethically acceptable - Serving ability/assessment: Visualise if bull can serve only one cow.

Answer 106

Results: Tick: Fertile Cross: Not to standard Q: Qualifies but doesn't meet all NT: Not tested 1. Physical - BCS - Gait - Eyes - Conformation: Legs, joints, feet, head, length of prepuce - Penis: Method: penis is manually extended by grasping glans tip with gauze once it is extended with the electrojaculator Normal visualisation (NV), normal palpation (NP) or abnormal (A) 2. Scrotal - Palpation: Feel for neoplasia or growths - Measurement: Pull testes firmly into lower scrotum with thumbs and fingers loacted either side of the scrotum. Tape is pulled snuggly around the greatest diameter of the scrotum. OR with a Barth --> 2mm of green piston showing Depends on: Breed, weight, age Results: <90% interval = X unless pre pubertal, > 90% CI = investigate further Heritability of Scrotal Circumference is high = 0.30 to 0.45 3. Semen Described as above: Macro, micro and concentration Impacted by Age: Younger bulls have lower quality Re-testing: Done > 60 days since last test as spermatogenesis is 61 days 4. Serving: Visualisation of mating/serves in 10 minutes (For bos taurus) or 20 minutes (for Bos Indicus) 0 serves = Fail > 1 = Pass Measures: Libido or physical limitations for successful mating Method: - Individually or in groups. Young bulls separate, herds of same social group - Restrained or unrestrained females - Females may or may not be in oestrus. If not: Restrained When recording: I: Interest e.g. nose curcling, licking, false mounts M: Mounts: no. of full mounts by a bull S: Serves: No. of effective mounts with intromission, ejaculatory thrust and dismount with erect penis 5. Morphology: Sperm

Answer 107

1. Impotentia Coeundi: Conditions affecting desire/ability to copulate 2. Impotentia Generandi: Conditions affecting bulls ability to fertilise ova

Answer 108

- Head conditions that impact sight, grazing and maintenance of body weight - Low body condition: reduced libido, testicular atrophy, reduced sperm, delayed puberty - Over conditioned bulls: Accumulate scrotal fat, interferes with temp regulation - Poor conformation: Affects ability to copulate, mount and reduces libido - Rapid growth causes degenerative joint disease Examples: - Post-leggedness: Predisposes to stifle & hock joints --> lameness and decreased mounting - Foot Issues: Cork-screw toe, interdigital fibroma, laminitis, overgrown claws, footrot - Arthritis: Distension: Tibiotarsal joint --> resolve or limit serving + correlation with growth rate Oesteoarthritis: in the distal, intertarsal, tarsometatarsal & stifle joints Score: Q or F depending on degree, no. joints, signs of lameness--> Re-evaluate to assess resolution and serving ability. Avoid: - Rapid growth (>1kg/day) between 6-12 months, - Feeding excess rapidly fermenting carbs 12-24 months. - Ruptured Cranial Cruciate - Dislocated hips/fractured - Sickle hocks - Ankylosis & Sponylosis of Vertebrae: Sore back --> Improper mounting

Answer 109

- Dominance Rank: Dominant bulls preventing lower ranked bulls from mating - Libido: Genetic potential for serving capacity varies between bulls - Immature bulls: have lower libido - Pain, over conditioning. under conditioning

Answer 110

Scrotum: All but dermatitis cause swelling - Inguinal hernia: Most common on left side, contents replaceable and not firm unless incarcerated - Orchitis/Epididymitis: +- Sensitive palpation, tesitis larger, firmer than normal - Neoplasia - Varicocoele - Trauma/wound - Hydrocoele: Unknown aetiology, incidental finding no other CS. Self-limiting and will resolve over time. - Haematocele: Irregular hypoechoic (Fluid) & hyperechoic– no heat or systemic Sx, ↓ w/ time - Spermatic cord torsion - Sickle hocks - Dermatitis: Dermatophillus Congolensis, Chorioptes Bovis, Lice → Interferes w/ thermoregulation & fertility, Frostbite → Older bulls more likely

Answer 111

Types of Issues: Congenital, infectious, nerve damage, disruption of erectile process Examples: - Diphallus: Duplication of glans penis. Congenital - Short Penis - Short retractor penis muscle - Persistent frenulum --> Persistent band from median raphe of prepuce near glands w/ blood vessels in the centre. Normal: Separation of penis from sheath at 1month --> Completes at 8 month. Consequence: Prevents complete extension & often results in penile deviation Treatment: Ligation/transection of frenulum. Only treat bulls used as terminal sires. - Hypospadias: Failure of urethra to fuse ventrally: Hole located along penile shaft - Hair ring: Hair located around base of glans: Constriction & stenosis --> Necrosis, irritation Cause: Homosexual behaviour drawing hair from back of bulls into prepuce Treat: Removal of hair and local treatment. - Penile Deviation --> Spiral/Corkscrew: Most common in polled > horned. Onset >1-2 normal breading seasons. Can occur during electrojaculation, can diagnose as during natural services. --> Ventral deviation --> Rainbow deviation --> Dorsal deviation Treat: Surgically correct via apical ligament splitting/interweaving or fascia latae autographs. Not recommended as likely genetic.

Answer 112

Swellings of the Prepuce - Penile Haematoma: Rupture of tunica albuginea allowing blood to escape from corpus cavernosum CS: swelling cranial to scrotum + Preputial prolapse Location: Site of rupture is the dorsal penile surface opposite attachment of the retractor penis muscles Cause: Downward penile deviation during mating or bent while thrusting into hard surface Diagnosis: Cranial to scrotum can see abscesses Ultra sound: Signs of clot formation, no definitive capsule with haematoma Fine needle aspiration: AVOID. as can inoculate site with bacteria --> formation of abscess Treatment: - Sexual rest - Surgery - Slaughter - Hydrotherapy - Antibiotics to prevent abscess formation Guide: - If haematoma <20cm in diameter, >70% may recover with antibiotics + 6 months sexual rest - If haematoma > 20cm, about 50% will recover with antibiotics and sexual rest Complications of penile haematomas: - Peripenile adhesions due to fibrosis - Abscessation - Erection failure - Loss of sensation to penis due to damage to the dorsal nerves of the penis

Answer 113

- Penile Wart/Fibropapilla Cause: Bovine Papilloma Virus Hosts: Young bulls in groups Consequences: Pain/bleeding during servicing, paraphimosis, penile trauma Treatment: Often spontaneous resolution or surgical removal, ligation/removal if pedunculated Cryotherapy, cautery, laser surgery, wart vaccines - Balanoposthitis BHV-1.2 caused Transmission: Venereal, AI Clinical signs: Coalescing vesicles with yellow-white fibrinous exudate --> Extensive haemorrhage/ulceration - Phimosis: Inability to protrude penis Cause: Persistent frenulum, preputial orifice stenosis, immature - Paraphimosis: Inability to retract penis Cause: 2nd to trauma causing preputial stenosis Desensitisation of the glans penis - Cause: Trauma to dorsal nerves, hair ring, artificial vagina, penile haematoma, severe balanoposthitis Clinical signs: Trouble locating vagina, may not thrust/ejaculate. Decreasing libido - Prolapsed prepuce Bos indicus have pendulous prepuce --> Relaxation and preputial protrusion --> Trauma - Preputial Injury: Treatment: Systemic/topical antibodies, anti-inflammatories, hydrotherapy, bandaging

Answer 114

Causes: - Congenital: Free-martinism, Abnormal karyotype - Endocrine - Febrile - Aging - Toxicants: Heavy metal, cadmium, griseofulvin, ethylene, cottonweed, locoweed - Hormones: Oestrogen, androgen - Inflammation: Pampiniform phlebitis, frostbite, dermatitis, trauma, biopsy - Testicular fibrosis: Scale: 0-5 severity Timing: Common >10m (7-40%) Consequences: Minimal effects on semen unless >4

Answer 115

Problems of the accessory sex organs 1. Seminal Vesiculitis Common in young bulls Cause: T. Pyogens Route: Ascending, descending, direct invasion, congenital abnormalities, haemtogenous CS: - No obvious signs - Increased size/firmness of glands on rectal palpation - Excess WBC/pus in semen - Abscessation --> Fistulation (rectum, bladder, peritoneal, ischiorectal fossa) --> Bloody poo Treatment: - Many spontaneously recover Surgery: Vesiculectomy: Variable results - Medical: Unrewarding - Intraglandular injection of Ab has no benefit - Systemic antibiotics: Penicillin, tilmicosin, trimethoprim, erythromycin, IV fluoroquinolones

Answer 116

1. Genetic Improvement Adv: Doubles genetic gains, reduced generation intervals using heifer donors. Performance: Embryo transfer bulls are compared to ET derived sisters rather than daughters The rate of genetic improvement can be determined by: a) Selection intensity b) selection accuracy c) Genetic variability d) Generation interval 2. Disease Control: zona intact, washed embryo will not transmit infectious diseases 3. Distribution and transport of valuable genotypes: Cheap import/export of disease free stock 4. Number: 600,000 in 2002 after freezing + thawing. 5. Conservation and insurance of valuable animals 6. Research: Embryo development, endocrine control, clones 7. Improve fertility: Infertile/sub-fertile cows can reproduce via embryo harvest 8. Diagnosis of infertility: Repeated failure to collect embryos in ovulation --> Non-patent oviducts 9. Efficient use of sexed semen: Recovery rates are lower due to short lifespan of semen in reproductive tract + Low doses. 10. Bypass Embryonic mortality via heat stress

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- Cost - Labour Intensive - Unpredictable in response to superovulation - Requires Skill - Can delay calving to conception intervals in donors and recipients.

Answer 118

- Average no. transferable embryos/flush: 5-6 - No/Non-viable embryos: 25% of donors Recovery: 70% of embryos recovered from 40% best donors.

Answer 119

1. Selection of Donors - Genetic merit - Repro normal - BCS - Virgin heifers require >2 cycles, 18-24 day inter- oestrus interval - Postpartum interval: >50 days - Cervix passes catheter (15 months) - History: Successful donor in the past?

Answer 120

2. Superovulation of Donors Aim: produce max no. of embryos that result in high preg rates post thaw/transfer by synchronising ovulation in super-ovulated donors & normal ovulating recipients Increase results: - Strat treatment of donor 9-12 day of the cycle (new wave emerging) - Follicles >2mm in diameter - Absence of large dominant follicle *Initiation of superstimulatory treatments at the time of wave emergence enhances the response. Insemination of Donors: a) AI: 4hrs after onset of oestrus, 12 hours inbetween inseminations b) Inducing ovulation: inseminate 12hrs after GnRH, and then again 12 hours later c) Optional: Additional AI 36hrs post oestrus Assessment of Superstimulatory Response: Count CL’s: Palpation or US, accuracy decreases >6 CL’s Poor Response to Treatment: - Compliance of protocol, dosages, site of admin - Improve nutrition - Time of year - Try again Post Calving Methods to sync follicular emergence before starting superovulatory treatments? - GnRH: 1.5 days prior - Follicle Aspiration: 1-2 days prior - Oestradiol benzoate/17B oestrodial + P4: 4 days prior - Slow release GnRH agonist: Down-regulation of anterior pituitary: 7 days prior Methods of Super-Stimulation: 1. eCG Dis: prolonged 1/2 life causes prolonged ovarian stimulation, high no. anovulatory follicles & low embryo quality 2. FSH: Timing: FSH treatment for 4 days. Decreasing doses & PG admin at 2-4 days, 1-2x a day Removal of CIDR and onset of Oestrus: 12-24 hours. Doses: Lower in bos indicus + heifers. High in superovulation/low embryo quality

Answer 121

3. Embryo Collection Timing: 6-7 days post oestrus for ideal developmental stage Prepare: Restrain in crush, no sedation but if needed acetylpromazine. Epidural Empty rectum if distended with faeces, wipe vulva with water, catheterise uterus Methods of Recovery: a) Body flush: Balloon is inflated within uterine body b) Horn flush: catheter is passed into uterine horn, balloon is inflated and horn is flushed. Then again on opposite horn. Flushing technique: a) Interrupted Syringe: infusion followed by recovery of fluid with 60mL syringe. Repeat process 4x b) Interrupted Flow: Catheter is connected to Y-piece, connected to tubing and then connected to a bag containing flushing media. Water is recovered through a filter to isolate embryos.

Answer 122

Evaluation of Embryos Principles of Embryo Handling: Avoid light, distraction, dust, bacteria, chemicals & use labels, clean equipment/fluids, rinse catheters, careful movement Embryo stages commonly transferred into ET recipients: Stage 4: Morula Stage 5: Early Blastocyst Stage 6: Blastocyst Stage 7: Extended blastocyst Can grade Embryo quality from 1-4: Grade 1: Excellent/Good – Symmetrical, spherical, individual cells w/ uniform size, colour, density, smooth pellucida, no adherence; 85% cell intact, viable mass Grade 2: Fair – Mod abnormal embryo shape & cell size, mass, colour, density; 50% intact, viable mass Grade 3: Poor – Major irregularities, 25% material intact, viable mass Grade 4: Dead/Degenerating – Degen embryos, oocytes or 1-cell embryos, non-viable

Answer 123

- Oestrus (36hrs prior - OR 12hr after donor) - BCS, gaining wt. - Readable (Double) identification - Medium or large frame: reduce risk of dystocia - Quiet temper AVOID: - History of infertility - Anoestrua - Reproductive culls - Poor PCS - Early post partum <50 days

Answer 124

6. Embryo processing: grading, washing, (± splitting, freezing, sexing) 7. Transfer of embryos

Answer 125

1. Sexed Semen Method: X/Y sperm separated by flow cytometry as X-sperm have 4% more DNA Timing: Optimally inseminated close to time of ovulation Adv: - Increase pool of replacement heifers - Higher preg rates - Reduced dystocia - Increased genetic gain by 15% - Decreased no. of unwanted males Dis: Higher costs, reduced viability of semen, limited no. of sires Optimise results: Careful Handling 2. Embryo Sexing: Method: PCR analysis on embryo biopsy to determine sex prior to embryo transfer Dis: - Embryo damage: decreased pregnancy rates and freezability - Time consuming - Skill & special equipment - Sexed semen in the future may reduce need for embryo sexing 3. Foetal sexing Goal: Diagnosing the sex of existing pregnancy to make management decisions Optimal: Cattle 60-80 days Method: 120-125 day transrectal Ultrasonography or >120 day transabdominal ultrasonography Anatomical landmarks: - Genital tubercule: precursor to clit & vulva in female or penis in male Hyperechoic and bi-loped In female it is ventral to the tail, male it is caudal to the umbilicus Gender Specific Structures Female: Clit, mammary gland, gonads --> Blood flow in peripheral medulla of ovary Male: Prepuce, penis, scrotum, gonads --> Blood flow restricted to central blood vessels

Answer 126

* Aspiration of oocytes from ovarian follicles * In–vitro maturation of oocytes * In-vitro fertilisation * In-vitro culture of zygotes to morula or blastocyst stage * Transfer of embryos to recipients Adv: - Can generate more embryos - Can be used early post partum (>30 days). Good for juvenile heifers that are too small for ET - Terminally ill/Slaughter cows - Ovaries from abbatoir acn be used - Alternatives to ET Dis: - Oocytes require transport to specialist lab & transported back for culture + Fertilisation - Preg rates low - Cyropreservation reduced preg rates - More expensive - success rates are low in horses via low oocyte fertilisation

Bovine Reproduction Flashcards

(151 cards)