Small ruminants medicine and production Flashcards

Question

What is flushing ?

Answer 1

Flushing Provide a nutritional spike in the lead up to mating. Supposedly increases ovulation rate - called the dynamic effect. - if you flush you also increase BCS - flushing with lupins helps a great deal but extremely costly - 500g/Hd/daily up-to two weeks prior to joining

Answer 2

Rate of fertilization Failure of fertilization is usually not a problem Failure - infertility of ewe or ram - phyto-oestrogens - ram percentage - choice of mating paddock - length of joining period

Answer 3

Phyto- oestrogens "clover disease" Temporary infertility - when ewes are mated on green oestrogenic clover - the cervical mucous increases in volume and becomes very watery - impairs sperm transport through the cervix - fertility returns to normal within a few weeks of removal from the pasture Permanent infertility can occur (rare) - ewes grazing in high / moderate rainfall areas of Australia on Cultivars of subterranean clover - T pratense - Trifolium subterraneum - grazed over consecutive years - permenant changes to the epithelia of the cervix and uterus (cyctic glandular hyperplasia).

Answer 4

Phyto-oestrogens Diagnosis - history - pasture inspection and identification of oestrogenic cultivars of sub clover (Trifolium subterraneum) - examination of animals - post mortem - histopathology of cervix uterus The clinical signs - may increase the incidence of dystocia - increase in rates of pre lambing vaginal prolapse - teat elongation and inapproprriate lactation - urolithiasis in wethers (water belly) - lambing typically lowered by 5-10%

Answer 5

Phyto-oestrogen recommendations Prevention - pasture renovation (expensive) - Formonetin is maximal in green plant - so use cattle to graze the high risk paddocks - cull sheep at a younger age when they are less susceptible to phyto-oestrogens

Answer 6

Embryonic mortality Embryonic mortality is relatively high 20% within the first 18 days Measure = increase in ewes lambing late (if there is time to return to oestrous) Embryonic loss may be influenced by - ovulation rate (higher multiple preg) - nutrition - age of ewe (higher in young sheep) - high temperatures - stress - shearing, treatments - genotype - Se deficiency - infectious diseases (Toxoplasmosis, Border disease)

Answer 7

Ewe factors - poor cycling, seasonality - poor ovulation rates - usually nutritional but may be affected by some toxic plants - failure of fertilization eg clover disease - embryonic mortality (post 20 days) can be high, has many causes which are not easily managed (except reducing stressors)

Answer 8

The importance of nutrition at all stages of pregnancy Conception - poor nutrition leads to a lower ovulation rate Placental development (D30-D90) - poor nutrition can reduce cotyledons and size of the placenta. This causes a reduction in the nutrient supply to the foetus and lower birth weights.

Answer 9

Scanning After 18-20 days - beyond this point pregnancy is usually very robust - scanning should track closely with the ewes that actually lamb - total number of lambs born should closely reflect what was scanned. If the number of ewes that do not lamb is > a few % less than those scanned THERE IS A PROBLEM.

Answer 10

Abortion is a problem 1. Ewes scanned in lamb detected as likely not in lamb at pre-lambing treatments (crutching, drenching). - these ewes will be obviously skinny, no udder development - investigate seroly may indicate Camplobacta or Toxo 2. Frank abortions should not be more than 0.5% or a few lambs per mob. - you should not see many 3. Wet / dry - useful if there is not scanned and issue only noticed at marking Dry - not lactating (no udder development) lost before lambing - lactating but no lamb; udder is involuting not much milk and it is watery - likely perinatal loss - lastating; live lamb / lambs Remember the metric 88% singles and 78% twins

Answer 11

How to wet dry ewes at marking - not lactating (no udder development) lost lamb before lambing - Lactating but no lamb; udder is involuting. Not much milk and it is watery - likely perinatal loss - Lactating - live lambs/lambs - Remember the metric should be 88% survival for singles and 78% for twins at marking.

Answer 12

Causes of abortion Diagnosis in 57% of cases; Camplobacter 32% (zoonotic) Listeriosis 9% Toxoplasmosis 26% Less common causes of abortion in Australia - Salmonellosis - pestivirus 'hairy shaker' leptospirosis - rRmulus (onion grass)

Answer 13

Campylobacteriosis Abortion storms 10-60% lamb loss (common Australian sheep) - spread through direct contact with discharges from the vagina, aborted foetuses and placenta - potential zoonosis - gastroenteritis Factors increasing spread - contaminated pastures where ewe aborted - close contact facilitates spread (high SR, trail feeding, rotational grazing or confinement feeding. - carrier animals - crows and magpies may carry disease for several months and help its spread

Answer 14

Pathology Abortion occurs within three weeks of the ewe coming into contact with the bacteria Aborting ewes will develop good immunity and are unlikely to abort again - abortion mid-late pregnancy - usually sporadic at first followed by an abortion storm 2-3 weeks later - mainly maiden ewes - still births - birth or premature lambs and apparently normal but non viable lambs ewes may remain placental membranes and develop metritus (rare) Most aborting ewes show no sign of sickness

Answer 15

Campylobacter Post mortem foetus - gross lesions variable and non specific - grey 'rosette-like' necrotic foci in foetal livers Isolation of organisms - aborted membranes, foetal stomache content

Answer 16

Prevention Campylobacteriosis Ewe hoggets may be grazzed on infected paddocks in order to infect them while not pregnant, or aborted ewes with hoggets or lambs. - vaccination (inactivated vaccine) 2 injection 2-3 weeks apart + yearly booster - recommended in high risk situations

Answer 17

Control Campylobacteriosis Control - hygiene (remove foetuses and membranes) - spread sheep out if possible (reduce stocking rate) - antibiotics oxytetracyclines, erythromycin or tulathromycin The earlier in pregnancy a diagnosis is made the better the out come watch for - lesions - unvaccinated - risk factors (crowding)

Answer 18

Toxoplasmosis Protozoa in the intestine of cats - final host cats Sheep are infected through contaminated water or feed - cat faeces containing toxoplasma oocyst - very resistant in the environment - cool wet climates

Answer 19

Clinical signs Ewes - most outbreaks in maiden ewes Clinical signs - If infected when not pregnant - no clinical signs - if infected in early pregnancy - no clinical signs / foetal death and reabsorption - if infected in mid pregnancy (D60-120) birth of a still born or weak lambs, mummification, abortion (last 2 months) - ewes no sign of sickness Upto 40% abort If infection in latter part of pregnancy (>120D0) - offspring normal (but infected and immune)

Answer 20

Pathology Toxoplasmosis Pathology ' necrotic, disgusting abortions' - placental cotyledons bright to dark red with white foci of necrosis (strawberry) - inter cotyledonary areas unaffected - mummified foetus Histopathology placental cotyledons, foetal brain, lung and liver

Answer 21

Control Toxoplasmosis Hygiene - limit the number of young cats - Treatment of valuable ewes SULPHONAMIDES - graze young stock on areas likely to be contaminated with cat faeces (hay sheds, farm buildings, house paddocks). - only feed grain from covered feed bins and silos NO VACCINE AUSTRALIA

Answer 22

Listeriosis Listeria monocytogenes (abortion, septicaemia in lambs and meningo-encephalitis) Bacteria survive for long periods in soil and on decaying vegetation + can be present in the gut of healthy sheep. - potential zoonosis - disease common under wet muddy conditions - outbreaks often associated with feeding poor quality silage (PH >5.5) - occurrence is sporadic and unpredictable - stressful conditions

Answer 23

Listeriosis Abortion occurs when a combination of stressful conditions are present - weakens ewes immunity - bacteraemia - bacteria in foetus and foetal membranes Clinical signs - abortion at any stage of pregnancy (usually late) - rate 2-20% - still births - aborting ewes show generally no signs of ill health, occasionally development of reddish brown discharge after aborting (clears up with out treatment) Post mortem foetus - rapid autolysis (decomposition) - multiple white foci

Answer 24

Listeriosis Diagnose - isolation of the organism from the foetus (liver, lungs and stomach) and placenta Prevention - feed good quality silage - reduce stress Treatment - none

Answer 25

Salmonella zoonosis S. typhimurium Infection is transmitted by ingestion Clinical signs Abortion in addition to enteric signs of infection usually associated with stressful conditions - mortalities, diarrhoea - foetal death, abortions (last 6 weeks 60%) - retained foetal membranes, septicaemia, high fever

Answer 26

Salmonellosis Diagnose - Isolation of organism from foetal stomach and placenta Treatment and control - separate affected animals from unaffected animals - reduce stocking rates - avoid further stress Possible antibiotics for affected animals and supportive therapy - no vaccine in Australia

Answer 27

Onion grass (Romulea rosea var australis) Primarily found in Victoria Poisoning occurs through ingestion of the plant or fungus (Helminthosporium) Clinical signs Abortions, infertility and staggers - ewes lose lambs early to mid pregnancy - marking rate low 20% in affected herds, aborted foetuses usually not seen Diagnosis is difficult as there is no specific pathological signs usually based on the composition of pasture. Prevention = renovate the pasture.

Answer 28

Ovine pestivirus Border disease - hairy shaker disease (hypomyelinogenesis, congenital trembles) Virus is transmitted by the mucous membranes - close contact needed - some sheep do not throw off the virus (carriers) - 'Hairy shaker' lambs that survive are especially likely to become carriers - virus can not survive on pasture more than a few days

Answer 29

Pestivirus 'hairy shaker syndrome' If infected when not pregnant - may develop a mild fever, but then develops immunity Infection before day 50 - foetal death - reabsorption, abortion (most common at about 3 months) - aborting ewes show no sign of sickness Infection day 50-85 outcome is variable - foetal death abortion - birth of dead or live lambs ('hairy shaker') Hairy shaker = hairy coats and varying degrees hypomyelinogenesis, cerebellar and cerebral dysgenesis, arthrogryposis There is no detectable antibody in persistently infected animals

Answer 30

Ovine pestivirus Diagnosis - clinical signs / pathology - virus isolation - Histopathology foetal nervous system (myelin deficiency) Prevention - maintain a closed herd - no effective vaccine in Australia Control - Identify and remove carrier animals - slaughter this years lamb crop (cull severely affected lambs and fatten lightly affected lambs for slaughter) - buy in ewe replacements - in endemically affected herds expose breeding animals early in life when not pregnant.

Answer 31

Chlamydia abortus - Enzootic abortion of ewes Clinical signs - abortion in the last three weeks of pregnancy - stillborn lambs and weak lambs - zoonosis - can affect up-to 30% of ewes in previously uninfected flocks - respiratory infection (flu like disease) - pregnant woman abortion / still birth

Answer 32

Chlamydia abortus Diagnosis -History, post mortem (necrotic placentitis, thick, leathery intercotyledonary are, foetus appears normal. - identification in stained smears Control - hygiene measures (isolate affected ewes and lambs), ewes usually immune after abortion - vaccines are available overseas - if entry into Australia quarantine with slaughter of infected animals

Answer 33

Chlamydia abortus Epidemiology Major source of infection is infected placenta and uterine discharges of aborting ewes Transmission = ingestion or inhalation (dust or fluid droplets) - introduced to the flock by purchase of infected animals - ewe lambs can acquire latent infection and will abort during their first pregnancy - aborting ewes remain chronically infected but do not abort again - zoonotic

Answer 34

Schmallenberg virus (SBV) New emerging disease in Europe Genus Orthobunyavirus not zoonotic Epidemiology - transmission of infection is by insect vectors (culicoides species) and vertically in utero - incubation period 1-4 days - short viraemic period (1-5 days) - low risk of introduction to Australia

Answer 35

Clinical signs Schmallenberg virus (SBV) Clinical signs Adult sheep and goats - no specific clinical signs Foetal deformities, stillbirths or abortions (lambs, kids) - brain and spinal cord damage and secondary muscles / skeletal abnormalities (arthrogryposis) - spider lambs Diagnosis - serology (Elisa) - Virus identification - PCR Treatment and control - no specific treatment available - no commercial vaccines available

Answer 36

Pregnancy toxaemia Lambing sickness - twin lambing disease - Occurs late in pregnancy when there is a very high energy requirement (foetal development, udder development and colostrum) - these requirements often exceed what is available from feed - so the ewe utilises body reserves - normal to lose condition Pregnancy toxaemia occurs when body tissues utilised very rapidly - metabolic overload - often precipitated by stress which could cause a sudden restriction in food intake for 12-24 hours

Answer 37

Risk factors for pregnancy toxaemia (7) - Very fat ewes (CS>4) interaction of energy requirements, fat mobilisation and appetite - Very thin ewes Prolonged undernutrition / drought preg tox - Twins vrs singles - Older ewes are more susceptible than maidens - More common in British breeds and cross breeds than merinos - Anything that decreases food intake Foot abcess, cold weather, stress, yarding overnight, pink eye, teeth problems etc - Anything that may increase energy requirements

Answer 38

Pregnancy toxaemia (ketosis) Clinical signs (progresses over a period of 2-7days) - dullness, loss of appetite, lags behind the mob - separation from the mob - reduced response to approach - stagger, stumble and fall down Ewe will become recumbent, may stargaze, sink in a coma and die - decreased birth weight and poor lamb growth Flocks with pregnancy toxaemia have a significantly higher than normal mortality in neonatal lambs (mismothering, starvation and exposure deaths) and often a severe decrease in wool quality.

Answer 39

Diagnoses of pregnancy toxaemia - History - Clinical signs - Clinical pathology Hypoglycaemia (may progress to hyperglycaemia) low blood sugar Ketonemie / Ketonurie Glossy pale liver

Answer 40

Treatment is often unrewarding If treating early vigorous treatment is necessary; no prospect of recovery once the ewe is down and unable to get up. Provision of carbohydrate, stimulation of gluconeogenesis and the removal of foetuses - increase energy intake and decrease output If appetite is regained best prognosis - glucose therapy/ fluid - corticosteroids - caesarean section - allow easy access to water - other calcium borogluconate

Answer 41

Management / prevention pregnancy toxaemia Match energy requirements with feed availability - assess quantity and quality of available pasture - autumn possible poor quality feed before autumn break - spring potential of low feed in late winter and cold climate - monitor body weight and condition score - supplementary feeding if required (grain) - pregnancy test and give preferential feeding to ewes carrying twins/ multiples Keep handling and holding of feed in late pregnancy to a minimum

Answer 42

Hypocalcemia There is a high calcium requirement in late pregnancy and early lactation. When calcium requirements are high, sheep will mobilise skeletal calcium reserves to maintain serum calcium level Predisposing factors - mature ewes during late pregnancy - stress factors - sudden reduction in calcium intake (change of feed, yarding) - ewes on lush pasture or oat crops in late winter after a drought - low dietary calcium intake and depeleted bone reserves from grain feeding during the preceding months

Answer 43

Clinical signs hypocalcaemia Sudden onset (10s/100s) - initially ewes become isolated and have a stiff gait with muscle tremors (rarely see this stage) - ewes then become weak and remain recumbent, often sternal recumbency - struggle when handled but unable to get up - if not treated condition is fatal - death may occur within a few hours upto two days after the start of CS

Answer 44

Hypocalcemia Diagnose - History -Clinical signs and a rapid response to treatment - no typical features upon postmortem examination Treatment - Calcium borogluconate - many sheep with hypocalcaemia also have low blood magnesium and low glucose levels - so treat magnesium sulphate and glucose solutions -

Answer 45

Hypocalcaemia Management - avoid stress in late pregnancy or early lactation - keep time in yards to a minimum - add 1.5% limestone as a calcium supplement when feeding grain - avoid access to plants containing high levels of oxalates - always spike grain supps with Ca Nutritional management risk factor - avoid long term exposure to green grass dominant or cereal grain pasture - movement from dry to cereal pastures

Answer 46

Hypomagnesium Grass tetany; occurs when cerebrospinal fluid Mg levels fall below normal Predisposing factors - high magnesium requirement during first few weeks of lactation (high milk producers greatest risk - older prime mothers) - no stores of Mg; Mg requirements must be meet by the diet - a sudden reduction of dietary intake eg yarding - lush grass dominant pastures or rapidly growing fodder crops during late winter Mg is actively absorbed through the rumen wall and can be affected by other factors - acid soils (low in sodium, or high in potassium) may reduce Mg availability

Answer 47

Grass tetany Clinical signs - Often found dead in the paddock - ataxia, muscle tremors, tetanic signs - collapse, convulsions with severe limb paddling, froth at the mouth - death 4-6 hours

Answer 48

Hypomagnesemia Diagnose - history, clinical signs, rapid response to treatment - Blood samples - post mortem examination (low conc of Mg within the fluid of the eye + clostridial diseases) Treatment - ASAP - magnesium and calcium causmag - relapse possible, keep under farmer observation and retreat if necessary

Answer 49

Perinatal lamb loss Average loss across the sheep industry of about 15-20% Risk factors - predation - lamb birth weight (optimal 4-6kg) - litter size - environmental conditions - age of ewe - nutrition of ewe (effect on placenta development, foetal growth and udder growth). Nearly all perinatal lamb losses result of a failure to rapidly establish and maintain an adequate ewe-lamb relationship

Answer 50

Perinatal loses - start estimation of loss numbers - History of management weather, nutrition, trace element supplementation (I, Se), lambing paddock, pre joining examination of ewes, breed and age of sheep. To diagnose carry out lamb post mortem - do as many of these as possible - dead / alive - if born alive why did it subsequently die - provide farmers with labels Must know - weight, sex - external examination (walked, cleaned signs of predation, pressence of meconium staining and check naval). - open lamb placed on its right side ( brown adipose tissue present around kidney and heart, milk in stomach?, lung aeration, hepatic rupture any abnormalities present).

Answer 51

Primary exposure - extreme weather event - normal viable lambs; breath, metabolised BAT, walked no significant CNS lesions - yellow subcutaneous oedema of extremeties (indicating hypothermia).

Answer 52

Dystocia Often high birth weight singletons - breed effect texels External examination - meconium stains on birth coat - subcutaneous oedema head and distal limbs Abdominal cavity - abdominal bleeding from liver trauma Thoracic cavity - petechia and ecchymoses of the pleura, thymus and heart Brain and spinal cord lesions - haemorrhage, congestion in and around the spinal meninges, presence of subdural clots

Answer 53

The trace minerals Selenium deficiency (weaner ill thrift) - white muscle disease in lambs - heart / skeletal muscle lesions Copper deficiency (weaner ill thrift) - sway back - enzootic ataxia - hypomyelinogenesis of the CNS Iodine deficiency - Goitre - subclinical iodine deficiency

Answer 54

Iodine deficiency Iodine is essential for thyroid hormone production The developing foetus has no stores of iodine; foetus synthesises its own thyroid hormones from maternal iodine - necessary CNS development - foetal growth - thermoregulation after birth Predisposing factors - Goitogens deficient in iodine; Brassica, canola ,turnips and white clover - high rainfall areas of the great dividing range and Tas are iodine deficient

Answer 55

Iodine deficiency clinical signs Subclinical iodine deficiency - decreased metabolic rate - impaired brain development, reduced lung development - impaired suckling behaviour - weak lambs very susceptible to cold stress Iodine deficiency - small woolless lambs which are weak and susceptible to cold stress - high incidence still births - Goitre - enlarged thyroid - may cause dystocia - goats are more susceptible than sheep

Answer 56

Iodine deficiency Diagnose - compare thyroid weight - histopathology of thyroid - ewe serum iodine concentration Treatment - Lugols iodine to lambs - shelter for lambs (protect cold stress) - potassium iodide drench - iodised salt blocks - prevent pregnant ewes grazing crops containing goitrogens

Answer 57

Preventing neonatal lamb mortality - ewe BCS and nutrition - scan (identify twin pregnancy provide better nutrition) - select appropriate lambing paddocks - predator control - avoid disturbing lambs - identify and kill poor mothers, or ewes with mastitis - adjust time of lambing (influence of available feed and weather conditions) - supplementing ewes with melatonin for lambs which experienced a compromised gestation (increase BAT)

Answer 58

BSE Identify those rams that are unsound for breeding (joining 1% of rams) - usually carried out prior to joining - generally check rams 10-12 weeks prior to the start of mating - pre sale post purchase - in response to a reproductive problem

Answer 59

Breeding soundness examination History - breed, age, ID 5T TEST = toes, torso, teeth, testicle and tossle Genitalia examination - palpation scrotal skin wool cover, lesions - palpation of scrotal contents (testis, epididymis) - size, tone and lesions - scrotal circumference (32cm 400ml) - semen quality and quantity is closely correlated with scrotal circumference - prepuce and penis - semen collection and evaluation

Answer 60

Genital unsoundness in rams - shearing damage inability to fully extrude penis (congenital defect, adhesions) - hypospadias (birth defect urethra not located tip of penis). - obstruction of urethra calculi (high feed concentrates - pizzle rot (balano-posthitis) - knob rot (balanitis) - testes degeneration, testicular atrophy - other diseases

Answer 61

Corynebacterium renale Primarily a disease of wethers, grazing lush, clover dominant pastures (protein rich) Pizzle rot may develop when bacteria are present + high concentration of urea in urine (protein rich diet) bacteria produce ammonia - cytotoxic - damages pizzle membranes and external skin

Answer 62

Pizzle rot necrotic ulcer on skin near the preputial opening; lesion often covered by scabs - prepuce is typically swollen and oedematous - ammoniac smell - risk of secondary myiasis - urolithiasis (kidney stone block)

Answer 63

Pizzle rot Rams do not usually develop severe internal lesions, most lesions are confined to the external prepuce - isolate the infected animals - acidify urine (restrict diet) ammonium chloride in water - flushing pizzle with a mild antisepticum -slitting of the pizzle in severe cases to allow drainage of urine and pus

Answer 64

Prevention of pizzle rot - ringing (castrate) - restrict diet at certain times of the year - testosterone injections (one treatment risk period spring) Do not treat rams when close to joining

Answer 65

Cause unknown - Trueperella pyogenes CS usually first observed during joining - paraphimosis (prolonged retracted foreskin) - necrosis and ulceration of penis - extensive blood clots in the prepuce - often concurrent vulvitis or vulvo vaginitis in ewe flock

Answer 66

Knob rot treatment - remove rams from ewes - antibiotic treatment - antiseptic lavage of penis and prepuce Some animals do not recover = euthanise

Answer 67

Testicular degeneration Increased testicular temperature - hot weather, any scrotal thickening, fever, septicaemia, over fatness, excessive wool over scrotum Carry out a physical examination and semen examination Treatment = shear ram, provide cool conditions (shade /airflow) recovery may take months

Answer 68

Brucellosis ovis (rams) - history - extending lambing period (8 weeks) - rams continue to work through joining period - if joining period is short increase in the number of dry ewes - More than 5% of rams with scrotal abnormalities Clinical signs Rams - soft swelling in the tail of the epididymis - may develop into abscess - epididymis is enlarged and hard - rams show no sign of sickness - semen varies from normal to aspermia (lack of) Can be present in a flock for many years without being detected

Answer 69

Brucellosis Pathogenesis The bacteria enter the body through any mucous membrane (preputial, penile, rectal, vaginal, nasal mucosal) - local - lymph node - bacteraemia - epididymis (usually unilaterally in the tail) and accessory sex glands. Transmission Venereal disease from infected semen - ewes vagina (infection not carried very long) - homosexual activity (most important) - intranasal infection can also occur when infected ewes have recently lambed and are excreting organisms in the vaginal discharges

Answer 70

Diagnose Brucellosis ovis - testicular palpation - prevalence >5% is suggestive for brucellosis - blood test serology - complement fixation test CFT - ELISA - gel diffusion test (GDT) - culture of semen / not routine / excretion is intermittent - microscopic examination of semen Ziel-Neelson stain - bacteriology PCR of genital tract Often use a combination of tests to confirm brucellosis in rams

Answer 71

Answer = B

Answer 72

Actinobacillus seminis / Histophilus somni Cause Gram negative bacterium - occurs most commonly in young rams 6-15 months - epidemiology and spread remains unclea Many rams carry A.seminis/ H.somni without showing lesions (lower urethra or prepucial area); only a small number proportion of rams develops lesions epididymitis.

Answer 73

Actinobacillus seminis / Histophilus somni Clinical signs - may have systemic symptoms in association with acute and severe epididymitis (isolate from flock, difficulty walking, may become recumbent). - abscess epididymis - atrophy testicle - if located in accessory sex glands: no obvious CS but semen quality will be affected - no signs of sickness in ewes Diagnose = CS, serology, culture, PCR Treatment = nil Prevention = environmental hygiene and examination of rams prior to joining

Small ruminants medicine and production Flashcards

(109 cards)