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28 Cards in this Set
- Front
- Back
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What is the differnce between early embryonic mortality, foetal death, abortion and premature births
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• Early embryonic mortality:
– <19 days – Embryonic mortality before maternal recognition of pregnancy (MRP) • Foetal death: Death >42 days • Abortion: Expulsion of a dead foetus (>45 to <260 days) • Premature births: Foetus delivered b/wDay 260 - full term |
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Name some causes of bacterial abortion in cattle
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• Brucella abortus
• Leptospira interrogans • Listeria monocytogenes • Campylobacter fetus subsp venerealis/Trichomonas foetus • Escherichia coli • Ureaplasma diversum • Mycoplasma • Hemophilus somnus • Arcanobacterium pyogenes • Salmonella spp • Mannheimia haemolytica • Bacillus spp. • Chlamydia psittaci • Pseudomonas spp. • Streptococcus spp. |
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Name some causes of viral abortion in cattle
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• Bovine viral diarrhoea virus
• Bovine herpresvirus-1 (infectious bovine rhinotracheitis virus) • Bluetounge virus • Akabane virus • Others: FMD, Rinderpes |
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Name some causes of mycotic abortion in cattle
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• Aspergillus
• Mortierella • Mucor • Rhizopus • Candida • Absidia |
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Name some causes of protozoal abortion in cattle
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• Neospora caninum (most common in cattle)
• Sarcocystis • Toxoplasmosis (may have been misdiagnosed and most cases are due to Neospora) • Theileria sp |
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What are the 2 mechanisms of abortion?
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• Disruption of normal endocrinology of pregnancy
• Foetal death or stress |
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What factors could induce an abortion in cattle?
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• Severe maternal illness
- High fever - Hypoxia - Endotoxaemia • Placentitis - Release of PGF2alpha - Foetal death - Foetal stress - premature delivery |
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What are some clinical manifestations of placntal and foetal infections in the first trimester?
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Regular or irregular return to oestrus
Apparent infertility, abortion |
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What are some clinical manifestations of placntal and foetal infections in the second trimester?
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Abortion, mummification, prolonged gestation,
retained placenta, prolonged inter-oestrus interval |
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What are some clinical manifestations of placntal and foetal infections in the third trimester?
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Abortion, mummification, stillbirth, weak neonate, emphysematous or autolyzed, may present as dystocia, retained placenta. Foetus will be serological positive (as it is able to amount an immune response)
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How would you approach the history in an abortion investigation?
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• History
- Define the problem: serverity & extent - orient the problem: who is affected, where & when - produce a timeline - age of animals & stage of gestation - method of breeding - animal movements: to/between herds - vaccination, toxins exposure, enironmental factors, disease problems - analyse the data |
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What specimens are important for the investigation of an abortion?
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Aborted foetuses: whole if possible
otherwise: HISTOPATH: placenta, liver, lung, spleen, cotyledons, brain, myocardium, skeletal muscle, and kidney in buffered formalin. SEROLOGY/CLIN. PATH.: Clear serous body fluid (pericardial, thoracic or peritoneal) or heart blood submitted chilled in separate sterile containers. Use a separate syringe and needle and transfer to a sterile tube eg plain vacutainer CULTURE: Fresh stomach contents, placenta, foetal spleen, lung, liver Cows Caruncles & uterine fluid from freshly aborted cows |
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Which animals would you use for serology samples in case of an abortion investigation?
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• From aborted animals and 10 animals or 10% of non-aborted pregnant animals
• Paired sera – acute and convalescent (10 to 21 days after acute sample) |
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What ongoing management would you implement in an abortion investigation?
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• Isolate pregnant animals –
from aborting animals, clean area separated from other pregnant animal groups • Isolate aborting animals – leave in affected area • Eliminate source of infection • Collect aborted foetuses and membranes • Bury/burn remaining specimens • Disinfect premises • Vaccinate or treat susceptible animals when appropriate/cost effective • Modify in the light of any positive diagnosis |
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Which opportunistic bacteria can be associated with abortions?
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• Examples include: Arcanobacterium pyogenes,
Bacillus spp., Escherichia coli, Histophilus somni, Ureaplasma diversum, Pasteurella spp., Pseudomonas spp., Serratia marcescens, Staphylococcus spp., Streptococcus spp., Salmonella spp. • Most common in 2nd half of gestation • Dam usually asymptomatic but retained placenta may occur |
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How does Brucella abortus infect cattle, what CS & pathology are associted with the infection and how would you diagnose the disease?
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Route of infection: ingestion, AI or venereal transfer, contaminated milking machines
Clinical signs: Cows: Abortion - 2nd half of gestation (>5 months). Abortion rate may be high 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: SAT, CFT |
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What vaccines are available to control Bovine Brucellosis?
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– Strain 19
• Live vaccine • persistent titers • causes clinical brucellosis in people • Heifers vaccinated at 3-6 months – RB-51 • Live vaccine • No persistent titres • Heifers vaccinated at 4 -12mths |
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How could yo reduce the spread of Bovine Brucellosis?
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– Control cattle movement
– Regular testing of cattle to identify carriers – Brucella ring test (bulk milk sample) – Repeated Blood sampling – Slaughter of reactor cows – Quarantine of infected herds |
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Compare and contrast how Trichomonas foetus and
Campylobacter fetus, subsp. venerealis can reduce reproductive performance in herds |
• Similar epidemiology
• Males asymptomatic carriers • Females: Immune following infection but not permanent (< 15 mths). • Transmission: Venereal, contaminated semen, AI equipment • Abortion: T. foetus (early <5mths) C. foetus (late 4-7 mths) • Post coital pyometra (T. foetus) • Increased calving to conception intervals • Long interoestrus intervals, greater variability in calf age • Greater number of cows not pregnant than expected at herd pregnancy test |
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• How would you diagnose the presence Trichomonas foetus and
Campylobacter fetus, subsp. venerealis as a cause of reproductive waistage within a herd? |
• History
• Isolation of the organism: Prepucial wash (both agents) • PCR • Vaginal mucus: T. foetus: wet prep/culture C. foetus: culture(early in infection), Ab (ELISA or VMAT) • Aborted foetal samples • Virgin heifer test mating • IFT (C. foetus) |
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How would you control an outbreak of Trichomonas foetus and
Campylobacter fetus, subsp. venerealis within a herd? |
Immunity develops in infected cows within 3 to 6 months, immunity may be transient
Older bulls become permanently infected • Cull infected bulls, retain younger culture negative bulls • Vaccination – C. fetus – eliminates and prevents disease (bulls; cows) – T. foetus - Variable responses, generally unreliable • Segregation of breeding herd by reproductive status: Not pregnant, < 5 mths, > 5 mths |
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Which infectious agents could be associated with an outbreak of vulvovaginitis in cows?
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Bovine Herpes-1 (Infectious Bovine Rhinotracheitis virus)
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• Which infectious agents might cause neurological lesions in aborted foetuses or neonatal calves?
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Bovine Herpes-1 (Infectious Bovine Rhinotracheitis virus)
Bluetounge Virus Akabane virus Neospora caninum |
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• Which fungal cause of abortion can also be associated with pneumonia in aborting cows? What is the likely outcome of this infection in cows that develop pneumonia?
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M. wolfii
invariable fatal |
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• What management options are available for controlling BVDV within a herd? What factors might influence which management options are implemented?
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.options that are available for controlling BVDV
– Vaccination – Partial vaccination – Autovaccination – Removal of PI animals – Biosecurity measures how may animals in the herd are affected risk of exposure to BVDV during the next mating period |
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Under what circumstances might you suspect that Listeria monocytogenes was causing abortion within a herd?
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• Can be associated with consumption of poorly fermented silage!
• Sporadic, with occasional abortion storms • Aborting cows may be asymptomatic or show signs of illness, fever, due to metritis • Abortions – usually in 3rd trimester, retained placenta often occurs, foetus often autolysed |
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What clinical signs would you expect in abortions due to Neospora caninum?
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• Abortion throughout gestation but most often during 2nd trimester
• Dams – asymptomatic, can abort again in subsequent pregnancies • Clinical signs are not apparent in calves >2 months of age • Apart from signs of difficulty rising, undernourishment and early neonatal loss, general signs associated with the neurological system can include proprioceptive defects, ataxia. • Abnormal appearance of the eyes - exopthalmus and assymetry. • Birth defects (hydrocephalus, narrowing of spinal cord) have been observed |
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What are some clinical findings associated with mycotic abortions?
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• Late abortion (6 to 8 months)
• Placentitis with necrosis of maternal cotyledons and leathery thickening of the intercotyledonary space • Skin lesions on foetus sometimes occur • Pneumonia also observed in some cases of M. wolfii which is invariably fatal. |
