1. Infectious Causes Impacting Reproduction

3. Fetal Mummification
Fetus dies, uterus contracts, and fluid is resorbed  fetus becomes dry/firm
Thickened uterus
CL present on ovary
No palpable cotyledons
No membrane slip
No fremitus in uterine artery
Palpable mass in uterus

4. Fetal Mummification
Most common at 4-6 months of gestation, but may go beyond gestation length
Genetic (uncommon) – Jerseys, Guernseys, certain Holstein families
Torsion of umbilical cord
Infectious diseases that cause minimal inflammation:
Campylobacter fetus
BVDV
Tx:
PGF2a IM to lyse CL and expel fetus in 2-3 days
+/- 2nd dose in 96 hrs if needed
Manually remove with lube
C-section

5. Fetal Maceration
Fetal death with partial cervical dilation  uterine contamination  bacterial growth (great medium!)
Any age of gestation
CS: abdominal straining, foul fetid vulvar discharge, fever, anorexia, milk production +/- diarrhea
Rectal: distended swollen uterus, gas crepetation in fetus
Prognosis for future reproduction POOR - treatment not always successful, endometrial damage extensive
Tx:
Cervix dilated: fetus removed manually with LUBE and SLOW manipulation. Re-examine for 2nd fetus!
Cervix closed: PGF2a +/- oxytocin (less successful than with mummies; may not be functional CL)

6. Abortion Severe maternal illness: Placentitis: Fetal origin:
Infectious diseases: high fever, inflammation (mastitis, pneumonia, virus…)
Toxins: plants and chemicals (nitrates, moldy sweet clovers, fescue molds, lupines, gossypol in cottonseeds, and industrial pollutants…)
Hypoxia (anemia, pneumonia…)
Endotoxemia
Placentitis:
Hematogenous
Ascending via cervix
Fetal origin:
Fetal stress → death

7. Abortion
Mechanism:
P4 and PGF2a  luteolysis + expulsion of fetus

8. Abortion
Due to the degree of autolysis and edema of fetuses in utero after death but before expulsion, gross placental/fetal lesions are not usually diagnostically significant.

9. Abortion What tissues samples shall I send off ? FRESH, keep cool
Fetal membranes/aborted fetus – BEST!
Fetal lung, liver, intestines, brain, kidneys…
Maternal serum, urine, vaginal discharge…
FRESH, keep cool
Better too many than too few samples…

10. Abortion Protozoal Bacterial Trichomonas Brucella spp Neospora
Infectious Causes:
Bacterial
Brucella spp
Listeriosis
Leptospirosis
Arcanobacterium pyogenes
Vibriosis
*Especially if abortion storm!
Protozoal
Trichomonas
Neospora
Viral
IBR
BVD
Mycotic

11. Brucellosis “Contagious abortion”, “Bangs disease” Brucella abortus
ZOONOTIC – Undulent fever in humans (via milk)
Eradication program  ~rare in US herds, but still in free-ranging bison/elk
Highly infectious – spread via aborted fetus, placenta, vaginal discharge, milk, or semen from infected bull
Lesions – chorionic placentitis,
Moroccan leather appearance,
focal necrosis of cotyledons,
thickened intercotyledonary
areas with yellow exudate

12. Brucellosis Abortion usually between 5th-8th month of gestation
Also frequently causes retained placenta, weak calves and infertility
Dx: serology/culture of fetal abomasal fluid, lung, and liver, placenta, uterine fluid, milk, serum, seminal plasma
Prevention/Control: Official calfhood vaccination
RB-51 vaccine (“bangs” vaccine) + Official USDA Brucellosis eartag + official ear tattoo
Calves 4-10 months of age
By state and federal brucellosis program personnel and USDA accredited veterinarians

13. Listeriosis “Circling Disease” Listeria Monocytogenes ZOONOTIC
Widespread in environment; transmission via ingestion of poorly fermented silage
Fever, weight loss, endometritis, encephalitis
Lesions: suppurative placentitis,
small white foci on fetal liver
and cotyledons, fibrin in fetal body cavity

14. Listeriosis Abortion usually during 3rd trimester
Sporadic or abortion storm
Retained fetal membranes
Control: stop feeding spoiled material, isolate aborting cows
Broad Spectrum Antibiotics  milk withdrawal due to milk residues!
NO vaccine in US

15. Leptospirosis Leptospira interrogans serovars hardjo & pomona
Transmission via infected urine, placental fluids, milk, or contaminated environment/water source
Abortion from 4 months to term
+/- yellow MM, blood tinged urine and milk
Weak calves or infertility is also common
Dx: Culture - organisms in fetal kidney
Tx: Vaccinate annually

16. Arcanobacterium pyogenes
Abortion at any stage of pregnancy
Normal inhabitant in nasopharynx of many cows, also in abscesses, NOT in fetuses or fetal membranes = always significant!
Bloodstream  endometritis & placentitis (diffuse with a reddish brown to brown color)
Fetus: autolyzed, with fibrinous pericarditis, pleuritis, or peritonitis possible, as well as bronchopneumonia
Dx: culture from placenta or abomasal contents
NO effective bacterin available

17. Arcanobacterium pyogenes
*Important cause of pyometra post-calving in DAIRY cows!
Diagnosed at pre-breeding check (~ 40 d post calving)
Occurs when cow ovulates in face of A. pyogenes in uterus  pyometra
Usually uterine contaminates are expelled from uterus during normal involution process
Pre-disposing factors: dystocia, RFM, metritis

18. Vibriosis Campylobacter fetus subsp venerealis
Bulls are asymptomatic carriers, permanent carries when > 4 yrs
Venereal transmission  organism attacks conceptus  early embryonic death (occasional abortions ~ 4-7 months of gestation)
Cows develop immunity and conceive, and maintain the disease in the herd (carriers)
Dx: Blood agar culture of preputial smegma, fetal abomasal contents, vaginal/cervical mucous
Tx: ID and cull carriers, topical antibiotic ointment
Control/Prevention: AI, prevent re-infection, blood culture all non-virgin bulls 6-8 weeks before breeding season, VACCINATE cows and bulls

19. Trichomoniasis Trichomonas foetus
Bulls are asymptomatic permanent carriers
Venereal transmission  organism attacks conceptus
Cows develop immunity and conceive (carriers)
*Important cause of pyometra post-breeding in BEEF cows
CS: infertility, pyometra, abortion
Dx: microscopic isolation of organism (preputial smegma or vaginal/cervical mucous) with Diamond’s medium (Klaas modification)
Control/Prevention: AI, use of virgin bulls
NO vaccine available

20. Neospora Neospora caninum
Cycles between canids and ruminants – oral or vertical transmission
Mid-gestation abortion (~4-6 months), pre-mature calf, birth of impaired calf, or normal calf
Brain hemorrhage, myocarditis

21. Oocysts ingested while grazing
 Sporozoites released, enter SI  reticulo-endothelial system
Tachyzoites = invade different tissues, placenta  fetus in pregnant animals
Bradyzoites = dormant, within tissue cysts (found mainly in neural tissue)
In future pregnancies, bradyzoites  tachyzoites  invade the fetus via the placenta

22. Infectious Bovine Rhinotracheitis (IBR)
Acute, contagious Bovine Herpes Virus
Infertility, respiratory infections, conjunctivitis, abortion storm usually > 5 months gestation
RFM, placental edema/vasculitis
Fetus: red serous body fluid, white foci on liver/lungs
Tx: Vaccinate annually
“red nose”

23. Infectious Pustular Vulvovaginitis
Also a Bovine Herpes Virus
Venereal/mechanical spread
Genital pustules (balanoposthitis)
Spontaneous recovery

24. Bovine Viral Diarrhea Virus (BVD)
Affects the digestive, respiratory, immune, nervous and reproductive systems
BVD Type I and Type II, each with:
Cytopathic (CPE) strains  cellular vacuolation and cell death
Non-cytopathic (non-CPE) strains  no visible cytopathic change in cell cultures

25. Bovine Viral Diarrhea Virus (BVD)
BVD infection in-utero:
Slows fetal growth  lower birth weight, bone growth
Abortion (at any trimester)
Early embryonic death
Stillbirth
Congenital Birth Defects (eye, thymus, brain)
Arthrogryposis
PI Calves (immunotolerant and persistently infected shedders)
Normal calf born with antibodies to the BVD virus
cerebellar hypoplasia

26. Bovine Viral Diarrhea Virus (BVD)
Results of fetal infection with BVDV
Outcome
Gestational age at time of in utero infection.
days
> 180 days
Normal, antibody negative calf X
Abortion
Early embryonic death, resorption
Mummification
Stillbirth
Congenital defects, antibody negative
Congenital defects, antibody positive
Persistently infected, "normal" calf
+/-
Normal, antibody positive calf

27. Bovine Viral Diarrhea Virus (BVD)
Mucusal disease:
PI calf (infected in-utero from d of gestation with non-CPE strain, seem normal, but have no immunity to the virus)
+ encounters CPE strain after birth (vulnerable to severe effects of the CPE cell-killing strain)
~6 months – 2 yrs old
High mortality

28. Bovine Viral Diarrhea Virus (BVD)
BVD infection after birth:
Usually 6 months to 2 yrs of age
CS: vary depending on the virulence of the strain
Viremic  develop antibodies  clear virus within 7-10 days
Subclinical (estimated 70-90% of BVDV infections)
Mild elevation in body temp, drop in milk production
Clinical = Acute BVD
Depression, fever, inappetence, nasal discharge, transient leukopenia, thrombocytopenia, petechial hemorrhages, diarrhea, high morbidity, low mortality
Eliminate Carriers = CULL!
VACCINATE before breeding

29. Mycotic Abortion Aspergillus, Absidia, Mucor, Rhizopus, Candida
More in WINTER when cattle housed/fed inside
Injury to respiratory/GIT  hematogenous  uterus  severe necrotic placentitis
Thick, leathery cotyledons + intercotyledonary placenta
Abortions in 3rd trimester
Head and neck lesions on fetus

30. “Given the low diagnostic success rate, the high cost of laboratory work, and the low profit margin in both the beef and dairy industries, veterinarians should not attempt to make an etiologic diagnosis in every abortion. Instead, veterinarians should become concerned if fetal loss is >3-5% per year or per month.”
~ The Merck Veterinary Manual