Bovine Subfertility and Infertility (Part 1) PDF

Spring 2025 DVM 724 - Theriogenology Bovine Subfertility and Infertility (Part 1) Mohammad A Ibrahim...

Spring 2025 DVM 724 - Theriogenology Bovine Subfertility and Infertility (Part 1) Mohammad A Ibrahim BVSc, MS, PhD, Dipl. ACT [email protected]  Objectives 1) Differentiate between embryonic death and abortion. 2) List common infectious and non-infectious causes of bovine abortion. 3) Apply diagnostic guidelines to analyze a suspected case of infectious abortion. 4) Identify patterns in abortion rates based on specific pathogens. 5) Develop a diagnostic decision tree for bovine abortion cases. Long Island University – College of Veterinary Medicine  Outline Pregnancy wastage terms. General abortion diagnosis guidelines Infectious causes of abortion Non-infectious causes of abortion Long Island University – College of Veterinary Medicine  Introduction Embryo vs Fetus Average fertilization rate ~80% Overall pregnancy rate 35-40% Conception Parturition Fetal Stage Embryonic Stage till day ~42 Long Island University – College of Veterinary Medicine  Pregnancy Wastage Embryonic Death: Loss of the conceptus before organogenesis (day 42 in cattle). Often go unnoticed à resorbed/aborted Embryonic death is a significant component of pregnancy wastage Abortion: Pregnancy loss after organogenesis, when the conceptus is considered a fetus. Loss of an annual production cycle for the cow and often results in culling Mid-gestation to term abortions result in economic losses of $600-1000 per case. An acceptable abortion rate: Beef cattle: 1-2% (up to 3-5% is concerning). Dairy herds: As high as 10% reported. Stillbirth: Pregnancy loss occurring late in gestation of a mature calve (after day 260), just before or during parturition, or within 48 h of birth. Long Island University – College of Veterinary Medicine  Abortion Diagnosis Challenges Discovering the cause of abortion in cattle can be one of the most frustrating problems 50% of cases submitted to a diagnostic laboratory are accurately diagnosed Causes: 50% infectious, 50% noninfectious Educate Producers/Clients What to do on abortions cases Sample Collection and preservation (1 in formalin and 1 chilled) Possible zoonosis Accurate herd records keeping Manage expectations Long Island University – College of Veterinary Medicine  Abortion Diagnosis Guidelines Pathognomonic gross lesions is uncommonà if any, may be masked by tissue autolysis. The placenta is a better diagnostic sample than the fetus. If fresh: the cotyledons will be bright red and the intercotyledonary (IC) areas translucent. Opacity to the IC spaces can also indicates edema, fibrosis, and inflammation. Exudate on the chorioallantoic surface is also indicative of inflammation. Fibrin can be present as yellow, friable material on the cotyledons. As autolysis occurs à cotyledons become a pale brown, IC areas à less translucent. Maternal blood provides limited information, especially if it is a single sample taken the day of the abortion. A titer response to an organism à only indicates exposure and might not distinguish natural exposure or vaccination. Good in unvaccinated animals. Better submit 2 samples, 3 weeks apart. Also, from uninfected animals in the herd for comparison. Long Island University – College of Veterinary Medicine  Abortion Diagnosis Guidelines The fetus Inspection of whole fetus à determine gestational age and condition of tissues. If the entire fetus cannot be submitted à formalin fixed and fresh chilled samples: Formalin Fixed Lung, Liver, Kidney, Spleen, Heart, Brain, Skeletal muscle, Thymus, Eyelid, Abnormal tissue Fresh Chilled Lung, Liver, Kidney, Spleen, Heart, Brain Abomasal contents, Thoracic fluid, Ocular fluid Fetal IgG concentration Fetal blood or thoracic fluid If elevated (>20mg/dL) à an active fetal immune response to an infectious organism. Long Island University – College of Veterinary Medicine  Abortion Pathogenesis The placenta is infected by either hematogenous or venereal routes. Placental inflammation/infection à stress on the fetus with potential spread of the organism to the fetus. The result depends on the stage of gestation, when placental and/or fetal infection took place: In the first trimester fetal death, resorption, mummification, maceration, or abortion. During the second trimester, fetal death, abortion, or mummification. During the third trimester fetal death, abortion, maceration, mummification, emphysema, stillbirth, or birth of weak nonviable calves. The dam might develop endometritis, metritis, or retained placenta Long Island University – College of Veterinary Medicine  Infectious causes of Abortion Bacterial Brucellosis, Campylobacteriosis, Leptospirosis, Listeriosis, foothill abortion, Chlamydiosis, Ureaplasma, Salmonella Opportunistic flora: T. pyogenes, Staph, Strept, E. coli, M. haemolytica, P. multocida, Mycoplasma, Histophilus Viral BVDV, IBR, Bluetongue Protozoal Trichomoniasis, Neosporosis, Toxoplasmosis Fungal Aspergillus, Mucor. Long Island University – College of Veterinary Medicine  Brucellosis Caused by Brucella abortus A zoonotic, reportable bacterial disease in cattle. Limited to wildlife (Bison & Elk) in the Greater Yellowstone Area (northwestern Wyoming, southwestern Montana, and eastern Idaho) In bulls à Orchitis, epididymitis, infection of accessory glands Infection of mature animals tends to persist indefinitely. The organism has an affinity for the erythritol present in placental trophoblast. Long Island University – College of Veterinary Medicine  Brucellosis Abortion Abortion Abortion d Rate Time Recurrence Transmission Lesions Diagnostics Up to 80% in 6–9 Rare Contact with Placentitis Gold standard: unvaccinated months (less than 20%) aborted Leathery placenta (Moroccan Isolation/ culture from herd (2nd half of tissues/fluids, leather), necrotic cotyledons, red- placenta or fetus lung, pregnancy) milk, or in utero yellow color, thickened spleen, abomasal contents. intercotyledonary areas. Serology Metritis & Retained placenta. Card agglutination test Dead fetus usually autolyzed due to expelled 1-4 days after death. Weak fetus pneumonia with cobblestone lung texture. jpc.org Long Island University – College of Veterinary Medicine  Brucellosis Control: No approved treatment. Positive animals à slaughter/Cull Vaccination: Strain RB-51 (doesn’t react with A in the serological test). Female calves between 4 and 12 months of age. Control of animal movement Avoid contact with wildlife Long Island University – College of Veterinary Medicine  Campylobacteriosis Campylobacter fetus subsp. fetus / jejuni GIT inhabitants. Not transmitted venereally. Sporadic abortions à Second and third trimester Campylobacter fetus subspecies venerealis García, et al. 2023 It is an obligate pathogen of the bovine reproductive tract (venereal disease). The organism is deposited in the vagina after coitus with an infected bull and ascends to the uterus/oviduct within 12-14 days. Bull are asymptomatic carriers Young bulls (< 3 yrs) à clear the infection within few weeks. Mature bulls (> 4 yrs) à chronic carriers (lives in folds of prepuce) Chiapparrone, et al. 2016 Long Island University – College of Veterinary Medicine  Campylobacteriosis Abortion Abortion Abortion Transmission Lesions Diagnostics Rate Time Recurrence EED EED Rare Venereal, via Placentitis Dark field microscopy coitus Leathery placenta like Brucella. Phase-Contrast microscopy Abortions are Abortions Placenta is typically expelled. Corkscrew-like motion sporadic 50% Usually if continues to Placenta impression smears last Ingestion of be feed RFM & Diffuse IC placentitis PCR environment trimester contaminated contaminated White/yellowish necrotic foci in IHC Vs silage silage cotyledons Feed Winter Fetus Expelled after days i.e. autolyzed Small liver with white necrotic foci like IBR Control Listeriosis vaccination is not commercially available for cattle Proper curing of silage During out break Tx: Penicillin or Oxytetracycline (OXT Contraindicated in lactating dairy cattle) Long Island University – College of Veterinary Medicine  Epizootic bovine abortion (Foothill Abortion) EBA results in the loss of an estimated 45k – 90k calves/year à >$10 million losses annually. Leading cause of abortion in beef cattle in California, Nevada, southern Oregon, and recently in Arizona (in foothill and mountain pastures). Caused by the Pajaroellobacter abortibovis, transmitted by soft-bodied Ornithodoros coriaceus tick. Clinical Signs: Late-term abortions (6–9 months of gestation). Recurrence is rare Birth of live but weak, unthrifty calves. Aborted fetuses à Specific lesions in thymus and lymph nodes Diagnosis: PCR, immunohistochemistry, serology Sublingual hemorrhages Control: Avoid grazing in tick-infested areas up to 60 days before breeding Vaccine: available since 2020 à Hygieia Biological Laoratories Long Island University – College of Veterinary Medicine  Chlamydiosis Chlamydophila abortus (intracellular gram-negative bacteria). In cattle à sporadic abortion, in ewe à enzootic abortion abortion, polyarthritis, encephalomyelitis, keratoconjunctivitis, pneumonia, enteritis, hepatitis, vaginitis, and infertility No Vaccination in cattle (only for ewe) Zoonotic Abortion Abortion Abortion Transmission Lesions Diagnostics Rate Time Recurrence Isolation of organism (gold Placenta: standard) Last Necrotizing placentitis, thickened Sporadic, Serial titers trimester yellow-brown exudate. Sporadic Rare ingestion or Histological examination of (6–8 Fetus: venereal cotyledons months) Fetal edema, ascites, pleuritis, Acid-fast staining, IHC, FAT, peritonitis, pneumonia, hepatitis PCR Long Island University – College of Veterinary Medicine  Other bacterial agents Opportunistic organisms à overgrown the uterus à sporadic abortion. Examples: Ureaplasma diversum, Trueperella pyogenes, Bacillus sp, Mycoplasma spp, Histophilus somni, and E. coli Ureaplasma diversum EED or Sporadic late term abortion. Aborted fetus à interstitial pneumonia Stillborn or Weak calves with neonatal pneumonia Placenta à retained, white opaque amniotic fibrosis, nonsuppurative placentitis T. pyogenes Sporadic abortions at ANY TIME, but also common in second half of gestation. Aborted fetus à small white foci in the lungs Bacillus sp. Sporadic abortion in the last trimester Aborted fetus à pericarditis. Long Island University – College of Veterinary Medicine  Bovine viral diarrhea (BVD) BVDV is a pestivirus, single-stranded RNA virus Genotypes: 1 & 2 (BVDV-1 and BVDV-2) Biotypes: Cytopathic and Noncytopathic BVDV A major infectious agent that affects cattle production worldwide. 70% to 90% are subclinical BVDV is the most commonly diagnosed virus in bovine abortion cases. Infection will have a different outcome depending on the stage of gestation at time of infection: During the first 40 days Day 40 and 125 Day 100–150 After Day 125 EED and infertility If infected by non Congenital malformations Abortion cytogenic form: § cerebellar hypoplasia, hydrancephaly, fetal immune Persistently infected hydrocephalus, microencephaly, and spinal response may calves if the fetus cord hypoplasia. clear the virus survives § Microphthalmia, retinal dysplasia, cataracts § Brachygnathism Long Island University – College of Veterinary Medicine  BVD immunosuppression Immune suppression à a hallmark sign BVDV Immunosuppression & Synergism BVD à BRSV, PI3, IBR Coinfection BVD à Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Mycoplasma bovis Coinfection Coinfection of >2 pathogens = Enhanced Pathogenesis Impaired response to Tx. Long Island University – College of Veterinary Medicine  Bovine viral diarrhea (BVD) Abortion Abortion Abortion Transmission Lesions Diagnostics Rate Time Recurrence Placenta: retained. Fetus EED Autolyzed, Mummified, Stillbirth, & Transplacental Congenital malformations: PCR, IHC, antigen capture Low Rare 4 months during viremia hydrocephalus, cerebellar hypoplasia, ELISA, fluorescent antibody to term microphthalmia, retinal dysplasia, test, virus isolation. cataracts, brachygnathism Control: Identification and Elimination of PI animals à ear notch sample (