Pregnancy Loss in Beef Cattle Guide B-228 John C. Wenzel and Timothy J. Hanosh1 Cooperative Extension Service • College of Agricultural, Consumer and Environmental Sciences This publication is scheduled to be updated and reissued 6/16. Abortion and loss of pregnancy in beef cattle can movement of cattle; origin of new cattle and occur for a variety of reasons. Many times the rea- bulls brought into the herd; results of semen son for the loss is complex and difficult to diagnose. evaluations; and diagnostic test results on bulls. This guide will briefly outline and discuss some of the more common diseases and causes of loss of 5. Keep a reproductive history on your cow herd, pregnancy. If a loss of pregnancy is suspected, con- including conception rate, calving rate, weaning tact your local veterinarian for assistance and advice rate, and dates when bulls are exposed to cows. for diagnosis and control of the causative agent in the pregnancy loss. The following are some helpful steps to take when an abortion is identified. Bovine virus DiarrHea CAUTION: Many diseases that cause abortion Bovine virus diarrhea (BVD) is a viral disease in cattle are caused by pathogens that can cause caused by a pestivirus with many syndromes. For disease in people. Follow good biosecurity measures this guide, only the abortion syndrome will be dis- and use personal protective equipment such as latex cussed. The pregnancy loss associated with BVD is gloves and a mask when handling the aborted fetus dependent on when in gestation the dam is exposed and materials. Use disinfectant soap when washing to the virus. Embryonic infection in the first tri- after handling aborted materials. mester can result in fetal reabsorption, mummifica- tion, or abortion, or can have no effect. Calves can 1. Contact your local veterinarian. become persistently infected (PI) if exposed to the virus during the first 120 days of gestation. These 2. Identify and isolate the aborting cows from the PI calves shed the virus in body fluids for life and rest of the herd if possible; this may help prevent are a great biosecurity risk to the cow herd. Cattle the spread of the disease and makes the cows that are exposed in the second trimester of gestation available for sample collection. may abort, deliver a live calf that has congenital de- fects that affect the brain and eye, deliver a weak or 3. Save the aborted fetus and placenta by placing stillborn calf, or deliver a normal calf. Exposure in them in a plastic trash bag and refrigerating. If the third trimester may result in a calf that is still- fetus and/or placenta are frozen when found, born, live but weak, or normal. Late-term abortions keep frozen until submitting to a veterinary di- with BVD are uncommon but do occur. Exposure agnostic laboratory. Do not wash the fetus to BVD virus can result in abortion storms when or placenta. acute infections occur. 4. Record all herd health practices, such as vaccina- tions used, date, and route of administration; 1Respectively, Extension Veterinarian, Department of Extension Animal Sciences and Natural Resources; and Associate Professor, Southwest Border Food Safety and Defense Center, both of New Mexico State University. To find more resources for your business, home, or family, visit the College of Agricultural, Consumer and Environmental Sciences on the World Wide Web at aces.nmsu.edu Diagnosis of BVD infections can be difficult and Many tests are available to help diagnose brucel- may require multiple sample submissions to ac- losis. Sample submission may include the fetus, curately diagnose the presence of infection. Blood membranes, and blood from the dam. This disease samples, ear notch samples, and examination of is easily transmitted to humans, and the use of per- aborted fetuses may all provide information that sonal protective equipment is highly recommended. is helpful in the diagnosis of BVD virus infection. The disease can be controlled with good biosecurity Your veterinarian will need to help you evaluate the practices and vaccination of females less than twelve laboratory results obtained from sample submission months of age. Vaccination for brucellosis may only due to the complex nature of this disease. be performed by a licensed, accredited veterinarian. Bovine virus diarrhea is a common viral patho- Some states require a negative test before cattle are gen and has widespread distribution throughout allowed to enter the state. the U.S. Control of BVD infection is only ac- complished through prevention. Good biosecurity practices, isolating incoming cattle, testing for PI CamPyLoBaCTeriosis (viBriosis) cattle, and developing a good vaccination program Campylobacteriosis is an abortion disease caused that includes properly using modified live vaccines by the bacteria Campylobacter fetus subsp. venerealis (MLVs) are all components of a BVD prevention and C. fetus subsp. fetus. These organisms can af- program. Preventing the introduction of the virus fect cattle, sheep, and humans. Campylobacter fetus onto your premises is the key component of a BVD subsp. venerealis is strictly a venereal disease spread control program. through breeding. The disease caused by this spe- cies of Campylobacter is characterized by endome- tritis (inflammation of the lining of the uterus) that BruCeLLosis (BanG’s Disease) results in early embryonic death, prolonged estrus Brucellosis was once a devastating disease that was cycles, delayed conception, reduced fertility, and very common in the U.S. A federal eradication (rarely) abortion. The infection is usually self-limit- program, conducted by the USDA, to eliminate the ing, and most cows recover in three to five months. disease in cattle has been very successful, and cattle Up to ten percent of infected females may become brucellosis is now limited to the greater Yellowstone chronic carriers of the disease and harbor the infec- area. The disease in cattle is caused by the bacterium tion until the next breeding season. Some females Brucella abortus, resulting in abortion in cows and may be rendered permanently sterile as a result infertility in bulls, and is a zoonotic disease that can of having the infection. This loss of pregnancy is cause undulant fever in humans. The bacterium can usually early in gestation, with no outward clinical be present in fetal fluids, milk, and semen. Many signs seen in the female. In the bull, the infection strains of brucellosis are present in the U.S., and can localize on the surface of the penis and prepuce, multiple species of animals are affected, such as which can result in prolonged survival of the organ- cattle, sheep, goats, swine, dogs, and wildlife, with ism being carried by the bull. some cross-species contamination occuring. Campylobacter fetus subsp. fetus may be spread A high rate of abortion may occur in susceptible venereally or by ingestion of the organism in feed herds. The occurrence of abortion is dependent on contaminated with fecal material. The organism when in gestation the dam is exposed to the bacte- may be absorbed from the intestine into the blood- rium. Cows infected at service abort after an aver- stream where it gains access to the reproductive age of 225 days, whereas those infected at seven tract. Either route of exposure may result in spo- months of gestation abort about 50 days later. In radic mid- to late-term abortions. fully susceptible herds, abortion rates vary from Laboratory diagnosis of the disease is very dif- 30 to 70 percent, but may be lower in chronically ficult and centers on isolating the organism in infected herds. Weak, full-term calves that die aborted materials from the cow and preputial shortly after birth are sometimes seen. Bulls that scrapings from the bull. Fresh and properly han- are exposed to the disease or vaccine may develop dled diagnostic specimens are needed to isolate inflammation of the testicles or seminal vesicles, the organism. Often the diagnosis of vibriosis is resulting in infertility. made by ruling out other causes of reproductive Guide B-228 • Page 2 loss. Prevention and control of Campylobacterio- many different symptoms, including abortion, sis includes vaccination, culling infertile cows and stillborn, and reproductive failure, may result from infected bulls, purchasing replacement animals Leptospira infection. There are many different spe- from herds with no history of the disease, and cies of Leptospira widely distributed throughout good biosecurity practices. the U.S. Several species have distinct strains, or serovars, that have different antigens. In cattle, the species of importance are L. hardjo, L. canicola, L. infeCTious Bovine rHinoTraCHeiTis icterohaemorrhagiae, L. pomona, and L. grippoty- Infectious bovine rhinotracheitis (IBR) is caused by phosa. The disease is transmitted venereally, across a herpesvirus that is widely distributed in the U.S. the placenta, through breaks in the skin, or is ab- This virus is a component of the “shipping fever sorbed across mucus membranes. A common route complex” that can cause severe respiratory disease of infection for livestock is by ingesting water con- and death. Exposure to the virus from a single in- taminated with infected urine excreted by wildlife. fected animal may result in widespread disease due There is an increase in human cases of Leptospirosis to the highly contagious nature of this virus. Some due to contact with infected livestock. animals may become chronic carriers of the virus The disease can cause abortions, infertility, mas- and will shed the organism during times of stress. titis, or weak or stillborn calves. Low conception Natural transmission occurs by direct contact with rates are a common finding in a herd with Lepto. droplets containing virus particles spread by nasal Severe abortion storms of late-term pregnancies secretions or semen, or through breeding. may be seen when susceptible herds are exposed Abortions from IBR may occur as long as 90 to the organism.