Dates to remember
April 23: Youth for the Quality Care of Animals training (4-H)
May 8, 15, 22: Caring for Kids, Mandan
Spring calving is underway for most producers in Morton County and around the state. It’s a great feeling to return to the calving barn to check on things and see a fresh calf nursing and see healthy calves hopping around on the straw. On the other hand, it’s tough to lose calves. While I haven’t gotten wind of it in our county, a number of producers in other western counties are reporting higher calf death loss than normal with causes that include late-term abortions or stillbirths. In the piece below, Janna Kincheloe, area Extension livestock specialist, and Gerry Stokka, Extension veterinarian, share some ways to identify the cause of pregnancy loss in beef cattle and how to prevent loss in the future. If you are experiencing death loss above normal rates, you may qualify for assistance through the Livestock Indemnity Program through the Farm Service Agency.
There are three categories of pregnancy losses in beef cattle: early embryonic death, abortion and stillbirth. Early embryonic deaths are those that occur within the first 42 days of gestation. After that point, losses are considered abortions. Abortion involves the expulsion of a dead fetus prior to approximately day 270 of gestation, while stillborn calves include full-term calves that are born dead or die within the first 24 to 48 hours after birth. In a 2007 survey of beef cow-calf producers across the nation, USDA-APHIS reported that 2.9 percent of beef calves were stillborn. Within a herd, a single stillborn calf may not be regarded as significant. However, investigation may be warranted when several stillbirths occur in the herd. The reasons for these losses are complex and not always easy to diagnose; however, some common causes of losses include dystocia, nutritional deficiencies and infectious diseases.
Dystocia or calving difficulty can result if calves are too big or do not exhibit normal presentation in the birth canal. Stress and lack of oxygen during calving can result in stillborn calves; however, these losses are often attributed to other causes. Dystocia and stillbirths are more likely to occur in first-calf heifers due to small pelvic area and/or in cows that are either overly conditioned or too thin. Heifers should have obtained at least 85 of mature weight and have a body condition score of 6 at calving, while mature cows should calve in a condition score of 5. Overconditioned females may have accumulated fat in the pelvis that can limit space in the birth canal.
Proper vitamin and mineral intake is essential for placental and fetal development. In particular, deficiencies of selenium, iodine, manganese, and vitamins A and E may result in abortion. Some abortions in late pregnancy may be due to injury or extreme stress. The fetus is well protected from trauma to the cow by the fluid-filled uterus; however, pain or inflammation following maternal injury can cause stress and trigger release of hormones in the body that may initiate premature labor.
Infectious diseases caused by bacteria, protozoa, and viruses are often a cause of abortions and/or stillbirths in cattle. Bacterial diseases include brucellosis, leptospirosis and vibriosis, all of which have vaccines to reduce the risk of losses. Diseases such as trichomoniasis, sarcocyctosis and neosporosisare caused by protozoa and can be more difficult to manage since vaccines are either unavailable or may be ineffective. Common viral diseases include BVD (bovine viral diarrhea) and IBR (infectious bovine rhinotracheitis). Vaccines to prevent losses due to IBR and BVD are available and effective.
Laboratory diagnosis of disease issues that contribute to calf losses can be difficult because the infectious agents are often undetectable in tissue or blood samples. The placenta is often key to obtaining a diagnosis; therefore, submit the placenta in addition to the fetus whenever possible. Prompt identification of aborting cows and isolation from the herd is recommended to help prevent the spread of infectious diseases if applicable. When collecting aborted fetuses and tissues for analysis, use appropriate biosecurity measures such as latex gloves and a mask to avoid diseases that can be passed from livestock to humans. The fetus and placenta should be placed inside a black garbage bag and kept cool until arriving at the laboratory. Avoid freezing unless they were already frozen when found.
Sample submission to the NDSU Diagnostic Laboratory is encouraged if abortion rates are in excess of 1 to 2 percent.
When trying to determine the cause of abortions, it may be helpful to estimate the age of the fetus based on size. One standard measure used to do this is the crown-rump length, a diagonal measurement from the head to the tail. A bovine fetal age calculator based on crown-rump length is available at www.ansci.wisc.edu/jjp1/ansci_repro/lab/female_anatomy/crown_rump_calculators.htm.
Additional factors to consider when trying to determine the cause of losses include nutrition of the herd; age and parity of the cow; vaccination program; body condition score of cows at calving; length of calving, calving difficulty and whether assistance was used; visible abnormalities in the calf; cloudy eyes in the calf indicating it has been dead for several hours.