Six to 10 percent of all calves born in beef cow herds in the U.S. die at or soon after birth. About half of those deaths are due to calving difficulty (dystocia). About 80 percent of all calves lost at birth are anatomically normal. Most of them die because of injuries or suffocation resulting from difficult or delayed parturition (calving). Factors contributing to calving problems fall into three main categories — calf effects, cow effects and fetal position at birth. This multi-million dollar annual loss is second only to losses from failing to conceive.
Calving difficulty has received much more attention in recent years, primarily because of the mating of larger European breeds of bulls to British breeds of cow. Increased calving problems are also being encountered within purebred breeds, as genetically large bulls are often mated to cows of only average size.
First-calf heifers require more assistance in calving than do cows, because they are usually structurally smaller. Pelvic area (birth canal) increases as the female develops to maturity. Thus, a higher proportion of calving difficulty in 2- or 3-year-old cows is due to smaller pelvic openings.
Therefore, how many producers have asked themselves the question, “If she had problems calving this year, what about next year?” “Should I culler from the herd this fall or chance another wreck next spring?”
Research conducted by Colorado State University and published in 1973 looked at parturition records of 2,733 Hereford calves sired by 123 bulls and born to 778 cows/heifers. Of 195 heifers, which had no difficulty in calving at 2 years of age, 7.2 percent had difficulty as 3-year-olds. Of the 77 2-year-old heifers that experienced calving difficulty, 11.7 percent had difficulty again as 3-year-olds.
Heifers that experienced calving difficulty as 2-year-olds weaned 59 percent of calves born, whereas, those having no difficulty weaned 70 percent of calves born. Calving difficulty as 2-year-olds affected the number of calves weaned when 3 years of age, and the weaning weight of those calves. Heifers having calving difficulty as 2-year-olds weaned a 63 percent calf crop as 3-year-olds. Heifers having no difficulty as 2-years-olds weaned a 77 percent calf crop as three-year-olds.
From this research, we learned that calving difficulty as a two-year-old had a profound effect on productivity. The likelihood that calving difficulty will happen again next year is only slightly greater than in heifer counterparts that calved unassisted this year.
The following are some tips to help prepare for a successful calving season:
• Body condition: It is important for cows to maintain a body condition score (BCS) between 4.5 and 5.5 during the final trimester. A higher body condition score allows for improved calving ease, along with higher quality colostrum. First-calf heifers should have a BCS of 5.5 to 6 before calving.
• Vaccinations: Entering the third trimester, producers should consider vaccinating with a killed-virus vaccine to boost immunity. The immune response developed from the vaccination forms antibodies that pass from cow to calf through the colostrum.
• Be Prepared: Don’t wait until you have problems to develop a plan. Before calving season make sure, you have clean calving area, calf jack, obstetric chains, latex gloves and good functioning lights for nighttime calving problems.
• Post-partum: After the calf arrives safely, make sure the calf consumes at least one quart of colostrum within six hours of birth. This is also a good time to make sure the calf is getting up and around without any motor function problems. To get off to a really good start health-wise, the calf should consume three quarts of colostrum within the first 24 hours of life.
A good publication for more information on calving success is, Preparing for a Successful Calving Season, Greg Lardy, Ph.D. NDSU Animal Sciences Department, Charlie Stoltenow, D.V.M. Agriculture and Natural Resources NDSU Extension Service: https://www.ag.ndsu.edu/publications/livestock/preparing-for-a-successful-calving-season-nutrition-management-and-health-programs/as1207.pdf
Tips To Prepare For Calving Season, Boehringer Ingelheim Vetmedica, Inc.
Repeatability of Calving Difficulty, By: Glenn Selk, Oklahoma State University Emeritus Extension Animal Scientist.