Are Your Cows Getting Pregnant?
The cow-calf business depends on the production of calves. Too many producers leave that up to chance. What about you?
By: Phil Durst, Michigan State University Extension
It’s cattle breeding season for many beef cow-calf producers. Do you know if your bulls are settling cows?
According to Wayne Ayers, DVM of the University of Idaho, profits in the cow-calf business are "determined by the maximum number of cows becoming pregnant in the shortest period of time and raising that calf until weaning." Most producers rely on natural service to get the cow herd bred and if we consider an average of 25 cows a bull is expected to breed, then the value of the crop expected from that bull is at least $25,650 (based on $1.80/lb. for 600 lb. calves and a 95 percent calf crop).
That is a lot of trust a producer puts into his or her bulls. Is the trust being well-placed?
According to Dan Grooms, DVM, Ph.D. at Michigan State University, the percentage of bulls that passed a Breeding Soundness Exam in 2014 was 72 percent on over 200 bulls. Over the past 8 years, the range in Breeding Soundness Exam pass rate has been from 72 percent to 87 percent. Every year, there are a significant number of bulls that are found not to be of optimal fertility and ready to breed cows.
In a survey completed by 53 producers in 2014 during the Breeding Soundness Exam clinics, 57 percent said that they have had at least one bull classified as an unsatisfactory breeder. Producers who have this information prior to breeding season can make adjustments to their breeding program. Producers who do not have bulls checked through a Breeding Soundness Exam can’t.
However, rather than finding out at calving season, there are several things that cow-calf producers should consider, according to Michigan State University Extension beef team members. Observe bulls in action. Watch to see if bulls show interest in breeding and are successful in intromission (process of insertion into the vagina).
Observe bulls to see if they appear healthy and are walking without lameness. Lameness can be a big cause of a failure to breed cows. While observation can only provide basic information, and does not tell you if the bull is settling any cows, it is an important first step.
Beyond simple observation of bull behavior and appearance, consider pregnancy testing. Pregnancy testing can be conducted in several ways. A veterinarian can palpate a cow or heifer beginning approximately 35 days after breeding to determine is the animal is pregnant. In addition, testing that relies on detection of a specific proteins produced by the placenta can be used to determine if an animal is pregnant.
These proteins, called Pregnancy Specific Glycoproteins, or PAG’s, can be found in both blood and milk. Whether pregnancy diagnosis is made via a blood or milk sample, the sample can be taken 30 days (blood) or 35 days (milk) after breeding and is highly specific for pregnancy (97 percent accuracy in blood, 98 percent accuracy in milk).
The blood pregnancy test is marketed under the trade name "BioPRYN" and is available from licensed labs including in Michigan, West Michigan Veterinary Service. The milk test is commercially available through Antel Bio. One advantage of this test is that the same milk sample can also tested for Johne’s Disease, Leukosis or BVD for additional cost. With both milk or blood samples, pregnancy results are available within 24 hours.
It would be a good practice to check all cows for pregnancy and to sell open cows before feeding them on harvested feed.
The profit margin in the cow-calf business can be slim. Reducing the potential for open cows by routine Breeding Soundness Exam of all bulls prior to breeding season and pregnancy checking cows and heifers can help improve profit potential.
