SEDALIA, Mo. — In spite of pandemic interruptions, some things in agriculture need to happen in sort of a clockwork fashion, and breeding season for spring calving cows is one of those annual occurrences. As cows transition from winter hay feeding to grazing spring grass with newborn calves by side, there are management targets cow/calf producers need to be aware of in order to maintain a successful level of ranch productivity. In the case of beef cows, there is a very critical window of about 85 days after calving that sets the tone for the whole beef cattle enterprise.
In order for a cow to calve in an approximate 12-month cycle, she must be re-bred within 85 days of calving. Economics also tells us older, heavier calves at sale time return more dollars per head than younger, lighter calves. The production goal for cow/calf producers then becomes having as many calves as possible born as early in the calving season as possible.
Many factors influence re-breeding rates for beef cattle including body condition score, length of post-partum interval, pasture condition, and nutritional program to name a few. Research is clear that cows with a body condition score of 5 or better at breeding have greater conception rates earlier in the breeding season than thin cows. Late-calving cows also have problems getting bred early in the breeding season since some of them may not have begun cycling after calving.
Synchronizing estrus and artificial insemination (AI) are great ways to get more calves born earlier in the calving season, provided cows are in adequate body condition and have a longer interval between calving and breeding. Some producers are not willing to consider AI, but there are a couple of protocols that can effectively synchronize estrus and utilize natural service mating to tighten calving windows.
Dr. Jordan Thomas, MU Extension beef cattle specialist, recommends utilizing a 7-day CIDR program with natural service synchronization programs. Using this protocol with natural service, a CIDR is simply placed and removed after one week; there is no need to administer other hormones at CIDR insertion or removal. Bulls should be turned in on the day of CIDR removal. This option has the advantage of inducing cyclicity in late-calving cows. According to label directions, cows must be at least 21 days post-calving in order to receive a CIDR. By jump-starting late-calving cows, more total females can potentially be bred and conceive earlier in the breeding season, resulting in more calves born early in the subsequent calving season which results in heavier, older calves at weaning.
For herds that already have a short calving season, cows can be injected with prostaglandin and turned in with bulls on the same day. This protocol will not jump-start cyclicity in cows however.
Before attempting a natural service synchronization program, cows must be in adequate body condition and preferably on a rising plane of nutrition. Bulls must be able to service the increased number of cows in estrus at any one time. Breeding soundness exams for bulls to ensure they are capable of breeding and settling cows is critical. Using mature bulls in a 1:15 ratio of bulls to cows is another critical piece of this type of breeding system. Monitor condition of bulls closely during the breeding season to be sure they are adequately servicing cows.
Estrus synchronization and natural service breeding systems can have a positive influence on the productivity and profitability of a cow herd, but paying attention to details is critical with this type of program. If you have additional questions, contact me by e-mail at schmitze@missouri.edu or by phone during the lockdown at (660) 723-3621. Have a great week.
— University of Missouri Extension
For more news from Missouri, click here.
