Proper nutrition before, during and after calving season is a key element in achieving reproductive success in a beef cattle herd.
To ensure cows can breed back quickly, Dr. Shane Gadberry, University of Arkansas professor and specialist in beef cattle nutrition, says pre-calving nutrition is essential. Shane said, “The challenge we typically get into is from the point of weaning to rebreeding. Weaning time is typically when we see cows are at their thinnest, and the type of diet that they’re going to be on for the majority of the time after weaning will determine whether or not we need to make adjustments.”
Shane said growing forages typically provide enough energy and protein to keep cows in good body condition, as long as there’s enough volume to meet the cow’s dry matter intake needs each day.
But when a rancher is using a controlled breeding season, body condition score can make a dramatic difference in breeding back; while a cow with a score of five will be successfully bred back 88-90 percent of the time, the success rate drops into the 70s with a score of four.
While it’s important to meet the herd’s nutritional requirements year-round, those requirements are heightened during breeding season because the cow is also normally nursing. “She’s still at the earlier stages of lactation,” Shane said, “so her requirements for protein and for energy are definitely going to be higher at that point than they will be at the time when she’s ready to wean the calf.” It’s also critical to reproduction to ensure needs are being met for vitamins like vitamin A and trace minerals such as copper, zinc and selenium.
Dr. Mike Smith, professor of reproductive physiology with the Department of Animal Science at the University of Missouri, said body condition “can be measured by looking at the fat cover that the cow has, in particular down the back, over the ribs, around the hooks and pins…The thing we do know is you want a cow to be in a minimum body condition score of a five; with a first calf heifer, maybe a six would be ideal knowing that they’re going to lose some weight, due to the fact that they’re not only trying to come back in heat but are growing and lactating for the first time.”
Mike said heifers should be at roughly 65 percent of their mature body weight about a month prior to the start of the breeding season, and at 85 percent of mature weight before they reach 2 years of age.
He said it’s critical to measure body condition score at weaning, because that provides the best opportunity to put weight on a cow. “This may not be true for all breeds,” Mike said, “but a general rule of thumb is you want a cow to gain about 80 pounds of body weight for every condition score.” If a producer has the facilities and the ability to segregate herds, thinner cows should be sorted off so supplemental feed can be used most efficiently.
