by Gilda V. Bryant
What you do before calving counts
Planning for the successful conception of either a seasoned cow or first-calf heifer is similar to solving a puzzle. It requires the right pieces to make a complete picture—good quality forage or other feedstuffs, healthy body condition score, a good mineral supplementation program, proper amounts of energy given to
cattle at the right time and a healthy, active bull.
Jeff Hill, PhD, ruminant nutrition expert and Beef Business Manager with ADM, says that
it’s not what you feed prior to breeding, but what you do before calving that makes the
next calf crop possible.
“Make sure cows are in good condition,” Hill advises. “I’d say a body condition score (BCS) of five is the bare minimum. Pushing six would be preferable. It would give you a little more latitude.” He adds, “When calves are worth as much as they are right now and with cheaper feeds, the economics are probably in favor of pushing them to a six. If calves are worth less, that incremental gain that you get may not be economically justified.”
If the cow’s BCS has dropped below a five, feeding higher energy 60 to 90 days before calving helps her maintain body condition and allows her to cycle. Hill says, “The body condition score the cow has at calving is critical
because she’s probably going to lose some weight anyway. If you try to feed her to gain weight, she will just
produce more milk. If you don’t have a good BCS at calving, by the time she starts lactating, you can’t make it up.”
Hill gives this advice, “You’ve got to start thinking about it sixty to ninety days prior to calving.”
Steve Blezinger, PhD, PAS (Professional Animal Scientist), ruminant nutritionist and management
consultant, says that both cows and heifers need to be healthy and receiving good feed and minerals. He adds, “Since heifers are still growing, their level of nutrition should be properly matched to age and size. This somewhat higher nutritional plane should continue through pregnancy and postcalving to insure the heifer continues to grow and develop so she reaches a proper mature size.”
However, Blezinger cautions producers to make sure that heifers are not overly fat prior to and at calving. This can lead to increased calving problems including dystocia, a difficult birth that needs assistance.
Rancher Rodney Howell, owner of Lone Star Angus near Gainesville, Texas, likes for his cows and first-calf heifers to carry good flesh. Part of his cattle management strategy includes separating cows by age groups and calving dates so they can be fed for their ages and stages of pregnancy.
Jeff Hill reports that during the third trimester, the cow’s feed intake will drop between 15 to 20 percent due to the size of the fetus. Hill recommends concentrating nutrients to make up for her reduced intake.
Minerals play a vital role in the reproduction cycle. To support the cow post-calving and to prepare for breeding,
she needs calcium, phosphorus, magnesium, copper, selenium and zinc. Blezinger advises, “These, along with all the other required minerals, should be accessible at all times, but for certain, at least 60 days prior to calving and through the breeding season.”
Because the microbes in the rumen tend to absorb trace minerals, especially copper, zinc and manganese,
the animal often doesn’t get the amounts needed for healthy body function. Fortunately, treated trace minerals known as chelates can be beneficial. Chelates pass unscathed through the rumen, eventually entering the small intestine where they are absorbed and utilized by the animal.
A new class of minerals now available to the beef industry shows promise for transporting copper, zinc and manganese for the animal’s use. Known as hydroxy forms, they act like chelates because they aren’t absorbed in the
rumen. They have low solubility until they reach a low acid environment, which just happens to occur in the small
intestine, where absorption occurs.
Another piece of the puzzle is the bull. The key to sperm production is a good mineral program, which can be the same one the rest of the herd receives. He needs at least 60 days on minerals before turnout to produce healthy, active sperm. Hill says, “The one trace mineral that relates to spermatogenesis is zinc. Paying attention to a good, available source of zinc would be prudent.”
Like the females, a bull should have a BCS of at least five. Hill reports the bull shouldn’t be overconditioned because
he needs to travel and to be able to breed. To avoid going lame, his feet and legs should be in good condition.
“Bulls should also have been given proper exercise or conditioning prior to joining the herd,” Blezinger advises. “For example, if the bulls are kept in their own pasture or trap prior to breeding season, the pasture should be laid out in such a way as to promote exercise. Providing feed and forage at one location and water at another allows for movement and exercise.”
In addition, a veterinarian should conduct a breeding soundness exam about 30 days prior to the start of the
breeding season to make sure the bull is ready to be turned out.
“I feel like the oversupplementation of trace minerals has the potential to be as negative as undersupplementation,”
Hill shares. “Find that optimal balance. Try to get those minerals in the best form, delivered to the right location [for absorption].”
Blezinger adds, “While we talk about specific minerals that have been shown to be particularly important for reproduction, all minerals are important to the cow and bull’s performance and health. The mineral should be matched to the forage base the herd is on. This means forage testing and matching to the mineral values
shown in the assay. Subsequently this should mean finding an “off the shelf” product that meets the requirements
as closely as possible or, if the herd size is adequate, having a custom mineral formulated. The mineral program
is the basis for a sound nutritional program.”