Energy and protein supplements essential
TAMPA, Fla. — Heifers need special treatment if they are expected to succeed later in life.
They need to gain enough weight after weaning to attain puberty, conceive early, deliver a live calf unassisted and then rebreed.
Their biggest challenge is to conceive quickly again, said Mike Smith of the University of Missouri’s animal science division.
Producers tend to select replacements from older, heavier females at weaning. Avoid selecting those that received hormone implants in the first 30 days of life because these impair proper uterine development.
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“Age of puberty is not really affected, but pregnancy rate is,” he said.
He also recommended that veterinarians check heifers four to six weeks before breeding. The vet can palpate the uterus and ovaries to assess development to sort those that could have trouble or have a high likelihood of conceiving early.
Heifer weight is not an accurate way to assess puberty, he added.
Measuring the pelvis is a measure of the skeleton and not puberty. It is useful to identify those with small pelvises so they can be removed. A large pelvis may mean a big female that will have a big calf.
Administer prebreeding vaccines at this time because they will have enough immunity. As well, side-effects will be worn off by breeding time.
Heifers should be bred two to three weeks before the cows.
“You should consider the use of synchronization and AI in your heifer program,” Smith said.
“It is easier to implement a synchronization program in your heifers from a management point of view and it allows you to get a large number of them pregnant on the first day of the breeding season.”
Animal scientist Rick Funston from the University of Nebraska-Lincoln said nutrition has a profound effect on reproductive potential.
Body condition is a useful indicator of nutritional status when combined with body weight. Females’ greatest needs are energy and protein supplemented with minerals and vitamins to optimize reproduction.
“The consequences of nutrient restriction ought to be considered not only for the individual animal performance but all for offspring,” said Funston.
Studies have found nutritional balance can affect the animals’ genetic potential.
“Things happening that are being passed down by nutritional state, by physiological state and physical condition is impacting the expression of the DNA even before conception,” he said. “The decision to supplement or not during gestation impacts those cows and the steer calves.”
Steers born to dams with poor nutrition during pregnancy gain less at the feedlot and have a lower quality grade. Heifers may be slower to gain weight and breed if their dams were not supplemented.
Heifers should be 65 percent of their mature weight when they are bred. They do not need to gain more than 1.5 pounds per day during the development phase. They do not have to be placed in a feedlot to bring them along.
