Minimizing heifer-raising costs while maximizing returns is key to a dairy, since replacements often represent the third-largest expense after feed and labor.
Because feed is the largest component in heifer-raising, it clearly represents the major way to control heifer costs, Jud Heinrichs, professor of Dairy and Animal Science at Penn State University, said today at World Dairy Expo.
“We are often reminded of the importance of feed efficiency for lactating dairy cows, yet the concept is seldom mentioned for the growing heifer,” Heinrichs said. “However, dairy animals spend over half of their lives on most farms as a calf or heifer, which means that their feed efficiency is critical as well.”
Many factors can impact feed efficiency in dairy heifers, including:
· Forage quality (fiber and dry matter digestibility)
· Feed intake level
· Growth rate or stage of growth
· Body condition or change in body composition, gestation
· Heat or cold stress (environmental stresses)
· Exercise level
“From a genetic standpoint, as we increase body size relative to milk production, we increase maintenance costs for energy, protein and most other major nutrients,” said Heinrichs. “Similar principles are true in terms of growth rates for the heifer. The smaller the body weights of the heifer at a given age, the lower the maintenance requirements of that animal.”
Even so, the heifer must be large enough to cycle for breeding purposes and, more importantly, large enough to calve successfully. Body weight and structural height at a given age for the management objective for the given farm are critical, Heinrichs said.
The heifer must also have a large digestive capacity to achieve high dry-matter intakes in the first lactation to be also considered successful.
Changing body composition over various stages of maturity also affects a heifer’s feed efficiency. That includes the added requirements for heifers in late gestation. Environmental stresses and exercise are additional factors that affect maintenance requirements – and heifer feed efficiency.
Diet type and amount fed also impact feed efficiency. “Forage and ration digestibility are important,” Heinrichs said. “The more digestible the feedstuffs used in the ration, the more efficient the heifer will be.”
Greater efficiency will also lead to reduced nitrogen excretion into the environment. In addition, the greater the dry matter intake fed as a percent of body weight, the lower the feed efficiency will be
“Much research has been done in the past five years at precision-feeding highly digestible diets to dairy heifers for improving feed efficiency and nutrient waste,” Heinrichs said.
Feed efficiency in dairy heifers can be optimized by selecting animals that have the genetic propensity for high dry-matter intake in first lactation. Also look for those animals that have the ability to grow at uniform rates to meet the body size requirements for calving at 22 to 24 months of age.
“Maintaining optimal body size during the growing phase is important to minimize heifer maintenance requirements,” Heinichs said.
Finally, feeding precise amounts of highly digestible and perhaps higher concentrate rations will minimize a heifer’s energy and protein requirements.