Feeding calves higher levels of liquid nutrients than traditional "restricted" feeding programs allow has been proven to have myriad benefits for calf productivity, according to University of Florida assistant professor of animal science Emily Miller-Cushon.
Among those advantages are higher average daily gain; reduced age at first conception and calving; improved milk production and/or milk fat yield in the first lactation; and increased time sucking (which promotes digestive health).
But, said Miller-Cushon, the Achilles heel of intensively fed calves may be weaning. Through her research and that of others, she reported that calves fed higher levels of liquid nutrients consume less total starter grain in the pre-weaned phase; do not eat grain concentrate as frequently; and eat smaller meals when they do consume it.
"This can be problematic when calves are weaned, because they are not as accustomed to the grain diet, and are not as advanced in their rumen development as calves that have been consuming less milk and more grain," she said. "If transition to weaning is not managed successfully, those calves may stop gaining or even lose weight for a period of time during weaning."
Ultimately, Miller-Cushon said the goal is to keep intensively fed calves in a continued pattern of growth and weight gain. "The worst thing that could happen is that the tremendous growth they experience in their first weeks of life is wasted because they lose momentum at weaning," she said.
Some studies have shown that the post-weaning growth lag in intensively fed calves is only temporary and may be resolved after the first week of weaning. But Miller-Cushon would prefer that lag didn't exist at all. She outlined three strategies that can help intensively fed calves transition more successfully off of the liquid diet:
(1) Weaning method - Weaning methods that encourage solids intake prior to complete removal of milk are desirable. Miller-Cushon cited a study that showed calves weaned with the same protocol at weeks 7 and 13 of life, respectively, transitioned better after receiving milk for the longer, 13-week feeding period. Gradual versus abrupt weaning also may be helpful. A University of British Columbia study showed that gradually weaning calves over a period of 21 days resulted in animals that were consuming significantly more starter grain on day 41 of life, compared to those weaned abruptly on Day 41.
(2) Dry feed nutrition - That ever-debated ingredient, hay, may play a valuable role in helping encourage dry-matter feeding in preweaned calves. Miller-Cushon's own research has revealed that preweaned calves select for hay versus starter grain. "While many nutrition experts worry that too much hay consumption will negate the rumen-developing value of concentrates, the presence of some hay in the diet may be helpful in encouraging calves to consume dry feed in general," she said.
(3) Housing and socialization - Many intensively fed calves are raised in group housing, which appears to be beneficial to successful weaning. Miller-Cushon cited data concluding that group-housed calves consume more solid feed prior to weaning, vocalize less, and gain more consistently through weaning. That consistent gain may be due to better dry-feed intake, reduced stress, or both. Miller-Cushon noted one downside to group housing and feeding on a shared nipple: competition for the nipple appears to create calves who are aggressive eaters. "That may be a good trait for growing calves and heifers," she said. "But it also could result in adult cows that are prone to 'slug feeding' - consuming fewer, larger meals - which is not preferred for lactating animals."
To view a webinar by Miller-Cushon discussing intensive calf-feeding programs in greater detail, follow this link.