U of I grad student studies new approach to dairy calf feeding

A University of Idaho graduate student's research could help a large Mountain Home dairy reduce the time calves require to mature into productive herd members by changing the way they are fed.

Katie Corder-Steiner, of Mountain Home, is pursuing a master’s degree in animal science, and her thesis project is aimed at eliminating a one- to two-week weight-gain lull dairy calves typically experience following weaning.

She chose the perfect time to invite Caleb Degroot, with Sunview Dairy, to collaborate on the study, as Degroot and his staff were also considering ways to address that lull.

“Katie approached us last spring with the idea of feeding forages and hay to our calves at an earlier age than most people do,” Degroot said. “That had been something our nutrition team had been looking at for a long time.”

If study results support her hypothesis, Corder-Steiner’s research could lead other Idaho dairies to rethink a long-standing tradition of waiting until after calves are transitioned off milk, known as weaning, before introducing forages into their diet.

In addition to milk, most dairies feed calves grains — such as corn, barley, oats, wheat or sorghum — which support rumen development until they are weaned, which typically occurs when they are between 75 and 90 days old. In ruminant animals such as cows, the rumen is the first of four stomach compartments, serving as a fermentation chamber where microbes break down fibrous plant material. Grain helps calves develop their rumen by providing readily fermentable starches that stimulate the growth of rumen microbes and papillae, which are the tiny finger-like projections that line the rumen wall and absorb nutrients. 

Forages such as alfalfa hay pack a lot of energy, but they can be difficult for calves to digest before they have a fully developed rumen. Dairymen typically don’t feed forages to calves until just after weaning, and it takes a while for their systems to acclimate to the new feed source which temporarily slows weight gain.

For her experiment, Corder-Steiner selected 100 first-generation Holstein and Jersey cross calves born at Sunview Dairy June 15-20. Over the course of the 121-day study, she’s feeding half of the calves the usual way — they’ll be fed milk and grain until they are weaned, when they’ll also begin receiving hay and forages. The remaining calves will have access to a trough filled with hay, in addition to milk and grain, beginning a few days after birth.

Corder-Steiner is hoping the early exposure to forage will help calves adjust sooner to it, thereby eliminating the usual period after weaning when they don’t gain much weight. She’ll also be comparing health and mortality data from the two groups, in addition to running an economic analysis to determine if the additional feed and labor costs associated with earlier exposure to forages warrant the investment.

“They love the forage. We are having to refresh it every day,” Corder-Steiner said. “The worry in the past was if we offered them both, they would eat too much hay and not enough grain.”

Corder-Steiner’s advisor, Mireille Chahine, an emeritus professor of animal and dairy science, believes it’s the right time to revisit when to begin feeding forage to dairy calves because dairies have changed other practices during the past decade. Mainly, dairies have begun feeding calves significantly more milk than in the past, which could provide them with more energy to digest their food.

“Maybe if there’s more energy and nutrients coming from milk and the forage is of reasonable quality it will not affect rumen development,” Chahine said.

Studies conducted in Europe at a shorter length and involving different calf breeds have shown promise for feeding forages earlier.

Corder-Steiner met with several Idaho dairymen prior to starting the project to gage their interest in the concept.

“If it shows good results, it would be something worth considering,” she said.

Degroot believes dairymen still have much to learn about calf management and behavior. Beyond expediting weight gain, Degroot sees potential to lay a stronger foundation for long-term animal health through Corder-Steiner’s approach.

“It’s kind of like an early investment into a bank account,” Degroot said. “The idea of feeding forages and hay to calves at an earlier age is you want to develop the rumen. The earlier you can develop the rumen, the healthier it is and the more productive of a lactating cow she can be.”