News from the Midwest Sectional Meetings, March 16-18, 1998, Des Moines, Iowa
Contact:
Michael VandeHaar, MSU Department of Animal Science, 517-355-8489
Jamie DePolo, Outreach Communications, 517-432-1555, ext. 22.
Heifers Having Heifers?
Farmers usually spend around $1,200 raising a heifer to puberty. This takes between 22 and 30 months so the heifers can grow adequately in size and pelvic structure to safely carry a calf and give birth. But because of costs, farmers have been trying to accelerate heifer growth and development so they calve sooner. Theoretically, the result would be decreased breeding costs and increased profits for farmers.
Michigan State University associate professor of animal science Michael VandeHaar has reviewed all of the research available on this subject and has concluded that rapid growth rates of more than two pounds per day are beneficial to heifers or farmers.
"When heifers are grown rapidly, it generally affects tissue development in the mammary gland, which is important for milk production," VandeHaar said. "Rapid body growth in the first year of life decreases mammary development. Throughout the published studies, it is also clear that feeding low protein impairs mammary development--a consideration that’s especially important when feeding corn silage diets."
VandeHaar also said that he wouldn't recommend that farmers grow heifers more than 2 pounds a day, especially from three to 10 months of age, which is the period of time most important for mammary development. Protein requirements for this growth rate are 15 to 16 percent of the diet. Farmers usually drop protein levels to 12 percent after 6 months because of costs.
VandeHaar presented his findings at the joint Midwest Sectional Meeting of the American Society of Animal Science and American Dairy Science Association in Des Moines, Iowa, on March 16-18.