To manage through the drought, this year many producers have turned to early weaning their calves. How does this practice impact heifers meant for replacements?
“Research indicates that early weaning does not impact a heifer’s opportunity to be retained as a replacement in the herd,” said Robin Salverson, SDSU Extension Cow/Calf Field Specialist. “Early weaning can also improve the condition and reproduction of the dam and manage through drought conditions.”
Salverson added that the data also indicates early weaned heifers have the similar or greater reproductive success than normal weaned heifers.
Salverson pointed to research conducted at the U.S. Department of Agriculture Livestock and Range Research Laboratory in Miles City, Montana. In this study, heifers were either early weaned at 80 days or the typical 213 days of age. Data was then analyzed to better understand weaning and its impact on heifer development phases.
Diet & Weight
The early weaned heifers were fed a 17.5 percent protein and 75 percent total digestible nutrients diet after weaning. While the other group of heifers, the control group, remained on their dams for an additional 133 days.
By the time the control group was weaned, the early-weaned heifers, fed on a mixed ration, were heavier than the control group, weighing 526 pounds versus 493 pounds. “This result indicates that early weaned heifers are able to successfully gain weight,” Salverson said.
Feed quality essential
When early weaning onto pasture, Salverson said it is critical to have high-quality pasture along with a supplement to compete with a mixed ration.
Salverson referenced research conducted at the SDSU Antelope Range and Livestock Research Station in Northwestern South Dakota that confirms heifers can be early weaned on pasture with a supplement and have similar gains as their mates that stay on the cow.
She referenced another study conducted at the Range Research Laboratory in Miles City in which, during the heifer development phase, all heifers, early and normal weaned, were fed a 12.5 percent protein and 63 percent total digestible nutrient diet from the time after normal weaning to the end of the treatment in April.
Both groups of heifers received either a 72 or 82 percent rumen degradable protein. “Regardless of the type of protein provided, the early weaned heifers remained heavier throughout the development period,” Salverson said.
Results from reproductive performance studies conducted at both SDSU Antelope Range and Livestock Research Station in Northwestern South Dakota and the U.S. Department of Agriculture Livestock and Range Research Laboratory in Miles City, Montana showed no difference between heat response, AI and overall pregnancy rates when looking at results from early weaned and control groups of heifers.
“These results indicate that early weaned heifers can be reproductively sound females that can stay in the herd as replacements,” Salverson said