Little research exists regarding the best strategies for feeding post-weaned heifers. Driven by feed costs, heifer-feeding dogma has long been to transition young animals to a forage-based, low-cost diet shortly after weaning. Yet research conducted at Purdue University found that component-feeding heifers as they entered the growing phase gave them an edge over their 300-pound counterparts that were immediately switched onto a TMR.
"Dietary composition is an important aspect of feeding heifers, but the delivery method can also have an impact," noted noted Tamilee Nennich, formerly with Purdue University, during a presentation at the Tri-State Dairy Nutrition Conference.
A study conducted by Nennich's research group evaluated the effects of feeding heifers a TMR, feeding them concentrate and hay side-by-side in a feed bunk (SBS), or feeding grain in a bunk and hay in a feeder (HF) on growth and intake of post weaned heifers.
From Day 49 to the end of the trial, heifers fed using a hay feeder were significantly heavier than those fed side-by-side in a bunk. Delivering feed using a hay feeder resulted in animals that were, on average, 12.1 and 7.3 pounds heavier than heifers fed using SBS and TMR, respectively.
Heifer weights at the conclusion of the grower period were 605, 576 and 575 pounds for HF, SBS and TMR, respectively.
Average daily gains varied depending on the time period of the study. Heifers fed a TMR had lower daily gains during weeks two and three, but gained better than those fed a side-by-side diet during the trial's fourth week.
"These results suggest that post-weaned heifers require more time to adjust to new diets when feeding a TMR compared with component feeding," added Nennich.
Heifers fed using HF averaged an additional pound of dry matter intake per day compared with SBS and TMR. However, from Day 63 on, TMR fed heifers had greater intakes.
Along with responses in average daily gains, component-fed heifers maintained intakes and weight gains when transitioning to a new diet, while TMR-fed heifers caught up towards the end of the transition period and throughout the grower period.
"Our work indicates that there may be a certain point during the growth of a heifer when it is ideal to switch over to TMR-feeding," concluded Nennich.
The author, Amanda Smith, was an associate editor and an is animal science graduate of Cornell University. Smith covers feeding, milk quality and heads up the World Dairy Expo Supplement. She grew up on a Medina, N.Y., dairy, and interned at a 1,700-cow western New York dairy, a large New York calf and heifer farm, and studied in New Zealand for one semester.
