Dr. Hugh Chester-Jones, Animal Scientist, SROC

February 11, 2006

Recent feeding systems for contract-raised commercial dairy heifers at the University of Minnesota Southern Research and Outreach Center (SROC) Calf and Heifer Research and Extension Facility in Waseca have evaluated grain mix options for group pens following post weaning transition from individual calf pens. Heifers are fed their calf starter diets for the first 7 to 10 days in group pens then offered grower diets. The objectives of the programs are to develop consistent heifer growth to attain target goals for frame size and body weight by 25 weeks of age without excessive body condition. An important aspect is to reduce the variation within and across pen groups, which will improve efficiency of the feeding program.

One of the first programs evaluated a conventional 16% crude protein (CP) grain mix (cracked corn, 34% CP pellet, oats and molasses) with either a 16% CP whole corn:pellet mix (34% CP pellet) or a 16% CP complete pellet. All grain mixes were limit fed to 6 lbs/heifer daily with free choice hay (medium quality alfalfa, 19% CP). Diets were fed for 16 weeks. Initial body weight, hip height and body condition score were 190 lbs, 36.8 inches and 3.0, respectively. Daily grain and hay intake by days on feed are summarized in Table 1.

Average daily hay intake was 5.7 lbs/heifer. Heifers fed the whole corn:pellet program had 4.5% faster rates of gain and used their feed 5% more efficiently than those fed the other two diets. Heifers gained well over 2 lbs daily on all diets with good frame growth but perhaps a little too much body condition. Heifers averaged 456 lbs at 25 weeks of age and 44.9 inches hip height. Heifer dry matter intake (DMI) averaged 2.9% of body weight over the feeding period.

In a follow-up 16-week study, 212-lb dairy heifers in similar body condition and frame-size were group fed a 16% vs 18% CP whole corn:pellet program, limit fed to 6 lbs/heifer daily with free choice medium quality alfalfa-grass hay. Average final body weight and hip height were 452 lbs and 45 inches respectively, being very similar to the first program. Feeding extra protein in the grain mix did not improve heifer performance. Hay averaged 5.6 lb/heifer daily, very similar to the first program, with an overall slight increase in total DM intake to 3.1% of body weight over the feeding period. Daily gain and final body condition were 11% and 5% lower, respectively, than the first program. Modifications of these programs have been to use the whole corn:pellet mix with varying low, medium and high quality hays, varying fiber levels or utilizing cracked corn grain mixes with different protein sources. Limit or free-choice grain mix feeding up to a 12-week feeding period are being evaluated with some programs.

The bottom line in conducting these research studies at SROC is to be able to develop nutritional management options for group-fed dairy heifers up to 6 months of age that will provide consistent performances across all seasons with considerations for economics efficiencies.

In the near future, heifers will be followed back to the milking herds to evaluate the effect of nutrition, management and health up to 6 months of age on first lactation performance. A summary of the first 897 dairy heifers from 2-4 days to 6.4 months of age (when they are transferred to the next stage grower), which have been raised at SROC from 2003-2005, indicate an average daily gain of just under 2 lbs, final hip height of 45.1 inches and final body weight of 469 lbs. Are these acceptable target growth goals for confinement heifers that will ensure high quality heifers for the owner dairies? These answers will be forthcoming as a result of tracking these calves from birth through their first lactation period.