The 2011 annual meeting of the American Dairy Science Association took place in New Orleans, La., in July. Scientists from around the globe gathered to share their research and learn the latest developments in all aspects of animal science. The following summary provides a few highlights on topics related to calf feeding and management.

Calf Health

Calves entering a commercial heifer raising facility were studied to evaluate the effects of treatment tulathromycin (Draxxin, Pfizer Animal Health) on calf health and growth in the first 8 weeks of life (Stanton et al.). The calves received tulathromycin or a placebo when they arrived at the facility and were housed in groups. Calves that received the placebo were 1.8 times more likely to be treated for scours, 3.7 times more likely to be treated for one-sided ear droop, and 1.7 times more likely to be treated for two-sided ear droop than calves that received tulathromycin on arrival. In addition, the tulathromycin calves gained 0.07 lbs more per day than the placebo calves.
 
Researchers observed that calves with failure of passive transfer (defined as total protein less than 5.4 mg/dL) gained 0.09 lbs less per day than calves with successful passive transfer. Average daily gain was reduced by 0.22 lbs in calves with respiratory disease and 0.15 lbs in calves with non-specific fever (defined as rectal temperature greater than 103.1 degrees F, off-feed, listless, dull with normal respiratory rate and no nasal discharge).

Fatty Acid Supplementation

Scientists from the Nurture Research Center (Hill et al.) presented the results of several studies investigating fatty acid supplementation. Some of this research was published in the June issue of Professional Animal Scientist. In one trial, calves were fed milk replacer with or without 1.25 percent of a blend of butyrate, coconut oil, and flax oil that provides medium chain fatty acids and linolenic acid (NeoTec4, Provimi North America). Calves fed NeoTec4 had greater average daily gain, starter intake, feed efficiency, and hip width change and an improved response to BVD and PI3 vaccination than control calves. In a second trial, calves fed 0.5 percent NeoTec4 in calf starter before weaning had greater average daily gain and hip width change than control calves or calves fed NeoTec4 plus soy oil. In another trial, the addition of 0.5 percent NeoTec4 to a grower diet, fed from 8 to 16 weeks of age, improved average daily gain compared to three other diets (control, 0.25 percent Flaxtech (Virtus Nutrition), or 1.5 percent soy oil).
 
In a final study, conducted in cooperation with Michigan State University, calves were fed milk replacer containing 1 percent NeoTec4. After weaning the same calves were fed a diet with no NeoTec4 for 28 days, and then half the calves were fed NeoTec4 for 28 days. Preweaning average daily gain, feed intake, and feed efficiency were greater in NeoTec4-fed calves than in control calves. In addition, calves fed NeoTec4 had fewer days with scours and improved response to vaccination compared to control calves. No differences were observed between treatments in the first 28 days after weaning, but when NeoTec4 supplementation resumed, calves had better average daily gains and feed efficiency than calves receiving no NeoTec4. These results support previous research that shows that calf diets, which are typically high in linoleic acid from corn and soybeans, can be improved by the addition of linolenic acid. Part of the reason for improved calf performance when linolenic acid is fed may be due to enhanced immune responses that help to reduce scours and improve weight gain and feed efficiency.

Milk Replacer Feeding Rate

University of Minnesota researchers in collaboration with Milk Products Inc. and Hubbard Feeds (Carlson et al.) studied several strategies to capture some of the growth benefits of higher milk replacer feeding rates without sacrificing starter intake. This group had previously attempted to feed greater amounts of milk replacer during the first 2 weeks of life and found that did not improve calf performance. Therefore, this study evaluated feeding higher rates of milk replacer for 21, 28, or 35 days. All calves were fed a 20 percent protein, 20 percent fat milk replacer and 18 percent crude protein, textured starter. The control treatment was fed 1.25 pounds of milk replacer powder per day through 35 days of age. The other treatments were each fed 1.5 pounds of powder, but the length of feeding was 21 days (ENH-21), 28 days (ENH-28), or 35 days (ENH-35). At 21 and 28 days respectively the ENH-21 and ENH-28 calves began receiving 1.0 pound of powder per day through 35 days of age. At 35 days of age, all calves had their current feeding rate cut in half to facilitate weaning at day 42. Calf body weight at 56 days was 8 pounds greater for ENH-35 and ENH-28 calves than for control calves, and average daily gain tended to be greater for ENH-35 calves compared to control calves (0.2 lbs/d advantage). Hip height change was also 0.5 inch greater in calves fed the ENH-35 or ENH-28 treatments compared to control calves. All calves had similar starter intake, which indicates feed efficiency was improved for calves on ENH-35 and ENH-28. Calf health was not affected by different feeding rates in this study. The authors concluded that conventional milk replacer could be fed at 1.5 pounds per day for 28 to 35 days to improve calf growth and maintain starter intake. Presumably this should result in a smoother transition to a dry feed diet at weaning, but the transition period was not included in this study.

Replacing Corn in Calf Diets

Minnesota researchers (Ziegler et al.) also presented the results of a study investigating glycerol as a partial replacement for corn in calf starter and grower diets. Glycerol is the primary byproduct of biodiesel production. In the first phase of this study, 120 calves were fed one of four starters: textured control, pelleted control (same ingredients as textured feed), pellet with 3 percent glycerol, or pellet with 6 percent glycerol. Calf growth and feed intake were similar for all four treatments; however, treatment costs per calf from day 1 to 56 were $1.23 higher for calves on the 6 percent glycerol treatment compared to the other treatments. In the second phase of the study, the same calves were randomly reassigned to three grain mixes (control, 3 percent glycerol, 6 percent glycerol) fed with free-choice hay. The grain mix contained cracked corn and a pellet, and glycerol partially replaced corn. Over 112 days, calf growth, total dry matter intake, and feed efficiency were not affected by the addition of glycerol to the grain mix. Hay intake was slightly higher (0.23 lb/d) for calves fed the control grain mix compared to calves fed glycerol.

Effect of Dry Period Length on Calves

Research from the USDA’s Animal Improvement Programs Laboratory (Norman and Hutchison) looked at the effects of the dry period length on factors affecting calves and heifers. The researchers examined calving difficulty, stillbirth rate, age at first breeding, and heifer survival to first calving using calving and breeding records for Holsteins from January 1997 through December 2010. Actual calving dates were required to be within 10 days of expected calving dates to ensure that the dry period lengths measured were intentional. Records were divided into 12 categories of days dry.

Calving difficulty increased linearly as dry period length increased up to 66 days dry. More stillbirths occurred with dry periods less than 35 days or greater than 71 days; the lowest stillbirth rates were observed with dry periods of 51 to 65 days. Heifer age at first breeding increased by 5 days when the dam’s dry period was 0 to 30 days compared to 56 to 60 days. Heifer survival to the first lactation was reduced when the dam’s dry period was 0 to 30 days or 91 to 120 days compared to 56 to 60 days. Dry periods of 56 to 65 days maximized the number of heifers that survived to their first calving. This study documents the risk of extreme dry periods, whether short (less than 35 days) or long (greater than 71 days), relative to calf and heifer survival.

Source: Coleen Jones, Research Associate, Penn State Department of Dairy and Animal Science