Winter weather has arrived or will be here soon and calf feeding programs need to change. Calves are especially susceptible to cold stress for several reasons. This is especially true for calves during the first three to four weeks of age before they begin consuming measurable quantities of calf starter grain.
First, these are small animals that lose body heat much more quickly than larger animals because they have a larger surface area. The smaller the calf, the more important this relationship becomes. Virginia Tech research revealed that small calves, such as Jerseys, had a maintenance requirement which was at least 15% higher than large breed calves such as Holsteins.
Second, the environment has a significant impact on maintenance requirements. During the winter, calves require deep, dry bedding to help them maintain the insulating capabilities of their hair coat. A wet environment with limited bedding greatly enhances heat loss.
Third, calves are born with relatively low reserves of body fat that they can mobilize during periods of low energy intake or environmental stress. The impact of cold weather on nutrient requirements is demonstrated by the following example with a calf weighing 100 lb.:
Another stress occurs due to the fact that most calves are fed equal amounts early in the morning and again later in the afternoon. Imagine the nutritional stress calves face during the long interval between the evening and morning feeding when the temperature drops at night. It’s apparent that calf feeding rates need to be increased during the winter. A 20% fat milk replacer is highly recommended over those with lower fat content. Feeding rates should be increased by 50% or doubled under extreme cold. Feeding 1.5 gallons of a 20% fat milk replacer reconstituted to 12.5% solids provides sufficient energy for 0.23 lb. of gain at 32oF. However, it would take 2 gallons of this liquid to maintain a growth rate of 0.4 lb. at 20oF. In response to our research indicating the higher susceptibility of small calves to cold stress, a 25% fat milk replacer was developed for Jersey calves.
Additionally, successful management of calves during the winter involves creating a dry, stress free environment with deep bedding and protection from drafts and dampness. Calf coats can help reduce heat loss if they are kept dry. Finally, it should be apparent that feeding management must change to enable calves to grow and resist digestive and respiratory disease. Don’t skimp on liquid feeding programs, especially during the first weeks of life when calf starter intake is low. Savings by limit feeding milk or milk replacer to less than 1.5 gallons daily (12.5% to 15% solids) or use of a poor quality milk replacer may reduce feed costs, but substantially increase treatment costs and possibly lead to conditions which lead to increased mortality and a restriction of lifetime performance of the animal.
Virginia Cooperative Extension materials are available for public use, re-print, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Alan L. Grant, Dean, College of Agriculture and Life Sciences; Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; Jewel E. Hairston, Administrator, 1890 Extension Program, Virginia State, Petersburg.
January 2, 2012