Traditional preweaning feeding programs have limit fed milk or milk replacer to encourage starter intake and early weaning as a means of reducing daily feed cost. More recently, research and experience by dairy producers has shown that the practice of feeding calves more milk or milk replacer before weaning has a positive impact on growth. However, given the current economic conditions, what are the benefits to offset these higher feed costs?
First, a higher liquid feeding rate during the first four weeks of life improves feed efficiency as a lower proportion of nutrients are devoted to body growth. This makes each pound of gain cost less. Second, many studies have shown that higher milk or milk replacer feeding rates are associated with higher milk production during the first lactation This is encouraging but when milk prices are low, we want to see positive economic returns sooner rather than later. A third advantage appears to be an improved immune response to feeding more milk or milk replacer during the preweaning period. This can result in lower treatment cost, less labor to treat sick calves, lower culling rates and possibly an additional milk response from healthier cows.
Workers at Texas Tech University compared the response of calves fed either a low plane of nutrition (1 lb. of milk solids) or a high plane of nutrition (1.8 lb. the first week and 2.4 lb. through 54 days of age) to a Bovine Herpesvirus and Mannheimia challenge at 81 and 84 days of age. (As a reference 1 lb. of milk solids equals about a gallon of milk and 2.4 lb. of milk solids is more than 2 gallons). All calves were weaned at 70 days of age. Calves fed the low plane of nutrition had lower blood glucose and mobilized more body fat during the challenge which indicated a more severe response to these respiratory challenges. In another study on a commercial calf ranch, sale barn calves in which more than 75% were colostrum deprived, were fed either 1 lb. of milk solids from a 20:20 milk replacer or 1.8 to 2.4 lb. of milk solids from a 28:20 milk replacer. Calves were weaned at 57 days. Although the calves fed more liberally had more bloat and looser manure there were no differences in health treatments. More liberally fed calves gained 1.2 lb. / day during the first 25 days vs. .2 lb. / day for the calves fed the 20:20 milk replacer. These advantages in body weight gain persisted throughout the study. The more liberally fed calves had higher feed efficiency (1.7 vs. 5.8 feed: gain ratio) for the first 25 days of life and over the term of the study (2.2 vs. 3.3 feed: gain). This later study demonstrated that higher feeding rates don’t predispose calves to more digestive disease.
More liberal feeding programs for calves based upon intakes of higher protein milk replacers or whole milk result in great body weight gains, improved feed efficiency, better health and improved first lactation milk yield when included in a well-designed feeding program for the postweaned dairy heifer.
Source: Virginia Cooperative Extension
