Reduced age at first calving: effects on lifetime production, longevity, and profitability

The primary advantages of reducing age at first calving (AFC) include reducing rearing costs as well as reducing time in which the heifer is only a capital drain on farm resources. The primary disadvantage of reducing AFC is that it is frequently associated with a reduction in first-lactation milk yield. Despite this reduction in first-lactation milk yield, production per year of herd life is typically increased by reduced AFC. Furthermore, although the first lactation yield may be influenced by AFC, future lactations are decidedly not. In addition, stayability and health of cows are not influenced by reduced AFC as long as heifers freshen at an adequate weight. Most analyses indicate that the financial advantage afforded from heifers that freshen at a low AFC seems to at the least offset any milk lost during the first lactation. Furthermore, when the time value of money is considered in this analysis, a reduced AFC (~22 months) seems likely to represent a more fiscally sound management decision. When applying these ideas on the farm, a properly managed feeding and breeding program should permit a firstlactation cow to weigh ~1,210 lb after freshening at 22 months of age. The National Research Council recommends a postpartum weight equal to 82% of her mature body weight. This can be achieved with a maximal prepubertal average daily gain (ADG) of 2 lb/day when a traditional preweaning program is employed or 1.8 lb/day when an intensified preweaning program is employed. Because of the well defined link between inadequate body weight at calving and increased mortality and morbidity in first-lactation cows, achieving this target post-calving body weight is of critical importance.; Dairy Day, 2004, Kansas State University, Manhattan, KS, 2004

Balancing for Intestinal Nitrogen Indigestibility in High Producing Lactating Cattle: One Step Closer to Feeding a Cow Like a Pig?

This information was presented at the 2014 Cornell Nutrition Conference for Feed Manufacturers, organized by the Department of Animal Science In the College of Agriculture and Life Sciences at Cornell University. Softcover copies of the entire conference proceedings may be purchased at http://ansci.cals.cornell.edu/extension-outreach/adult-extension/dairy-management/order-proceedings-resources or by calling (607)255-4285

Effects of Intensified Nutrition on Immune Cell Populations in Milk Replacer-Fed Neonatal Calves

Results from the present study confirm the growthpromoting benefits of feeding an intensified milk replacer to dairy calves. Effects of the elevated plane of nutrition on immune variables examined in the present study were minimal. The number of circulating leukocytes and the composition of the PBMC population as well as this population’s general responsiveness and capacity to secrete IgM were not affected by diet. Relative to responses of calves fed the traditional MR, calves fed the intensified MR demonstrated reduced IFN-γ responses and elevated NO responses during the latter stages of the study. Aberrant NO production, however, can result in undesirable host tissue destruction