Factors affecting neonatal beef calf metabolism and vigor

Abstract

Two studies were conducted to investigate factors affecting neonatal beef calf metabolism and vigor. In the first study, effects of late gestational nutrient restriction on colostrum yield, neonatal vigor, and blood chemistry and hematology measures were investigated in beef cattle. Colostrum volume and weight from nutrient restricted dams was 40 percent less compared with control dams. Although gestational nutrition did not affect gestation length or calf birth weight, calves born to control dams had faster times to attempt to stand and to stand. Calves born to nutrient restricted dams had greater serum protein metabolites from 6 to 48 h of age. Serum aspartate aminotransferase and creatine kinase concentrations were greater in nutrient restricted calves until 24 h postnatal. Red blood cells, hemoglobin, and hematocrit were greater in control calves at 6 and 12 h of age. In conclusion, calves born to nutrient restricted dams experienced more trauma at birth, reduced neonatal vigor, and had less colostrum available but greater serum protein concentrations. The objectives of the second study were to determine the effect of calving season on perinatal nutrient availability and neonatal vigor. Fall-born calves tended to have lighter birth weight and faster time to stand than spring-born calves. Spring-born calves had greater circulating 0 h glucose, 0 and 6 h NEFA, and 0, 6, 12, and 48 h triglycerides. Fall-born calves had greater sodium and magnesium during the first 48 h postnatal. Spring-born calves had greater aspartate aminotransferase and creatine kinase concentrations until 48 h of age. Albumin, chloride, calcium, and anion gap were greater in fall-born calves. Bicarbonate and direct bilirubin were greater in spring-born calves. In conclusion, spring-born calves are heavier at birth but were slower to stand. Additionally, differences in metabolites over time suggest that spring- and fall-born calves adapt to postnatal life differently where thermoregulation plays an important role.