Effects of once- versus twice-a-day feeding of pasteurized milk supplemented with yeast-derived feed additives on growth and health in female dairy calves

The objective of this study was to compare the effects of feeding preweaning dairy calves pasteurized milk once or twice a day with or without a combination of yeast-derived products. Holstein heifer calves (n = 48) from The Pennsylvania State University dairy herd were fed 3.8 L of colostrum in 1 feeding and randomly assigned to 1 of 4 treatments (once-a-day milk feeding with or without live yeast culture and mannan-rich fraction and twice-a-day milk feeding with or without live yeast culture and mannan-rich fraction). All calves were fed 6 L of milk daily. Weekly growth measurements and blood samples were taken 3 h after the morning milk feeding for all animals. Growth measurement included body weight, hip width, and withers height. Calf starter refusal was recorded weekly, and a sample was taken to determine dry matter intake. Daily health scores were recorded for each calf using a standard scoring system. Intake, growth measurements, haptoglobin, and health scores data were analyzed using repeated measures analysis with calf included as a random variable. Preweaning average daily gain was 553.4 and 512.1 g/d for calves fed milk once and twice a day, respectively, and we found no difference between treatments. Preweaning calf starter intake was 242.3 and 198.7 g/d for calves fed milk once and twice a day, respectively, and we found no treatment differences. Preweaning calf starter intake was 224.3 and 216.6 g/d for calves fed yeast and without yeast, respectively. Withers height and hip width were similar in calves fed milk either once or twice a day; however, calves fed yeast tended to have greater withers height and hip width than control calves. Haptoglobin concentration as a measure of stress had least squares means of 4.0 and 9.5 ± 3.5 µg/mL for calves fed milk once or twice a day, respectively, and we found no difference among treatments. Scours score and total daily score were similar for calves fed milk once or twice a day. These results suggest that feeding milk once a day can be successfully applied to a calf feeding system and that yeast products may improve structural growth.