The objective of this study was to determine whether addition of water to starter would improve performance, rumen fermentation parameters, blood metabolites, and behavior in dairy calves. For this purpose, 30 Holstein male calves (3 d of age; 42.0 ± 4.2 kg of body weight) were randomly assigned to 1 of the following 3 starter diets differing in moisture content: (1) 90% dry matter (DM), (2) 75% DM, and (3) 50% DM. Weaning and final body weight values were found to increase linearly with increasing dietary water. Moreover, starter intake increased linearly during the preweaning and overall periods. Average daily gain also increased linearly in calves receiving the 75% and 50% DM diets compared with those receiving the 90% DM diet. However, treatments had no effects on gain-to-feed ratio. Adding water to a starter with 50% DM led to linear increases in both total volatile fatty acids and molar proportions of acetate and propionate in the rumen but it had no effect on the molar proportions of butyrate, isovalerate, or valerate, nor did it have any effect on acetate-to-propionate ratio. Similarly, times spent on eating, ruminating, standing, lying, and nonnutritive oral behavior exhibited no differences across treatments. Finally, addition of water to the starter diet led to no significant changes in the concentrations of selected blood metabolites, respiration rate, or rectal temperature. Results indicate that calves readily accept wetter feeds with a DM content of 50% and that adding water to starter diets improves calf performance during the hot months of summer.

Two experiments were conducted to determine the effects of feeding equal quantities of milk during the pre-weaning period through different milk-feeding regimes on calf growth, starter intake and selected blood metabolites. In experiment 1, 44 female Holstein calves (3 days of age and 39.2±4.3 kg of BW) were distributed randomly to one of two milk-feeding programs (1 calf per pen; 22 pens per treatment group): (1) consistent (CONS; 6 l/day of milk from days 3 to 60 and 3 l/day from days 61 to 65 of age) or (2) step-up/step-down (SUSD; 5 l/day of milk from days 3 to 15, 8 l/day from days 16 to 40, 6 l/day from days 41 to 50, 3 l/day from days 51 to 60 and then 2 l/day from days 61 to 65 of age). No difference between treatments was observed in starter consumption, feed efficiency, hip width and heart girth. However, pre-weaning average daily gain (ADG) tended to be greater in CONS than in SUSD calves (0.78 v. 0.70 kg/day; P=0.07). Blood β-hydroxybutyrate at day 45 (pre-weaning) was lower in SUSD than in CONS calves (0.14 v. 0.21±0.013 mmol/l). In experiment 2, 26 male Holstein calves (3 days of age and 39.4±4.1 kg of BW) were assigned at random to one of two milk-feeding protocols (1 calf per pen; 13 pens per treatment group): (1) consistent (CONS; (7 l/day of milk from days 3 to 40 and 2 l/day from days 41 to 45 of age) or (2) step-down (STD; 8 l/day of milk from days 3 to 30, 4 l/day from days 31 to 40 and 2 l/day from days 41 to 45 of age). The milk-feeding program had no effect on the performance measurements, with the exception that ADG (days 15 to 30), starter intake (days 30 to 45) and heart girth (day 45) were greater in STD than in CONS calves. In conclusion, it appears that if the total amount of milk intake is held constant over the course of milk-feeding period, the method of milk feeding would have negligible effects on calf performance.