Effects of supplementing concentrates differing in carbohydrate composition in veal calf diets: I. Animal performance and rumen fermentation characteristics.

The aim of this experiment was to examine the effects of concentrates in feed, differing in carbohydrate source, on the growth performance and rumen fermentation characteristics of veal calves. For this purpose, 160 Holstein Friesian x Dutch Friesian crossbred male calves were used in a complete randomized block design with a 5 x 2 factorial arrangement. Dietary treatments consisted of 1) milk replacer control, 2) pectin-based concentrate, 3) neutral detergent fiber-based concentrate, 4) starch-based concentrate, and 5) mixed concentrate (equal amounts of concentrates of treatments 2, 3, and 4). Concentrate diets were provided as pellets in addition to a commercial milk replacer. Calves were euthanized either at the end of 8 or 12 wk of age. The overall dry matter intake of the concentrate diets varied between 0.37 and 0.52 kg/d. Among the concentrate diets, the dry matter intake was lower in the starch diet (0.37 kg/d of dry matter) and differed between the NDF and pectin diets. The average daily gain for all the dietary treatments varied between 0.70 and 0.78 kg/d. The mixed- and NDF-fed calves had an increased average daily gain (0.78 and 0.77 kg/d, respectively) compared with the starch- and pectin-fed calves (0.70 and 0.71 kg/d, respectively). Rumen fermentation in the calves fed concentrates was characterized by a low pH (4.9 to 5.2), volatile fatty acid concentrations between 100 and 121 mmol/L, and high concentrations of reducing sugars (33 to 66 g/kg of dry matter). The volatile fatty acid concentrations of calves fed concentrates were higher than those of the control calves. All concentrate treatments showed a low acetate-to-propionate ratio in rumen fluid (between 1.3 and 1.9). Among the concentrates, the NDF diet had the highest (55.5%) and starch the lowest (45.5%) molar proportions of acetate. Calves fed the mixed, pectin, and starch diets had significantly higher molar proportions of butyrate (13.1 to 15.8%) than the NDF- and control-fed groups (9.9 and 9.6%, respectively). Calves fed the control diet had a higher lactate concentration (21 mmol/L) than the concentrate-fed calves (between 5 and 11 mmol/L). With the exception of the NDF diet, polysaccharide-degrading enzyme activities in the rumen contents generally showed an adaptation of the microorganisms to the carbohydrate source in the diet. The mixed diet exhibited the least variation in rumen polysaccharide-degrading enzyme activities among the enzymes systems tested. Results indicated that the carbohydrate source can influence intake, growth rate, and rumen fermentation in young veal calves.

Effects of pair versus individual housing on the behavior and performance of dairy calves.

This study compared the health, performance, and behavior of individually and pair-housed calves fed milk ad libitum by artificial teats. Calves were separated from their dams within 24 h of birth and assigned to housing in either a single pen (10 calves) or a group pen (10 pairs of pair-housed calves). Calves were gradually weaned at approximately 5 wk of age and remained on the experiment until wk 8. Behavior was video recorded during wk 2 to 8. Before and after weaning, calves gained weight steadily with no differences between treatments. During the week of weaning, pair-housed calves continued to gain weight normally, but the individually housed calves experienced a growth check. There were no differences between groups in the amounts of milk, starter, or hay consumed, or in the incidence of scouring. There were also no differences in the amount of time spent self-grooming, sucking on the teat, or lying down. However, pair-housed calves spent more time standing inactive, more time moving, and less time with their head out of the pen than individually housed animals. Paired calves spent approximately 2% of the day in social contact, and the incidences of agonistic behavior and cross-sucking were very low. These results indicate that housing dairy calves in pairs allows benefits such as increased space for movement and social opportunities with no disadvantages in health and weight gains.