Interactions between grain source and alfalfa hay particle size on performance, ruminal fermentation, skeletal growth and blood parameters in Holstein dairy calves

This study was conducted to investigate the effect of grain sources (corn or barley) and alfalfa hay particle size (PS; fine or medium) on growth performance, blood parameters and ruminal fermentation of dairy calves. Thirty-two 3-d-old Holstein dairy calves (36.4 ± 2.0 kg of body weight) were used in a completely randomized design with 2 × 2 factorial arrangement. Experimental diets consisted of diet containing barley grain with fine alfalfa hay PS, barley grain with medium alfalfa hay PS, corn grain with fine alfalfa hay PS and corn grain with medium alfalfa hay PS. Starter feed intake was greater for calves fed corn than those fed barley during the pre- and post-weaning and overall periods. Calves fed corn had greater final body weight as well as overall average daily gain (ADG) than barley calves. However, alfalfa hay PS had no effect on starter intake and ADG. Hip and wither heights were greater in calves fed corn than those fed barley. Total volatile fatty acids concentrations increased and the molar proportion of acetate decreased in calves fed corn compared to those fed barley. These results showed no interactions between grain sources and alfalfa hay PS on calf performance; however, corn inclusion in starter diet improved the growth performance of Holstein calves during the transition from liquid to solid feed.