Influence of Dietary Nucleotide Supplementation in Milk Replacer on Growth Performance and Blood Composition of Japanese Black Suckling Calves

The present study aimed to investigate the effects of dietary nucleotide supplementation of an antibiotic-free milk replacer on the growth performance and blood composition of Japanese Black calves. Eighteen calves were divided into two groups: antibiotics-free milk replacer supplementation with (RM group) and without (CT group) nucleotides. No differences in dry matter, crude protein, or total digestible nutrient intake were found between the groups during the suckling period. The suckling period from the beginning of the study at age 11.6 ± 0.9 days to weaning was significantly shorter in the RM group than in the CT group. Body weight was not significantly different between the two groups at any time point. However, the daily gain (DG) and feed efficiency during the suckling period were significantly higher in the RM group than in the CT group. Body measurements and fecal condition of calves were recorded, but no significant differences in any values were observed between the two groups. Post-weaning blood β-hydroxybutyrate values in both groups were significantly higher than those in the suckling period. Feeding nucleotides to Japanese Black suckling calves led to enhanced growth performance, increased DG, and improved feed efficiency, resulting in a shorter duration of suckling.