Short communication: Performance of Holstein calves fed high-solid milk with or without nucleotide

Our initial hypothesis was that the exogenous supply of nucleotides to neonatal calves would improve the development and functionality of gastrointestinal tissue, thereby enhancing their capacity to efficiently digest and utilize the nutrients in high-solids milk. Twenty 3-d-old male Holstein calves (37.9 ± 2.24 kg of body weight) were distributed randomly to 1 of 2 treatments (1 calf per pen; 10 pens per treatment) without or with added nucleotides to their daily milk. Dry milk powder was added to pasteurized milk and offered as 4 L/d from d 3 to 15, 6 L/d from d 16 to 49 (at 0900 and 1600 h), and 2 L/d in morning feeding from d 50 to 55. High-solids milk (fat = 4.47%, protein = 4.64%, lactose = 8.13%, and total solids = 17.7%) was made through the addition of milk powder into whole milk and supplemented without or with 2 g/d of a commercially available nucleotide product, and then fed until weaning. Nucleotide supplementation had no effect on preweaning growth rate, but tended to increase postweaning daily weight gain (d 56-75). Unexpectedly, nucleotide supplementation tended to increase fecal score within the 10 d of calf life; thereafter (until weaning), no difference was detected in fecal consistency. Nucleotide supplementation tended to increase and increased pre- and postweaning dry matter intake, respectively. Efficiency of feed utilization (kilogram of weight gain per kilogram of dry matter intake) was not influenced with treatment. The net gain (d 1-70) of withers height and hip height tended to be greater in nucleotide-fed calves. Overall, addition of nucleotides to the high-solids milk had marginal effects on preweaning performance and tended to increase fecal scores (looser feces) in the initial phase of life; however, it increased starter feed intake and growth rate after weaning. A longer-feeding experiment is recommended to elucidate the potential effects of nucleotide supplementation in high-solids milk on calf performance.