The effects of maternal supplementation of rumen‐protected lysine during the close‐up dry period on newborn metabolism and growth in Holstein calves

Abstract

This study aimed to evaluate the effects of rumen‐protected lysine (RPL) supplementation during the close‐up period on blood metabolites and calf growth. Forty multiparous Holstein dams were selected based on parity, body condition score, and expected calving date, and randomly assigned to a group: with RPL (n = 22) or without (control [CON], n = 18). RPL dams were supplied daily with 80 g of RPL from Day 21 before the expected calving date to parturition. Blood samples were obtained from the dams before the start of supplementation, 1 week before calving, and immediately after calving, and from calves immediately after birth and weekly until 8 weeks of age. Body weight measurements were performed immediately after birth in all calves and at weekly intervals until 8 weeks of age in female calves. No significant difference was observed in serum metabolite levels and plasma amino acid concentrations between the RPL and CON dams before supplementation, whereas plasma lysine concentrations tended to be higher in RPL dams immediately after calving (p = 0.07). Serum total protein levels (p < 0.05) were higher, whereas plasma total amino acid, total essential amino acid, total non‐essential amino acid, and other amino acid concentrations were lower in the calves of RPL dams than those of CON dams (p < 0.05). There were no significant differences in calf birth weight between the two groups, although female calves of RPL dams (n = 7) had higher serum total protein (p < 0.05) and tended to have greater body weight (p = 0.09) from 1 to 8 weeks of age than those of CON dams (n = 11). Overall, RPL supplementation during the close‐up period may increase placenta‐mediated amino acid transfer to the foetus and enhance protein synthesis in the calf, leading to improved weight gain during the suckling period.

Comparative Analysis of Maternal Colostrum and Colostrum Replacer Effects on Immunity, Growth, and Health of Japanese Black Calves

“…The CR was manufactured using carefully selected high-quality cow colostrum as a raw material. The inherent variability of colostrum is standardized to a certain quality to ensure a high level of safety, and the positive outcomes attributed to the utilization of the CR were evidenced in previous study [15].…”

Supplementation of rumen‐protected lysine during the close‐up period improves vaginal discharge clearance in Holstein dairy cows

“…Yet, because the plasma AA levels 1 week before calving were similar in both groups, the difference in serum protein levels between the two groups was smaller than that at the onset of the experiment. Previous studies have shown that RPL supplementation before calving increases blood lysine concentrations as well as other AA concentrations (Lee et al, 2019), while others have reported increased blood lysine levels but a decrease or no change in other AA concentrations (Fehlberg et al, 2020;Kawashima et al, 2023). Lee et al (2019) indicated that the rate of catabolism and lysine transamination may increase when the AA supply exceeds the demand for cows.…”