Responses of cows to abomasal infusion of lysine and methionine at two levels of dietary protein

Abstract

The response in dairy cows fed high-concentrate diets to abomasal infusion of lysine (Lys) and methionine (Met) at two levels of dietary CP was examined. Four multiparous Israeli Holstein cows (day in milk=l 80±30, means ± SE) were utilized in a 4x4 Latin square design experiment that included a 2x2 factorial arrangement with 18-d periods. Cows were surgically prepared with abomasal cannulae and catheters implanted in the costoabdominal artery. Two diets were composed to contain high and low crude protein (CP) content (152 vs 132 g/kg dry matter). Abomasal infusion of either water or Lys (38 g/d) plus Met (14 g/d) was performed with each diet. On the last day of the experimental period the metabolism of amino acids (AA) across the mammary gland was monitored. Dry matter intakes and milk and protein yields were not affected by either dietary CP level or postruminal infusion of Lys plus Met and averaged 15.9, 21.4, and 0.694 kg/d, respectively. Milk fat content and yield were not affected by dietary CP concentration, but did increase with abomasal infusion of Lys plus Met (33.3 vs 37.2 g/kg; PO.04, and 0.703 vs 0.762 kg/d; PO.05, respectively). Arterial plasma concentration of Lys and Met increased by 2.4-and 3.5-fold, respectively, when these AA were infused abomasally.

Significance of rumen protected L-arginine –supplementation on certain blood parameters, mammary gland functions and growth rate of newly born lambs

“…However, highly significant differences (P<0.01), between ARG treatment and control one, in RUD, LUD and LDTC, Also, the ARG treatment has significant differences (P<0.05), then control one, on RUW, right teat canal (RTC), LUW, LUC, and (LTC) left teat canal (Table 1). A work on arginine in ruminant mammary gland has been undertaken in 2011; their results showed that milk protein yield was increased by infusion of Arginine compared with the control, and there were Studies reported that the ARG might have plays multiple roles in the body, including metabolism, immune function, and hormones secretion (Mabjeesh et al, 2002). Injection of ARG increased plasma concentrations of somatotropin, insulin, prolactin, and placental lactogenic (Vicini et al, 1988).…”