Co-Authors:
Mabjeesh, S.J., Department of Animal Sciences, Faculty of Agricultural, Food/Environmental Quality Sciences, P.O. Box 12, Rehovot 76100, Israel
Smoler, E., Department of Animal Sciences, Faculty of Agricultural, Food/Environmental Quality Sciences, P.O. Box 12, Rehovot 76100, Israel
Abramson, S.M., Department of Animal Sciences, Faculty of Agricultural, Food/Environmental Quality Sciences, P.O. Box 12, Rehovot 76100, Israel
Bruckental, I., Physiology and Nutrition Department, Institute of Animal Sciences, Agriculture Research Organization, Bet Dagan 50250, Israel
Zamwel, S., Department of Animal Sciences, Faculty of Agricultural, Food/Environmental Quality Sciences, P.O. Box 12, Rehovot 76100, Israel
Nanjappan, K., Department of Physiology, Vet. College Research Institute, Namakkal, 637002, India
Arieli, A., Department of Animal Sciences, Faculty of Agricultural, Food/Environmental Quality Sciences, P.O. Box 12, Rehovot 76100, Israel
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=180±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; P<0.04, and 0.703 vs 0.762 kg/d; P<0.05, respectively). Arterial plasma concentration of Lys and Met increased by 2.4- and 3.5-fold, respectively, when these AA were infused abomasally. Net mammary gland uptake of both AA increased during the abomasal infusion in the low CP diets but not in the high CP diets. The ratio of uptake across the udder of these AA to their corresponding output value in milk, suggested that there was no shortage of supplying Lys and Met from dietary intake. It was also apparent that increased uptake of Met across the udder was accompanied with higher fat secretion in milk.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם
