1503 The effect of metabolizable protein supply for dry Holstein dairy cows on periparturient feed intake, metabolism, and lactation performance

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 729-730
Author(s):  
K. M. Hultquist ◽  
K. W. Cotanch ◽  
C. S. Ballard ◽  
H. A. Tucker ◽  
R. J. Grant ◽  
...  
1990 ◽  
Vol 63 (2) ◽  
pp. 177-186 ◽  
Author(s):  
J. A. Lees ◽  
J. D. Oldham ◽  
W. Haresign ◽  
P. C. Garnsworthy

Four groups of seven dairy cows were given hay plus high-fibre concentrates based on sugar-beet feed (hay-concentrate, 40:60 w/w) or high-starch concentrates based on flaked maize (hay-concentrate, 20:80 w/w), with a crude protein (nitrogen x 6.25) content of either 160 or 220 g/kg dry matter, over weeks 4–18 of lactation. Performance during week 3 of lactation, when all cows were fed on a standard ration, was used as a covariate. For diets with a high-fibre content, higher protein concentrations led to increases in yields of milk and milk fat, with no effect on live-weight loss. For diets with a high-starch content, higher protein concentrations did not affect milk yield or composition but resulted in an increase in live weight rather than a decrease. Diets with a high-starch content led to increased proportions of propionic acid in the rumen and increased concentrations of insulin in the blood. It is concluded that the source of carbohydrate needs to be taken into account when predicting the response to protein supply by dairy cows.


2011 ◽  
Vol 149 (5) ◽  
pp. 639-646 ◽  
Author(s):  
M. ARDALAN ◽  
M. DEHGHAN-BANADAKY ◽  
K. REZAYAZDI ◽  
N. GHAVI HOSSEIN-ZADEH

SUMMARYForty Holstein dairy cows in their first and second lactations were used from 4 weeks prepartum to 10 weeks postpartum to investigate the effects of feeding ruminally protected methionine and choline on plasma metabolites. Cows were randomly assigned to one of the following treatments in a 2×2 factorial design 4 weeks before their expected calving dates, using randomized blocks based on parity: no supplement (control), 18 g/d of rumen-protected methionine (RPM) product, 60 g/d of rumen-protected choline (RPC) product, or 18 g/d of RPM+60 g/d of RPC. Treatments did not affect plasma triglycerides, glucose, total protein, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), plasma urea nitrogen (PUN) or aspartate aminotransferase (AST) during the prepartum period. For postpartum plasma NEFA concentrations, there were interactions between RPC or RPM and week postpartum. Feeding RPM increased plasma AST concentrations (P<0·05) and decreased plasma protein concentrations (P<0·05) in postpartum cows. After calving, feeding RPC increased (P<0·05) dry matter intake (DMI), milk yield, 40 g/kg fat-corrected milk (FCM) yield and energy-corrected milk (ECM) yield. This suggests that supplemental RPC can improve lactation performance of dairy cows.


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