scholarly journals Effect of forage source and a supplementary methionine hydroxy analog on nitrogen balance in lactating dairy cows offered a low crude protein diet

2011 ◽  
Vol 94 (10) ◽  
pp. 5080-5089 ◽  
Author(s):  
S.J. Whelan ◽  
F.J. Mulligan ◽  
B. Flynn ◽  
C. McCarney ◽  
K.M. Pierce
Keyword(s):  
Dairy Cows ◽  
Nitrogen Balance ◽  
Crude Protein ◽  
Protein Diet ◽  
Lactating Dairy Cows

Effects of dietary protein concentration on the efficiency of nitrogen utilisation in lactating dairy cows

2009 ◽  
Vol 2009 ◽  
pp. 78-78
Author(s):  
T Yan ◽  
F J Young ◽  
D C Patterson ◽  
C S Mayne
Keyword(s):  
Dairy Cows ◽  
Crude Protein ◽  
Protein Concentration ◽  
Production Systems ◽  
Mitigation Strategies ◽  
The European Union ◽  
Dietary Crude Protein ◽  
Lactating Dairy Cows ◽  
Stocking Rates ◽  
Animal Production Systems

The European Union Nitrates Directives set a limit on the amount (170 kg/ha) of manure nitrogen (N, = faecal N + urine N) that may be applied to land each year. This limit has very significant implications for stocking rates on intensive livestock farms. Consequently, there is increasing interest in developing mitigation strategies to reduce N output in faeces and urine in animal production systems. The objectives of the present study were to evaluate the effects of dietary crude protein (CP) concentration on the efficiency of N utilisation in lactating dairy cows.

CHROMIC OXIDE IN DIGESTIBILITY STUDIES WITH LACTATING DAIRY COWS

1969 ◽  
Vol 49 (3) ◽  
pp. 383-388
Author(s):  
A. L. Hoogendoorn ◽  
C. M. Grieve
Keyword(s):  
Dairy Cows ◽  
Conventional Method ◽  
Crude Protein ◽  
Dry Matter ◽  
Chromic Oxide ◽  
Daily Administration ◽  
Apparent Digestibility ◽  
Lactating Dairy Cows ◽  
Holstein Friesian ◽  
Friesian Cows

Chromic oxide (Cr2O3) in paper pellets was used as an indicator for digestibility studies with four Holstein-Friesian cows fed rations composed of different roughage to concentrate ratios. Cows A and B received one pellet, or 3.46 g of Cr2O3, whereas cows C and D received three pellets, or 10.38 g of Cr2O3, daily.Recovery of Cr2O3 in the feces varied from 84 to 103% for animals A and B and from 92 to 95% for animals C and D. The coefficients of apparent digestion of dry matter were lower (P < 0.01) when the Cr2O3 method was used instead of the conventional method. When samples were taken at 0500, 0900, 1300 and 1700 hours, the Cr2O3 method gave average estimates of digestibility for animal pairs A, B and C, D that were 94.2 and 97.5% of those obtained by the conventional method. Standard deviations for both the Cr2O3 and conventional methods were relatively high.Excretion patterns of Cr2O3 were not signicantly correlated with those of crude protein, phosphorus and calcium. The average concentrations of crude protein, phosphorus and calcium in compounded feces samples collected at 0500, 0900, 1300 and 1700 hours were 101.3, 100.6 and 96.7% of those in samples of the total excretions.The daily administration of 10.38 g of Cr2O3 at 0900 hours for eight days, and the collection of fecal grab samples at 0500, 0900, 1300 and 1700 hours daily during the last five days seemed satisfactory for estimating apparent digestibility of dry matter.

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