Author
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WU, Z - UNIV OF WISCONSIN MADISON |
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Satter, Larry |
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Submitted to: Journal Dairy Science Supplement
Publication Type: Abstract Only Publication Acceptance Date: 6/23/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Milk production response to four different amounts of protein supplementation was measured in a complete lactation study utilizing 58 multiparous Holsteins treated with bST. The four treatments were as follows, with the first number being the dietary CP content (% of DM) during the first 16 wk of lactation, and the second number the CP content for wk 17 to 44 of lactation: 15.4-16.0, 17.4-16.0, 17.4-17.9, and 19.3- 17.9. High moisture ear corn was finely ground to promote ruminal fermentation and microbial protein synthesis, and roasted soybeans and expeller processed soybean meal were used as the protein supplements to provide RUP. Alfalfa silage and corn silage (3 : 2) provided the forage. Milk yield for the 308-d lactation for each of the treatment groups was: 10,056**c; 10,831**b; 11.095**a; and 11,132**a kg (a > c, P < .04; b > c, P < .12). Cows of this production level treated with bST benefit from dietary yCP of approximately 17.5% during the first 30 wk of lactation. A reduction in CP to 16% can be made around wk 30 of lactation. Dietary CP%: weeks 1-16 Dietary CP%: weeks 17-44 15.4- 17.4- 17.4- 19.3- Item 15.4 17.4 19.3 SEM 16.0 16.0 17.9 17.9 SEM DMI, kg/d 21.2 22.3 21.8 .6 24.o**b 24.2**b 25.4**a 24.7 .5 Milk, kg/d 36.9**b39.5**a 40.8**a 1.0 30.1**b 32.9 33.8**a 33.5**a 1.4 Milk fat, % 3.97 4.05 3.94 .12 4.06**a 3.96 3.98 3.72**b .14 **a,b a>b (P < .10) within a row and period |
