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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #105623

Title: MILK PRODUCTION AND REPRODUCTIVE PERFORMANCE OF DAIRY COWS FED DIFFERENT AMOUNTS OF PHOSPHORUS

Author
item WU, Z - UNIV OF WISCONSIN MADISON
item Satter, Larry

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: Response of dairy cows to different dietary P levels was determined in two full-lactation trials. Trial 1 was the 2nd yr of a 2-yr study (first yr data were reported last yr). The lactation period included confinement feeding (~ 2/3 of lactation) and grazing (~ 1/3 of lactation) for most cows (75%), and only confinement for the remaining animals. Twenty-six cows received no supplemental P (dietary P was ~ .37% of DM during confinement and ~ .31 % during grazing) and 27 cows received NaH2PO4 and CaHPO4 to increase dietary P to ~ .47% during confinement and ~ .44% during grazing. Thirty of the cows were in their 2nd yr of treatment. Milk production and reproductive performance were not affected by P levels, consistent with results in yr 1 of the trial. Milk yield for cows in their 2nd yr of treatment was 11,457 and 11,358 kg/308 d (P = .86) for the low and high P treatments. In trial 2, .31, .40, or .49% dietary P (varied by NaH2PO4) was sfed to 8, 9, and 9 cows. Reducing P from .49 to .40% did not impair milk production or reproductive performance, but a further reduction to .31% reduced milk yield in late lactation. Phosphorus at .37-.40% is adequate for high producing cows. Dietary P%: Trial 1 Dietary P%: Trial 2 Item .31-.37 .44-.47 SEM .31 .40 .49 SEM Milk, kg/308 d 9864 9898 340 10790 11226 11134 607 Milk fat, % 3.78 3.65 .10 3.65 3.69 3.71 .11 Milk protein, % 3.14 3.14 .04 3.08 3.07 3.11 .08 Days open 103 105 13 78 106 112 15 Pregnancy rate, % 96 86 ... 100 89 89 Services/concept. 1.6 2.1 .2 1.4 1.6 2.3 .4