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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #89696
Title: MILK PRODUCTION AND REPRODUCTIVE PERFORMANCE OF DAIRY COWS FED LOW OR NORMAL PHOSPHORUS DIETS

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

Submitted to: Journal Dairy Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The objective was to determine if P supplementation of a typical lactation diet is necessary. At calving (September to October) 48 Holsteins were assigned randomly to either a low or normal P diet. Cows were fed a TMR (corn silage, alfalfa silage, high moisture ear corn, and roasted soybeans) in free stalls until the middle of May. Pasture provided the forage until the end of August, by which time all of the cows were dried off. Supplemental mixes were fed during grazing (7.0 kg/d, DM) to provide approximately 40% of total feed intake. The P content was .35 or .45% of the TMR (DM basis), and .35 or .65% of the supplements for the low and normal P diets. Pasture herbage averaged .30% P. Supplemental P was fed to achieve the higher P amounts. Milk yield averaged for the entire lactation did not differ between the groups. Milk protein concentration was reduced in the low P group; however, protein yield did not differ. Blood serum P concentrations were within normal ranges for both groups. Cows on low P were detected in estrus 8.3 d later than those on normal P, but pregnancy rates were not different. Reducing dietary P from .45 to .35% for a complete lactation did not impair milk yield or reproductive performance. Inclusion of a P supplement in the diet was without apparent benefit, except for possibly a small increase in milk protein percentage.