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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #187393
Title: PERIPARTURIENT RESPONSES OF MULTIPAROUS HOLSTEIN COWS FED DIFFERENT DIETARY PHOSPHORUS CONCENTRATIONS PREPARTUM

Author
item PETERSON, A - MICHIGAN STATE UNIV
item ORTH, M - MICHIGAN STATE UNIV
item Goff, Jesse
item BEEDE, D - MICHIGAN STATE UNIV

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2005
Publication Date: 10/20/2005
Citation: Peterson, A.B., Orth, M.W., Goff, J.P., Beede, D.K. 2005. Periparturient responses of multiparous Holstein cows fed different dietary phosphorus concentrations prepartum. Journal of Dairy Science. 88(10):3582-3594.

Interpretive Summary: The National Research Council (NRC) Nutrient Requirements of Dairy Cattle publication of 2001 included a rather large reduction in the requirement of the pregnant cow for phosphorus (P) when compared to the 1989 publication. This recommendation had been based on a mathematical estimate of the requirement rather than experimental data, so these recommendations have been met with some skepticism in the field. This experiment tests the accuracy of those calculations. Late pregnancy cows were fed diets varying only in P content. One diet was 0.31% P - as the new NRC model suggested these cows be fed. The other diets were higher (0.44%) or lower (0.21 %) in P. The cows were fed these diets until they calved and various indices of health and milk production were compared in the cows over the ensuing months. No differences were seen in health or milk production across any of the three diets. Blood calcium concentration was deleteriously depressed in cows fed the 0.44% P diet – the 1989 NRC recommended level. Since no deleterious effects were observed in these cows even when they were fed just 0.21% P diet, the experiment confirms the new NRC recommendation of 0.31% P is justified. Producers adhering to the new guidelines will save money on P supplements and reduce P in manure, often associated with pollution of waterways.

Technical Abstract: Our objective was to compare the effects of different prepartum dietary phosphorus concentrations on periparturient metabolism and performance. Forty-two late pregnant multiparous Holstein cows were fed 0.21, 0.31, or 0.44% P (dry basis) for 4 wk before expected calving. After parturition, all cows were fed a common lactation diet (0.40% P). In the prepartum period, cows fed 0.21% P had lower blood serum P concentrations compared with cows fed 0.31 or 0.44% P. However, serum P concentrations of all cows were within the normal range (4 to 8 mg/dL) until the day of calving when average concentrations dropped below 4 mg/dL. From 3 to 14 d postpartum, serum P of cows fed 0.21% P was greater than that of cows fed 0.31 or 0.44% P. No cows presented with or were treated for clinical hypophosphatemia in the periparturient period. Total serum Ca was lower before calving through 2 d postpartum for cows fed 0.44% P compared with those fed 0.21 or 0.31%. Prepartum dietary P treatments did not alter blood osteocalcin, hydroxyproline, and deoxypyridinoline, indicators of bone metabolism, or concentrations of parathyroid hormone or 1,25-dihydroxyvitamin D3. Energy-corrected milk yield and milk composition (first 28 d of lactation) were not affected by prepartum dietary P concentrations. It is concluded that feeding 0.21% P (34 g of P/cow daily) prepartum is adequate for periparturient multiparous Holstein cows with high metabolic demands and genetic potential for milk production. No adverse effects on periparturient health, dry matter intake, or 28-d lactation performance resulted.