title: Effect of prepartum dietary calcium on intake and serum and urinary mineral concentrations of cows.
abstract: Nine multiparous and 12 primiparous cows were fed diets containing an anionic salt supplement and moderate Ca (0.99%) or high Ca (1.50%) concentrations for 21 d prepartum to determine the effects of dietary Ca concentration on serum and urine electrolytes and on postpartum intake and milk yield. Blood samples were collected during 21 to 1 d prepartum, 0 to 2 d postpartum, and 3 to 21 d postpartum. Dietary cation-anion difference (DCAD) for prepartum diets was approximately -6 mEq/100 g of dry matter (Na + K - Cl - S). Immediately postpartum, cows were fed diets with positive DCAD with greater than 1.00% Ca concentration. Mean serum Ca concentrations 21 to 1 d prepartum, 0 to 2 d postpartum, and 3 to 21 d postpartum were 9.62, 8.41, and 9.38 mg/dL. There were no treatment effects on serum Ca concentration. Mean serum Ca concentration was higher for primiparous than multiparous cows (9.34 vs. 8.93 mg/dL) for the trial and at calving (8.77 vs. 8.13 mg/dL). Mean serum HCO(3)(-) and urinary pH, respectively, were 20.32 mEq/L and 5.67 prepartum, 25.82 mEq/L and 7.62 at calving, and 26.08 mEq/L and 8.25 postpartum. No differences due to treatment were observed for serum and urinary concentrations of HCO(3)(-), pH, Mg, Na, K, and Cl. Milk yield was similar for 0.99 and 1.50% Ca treatments (22.8 and 20.7 kg/d). Diets containing 0.99 or 1.5% Ca maintained serum Ca at adequate levels around parturition and resulted in similar dry matter intake and postpartum milk yield.
authors.affiliation: Department of Animal and Dairy Science, University of Georgia Coastal Plain Experiment Station, Tifton 31793-0748, USA.
authors.forename: P S
authors.initials: PS
authors.lastname: Chan
authors.forename: J W
authors.initials: JW
authors.lastname: West
authors.forename: J K
authors.initials: JK
authors.lastname: Bernard
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001639:Bicarbonates / Q000097:blood / Q000652:urine; D002118:Calcium / Q000097:blood / Q000652:urine; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002417:Cattle / Q000502:physiology*; D002712:Chlorides / Q000097:blood; D004032:Diet; D005260:Female; D006863:Hydrogen-Ion Concentration; D007774:Lactation; D016014:Linear Models; D008892:Milk / Q000737:chemistry; D008903:Minerals / Q000097:blood* / Q000652:urine*; D010298:Parity; D010758:Phosphorus / Q000097:blood; D049590:Postpartum Period; D011247:Pregnancy; D014556:Urine
chemical_list: D001639:Bicarbonates; D002136:Calcium, Dietary; D002712:Chlorides; D008903:Minerals; D010758:Phosphorus; D002118:Calcium