title: Effect of anionic salts in prepartum diets based on alfalfa.
abstract: This study compared prepartum diets based on grass, alfalfa, or alfalfa and anionic salts to investigate their effect on Ca metabolism, acid-base status, endocrine response, disease incidence, and lactational performance of periparturient dairy cows. Forty-five nonlactating Holstein cows in their last 3 wk of gestation were fed a control diet based on grass hay with a dietary cation-anion difference [expressed as milli-equivalents of ((Na + K) - (Cl + S))/100 g of dietary dry matter] of +30 or diets based on alfalfa with a dietary cation-anion difference of either +35 or -7. Cows fed the diet with the dietary cation-anion difference of -7 had the lowest urine pH prepartum and had the highest concentrations of ionized Ca in blood and total Ca in serum at parturition. Increases in 1,25-(OH)2 vitamin D per unit decrease in total Ca in serum were greatest for cows fed the diet with a dietary cation-anion difference of -7. Also, cows fed this same diet consumed the most dry matter postpartum. Incidences of health disorders were 13% (10 of 75), 12% (9 of 75), and 5% (4 of 75) for cows fed the diets with dietary cation-anion differences of +30, +35, and -7, respectively. Results indicate that alfalfa, when supplemented with anionic salts, is a viable forage for prepartum dairy cows.
authors.affiliation: Department of Animal and Veterinary Science, University of Idaho, Moscow 83844, USA.
authors.forename: P W
authors.initials: PW
authors.lastname: Joyce
authors.forename: W K
authors.initials: WK
authors.lastname: Sanchez
authors.forename: J P
authors.initials: JP
authors.lastname: Goff
mesh_terms: D000136:Acid-Base Equilibrium; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000838:Anions; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood / Q000652:urine; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases; D002712:Chlorides; D005260:Female; D006863:Hydrogen-Ion Concentration; D007774:Lactation; D000455:Medicago sativa; D010758:Phosphorus / Q000097:blood; D011188:Potassium; D011247:Pregnancy; D012492:Salts; D012964:Sodium; D013455:Sulfur
chemical_list: D000838:Anions; D002712:Chlorides; D012492:Salts; D010758:Phosphorus; D013455:Sulfur; D012964:Sodium; D002117:Calcitriol; D011188:Potassium; D002118:Calcium