title: Effect of dietary cation-anion difference on performance of lactating dairy cows and stability of milk proteins.
abstract: Casein micelle stability is negatively correlated with milk concentrations of ionic calcium, which may change according to the metabolic and nutritional status of dairy cows. The present study aimed to evaluate the effect of dietary cation-anion difference (DCAD) on concentrations of casein subunits, whey proteins, ionic calcium, and milk heat and ethanol stability. Sixteen Holstein cows were distributed in 4 contemporary 4 × 4 Latin square designs, which consisted of 4 periods of 21 d and 4 treatments according to DCAD: 290, 192, 98, and -71 mEq/kg of dry matter (DM). The milk concentrations of ionic calcium and κ-casein were reduced as DCAD increased, whereas the milk urea nitrogen and β-lactoglobulin concentrations were increased. As a result of these alterations, the milk ethanol stability and milk stability during heating at 140 °C were increased linearly with increasing DCAD [Y = 74.87 (standard error = 0.87) + 0.01174 (standard error = 0.0025) × DCAD (mEq/kg of DM) and Y = 3.95 (standard error = 1.02) + 0.01234 (standard error = 0.0032) × DCAD (mEq/kg of DM), respectively]. In addition, 3.5% fat-corrected milk and fat, lactose, and total milk solids contents were linearly increased by 13.52, 8.78, 2.5, and 2.6%, respectively, according to DCAD increases from -71 to 290 mEq/kg of DM, whereas crude protein and casein content were linearly reduced by 4.83 and 4.49%, respectively. In conclusion, control of metabolic changes in lactating dairy cows to maintain blood acid-base equilibrium plays an important role in keeping milk stable to ethanol and during heat treatments.
authors.affiliation: Department of Nutrition and Animal Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo, Brazil 13635-900.
authors.forename: C M M R
authors.initials: CM
authors.lastname: Martins
authors.affiliation: Department of Nutrition and Animal Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo, Brazil 13635-900.
authors.forename: M A
authors.initials: MA
authors.lastname: Arcari
authors.affiliation: Department of Animal Science, School of Food Engineering and Animal Science, University of São Paulo, Brazil 13635-900.
authors.forename: K C
authors.initials: KC
authors.lastname: Welter
authors.affiliation: Department of Animal Science, School of Food Engineering and Animal Science, University of São Paulo, Brazil 13635-900.
authors.forename: A S
authors.initials: AS
authors.lastname: Netto
authors.affiliation: Department of Food Engineering, School of Food Engineering and Animal Science, University of São Paulo, Brazil 13635-900.
authors.forename: C A F
authors.initials: CA
authors.lastname: Oliveira
authors.affiliation: Department of Nutrition and Animal Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo, Brazil 13635-900. Electronic address: mveiga@usp.br.
authors.forename: M V
authors.initials: MV
authors.lastname: Santos
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000838:Anions / Q000378:metabolism; D002118:Calcium / Q000032:analysis; D002364:Caseins / Q000737:chemistry; D002412:Cations / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D005260:Female; D007477:Ions / Q000032:analysis; D007774:Lactation; D008892:Milk / Q000737:chemistry*; D000067816:Whey Proteins / Q000737:chemistry
chemical_list: D000838:Anions; D002364:Caseins; D002412:Cations; D007477:Ions; D000067816:Whey Proteins; D002118:Calcium
keywords: casein; dietary cation-anion difference; ionic calcium; milk ethanol stability