Effects of sodium bicarbonate and calcium magnesium carbonate

Animal Feed Science and Technology 177 (2012) 180–193

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Effects of sodium bicarbonate and calcium magnesium carbonate supplementation on performance of high producing dairy cows R.E. Rauch a,∗ , P.H. Robinson b , L.J. Erasmus a a b

Department of Animal and Wildlife Sciences, University of Pretoria, Pretoria, South Africa Department of Animal Science, University of California, Davis, CA 95616, USA

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Article history: Received 4 October 2011 Received in revised form 13 August 2012 Accepted 24 August 2012

Keywords: Buffer DCAD Holstein cows

a b s t r a c t Sodium bicarbonate (SB) is a common dairy feed supplement, although recent research on its rumen buffering efficacy in contemporary dairy diets with low starch levels is limited. In California, and other areas of the world, new environmental regulations aim to minimize the amount of fixed solids (FS), including Na, which are discharged from dairy farms. Our aim was to determine effects of SB or calcium magnesium carbonate (CMC; a potential alternative buffer which does not contribute to Na discharge), on performance of early lactation high producing Holstein cows. The study was a Latin square design with 3 periods of 28 d, 3 treatments (i.e., control (C), SB, CMC) and 3 pens of ∼310 cows. The total mixed ration was supplemented with 8 g/kg dry matter (DM) of SB or CMC, and contained 519 g/kg DM and 158 g/kg crude protein (CP), 334 g/kg aNDF (i.e., neutral detergent fiber assayed with a heat stable amylase expressed inclusive of residual ash) and 160 g/kg starch (DM basis). The dietary cation anion difference (DCAD) for the C, SB and CMC supplemented diets was 375, 456 and 381 mEq (Na + K − Cl)/kg DM, respectively. The DM intake for C, SB and CMC cows did not differ (28.2, 28.5, 28.6 kg/d, respectively), but the SB supplemented diet tended (P=0.053) to reduce DM digestibility (637 versus 656 g/kg DM) and increase (P=0.09) fecal pH (6.65 versus 6.60) compared to C. The CMC supplemented cows had higher (P