Effect of Chromium Methionine Supplementation on the Lactation Performance, Hepatic Respiratory Rate and Antioxidative Capacity of Early-Lactating Dairy Cows

Abstract

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Backgrounds:</jats:bold> Chromium is an important trace element that may regulate dairy cow metabolism. The objective of this study was to investigate the effect of chromium methionine (Cr-Met) supplementation on lactation performance, hepatic respiratory rate and anti-oxidative capacity in early-lactating Holstein dairy cows. <jats:bold>Results:</jats:bold> Sixty-four multiparous cows were grouped into 16 blocks based on parity, days in milk and milk production, and four cows within a block then were assigned randomly to one of four dietary treatments with 0, 4, 8 or 16 g/d of Cr-Met per cow in addition to a basal diet. The experiment lasted for 14 weeks, with the first two weeks as adaptation period. Milk yield and composition were recorded weekly. Dry matter intake was measured every other week. The plasma variables were measured in weeks 4, 8 and 12 of the experiment. Supplementation of Cr-Met did not affect dry matter intake of early-lactating dairy cows. As the supplementation of Cr-Met increased, yields of milk, fat, lactose and energy corrected milk increased in a linear manner (<jats:italic>P </jats:italic>&lt; 0.01). In terms of plasma variables, insulin concentration decreased in a linear manner with Cr-Met supplementation (<jats:italic>P </jats:italic>= 0.04). As for variables relative to hepatic respiration rate, concentrations of pyruvate and NADH in the plasma were increased in linear (<jats:italic>P </jats:italic>&lt; 0.01) and quadratic manners (<jats:italic>P </jats:italic>&lt; 0.01), and lactic dehydrogenase activity was linearly increased as the feeding levels of Cr-Met increased (<jats:italic>P </jats:italic>&lt; 0.01). Moreover, plasma glutathione peroxidase and superoxide dismutase activity were increased in a linear manner (<jats:italic>P </jats:italic>&lt; 0.01). <jats:bold>Conclusion:</jats:bold> The results suggest that Cr-Met supplementation improved lactation performance of early-lactating dairy cows through enhancing antioxidant capacity and hepatic cellular respiration.</jats:p>