Supplemental biotin effects on performance and dynamics of fat mobilization and on in vitro fiber digestion using periparturient Holstein cows

The objectives of a controlled animal study were to explore the effects of biotin supplementation on performance, energy status, and hepatic lipidosis of periparturient multiparous Holstein cows. Twenty cows were fed biotin from an average of 17 d prepartum to calving (20 mg/d) and from calving to 70 d postpartum (30 mg/d). Eighteen cows were fed 0 mg of biotin/d during the same pre and postpartum periods. Mean concentration of biotin in plasma sampled weekly was greater in cows fed biotin (9.4 vs. 4.3 nmol/L). Dry matter intake during lactation tended to be higher for the biotin supplemented cows (23.8 vs. 22.1 kg/d) but was not different when expressed as a % of body weight (4.0 vs. 3.9 kg). Milk yield (35.8 vs. 34.8 kg/d) and milk fat concentration (3.59 vs. 3.69%) were similar for cows fed 0 or 30 mg/d biotin postpartum, respectively. Concentrations of plasma non-esterified fatty acids were lower at weeks 2 (652 vs. 413 μEq/L) and 4 (381 vs. 196 μEq/L) postpartum whereas mean concentration of plasma glucose was greater (63.4 vs. 66.6 mg/dL) for lactating cows fed supplemental biotin. Both total lipids and triacylglycerol concentrations of liver (wet basis) tended to decrease at a faster rate between 2 and 30 d postpartum with biotin supplementation.; In vitro batch culture experiments tested whether supplemental biotin would increase forage fiber digestibility and/or overcome the negative effect of low pH on forage fiber digestibility. Supplemental biotin added to the fermentation media (0, 10, and 20 μg/26 ml) did not improve ruminal fiber digestibility or minimize the depression on forage fiber digestibility caused by low pH (pH 5.3).; Plasma and liver vitamin A and β-carotene concentrations were measured in samples collected from the animal study, and cows were classified as having normal or subclinical fatty liver using a threshold of 2% liver triacylglycerols (wet basis) at d 2 after calving. Concentration of plasma non-esterified fatty acids was positively and negatively correlated with concentrations of plasma β-carotene and retinol, respectively, which indicates an association between fatty liver development and reduced vitamin A and β-carotene status in periparturient dairy cows.