Case Study: Concentrations of biotin in blood of Holstein bull calves supplemented with biotin and pantothenic acid

Pantothenic acid interferes with biotin absorption in nonruminants. The objective of this study was to determine whether pantothenic acid affects the concentration of biotin in the blood of young calves. Weaned bull calves (n = 16) were fed ad libitum a pelleted starter including no supplemental B-vitamins and hay for 2 wk before the beginning and until the end of the experiment. Water was available ad libitum at all times. Two wk after weaning, calves were blocked by age and randomly assigned to 4 treatments according to a randomized complete block design. Treatments consisted of administering, for 14 d, a daily gelatin capsule containing no B-vitamins, 10 mg of biotin, 240 mg of pantothenic acid, and 10 mg of biotin + 240 mg of pantothenic acid. Expeller soybean meal was used as a carrier of the vitamins in the capsules. Blood samples were collected by venipuncture of the jugular vein at d 0 and 14. Concentrations of avidin-binding substances (ABS) in plasma were determined by a single-step competitive enzyme-binding assay. The concentrations of ABS in plasma were similar for all treatments (P > 0.24) and did not change after dosing vitamins over time (3.47 and 3.07 ng/mL for d 0 and 14, respectively; SEM = 1.5 ng/mL; P > 0.63). Plasma concentrations of ABS were substantially greater than those previously reported for lactating dairy cows (0.7-2.1 ng/mL). Based on these data, we cannot conclude whether or not an interaction exists between biotin and pantothenic acid in regards to biotin absorption.