Milk replacers should be fortified with pyridoxine in accordance with NRC minimum requirements. Calves, such as veal calves, that are raised under accelerated growth programs while on liquid feed may benefit from slightly higher levels of vitamin.
B6, especially if high rates of protein deposition are achieved. However, this hypothesis has not been tested.
Supplemental vitamin B6 is reported to have a higher bioavailability and stability than the naturally occurring vitamin, probably due to the presence of bound pyridoxine in feedstuffs. The recovery of vitamin B6 as pyridoxine hydrochloride, in a multivitamin premix not containing trace minerals was 100% even after three months of storage at 37ƒC. However, stability in a premix containing trace minerals was poor with only 45% recovery after three months at 37ƒC (Adams, 1982). Verbeeck (1975) found vitamin B6 to be stable in premixes with trace minerals as sulfates. However, carbonate and oxide trace minerals reduced pyridoxine activity by up to 25% after three months. Choline chloride accelerates this reaction. Retention of vitamin B6 in vitamin supplements was 98% after six months, but was only 56% for supplements that also contained choline and trace minerals (Coelho, 1991). Gadient (1986) considers pyridoxine to be very sensitive to heat, slightly sensitive to moisture and light, and insensitive to oxygen. Retention of B6 activity in pelleted feeds after three months at room temperature is approximately 80% to 100%.
