The effect of increasing the Vitamin B12 status of Romney ewes on foetal liver Vitamin B12, milk Vitamin B12 and liver Vitamin B12 concentrations in suckling lambs

Aim. To determine the effect of increasing the Vitamin B-12 status of the ewe on the Vitamin B-12 supply to the suckling lamb. Methods. The Vitamin B-12 status of the ewe was increased during gestation and lactation by three injections of a long-acting preparation of Vitamin B-12 microencapsulated in an organic add polymer. The Vitamin B-12 status of the ewes and suckling lambs was assessed from changes in serum and liver Vitamin B-12 concentrations. Results. Compared to untreated animals, serum and liver Vitamin B-12 concentrations of the treated ewes were increased at least 70% during gestation. Foetal liver Vitamin B-12 concentrations were increased 270%. Over the lactation, ewe serum and milk Vitamin B-12 concentrations were increased at least 200% and 44%, respectively. The liver Vitamin B-12 stores of the new born lambs from Vitamin B-12-treated ewes were depleted within 58 days. There were no significant differences in the serum Vitamin B-12 concentrations of suckling lambs from Vitamin B-12-treated and untreated ewes. Conclusion. Ewes with a high Vitamin B-12 status will ensure an adequate supply of vitamin B-12 to their lambs for at least the first 30 days of life. Clinical significance. In flocks grazing Co-deficient pastures, treating ewes with a long-acting Vitamin B-12 supplement at mating will prevent Vitamin B-12 (Co) deficiency in ewes, as well as their lambs, until they can be treated at tailing at 4-6 weeks of age.