The effect of increasing the Vitamin B-12 status of Romney ewes on foetal liver Vitamin B-12, milk Vitamin B-12 and liver Vitamin B-12 concentrationsin suckling lambs

Aim. To determine the effect of increasing the Vitamin B-12 status of the e we 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 V itamin B-12 concentrations. Results. Compared to untreated animals, serum and liver Vitamin B-12 concen trations of the treated ewes were increased at least 70% during gestation. Foetal liver Vitamin B-12 concentrations were increased 270%. Over the lact ation, ewe serum and milk Vitamin B-12 concentrations were increased at lea st 200% and 44%, respectively. The liver Vitamin B-12 stores of the new bor n 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 su pply 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 ew es with a long-acting Vitamin B-12 supplement at mating will prevent Vitami n B-12 (Co) deficiency in ewes, as well as their lambs, until they can be t reated at tailing at 4-6 weeks of age.