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

Abstract

Aim. To determine the effect of increasing the Vitamin B₁₂ status of the ewe on the Vitamin B₁₂ supply to the suckling lamb.

Methods. The Vitamin B₁₂ status of the ewe was increased during gestation and lactation by three injections of a long- acting preparation of Vitamin B₁₂ microencapsulated in an organic acid polymer. The Vitamin B₁₂ status of the ewes and suckling lambs was assessed from changes in serum and liver Vitamin B₁₂ concentrations.

Results. Compared to untreated animals, serum and liver Vitamin B₁₂ concentrations of the treated ewes were increased at least 70% during gestation. Foetal liver Vitamin B₁₂ concentrations were increased 270%. Over the lactation, ewe serum and milk Vitamin B₁₂ concentrations were increased at least 200% and 44%, respectively. The liver Vitamin B₁₂ stores of the new born lambs from Vitamin B,,-treated ewes were depleted within 58 days. There were no significant differences in the serum vitamin B₁₂ concentrations of suckling lambs from vitamin B₁₂-treated and untreated ewes.

Conclusion. Ewes with a high vitamin B₁₂ status will ensure an adequate supply of vitamin B₁₂ 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 B₁₂ supplement at mating will prevent Vitamin B₁₂ (Co) deficiency in ewes, as well as their lambs, until they can be treated at tailing at 4-6 weeks of age.

Keywords:

• Ewes
• lambs
• Co deficiency
• long-acting vitamin B₁₂