Ramos J J, Saez T, Bueso J P, Sanz M C, Fernandez A
Dpto de Patología Animal, Facultad de Veterinaria, Zaragoza, Spain.
Vet Res. 1994;25(4):405-9.
Vitamin B12 was measured in samples of normal ovine colostrum and milk and in sera of lambs and ewes taken at various stages of lactation, from lambing up to 16 d. Colostrum obtained within 24 h of lambing contained high concentrations of vitamin B12, but within a few days the levels fell. The lambs received high levels of vitamin B12 from their dams' colostrum but a parallel decrease of vitamin B12 levels in lambs' serum and ewes' milk was subsequently observed. Milk vitamin B12 was analysed by the microbiological method (Lactobacillus leichmannii, ATCC 7830) and a radioisotope dilution (RID) technique. Milk vitamin B12 concentrations were greater with the microbiological technique compared with the RID method. The radioassay method has been shown to be as reliable as the microbiological method for measuring vitamin B12 in ovine milk except for very low levels.
对正常羊初乳、乳汁以及羔羊和母羊在泌乳各阶段（从产羔到16天）采集的血清样本进行了维生素B12含量测定。产羔后24小时内获取的初乳中维生素B12浓度很高，但几天内该水平就会下降。羔羊从母羊的初乳中获得了高水平的维生素B12，但随后观察到羔羊血清和母羊乳汁中维生素B12水平平行下降。采用微生物学方法（赖氏乳杆菌，美国典型培养物保藏中心7830）和放射性同位素稀释（RID）技术对乳汁中的维生素B12进行分析。与RID法相比，微生物学方法测得的乳汁维生素B12浓度更高。除了极低水平外，放射性测定法已被证明在测量羊奶中维生素B12时与微生物学方法一样可靠。
