The Effect of Ration on the Riboflavin, Niacin, and Vitamin B12 Concentration of the Blood and Milk of Sheep

Abstract

Statistical analysis of the data on riboflavin and niacin content of the blood and milk of ewes and of the blood of their lambs did not reveal any significant difference caused by protein or mineral supplementation. The riboflavin content of ewes' blood was 0.4 γ/ml. at parturition. Six weeks later it had decreased to 0.22 γ/ml. On the other hand, niacin tended to remain constant with an average of 10 γ/ml. In the case of both riboflavin and niacin, the level in lambs' blood decreased gradually from birth to 6 weeks. The values were 0.5 and 20 γ/ml. and decreased to 0.3 and 12 γ/ml. for riboflavin and niacin, respectively. Riboflavin was 7–8 times higher in colostrum than in normal milk. The colostrum content was 25.8 γ/ml. and it decreased to 4.9 γ/ml. at 6 weeks. The reverse was true for niacin, 2.3 γ/ml. in colostrum and 6.6 γ/ml. in milk 6 weeks later. The vitamin B12 content of the blood at parturition was of the same order, approximately 1.5 γ/ml., in all groups. Following parturition, the cobalt-supplemented groups showed an increase in the vitamin B12 content, whereas in the unsupplemented groups a decrease was observed. Lot III (bone meal + cobalt) was significantly higher than the other groups at 6 weeks. The vitamin B12 concentration of the lambs' blood at birth was approximately the same in all groups, 1 mγ/ml. Ten days after birth a marked increase in the vitamin B12 content was observed in the cobalt-supplemented groups. The other two groups showed very slight decrease. The marked increase in the cobalt-supplemented groups may be attributed to the high vitamin B12 potency of the milk of their dams. The vitamin B12 content of colostrum in lots I (basal) and IV (bone meal) was 5.05 and 7.3 mγ/ml., respectively, as compared to 19.80 and 23.20 mγ/ml, in lots II and III (Co-supplemented). The latter values decreased quite markedly at 6 weeks. Lot III with 2.59 mγ/ml. was significantly higher when compared with the other groups. Placental transfer of all these vitamins occurred in the pregnant ewes. Supplementation with calcium and phosphorus alone or in combination did not affect the vitamin B12 content of blood. Hence it is believed that the vitamin B12 concentration in both the blood and milk is directly dependent upon the amount of cobalt ingested. Since vitamin B12 is important as a growth and hemopoietic factor, supplementation with cobalt in the ration of the pregnant ewe is advised.