BLOOD SERUM CONCENTRATIONS OF FOLATES AND VITAMIN B12 DURING GROWTH PERIOD OF WHITE VEAL CALVES

Variations of hemoglobin, hematocrit, folates and vitamin B 12 concentrations in blood serum were studied during the rearing period of 62 rapidly growing (1.6 kg d −1 ) white veal calves. The animals were fed exclusively with milk replacers during the 110 d rearing period. Hemoglobin and hematocrit decreased linearly with time (P < 0.0001). There was an age effect (P < 0.0001) on serum concentrations of vitamin B 12 and folates during the rearing period. The serum concentrations of vitamin B 12 increased during the first 3 wk from 214.8 pg mL −1 to 422.6 pg mL −1 and then were stable until the 13th week of the rearing period. Serum concentrations of folates decreased during the 3 wk from 11.3 ng mL −1 to 5.1 ng mL −1 and then increased to reach a stable concentration of about 14 ng mL −1 from 6 wk to the end of the rearing period. Males had significantly lower serum folates concentrations than females (P < 0.0001) but their serum profiles during the rearing period were similar. Further studies will be necessary to elucidate the consequences of a decrease in serum folates during the starting period on the growth performance of white veal calves. Key words: White veal calves, blood serum folates, vitamin B 12