Vitamin B12 in Blood of Newborn and Colostrum-Fed Calves and in Colostrum and Normal Milk of Holstein and Jersey Cows

Summary Vitamin B 12 determinations were made on the blood of calves before ingestion of colostrum and subsequently to 8 days of age. No significant differences were observed in relation to age (within this range), breed or the food ingested. Holstein colostrum showed nearly double the values observed on Jersey colostrum. The colostrum B 12 values for both breeds declined gradually. The Jersey milk, showing averages of 7.0 millimicrograms after the 15th day, appeared to have declined to herd levels. The Holstein milk maintained a slightly higher value through the 45th day. Forty-eight Jersey cows fresh from 6 to 351 days showed an average vitamin B 12 value of 7.6 millimicrograms per milliliter. Morning milk averaged 8.7 versus 6.9 for evening milk (with significance at the 0.05 level).