Bovine Milk Orotate: Differences between Cows and Changes during Lactation

Orotate in the morning milk of 250 cows from five dairy breeds averaged 81.1 μg/ml but exhibited large variability as indicated by a standard deviation of 48.6 and a range from 19 to 664 μg/ml. Much of this variability in milk orotate is likely attributable to variation between individual cows. Some variation was due to breed, number of lactations, and stage of lactation. Jersey and Guernsey cows produced milk with lower orotate than Ayrshire, Brown Swiss, or Holstein cows. Cows with more lactations had lower orotate concentrations. Stage of lactation also affected orotate concentration; this was reverified by periodic monitoring in individual cows at various stages of lactation. Orotate in first-drawn colostrum averaged 13.2 and 5.8 μg/ml for seven uniparous and eight multiparous Holstein cows. Within 2 wk, these animals had increased to 60 μg/ml with uniparous animals rising more rapidly. For eight other Holstein cows monitored biweekly from 2 to 44 wk of lactation, orotate rose to 76 μg/ml by wk 10 and remained fairly constant through wk 38. The cow with the highest concentration of milk orotate produced milk with four to ten times more orotate than these eight animals at all stages of lactation; the average from 10 through 38 wk was 558 μg orotate/ml and a sample approached 800. During the dry period, orotate concentration in lacteal secretions decreased to that in first-drawn colostrum.