Figure 2.

Volume of first milking/colostrum within 2 hr postpartum is highly variable. (A) First milking colostrum volume data from Holstein dairy cows (n = 130) was collected and sorted based on cow parity. When primiparous and multiparous groups were compared, there was no difference in colostrum volume produced. Within the multiparous group, comparing colostrum volume produced across the 5 different lactations, also did not show a significant difference in volume produced. The full range of colostrum volumes was between 0.1 and 22 L as recorded across all animals/groups. (B) First milking after oxytocin for inducing complete let-down also showed significant variability in volume between individual animals (range = 0.75 to 15.36 L), indicating differences to mammary secretion eliminating environmental factors that might have affected milking yield.