Short communication: Effects of milking frequency on udder morphology, milk partitioning, and milk quality in 3 dairy goat breeds

摘要

Thirty-six dairy goats of 3 breeds (Majorera, Tiner-fena, and Palmera) in mid lactation (124 ± 8 d in milk) were subjected unilaterally to once (×l) or twice daily milking (×2) for 5 wk to evaluate udder morphology, milk partitioning, and somatic cell count. Majorera and Palmera goats presented the highest and lowest udder depth values, respectively, whereas the differences between initial and final cistern-floor and teat-floor distances were not affected by milking frequency or breed factors. Cisternal and alveolar milk percentages were similar between ×1 and ×2 in the studied breeds. Milking frequency did not affect milk composition in the cisternal fraction, suggesting a greater transfer of milk from the alveoli to the cistern during early udder filling. However, milking frequency caused diverse changes in the milk composition in the alveolar fraction, especially in fat, lactose, and total solids contents. No udder halves presented clinical mastitis during the experimental period, suggesting that ×1 does not impair udder health and indicating that the studied breeds are adapted to this milking frequency.