Milking frequency and the effect of fill time on the production and conformation in Nordestino ecotype donkeys

This study aimed to assess the effects of milking frequency and udder fill time on milk production and the morphophysiological characteristics of udder and teats. Using a group of 15 female donkeys aged 3-7 years, the study was split into two trials: The first assessed the effects of different udder fill times (2, 3, and 4 h) on milk production and mammary morphometry, while the second analyzed the impact of milking frequency (once, twice, or three times a day) on milk production and somatic cell count (SCC). Trial 1 showed that a 4-h fill time resulted in greater milk volume (313 g), with significant increases in udder length (4.5%), depth (3.6%), and teat diameter (9.7%) (P < 0.05). Most morphometric variables showed positive correlations with milk production, with the highest coefficients observed for udder and teat length. In Trial 2, increasing milking frequency from once to three times a day increased milk production by up to 457%. SCCs did not differ between treatments, suggesting that increased milking frequency did not compromise mammary health. It is concluded that an udder fill time of 4 h and milking three times a day favors milk production in donkeys of the Nordestino ecotype. The moderate to strong correlations between morphometric characteristics and milk production suggest potential use of those parameters as criteria in genetic selection programs targeting donkey milk production.