Relationship between the udder filling time and the morphophysiological characteristics of the udder and teats in female donkeys of the Northeastern ecotype.
Mammary gland, Female donkey (or mare, in some contexts), Morphology, Milking
The morphological characteristics of the udder are essential for genetic selection, maximizing milk production and directly influencing the secretion capacity and efficiency of milk ejection. In this regard, the aim was to relate the udder filling time to the morphophysiological characteristics of the udder and teats in female donkeys of the Northeastern ecotype. Fourteen female donkeys of the Northeastern ecotype, aged between 3 and 7 years, with an average live weight of 185 ± 30 kg, were used. The mares were separated from their foals at 5 a.m., with intervals of 2, 3, and 4 hours for udder filling. Before manual milking, measurements were taken of the udder and teats, followed by milking and milk weighing. The results were subjected to normality, variance, and correlation tests. There was an increase in the udder filling time of the female donkeys, resulting in a higher volume of milk being milked and an increase in the dimensions of the udder and teats (P<0.05), with an average production of 313 g after 4 hours. The morphometry of the mares' udders showed changes in the filling time (2-4 hours), presenting the highest percentage increase (4.5%) in the udder length, with increases of 2.6%, 2.0%, and 3.6% in width, circumference, and depth, respectively. Regarding the morphometry of the teats, the greatest effect was observed in the diameter of the teats, with a 9.7% increase (right and left), while the length and distance between them showed increases of 7.0% and 6.0%, respectively. Although most of the morphometric variables showed a correlation with milk production, only the udder length, and the length and diameter of the teats were correlated with the volume of milk milked. It is concluded that increasing the udder filling time resulted in greater milk production, in addition to promoting changes in the dimensions of the udder and teats. These findings highlight the relevance of the morphometry of these structures as determining factors in milk production efficiency, providing important insights for the selection and management of females with higher productive potential.