engleski

Udder morphology, milk production, and composition in pasture-based dairy ewes during lactation

The aim of this article is to determine udder morphology and milk production changes during lactation in different pasture-based dairy ewes mainly used for the production of fine cheese varieties. Milk production, udder morphology and body weight were measured and milk composition samples (milk fat, protein, lactose and dry matter percentage) were collected during early (d 80–100), mid (d 140–160) and late (d 200–220) lactation in Kupres (n = 267), Privor (n = 204) and Stolac (n = 226) pramenka ewes. For the statistical analysis, a repeated measures model was used with ewe as a random effect and breed, lactation number and day of lactation, defined as fixed effects. Milk yield was positively correlated with udder width (r = 0.78), udder height (r = 0.66), teat width (r = 0.40), teat length (r = 0.35) and negatively with cistern height (r = −0.16) and teat angle (r = −0.36 ; P < 0.05). Teat length and teat width were positively correlated (r = 0.89 ; P < 0.05). Throughout lactation stages, there was an increase in milk fat, protein and nonfat dry matter content. In contrast, milk production and lactose content decreased throughout lactation. Largest differences between and within breeds were found in early compared with mid and late lactation measurements. More pronounced decrease during lactation was observed in udder width and height and slight in teat width and length. Cistern height ranged from 0.76 cm in early for Kupres to 1.25 cm in late lactation for Privor pramenka ewes. Teat angle ranged from 26° for Kupres in early to 46° for Privor pramenka ewes in late lactation. Interaction between breed and lactation was significant (P < 0.05) for all observed variables. Breed with highest milk production and udder height and width was Kupres compared with Privor and Stolac pramenka ewes. Udder and teat measurements in all breeds were medium-sized and acceptable for machine milking resulting in low teat angle and cisternal height below the teat orifice. Most of the observed udder morphology traits had positive correlations with milk yield and therefore could be applied in breeding programs.

udder morphology, milk production, dairy ewes

nije evidentirano