Effects of lactation stage, lactation order and udder types on udder traits and composition of milk in Tuj ewes

Abstract

The present study was undertaken to assess the influences of lactation stage, lactation order, and udder types on udder traits and chemical composition of milk in Tuj sheep. Udder circumference (UC), udder depth (UD), udder bottom height (UBH), udder upper height (UUH) and udder width (UW) were significantly affected by lactation stage (P<0.01, P<0.001). The effects of lactation order on udder measurements and chemical composition of milk and a udder type on chemical composition of milk were found to be not significant (P>0.05). UW was significantly affected by udder type (P<0.05). Fat, solid non fat (SNF), density, lactose and mineral was significantly affected by lactation stage (P<0.05, P<0.001). Significant positive correlations (P<0.05, P<0.01, P<0.001) were established between UC with each of UD (0.41 and 0.52), UW (0.62 and 0.68) and teat diameter (TD) (0.35 and 0.40) and between UD with each of TD (0.42 and 0.41) and UW (0.53 and 0.54) and also between teat length (TL) and TD (0.37 and 0.37); TD and UW (0.42 and 0.42); UBH and UUH (0.49 and 0.49); UUH and UW (0.37 and 0.36) at the 70 and 100 days of the lactation. The strongest positive correlations were found between SNF with each of density (0.92 and 0.96), lactose (0.95 and 0.96), and mineral (0.98 and 0.99) at the 70 and 100 days of the lactation. The results of the study indicate that the influence of lactation stage on some udder traits and chemical composition of milk are very important and ought to be taken in to account in sheep breeding.