EFFECTS OF WEANING SYSTEM ON MILK AND EXTERNAL MAMMARY CONFORMATION TRAITS OF SICILO-SARDE TUNISIAN DAIRY EWE
A better development of the Sicilo-Sarde dairy sheep in Tunisia needs a review of its behavior by adopting early weaning and generalizing mechanical milking that involves an adaptation of the external mammary morphology (MM). Thirty ewes were divided into two groups (early and late weaning; EW and LW respectively) to study the effects of weaning system (WS) and milking time (MT) on milk and external MM traits in early milking period. MM was evaluated by six measurements and three scores of udder and teat. EW group had higher milk production (MP) and lower fat and protein amounts that increased with MT
advancement (P<0.001). WS did not affect MM traits (P>0.05), only teat length was higher for LW ewes (P<0.05). Udder depth, teat diameter, distance between teats and teat angle score decreased with MT (P<0.01). Significant interactions were noted between WS and MT for most traits studied. MP was negatively correlated with fat and protein amounts (-0.38 and -0.50 respectively) and moderately correlated with udder depth, cistern height, teat diameter (from 0.31 to 0.42). Fat and protein had negative correlation with udder depth, teat diameter and distance between teats. Higher correlation was determined between udder depth and distance between teats (r=0.60; P<0.001). In conclusion, EW system allows a better start of the milk production in early milking period. Cistern height, teat length and teat angle score are the prominent traits which affect milk ability and
adaptation of ewe to machine milking and consequently they must be included in selection program.