FACTORS AFFECTING VARIATION OF UDDER TRAITS OF DAIRY EWES

Udder depth, width, and circumference; cistern height; teat position, angle, length, and width; and milk yield at 120 d were studied in 113 Churra sheep from three flocks. Means were 9.30, 12.18, and 46.55 cm, respectively, for udder depth, width, and circumference; 1.48 cm for c istern height; 3.64 (scored from 1 to 5) for teat position; 50.39 degr ees for teat angle; 3.83 and 1.93 cm, respectively, for teat length an d width; and 132.39 L for milk yield. Analysis of variance showed sign ificant effects for lactation month, flock, parity number, and milk yi eld. The traits related to udder size (depth, width, and circumference ) were significantly influenced by lactation month, flock, and milk yi eld and showed low repeatability (.17 to .18). The traits related to c istern morphology (cistern height, teat position, and angle) were sign ificantly influenced by flock and parity number. These traits, togethe r with teat length and width, had high repeatabilities (.45 to .77). C istern height, teat position and angle, and size of teats are related to aptitude of the udder for mechanical milking. This association, as with cattle, would justify focusing genetic improvement on these trait s.