Genetic improvement in milkability of the Corriedale breed: morphological study of udder traits

摘要

A morphological study of udder traits in 106 Corriedale sheep was carried out during a complete lactation period at the Experimental farm of the Veterinary College (Migues, Uruguay) during 1996. Ewes were machine milked without "repasse". Four series of measurements (n = 424) were taken at monthly intervals during the 1st, 2nd, 3rd and 4th months of lactation. The methodologies used for measuring the mammary traits were those described in the Food and Agricultural Organization study (Project M4) onthe mechanical milking suitability of the main ovine breeds from the Mediterranean basin. Means for udder depth, height, width and circumference were 13.48, 12.45, 11.80 and 42.55cm, respectively and for teat angle were 35.97 deg, for teat position (score from 1 to 5) 2.61, and for teat width and length. 1.60 and 3.1 cm, respectively. Cistern height's mean was 0.47cm, with this trait showing a great coefficient of variation. Phenotypic correlations were estimated between all measured traits. High, positive and significant coefficient correlations were shown between the characters related to udder size: depth, height, width and circumference. Teal length and width were correlated positively and highly (.75). The traits related to cistern morphology (cistern height, teat position and teat angle) showed a positive correlation. These correlations were in agreement with other studies in milking sheep breeds.