Evaluation of the performance of grade and crossbred ewes

Data from 924 lambs were analyzed by least-squares technique to compare the performance of grade, mixed and crossbred ewes. Birth weight was significantly influenced (P\u3c.01) by sex, type of birth, breeding of lamb and age of dam. Lambs whose breeding involved more breeds were heavier than lambs of grade and mixed breeding. Lambs from ewes over three years of age were heavier than lambs from ewes three years old and younger, Weight of lambs at 120 days was significantly influenced (P\u3c.01) by sex, breed of dam, breeding of lamb, type of birth and rearing and age of dam. Male lambs were heavier than females and lambs born and raised as singles surpassed lambs born as twins, whether raised as singles or as twins. Ewes 4 years old and older produced the heaviest lambs followed by 3-, 2- and 1-year-old dams. Lambs from crossbred ewes were heavier than lambs from grade ewes and ewes of mixed breeding. Analyses of average daily gain, weaning weight and condition score gave results similar to those obtained from the analyses of the other variables studied. Effect of sex on condition score was not significant. From these data it can be concluded that: (l) the performance of crossbred lambs excelled that of grade or mixed breeding (breed composition not precisely known) in all traits studied, (2) lambs from crosses involving more breeds exceeded lambs from crosses involving fewer breeds, and (3) crossbred ewes surpassed ewes of grade and mixed breeding with respect to all traits studied