Abstract
Preweaning lamb survival was studied at 7 days, one month and 3 months of age (weaning age) in 390 lambs comprising 112 Najdi, 113 Awassi and 165 Hejazi breeds of sheep. Least squares analysis (considering survival as 1 and mortality as 0) showed that year of birth significantly (P < 0.05) affected survival at all ages examined, whereas season of birth, sex of lamb and type of birth had no significant effect on survival. Similarly, ewe weight at lambing, ewe age and lamb birth weight did not affect survival at any of the ages examined. Generally, Najdi lambs had a lower pre-weaning survival rate than Awassi or Hejazi lambs at all stages examined. Least-squares means for survival rates of winter- or summer-born lambs were reasonably similar; likewise, those of male and female lambs. Single lambs had higher survival rates than twins at all ages studied.
