Abstract:
Proc. Aust. Soc. Anim. Prod. (1978) 12: 262 EFFECT OF MERINO STRAIN ON PRODUCTION BY BORDER LEICESTER X MERINO EWES K.T. BEARD* and R.W. HODGE** There Merino ewes that strain of the first is little information on the performance of Border Leicester x derived from different Merino strains although it is possible differences contribute to the observed variation in production cross ewe. Mature Bungaree Merino ewes and mature Peppin Merino ewes (mean live weight 55 and 40 kg respectively) were run as one flock and mated to Border Leicester rams in February, 1974. Vasectomized rams fitted with . marking crayons were run with the female progeny (112 Bungaree crossI ,, 90 Peppin cross) from March, 1975 until mating with entire Dorset Horn rams in February, 1976. The first cross ewes were again mated with Dorset Horn rams in March, 1977 and ovulation rate was determined by endoscopy after mating at this time. Live weight, wool production and reproductive performance of thecrossbred ewes are set out in Table 1. Bungaree cross ewes were heavier than Peppin cross ewes throughout the observations and this was associated with heavier fleece weights but not with increased reproductive performance. There tias no difference in the ovulation rate (1.86 corpora lutea per ewe) of the two strains at mating in March, 1977 or in percentage of lambs alive at two weeks of age. There was also no significant difference in growth rate of the lambs reared by the ewes in 1976. The exhibited mated at attained significantly higher percentage of Bungaree cross ewes that oestrus in 1975 suggests that more of this strain could be 12 months of age and a higher percentage of lambs would be from an early mating in November-December. * Department of Agriculture, Treasury Place, Melbourne, Vic. 3000. ** Animal Research Institute, Department of Agriculture, Werribee, 3030. 262. '
