A comparison between the Romney and Merino × Romney on hill country

Abstract

Abstract Lifetime performance was studied in 57 Romney (R) and 86 Merino × Romney (MR) ewes bred from straightbred hill country Romney ewes with a wide variation in fleece type. The MR lambs had lower perinatal mortality than the R. Although weights were similar at weaning, MR ewe lambs had a lower growth rate than wethers from 4 to 14 months of age. This was confirmed by the average growth of contemporary MR wether lambs when grazed at a different location at three stocking rates from 5 to 15 months of age. As well as lower live weight the MR wethers had lighter carcasses. R and MR ewes were mated to Merino rams to produce four lamb crops. Each year MR ewes showed earlier oestrus (except in the hogget stage) than the R and averaged lower live weights at pre-mating, pre-lambing, and weaning. However, the breeds did not differ in reproductive performance (barrenness, multiple birth rate, lamb survival, and lambs weaned per ewe joined). Birth and weaning weights of lambs from R and MR ewes were similar. MR ewes produced lower fleece weights with a shorter staple but showed more financial return per sheep. They also showed a higher mortality than R ewes.