Comparing breeds of sheep in the feedlot or on pasture and in the feedlot

Abstract

A terminal sire study was conducted to evaluate production and carcass traits of Texcl sired offspring compared to Suffolk and Columbia offspring. Breeding and lambing occurred on pastures during a 2-yr study. The Iambs were weaned at an average age of 70 and 94 d and allocated to one of two finishing programs. The finishing programs were 1) direct to feedlot (FPl) and 2) pasture followed by feedlot (FP2). Lambs were slaughtered at an average weight of 57.8 kg. Birth weights, weaning weights and pre-weaning daily gains of lambs sired by Texel rams were similar to Iambs sired by Suffolk rams but greater (P < .05) than Iambs sired by Columbia rams. However, survival to weaning for Iambs sired by Texel, Suffolk or Colxmibia rams did not differ. In a pasture lambing system an estimated $19.21 per ewe per year was saved through feed costs alone, as compared to more intensive shed lambing systems. After weaning Suffolk sired lambs gained faster (P < .01) than Columbia and Texel sired lambs. Post-weaning average daily gains were greater (P < .01) in FP 1 than FP2 and led to an increase of 31 d to reach slaughter weight for lambs that initially grazed as compared to Iambs placed directly in the feedlot. Texel crossbred lamb carcasses had larger (P < .01) loineye area (LEA) than Suffolk and Columbia Iamb carcasses. Backfat (BF) was also higher (P < .05) in Texel than Suffolk crossbred Iambs. Body wall thickness (B WT) Was less (P <. 10) in Texel and Suffolk crossbred lamb carcasses than Columbia lamb carcasses. Dressing percentage and quality" grades were similar across sire breeds. Lambs finished in FP2 had more LEA (P < .05), and less BF (P < .10) and BWT (P < .01) than lambs finished in FP I. It was concluded that Texel rams used in a forage-based lambing system might have some potential for increasing lean mass in their offspring. However, V increase in lean mass of Texel crossbred lambs is counterbalanced by slower growth rate than Suffolk and Columbia crossbred lambs. Grazing lambs prior to finishing in drylot improved leaimess in lambs in this study. I CHAPTER 1. GENERAL INTRODUCTION

The comparative results of myostatin introgression from donor Texel to recipient Ramlıç sheep with the aspects of growth, pre-, and post-slaughter carcass traits in the second backcross generation

“…ADG in Ramlıç and crosses were found within the limits of 0.127-0.360 kg determined by different researchers (TAGEM, 2009;Bromley et al, 2000;Hultz et al, 1935;Jackson et al, 1997;Omar and Glafiro, 1995). The finding of the current study for Texel was just behind the 0.190-0.318 kg reported by different researchers (Ali, 1999;de Vargas Junior et al, 2014;Maxa et al, 2005). The differences may have resulted from the conditions of the farm operation, weaning ages, and statistical model.…”