HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Blackburn, H. Articles by Roehrkasse, G. P. Search for Related Content PubMed Articles by Blackburn, H. Articles by Roehrkasse, G. P.

Influence of Sire, Breed and Environment on Live and Carcass Traits of Heavy Lambs^1,2,

University of Wyoming, Laramie 82071

Abstract

Performance tests with ram lambs were conducted in 1975, 1976 and 1977, and ensuring progeny tests were carried out in 1977, 1978 and 1979. The ram lambs were of three breed groups: Suffolk, Columbia and triplet (western white faced sheep selected for multiple birth). Performance was evaluated with an index combining postweaning growth rate to 72.5 kg and fat depth. Approximately the top one third of each ram breed group was selected for progeny testing. All male (wether) progeny were fed to 64 kg, then sheared and slaughtered, and their carcasses were evaluated. Suffolk-sired lambs were superior to lambs sired by triplet or Columbia rams in growth rate and carcass desirability. Columbia sired and triplet sired Iambs reflected a year x breed of sire interaction, with no overall advantage for either group. Significant sire differences were apparent in production traits as well as carcass traits. Most rams sired lambs with desirable carcasses at heavy weights, but in some sire groups, most of the carcasses were overfinished. Sire and progeny performance indexes were significantly correlated, but selection on the basis of sire performance records did not ensure desirable carcasses among progeny. Year x breed of sire interactions were significant for fat depth and slaughter age. Twins had lower weaning weights than single lambs and thus were older at slaughter and sheared heavier fleeces, but differences due to type of birth in feedlot gain or carcass measurements were not significant. Feed efficiency decreased with increasing weight and time in the feedlot.

¹ Published with the approval of the Director, Wyoming Agr. Exp. Sta. and Journal Article No. 1066.

² Data obtained as part of Western Regional Project W(M)137.