CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Crop and Pasture Science   
Crop and Pasture Science
Journal Banner
  Plant sciences, sustainable farming systems and food quality
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Structure
Online Early
Current Issue
Just Accepted
Virtual Issues
All Issues
Special Issues
Research Fronts
Farrer Reviews
Sample Issue
For Authors
General Information
Submit Article
Author Instructions
Open Access
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates
Library Recommendation

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter logo LinkedIn

red arrow Farrer Reviews
blank image

Invited Farrer Review Series. More...

red arrow PrometheusWiki
blank image
Protocols in ecological and environmental plant physiology


Article << Previous     |     Next >>   Contents Vol 57(6)

Effects of available nutrition and sire breeding values for growth and muscling on the development of crossbred lambs. 1: Growth and carcass characteristics

R. S. Hegarty A G, C. Shands B, R. Marchant C, D. L. Hopkins D, A. J. Ball E, S. Harden F

A Beef Industry Centre of Excellence, NSW Department of Primary Industries, Armidale, NSW 2351, Australia.
B NSW Department of Primary Industries, Glen Innes ARAS, Glen Innes, NSW 2370, Australia.
C NSW Department of Primary Industries, Armidale, NSW 2350, Australia.
D NSW Department of Primary Industries, Centre for Sheep Meat Development, Cowra, NSW 2794, Australia.
E Meat and Livestock Australia, Armidale, NSW 2351, Australia.
F NSW Department of Primary Industries, Tamworth Agricultural Institute, Tamworth, NSW 2340, Australia.
G Corresponding author. Email: roger.hegarty@dpi.nsw.gov.au
 Full Text
 PDF (164 KB)
 Export Citation


The growth and development of 387 crossbred lamb progeny from 9 Poll Dorset sires representing muscle (M), control (C), and growth (G) sire-types was studied. Sires were selected on the basis of their LAMBPLAN estimated breeding values (EBVs) for post-weaning growth (PWWT) and depth of loin muscle (PEMD). Lambs were provided with either LOW or HIGH levels of available grazing nutrition from 10 days of age onwards. Liveweight gain (LWG) throughout the study was less on LOW nutrition than on HIGH nutrition, leading to a 9.5 kg lower weaning liveweight (LW) and a 14.9 kg lower final LW in LOW lambs. After adjustment for final LW, HIGH lambs had significantly greater fat depth at the C-site (approximately 40 mm from the midline over the 12th rib) and tissue depth at the GR site (110 mm from the midline over the 12th rib) than did LOW lambs. This effect was consistent across sire-types. Depth of fat at the C-site was positively associated with the EBV of the sire for fat depth. The improvement in pre-weaning LWG, weaning weight, and final weight of lambs resulting from use of sires with a greater PWWT EBV was dependent upon the level of nutrition. This interaction was identified as different slopes (coefficients) for the regression between PWWT and trait for the 2 nutrition levels, indicating that the expression of the sire’s genetic potential for growth at these times was significantly moderated by nutrition. The additional depth of lamb loin muscle resulting from use of sires of higher PEMD EBV was consistent across both LOW and HIGH nutrition treatments, with 1 mm of PEMD leading to a 0.6-mm increase in loin depth. Other consequences of sires having a high genetic capacity for loin muscle depth were reduced carcass C-fat depth with increasing sire PEMD and a tendency for conformation score to improve with the PEMD of the sire. The wool-growth response to improved nutrition was less in M lambs than in lambs of other sire-types, suggesting a difference in priority for protein partitioning between muscle and wool in lambs differing in genetic propensity for muscle growth.

Keywords: lamb, sheep, genetics, nutrition, carcass, muscling.

Legal & Privacy | Contact Us | Help


© CSIRO 1996-2016