Please use this identifier to cite or link to this item: https://hdl.handle.net/1959.11/18811
Title: Genetic correlations between body weight change and reproduction traits in Merino ewes depend on age
Contributor(s): Rose, G (author); Mulder, H A (author); Van Der Werf, Julius H  (author)orcid ; Thompson, A N (author); van Arendonk, J A M (author)
Publication Date: 2014
DOI: 10.2527/jas.2013-7378
Handle Link: https://hdl.handle.net/1959.11/18811
Abstract: Merino sheep in Australia experience periods of variable feed supply. Merino sheep can be bred to be more resilient to this variation by losing less BW when grazing poor quality pasture and gaining more BW when grazing good quality pasture. Therefore, selection on BW change might be economically attractive but correlations with other traits in the breeding objective need to be known. The genetic correlations (rg) between BW, BW change, and reproduction were estimated using records from approximately 7,350 fully pedigreed Merino ewes managed at Katanning in Western Australia. Number of lambs and total weight of lambs born and weaned were measured on approximately 5,300 2-yr-old ewes, approximately 4,900 3-yr-old ewes, and approximately 3,600 4-yr-old ewes. On a proportion of these ewes BW change was measured: approximately 1,950 2-yr-old ewes, approximately 1,500 3-yr-old ewes, and approximately 1,100 4-yr-old ewes. The BW measurements were for 3 periods. The first period was during mating period over 42 d on poor pasture. The second period was during pregnancy over 90 d for ewes that got pregnant on poor and medium quality pasture. The third period was during lactation over 130 d for ewes that weaned a lamb on good quality pasture. Genetic correlations between weight change and reproduction were estimated within age classes. Genetic correlations were tested to be significantly greater magnitude than 0 using likelihood ratio tests. Nearly all BW had significant positive genetic correlations with all reproduction traits. In 2-yr-old ewes, BW change during the mating period had a positive genetic correlation with number of lambs weaned (rg = 0.58); BW change during pregnancy had a positive genetic correlation with total weight of lambs born (rg = 0.33) and a negative genetic correlation with number of lambs weaned (rg = -0.49). All other genetic correlations were not significantly greater magnitude than 0 but estimates of genetic correlations for 3-yr-old ewes were generally consistent with these findings. The direction of the genetic correlations mostly coincided with the energy requirements of the ewes and the stage of maturity of the ewes. In conclusion, optimized selection strategies on BW changes to increase resilience will depend on the genetic correlations with reproduction and are dependent on age.
Publication Type: Journal Article
Source of Publication: Journal of Animal Science, 92(8), p. 3249-3257
Publisher: Amercian Society of Animal Science
Place of Publication: Champaign, United States of America
ISSN: 1525-3163
0021-8812
Field of Research (FOR): 070201 Animal Breeding
Socio-Economic Outcome Codes: 830311 Sheep - Wool
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
Statistics to Oct 2018: Visitors: 72
Views: 80
Downloads: 2
Appears in Collections:Journal Article
School of Environmental and Rural Science

Files in This Item:
2 files
File Description SizeFormat 
Show full item record

SCOPUSTM   
Citations

1
checked on Nov 26, 2018

Page view(s)

32
checked on Jan 12, 2019
Google Media

Google ScholarTM

Check

Altmetric


Items in Research UNE are protected by copyright, with all rights reserved, unless otherwise indicated.