Please use this identifier to cite or link to this item: https://une.intersearch.com.au/unejspui/handle/1959.11/773
Title: Genetic and phenotypic variance and covariance components for feed intake, feed efficiency, and other postweaning traits in Angus cattle
Contributor(s): Arthur, PF (author); Archer, JA (author); Johnston, D  (author); Herd, RM (author); Richardson, EC (author); Parnell, PF (author)
Publication Date: 2001
Handle Link: https://hdl.handle.net/1959.11/773
Abstract: Records on 1,180 young Angus bulls and heifers involved in performance tests were used to estimate genetic and phenotypic parameters for feed intake, feed efficiency, and other postweaning traits. The mean age was 268 d at the start of the performance test, which comprised 21-d adjustment and 70-d test periods. Traits studied included 200-d weight, 400-d weight, scrotal circumference, ultrasonic measurements of rib and rump fat depths and longissimus muscle area, ADG, metabolic weight, daily feed intake, feed conversion ratio, and residual feed intake. For all traits except the last five, additional data from the Angus Society of Australia pedigree and performance database were included, which increased the number of animals to 27,229. Genetic (co)variances were estimated by REML using animal models. Direct heritability estimates for 200-d weight, 400-d weight, rib fat depth, ADG, feed conversion, and residual feed intake were 0.17 +/- 0.03, 0.27 +/- 0.03, 0.35 +/- 0.04, 0.28 +/- 0.04, 0.29 +/- 0.04, and 0.39 +/- 0.03, respectively.Feed conversion ratio was genetically (rg = 0.66 ) and phenotypically (rp = 0.53) correlated with residual feed intake. Feed conversion ratio was correlated (rg = -0.62, rp = -0.74) with ADG, whereas residual feed intake was not (rg = -0.04, rp = -0.06).Genetically, both residual feed intake and feed conversion ratio were negatively correlated with direct effects of 200-d weight (rg = -0.45 and -0.21) and 400-d weight (rg = -0.26 and -0.09).The correlations between the remaining traits and the feed efficiency traits were near zero, except between feed intake and feed conversion ratio (rg = 0.31, rp = 0.23), feed intake and residual feed intake (rg = 0.69, rp = 0.72), and rib fat depth and residual feed intake (rg = 0.17, rp = 0.14).These results indicate that genetic improvement in feed efficiency can be achieved through selection and, in general, correlated responses in growth and the other postweaning traits will be minimal.
Publication Type: Journal Article
Source of Publication: Journal of Animal Science, 79(11), p. 2805-2811
Publisher: American Society of Animal Science
Place of Publication: United States
ISSN: 0021-8812
Field of Research (FOR): 070201 Animal Breeding
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
Other Links: http://jas.fass.org/cgi/content/abstract/79/11/2805
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