GENETIC AND GENOMIC APPROACHES TO IMPROVE EFFICIENCY OF SWINE PRODUCTION AND PRODUCT QUALITY
Location: Reproduction Research
Title: Genetic parameter estimates among scale activity score and farrowing disposition with reproductive traits in swine
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 20, 2011
Publication Date: November 1, 2011
Citation: Schneider, J.F., Rempel, L.A., Rohrer, G.A., Brown Brandl, T.M. 2011. Genetic parameter estimates among scale activity score and farrowing disposition with reproductive traits in swine. Journal of Animal Science. 89(11):3514-3521.
Interpretive Summary: An experiment was conducted to evaluate behavioral tendencies of female swine and to determine the genetic associations between behavior and reproduction. The objective of this study was to determine if behavioral traits could be useful in selecting for more productive females. Scale activity score at 5 months of age ranged from 1 to 5 (calm to very excited). Farrowing disposition score ranged from 1 to 3 (quiet and careful to agitated). Reproductive traits included age at puberty, number born alive, number born dead, litter birth weight, average birth weight, number weaned, litter weaning weight, average weaning weight, wean to estrus interval, post-weaning ovulation rate and ovulation rate including gilts. Estimated heritabilities for reproductive traits were similar to those found in the scientific literature and indicated that a genetic component was present for most traits. Genetic associations among scale activity score and farrowing disposition score with reproduction indicated that selection based on farrowing disposition score alone or on the combination of scale activity score and farrowing disposition score could potentially improve reproductive performance. Improvements in lowly heritable but economically important traits such as number born alive, number born dead, number weaned, and wean to estrus interval could have a financially viable impact on pork production. Future work is needed to identify more variation in the expression of the “quiet and careful” score of farrowing disposition.
A herd’s sow lifetime productivity is often reduced because a majority of animals are culled due to reproductive failure between replacement gilt selection and mating for the second parity. The ability to better identify young females with superior reproductive potential would have a major economic impact on swine production. The objective of this study was to determine if certain behavior traits were correlated with reproduction and if they could be useful in selecting for more productive females. A scale activity score (SA) taken at 5 mo of age and a farrowing disposition (FD) score taken at farrowing were selected as the behavioral traits. Scale activity score ranged from 1 to 5 and FD ranged from 1 to 3. Reproductive traits included age at puberty (AP), number born alive (NBA), number born dead (NBD), litter birth weight (LBW), average piglet birth weight (ABW), number weaned adjusted for cross fostering (NW), litter weaning weight (LWW), average weaning weight (AWW), wean to estrus interval (WEI), and ovulation rate including gilts (ORG), and post-weaning ovulation rate (OR). Linear mixed models (MTDFREML) were used incorporating fixed effects, covariates and an animal direct genetic effect. Estimated heritabilities were 0.15, 0.06, 0.19, 0.12, 0.02, 0.18, 0.44, 0.11, 0.22, 0.38, 0.02, 0.49, and 0.45 for SA, FD, AP, NBA, NBD, LBW, ABW, NW, LWW, AWW, WEI, OR, ORG, respectively. Genetic correlations between SA and reproduction ranged from -0.79 to 0.61. Three of the correlations, NW, LWW, and AWW approached significance (P < 0.10) and three, NBA, ABW, and WEI were significant (P < 0.05). The correlations were both beneficial and non-beneficial. In contrast, all but three of the FD correlations were beneficial and ranged from -0.66 to 0.67. Only one of the correlations, LBW, was significant (P < 0.05) and one, NBA, approached significance (P < 0.10). The consistent beneficial direction of all FD correlations except SA (0.02), AP (0.00) and AWW (0.17) show potential for inclusion of FD into a selection program. Improvements in lowly heritable but economically viable traits such as NBA, NBD, NW, and WEI could have an economic impact on pork production.