Lewis, Craig; Bunter, Kim L; Hermesch, Susanne

Author(s)

Lewis, Craig

Bunter, Kim L

Hermesch, Susanne

Publication Date

2012

Abstract

Uniform performance is required for optimal production. This study aimed to examine within-year variation observed on gilts for production traits and their subsequent breeding performance. Data consisted of 5060 gilts from 3 breeds (Large White, Landrace and Duroc) and 3 herds in Australia over 15 years. Production traits were average daily again (ADG μ = 662g/d) and backfat (BF μ = 10.9mm) recorded at a live weight (WT) of 100kg. Reproduction traits were total born (TB μ = 10.6), the number born alive (NBA μ = 9.76), the number of stillbirths (SB μ = 0.83) and farrowing age (FA μ = 384) recorded in the first parity. General linear models were utilized to examine variation associated with month (12 levels, calendar month) at recording. Significant effects for all traits were herd, year, month, breed and the interaction between month and breed, which were fully cross-classified in these data. Farrowing age was fitted as a linear covariate for TB, NBA and SB, and TB was a linear covariate for SB. The production traits were also corrected for dam parity and birth litter size. Models for reproduction traits also included the animal's performance traits fitted within month. Least squares means (LSM) and associated P-values by breed, month and the month*breed interaction were assessed to examine differences in the within-year variation for traits and any possible breed (genetic) differences. The ranges in LSM for the effects of month were ADG = 50g/d, BF = 1.1mm, TB = 0.67, NBA = 0.72, SB = 0.23 and FA = 15.7d (min and max for all traits P < 0.05 difference). Growth rate was higher and BF was lower in cooler months. The differences between winter and summer were larger in magnitude for Duroc in comparison to the other 2 breeds. For reproduction traits, less TB were produced in cooler months (mated during the summer) and SB was higher for summer farrowings. Further analyses showed that if variation is generated in growth performance before breeding, then there is a differential effect on variation in the reproductive traits. Linear regressions of FA on ADG nested within month of farrowing resulted in ADG solutions of -0.35d/g in winter and -0.12d/g in summer. Quantifying the different sources of within-year variation and their interactions is of economic importance and could suggest paths for intervention strategies to increase uniformity in performance.

Citation

2012 Joint Annual Meeting Abstracts (Breeding and Genetics: Swine Breeding), p. 721-721

ISSN

1525-3163

0021-8812

Link

https://hdl.handle.net/1959.11/12267

Publisher

Oxford University Press

Title

Effect of within-year variation on growth performance and subsequent reproductive performance in gilts

Type of document

Conference Publication

Entity Type

Publication

Author(s)	Lewis, Craig Bunter, Kim L Hermesch, Susanne
Publication Date	2012
Abstract	Uniform performance is required for optimal production. This study aimed to examine within-year variation observed on gilts for production traits and their subsequent breeding performance. Data consisted of 5060 gilts from 3 breeds (Large White, Landrace and Duroc) and 3 herds in Australia over 15 years. Production traits were average daily again (ADG μ = 662g/d) and backfat (BF μ = 10.9mm) recorded at a live weight (WT) of 100kg. Reproduction traits were total born (TB μ = 10.6), the number born alive (NBA μ = 9.76), the number of stillbirths (SB μ = 0.83) and farrowing age (FA μ = 384) recorded in the first parity. General linear models were utilized to examine variation associated with month (12 levels, calendar month) at recording. Significant effects for all traits were herd, year, month, breed and the interaction between month and breed, which were fully cross-classified in these data. Farrowing age was fitted as a linear covariate for TB, NBA and SB, and TB was a linear covariate for SB. The production traits were also corrected for dam parity and birth litter size. Models for reproduction traits also included the animal's performance traits fitted within month. Least squares means (LSM) and associated P-values by breed, month and the month*breed interaction were assessed to examine differences in the within-year variation for traits and any possible breed (genetic) differences. The ranges in LSM for the effects of month were ADG = 50g/d, BF = 1.1mm, TB = 0.67, NBA = 0.72, SB = 0.23 and FA = 15.7d (min and max for all traits P < 0.05 difference). Growth rate was higher and BF was lower in cooler months. The differences between winter and summer were larger in magnitude for Duroc in comparison to the other 2 breeds. For reproduction traits, less TB were produced in cooler months (mated during the summer) and SB was higher for summer farrowings. Further analyses showed that if variation is generated in growth performance before breeding, then there is a differential effect on variation in the reproductive traits. Linear regressions of FA on ADG nested within month of farrowing resulted in ADG solutions of -0.35d/g in winter and -0.12d/g in summer. Quantifying the different sources of within-year variation and their interactions is of economic importance and could suggest paths for intervention strategies to increase uniformity in performance.
Citation	2012 Joint Annual Meeting Abstracts (Breeding and Genetics: Swine Breeding), p. 721-721
ISSN	1525-3163 0021-8812
Link	https://hdl.handle.net/1959.11/12267
Publisher	Oxford University Press
Title	Effect of within-year variation on growth performance and subsequent reproductive performance in gilts
Type of document	Conference Publication
Entity Type	Publication

Effect of within-year variation on growth performance and subsequent reproductive performance in gilts

Files: