Livestock Production Science 65 2000 261–270 www.elsevier.com locate livprodsci
Genetic parameters for lean meat yield, meat quality, reproduction and feed efficiency traits for Australian pigs
3. Genetic parameters for reproduction traits and genetic correlations with production, carcase and meat quality traits
a , b
a
S. Hermesch , B.G. Luxford , H.-U. Graser
a
Animal Genetics and Breeding Unit , Joint Institute of NSW Agriculture and The University of New England,
University of New England , Armidale, NSW 2351, Australia
b
Bunge Meat Industries , Corowa, NSW 2646, Australia
Received 15 September 1998; received in revised form 12 November 1999; accepted 9 December 1999
Abstract
Genetic parameters were obtained using REML procedures applied to a multiple trait animal model for number born alive NBA, litter birth weight LBW, average piglet weight at birth ABW recorded in the first, second and third parity
NBA , LBW
, ABW and 21-day litter weight LW21 for 6050 Large White and Landrace sows. Heritability
1,2,3 1,2,3
1,2,3 1
estimates ranged from 0.06 to 0.22 for these reproductive traits, with lowest estimates for NBA and LW21 .
1,2,3 1
Reproductive performance in the first parity should be regarded as a different trait than reproductive performance in later parities range of genetic correlations rg: 0.52–0.78, 60.16–0.30. NBA
was unfavourably related with LBW ,
1,2,3 1
ABW and LW21 . In addition, NBA
was negatively correlated with growth rate traits, feed intake and weight of the
1,2,3 1
1,2,3
back leg and ham BLW, LMW rg range: 2 0.45 to 2 0.01, 60.13–0.15. In contrast, genetic correlations were favourable between LBW
, ABW and growth rate, BLW and LMW rg values: 0.08–0.55, 60.12–0.25. NBA
and ABW
1,2,3 1,2,3
1,2,3 1,2,3
were not genetically related with backfat measurements, while a low backfat was associated with a high LBW rg:
1,2,3
2 0.54 to 2 0.08, 60.09–0.36. Genetic correlations between reproduction traits and meat quality traits were inconsistent
between traits and parities. A lower intramuscular fat content was associated with a higher LBW and ABW
rg:
1,2,3 1,2,3
2 0.37 to 2 0.12, 60.12–0.18. In summary, genetic correlations between reproduction traits and performance traits were
only unfavourable between litter size and growth rate and feed intake. Genetic correlations between litter birth weight and average piglet weight at birth indicate that selection for leanness will also improve litter weight traits.
2000 Elsevier
Science B.V. All rights reserved.
Keywords : Pigs; Reproduction; Production; Carcase; Meat quality; Genetic parameters
1. Introduction
Corresponding author. Tel.: 1 61-267-73-3787; fax: 1 61-
Genetic improvement of sow productivity has
267-73-3266. E-mail address
: skahtenbmetz.une.edu.au S. Hermesch.
mainly been focussing on litter size i.e., de Vries and
0301-6226 00 – see front matter
2000 Elsevier Science B.V. All rights reserved. P I I : S 0 3 0 1 - 6 2 2 6 0 0 0 0 1 5 2 - 4
262 S
. Hermesch et al. Livestock Production Science 65 2000 261 –270
Kanis, 1994. However, an increase in litter size The proportion of crossbred litters for the first three
appears to be associated with decrease in piglet birth parities were 60.3, 64.4 and 74.2 for Large White
weight and survival Haley et al., 1988. Rydhmer et sows and 52.0, 56.2 and 69.1 for Landrace sows.
al. 1992 found that a low average piglet weight at Each litter originated from the first mating only and
birth increases piglet mortality. Therefore, in order to the proportion of litters from artificial insemination
increase the number of piglets weaned per sow was 18.3, 23.0 and 24.8 for the first to third parity.
through genetic improvement further reproductive The farrowing age for the first litter was restricted to
traits of the sow including litter birth weight, average 270–500 days. Age of litter when litter weight was
piglet weight at birth and 21-day litter weight should recorded ranged from 10 to 28 days with a mean of
be considered in breeding programs. In addition, 19 days.
these reproductive traits might have stronger genetic Reproductive traits were analysed as a different
relationships with other production traits as currently trait in the first, second and third parity and included
assumed. Knowledge about genetic parameters be- number of piglets born alive NBA
, litter birth
1,2,3
tween reproduction traits and other performance weight LBW
, average piglet weight at birth
1,2,3
traits is mostly limited to growth rate, feed intake ABW
and litter weight at 21-days in the first
1,2,3
and backfat Short et al., 1994; Rydhmer et al., 1995; parity LW21 . Records available for 21-day litter
1
Tholen et al., 1996; Crump et al., 1997 with varying weight recorded in the second and third parity were
estimates between studies and data sets. Breeding not sufficient to analyse them as separate traits.
programs consider a number of production, carcase Furthermore, recording procedures for litter birth
and meat quality traits, and their genetic relationship weight and consequently average piglet birth weight
with reproductive traits is required in order to changed in the third quarter of 1993 when litter
establish whether reproductive traits should also be weight was recorded 3 days after birth. In total,
analysed in a multitrait analysis. The objective of 13 518 litters were available for analysis.
this study was to obtain genetic parameters for reproductive traits of the sow and to obtain genetic
2.2. Production, carcase and meat quality data correlations between reproduction traits and product-
ion, carcase and meat quality traits. Analysis of production, carcase and meat quality
data was based on performance records from 1799 Large White and 1522 Landrace boars. Performance
2. Material and methods traits comprised growth rate from three to 18 weeks
