Genetic parameters between slaughter pig efficiency and growth rate of different body tissues estimated by computed tomography in live boars of Landrace and Duroc

Abstract

In this study, computed tomography (CT) technology was used to measure body composition on live pigs for breeding purposes. Norwegian Landrace (L; n 5 3835) and Duroc (D; n 5 3139) boars, selection candidates to be elite boars in a breeding programme, were CT-scanned between August 2008 and August 2010 as part of an ongoing testing programme at Norsvin's boar test station. Genetic parameters in the growth rate of muscle (MG), carcass fat (FG), bone (BG) and non-carcass tissue (NCG), from birth to ,100 kg live weight, were calculated from CT data. Genetic correlations between growth of different body tissues scanned using CT, lean meat percentage (LMP) calculated from CT and more traditional production traits such as the average daily gain (ADG) from birth to 25 kg (ADG1), the ADG from 25 kg to 100 kg (ADG2) and the feed conversion ratio (FCR) from 25 kg to 100 kg were also estimated from data on the same boars. Genetic parameters were estimated based on multi-trait animal models using the average information-restricted maximum likelihood (AI-REML) methodology. The heritability estimates (s.e. These results showed the difficulty in jointly improving LMP and ADG2. ADG2 was unfavourably correlated with FG (L: 0.84 and D: 0.72), thus indicating to a large extent that selection for increased growth implies selection for fatness under an ad libitum feeding regime. Selection for MG is not expected to increase ADG2, but will yield faster growth of the desired tissues and a better carcass quality. Hence, we consider MG to be a better biological trait in selection for improved productivity and carcass quality. CT is a powerful instrument in conjunction with breeding, as it combines the high accuracy of CT data with measurements taken from the selection candidates. CT also allows the selection of new traits such as real body composition, and in particular, the actual MG on living animals.

Simultaneous estimation of daily weight and feed intake curves for growing pigs by random regression

“…The heritabilities are, for both the breeds, lower (although more clear for Landrace) than the heritabilities reported by Gjerlaug-Enger et al (2011) on the same populations. They reported heritabilities for average daily gain from 25 to 100 kg using an animal model in the range of 0.41 to 0.42 for both the breeds.…”

“…They reported heritabilities for average daily gain from 25 to 100 kg using an animal model in the range of 0.41 to 0.42 for both the breeds. The differences between breeds are more apparent in this study compared with the results of Gjerlaug-Enger et al (2011). A possible explanation is that the genetic correlation between test days is generally lower for the Landrace than for the Duroc, which makes that, for the Duroc, the heritability at a particular test day is closer to the overall heritability across the entire test.…”

Osteochondrosis in pigs diagnosed with computed tomography: heritabilities and genetic correlations to weight gain in specific age intervals

“…The size of the voxel is determined by the resolution of the CT device (Hounsfield, 1976). The device used for scanning was a General Electric 32 slice VTC LightSpeed scanner, which is further described by Gjerlaug-Enger et al (2012). Images were compressed and stored on an image server that can be accessed for further image processing.…”

<i>In vivo</i> prediction of intramuscular fat in pigs using computed tomography

“…The boars were located at the Norsvin Delta testing station for boars described by GerlaugEnger et al [12] and Aasmundstad et al [13]. The pigs were CT scanned at 120 kg at the end of the testing period.…”