Genetic and phenotypic parameters of Australian Large White and Landrace boars performance-tested when offered food <i>ad libitum</i>

McPhee, CP; Brennan, Paul; Duncalfe, F.

doi:10.1017/s0003356100023072

Cited by 21 publications

(19 citation statements)

References 10 publications

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“…In the same report (Garwood and Diehl, 1987), the component traits of density were indicated to be highly heritable (82%, body weight; 66%, body volume). However, a similar situation has been reported in swine for the feed conversion ratio, wherein Bernard and Fahmy (1970) and Jungst et al (1981) reported realized heritabilities substantially less than estimates from the covariance among relatives (Dickerson and Grimes, 1947;Park, 1965;Robison and Berruecos, 1973;McPhee et al, 1979).…”

Section: Resultssupporting

confidence: 56%

Divergent Selection for Body Density in Japanese Quail (Coturnix coturnix japonica)

1989

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Japanese quail were selected divergently for body density over three generations for study of direct responses and correlated responses in body weight, volume, and shank length. Testing of differences occurred in the fourth generation by comparisons with a control population. Absolute standardized selection differentials were similar throughout generation-replicate subclasses. The line selected for high body density (H) and that selected for low body density (L) differed significantly (P-c.01) for body density and weight and shank length but not for body volume. Total gains in H and L, respectively, were: .015 and -.016 g-cm for body density; -3.6 and -1.2 g for body weight; and .3 and -.4 mm for shank length. Responses to selection were symmetric with respect to the control for body density and shank length but not for body weight and volume.(

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Section: Resultssupporting

confidence: 56%

Divergent Selection for Body Density in Japanese Quail (Coturnix coturnix japonica)

1989

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“…This is somewhat surprising, particularly in view of the substantial realized selection differentials achieved for this trait (Table 3). In addition, there is evidence to suggest that the genetic correlation between DLWG and carcass lean content may also be unfavourable under ad libitum feeding (McPhee et al, 1979). However, McPhee (1981) using a similar selection index and testing procedure to those of this study also produced no improvement in growth rate.…”

Section: (Fi 1 = H 2 [1 -H 2 {\ -P)} O 2 /Ns + H 2 a 2 /Ncmentioning

confidence: 58%

Index selection for improved growth and carcass characteristics in a population of Large White pigs

et al. 1988

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Request Permissions : Click here Downloaded from http://journals.cambridge.org/ASC, IP address: 128.218.248.209 on 16 Mar 2015Anim. 0()()3-3561/88/6020()265$(l2-(» ABSTRACT An experiment was carried out over 11 years to investigate selection for economy of production and carcass lean content under ad libitum feeding in Large White pigs. Two lines, a selection (S) and a control (C) line, were involved in the study. The S line comprised 80 females and 10 males and was based at two centres. Boars were performance tested centrally at one of the centres and gilts were on-farm tested. Testing was carried out in groups of two or three full-sibs over the live-weight range 27 to 87 kg. Selection was based on an index (I) incorporating individual daily live-weight gain (DLWG) and ultrasonically measured backfat thickness (USBF) and a group food conversion ratio (FCR) and generations were overlapping. The C line (32 females and 16 males) was maintained at one centre and males were performance tested alongside S boars to monitor genetic progress. Cumulative realized selection differentials over years 1 to 10 were equivalent to 5-5, 5 1 , 7-0 and 9-4 phenotypic standard deviations for DLWG, USBF, FCR and I respectively and generation intervals averaged 17-0 months. There was little genetic change in DLWG, however, USBF, FCR and I showed substantial improvements with cumulative responses in year 11 of -12-3 mm, -0-22 kg/kg and +45-2 points respectively. The reduction in USBF occurred in the first half of the study with no further improvements being achieved after year 6. This study illustrates the effectiveness of index selection for a limited number of economically important traits but highlights limitations to this approach.

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“…Determination of leanness is not straightforward, and unfavourable genetic correlations between growth and leanness (Mcphee et al, 1979;Cleveland et al, 1982) make joint improvement of these traits a challenge. Fowler et al (1976) showed that lean meat growth can be selected by using an economic selection index that combines lean meat content and growth or by using lean meat growth, which is measured as lean gain per day.…”

Section: Introductionmentioning

confidence: 99%

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

Gjerlaug-Enger

Kongsro

Ødegård

et al. 2012

Animal

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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.

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Genetic and phenotypic parameters of Australian Large White and Landrace boars performance-tested when offered food ad libitum

Cited by 21 publications

References 10 publications

Divergent Selection for Body Density in Japanese Quail (Coturnix coturnix japonica)

Divergent Selection for Body Density in Japanese Quail (Coturnix coturnix japonica)

Index selection for improved growth and carcass characteristics in a population of Large White pigs

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

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