Genetic parameters of growth and in vivo computerized tomography based carcass traits in Pannon White rabbits

doi:10.1016/j.livsci.2006.03.009

Livestock Science

Volume 104, Issues 1–2, October 2006, Pages 46-52

https://doi.org/10.1016/j.livsci.2006.03.009 Get rights and content

Abstract

Genetic parameters for average daily gain between the age of 5 and 10 weeks (ADG), the average cross-sectional area of the m. Longissimus dorsi (L) (between the 2nd–3rd and 4th–5th lumbar vertebrae-based on in vivo computerized tomography (CT)) and dressing out percentage (DoP) were estimated in a group of 28,686 Pannon White rabbits reared in 5044 litters and born between 2000 and 2003. Using multivariate animal models with Bayesian procedures, estimated heritabilities were moderate and moderately high for ADG, L and DoP (0.21 to 0.29, 0.25 to 0.42 and 0.19 to 0.71, respectively). Litter effects were moderate for ADG, L and DoP estimates (0.20 to 0.22, 0.10 to 0.18 and 0.09 to 0.30, respectively). Genetic correlation coefficient estimates between ADG and L and ADG and DoP were moderate and negative (− 0.41 to − 0.01, − 0.70 to + 0.10). A moderately high positive genetic correlation was found between L and DoP (0.13 to 0.83).

Introduction

Most of the current rabbit breeding programmes are based on three-way crosses. The F₁ of two maternal lines is used as the female parent utilizing the expected positive heterosis in reproductive traits. The F₁ is then crossed with a paternal line. The rabbits produced by the crossbred does are slaughtered for meat (Baselga, 2004). Paternal lines are selected either for average daily gain or for body weight at market time. The selection response on both traits is well documented (Lukefahr et al., 1996, McNitt and Lukefahr, 1996, Moura et al., 1997, Piles and Blasco, 2003).

Selection can also target dressing out percentage directly through progeny testing. Progeny testing is however costly and lengthens the generation interval. According to our knowledge it was only practised by Varewyck et al. (1986) and Szendrő et al. (1988). The utilization of X-ray computerized tomography (CT) to assess body composition in vivo opened up new possibilities (Skjervold et al., 1981). At the University of Kaposvár (Hungary), a special digital imaging centre was installed in 1990 utilizing CT for animal science and human diagnostics and research. CT-based selection in sheep is currently applied in the UK, Australia and New Zealand (Simm, 1987, Jones et al., 2002, Jones et al., 2004). Before 1999 there was no international precedent on the application of tomography in rabbits. The first stage of examination in Kaposvár aimed at selection for improved slaughter value of Pannon White rabbits. The determination was made of the sectional planes in which the CT data recorded are suitable for estimation. It was concluded that the correlations between the average cross section of the m. Longissimus dorsi and the carcass traits exceeded the level of 0.7 (Szendrő et al., 1992). The methods of using the CT system in rabbit research are summarised by Romvári et al. (1996). Preliminary results of CT-aided selection of Pannon White rabbits were reported by Szendrő et al. (1996). CT-based selection was re-started in 2000 and has been practised thereafter. Nevertheless, accurate genetic parameters are still to be determined for growth and carcass traits involved in this programme. As the structure of the accumulated data is highly unbalanced, the objective of the present study was to estimate genetic parameters for growth and CT-based carcass traits using Bayesian techniques.

Section snippets

Foundation population

The development of the Pannon White rabbit population was initiated at University of Kaposvár in 1988. The first stage of the programme took place between 1988 and 1990. During this stage the population consisted of 100 New Zealand White does. The farm served as a test centre for a large and some surrounding stock farms evaluating the weight gain and dressing out percentage of their bucks through progeny testing. The does were inseminated entirely through AI. The local population at Kaposvár

Results and discussion

Features of the marginal posterior distributions are given in Table 2, Table 3, Table 4. Monte Carlo standard errors were always low and the test of Geweke did not detect lack of convergence in any case. All posterior distributions were symmetrical and approximately normal, even in the case of genetic correlations.

Conclusions

Based on the estimated genetic parameters of ADG, L, and DoP it can be concluded that the moderate heritability of L and the moderately high and positive genetic correlation coefficient between L and DoP makes efficient CT-based in vivo non-invasive selection on DoP possible. Yet, because the estimated genetic correlation coefficient between L and DoP was far less than unity and the heritability of DoP exceeded that of L, the correlated response in DoP might be less than expected.

Acknowledgements

Financial help of COST 848 and OTKA F048355 is gratefully acknowledged.

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Genetic parameters of growth and in vivo computerized tomography based carcass traits in Pannon White rabbits

Abstract

Introduction

Section snippets

Foundation population

Results and discussion

Conclusions

Acknowledgements

Livest. Prod. Sci.

Prof. Anim. Sci.

Meat Sci.

Meat Sci.

Genetic improvement of meat rabbits

Harmonization of criteria and terminology in rabbit meat research. A revised proposal

World Rabbit Sci.

Allometric changes during growth in rabbits

J. Agric. Sci. Camb.

Selection response of growth rate in rabbits for meat production

Genet. Sel. Evol.