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Journal of Animal Science Abstract - Animal Genetics

Selection for increased number of piglets at d 5 after farrowing has increased litter size and reduced piglet mortality1

 

This article in JAS

  1. Vol. 91 No. 6, p. 2575-2582
     
    Received: Oct 15, 2012
    Accepted: Feb 19, 2013
    Published: November 25, 2014


    2 Corresponding author(s): bni@lf.dk
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doi:10.2527/jas.2012-5990
  1. B. Nielsen 2,
  2. G. Su,
  3. M. S. Lund and
  4. P. Madsen
  1. Pig Research Centre, Danish Agriculture and Food Council, DK-1609 Axeltorv, Denmark
    Department of Molecular Biology and Genetics, Aarhus University, DK-8830 Tjele, Denmark

Abstract

Selection for litter size at d 5 after farrowing (LS5) was introduced in 2004 to increase the number of piglets weaned and to reduce piglet mortality in Danish Landrace and Yorkshire. The objective of this study was to investigate selection responses for LS5, total number born (TNB), and mortality [MORT, defined as (TNB − LS5)/TNB] when selection for increasing LS5 was a part of the breeding goal. Data were collected from nucleus herds recorded from 2004 to 2010, including first litters of 42,807 Landrace sows and 33,225 Yorkshire sows. The data were analyzed using a 3-trait animal model of TNB, MORT, and LS5. Significant (co) variances were estimated between the 3 traits in both populations. The heritabilities of TNB, MORT, and LS5 were 0.10, 0.09, and 0.09 in Landrace and 0.12, 0.10, and 0.10 in Yorkshire. The genetic correlations were 0.28 and 0.22 between TNB and MORT, 0.74 and 0.68 between TNB and LS5, and −0.43 and −0.57 between MORT and LS5 in Landrace and Yorkshire, respectively. The results show that the genetic improvement of LS5 was a combination of increased TNB and reduced MORT. During the observation period, the genetic improvement was 1.7 piglets per litter for LS5, 1.3 piglets per litter for TNB, and 4.7% for MORT in Landrace and 2.2 piglets per litter, 1.9 piglets per litter, and 5.9% in Yorkshire. Phenotypic improvement was 1.4 piglets per litter for LS5, 0.3 piglets per litter for TNB, and 7.9% for MORT in Landrace and 2.1 piglets per litter, 1.3 piglets per litter, and 7.6% in Yorkshire. In addition, genetic gain was evaluated in 3 phenotypic groups of TNB, representing the 25% smallest litters, the 50% medium litters, and the 25% largest litters. In all 3 groups, the genetic and phenotypic gains of TNB and LS5 increased, whereas MORT reduced in both populations.

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