| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Animal Breeding and Genetics Group, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands
2 Holland Genetics, CR Delta, PO Box 5073, 6802 EB Arnhem, The Netherlands
Corresponding author: Chris Schrooten; e-mail: schrooten.c{at}hg.nl.
The aim of this paper was to explore general characteristics of multistage breeding schemes and to evaluate multistage dairy cattle breeding schemes that use information on quantitative trait loci (QTL). Evaluation was either for additional genetic response or for reduction in number of progeny-tested bulls while maintaining the same response. The reduction in response in multistage breeding schemes relative to comparable single-stage breeding schemes (i.e., with the same overall selection intensity and the same amount of information in the final stage of selection) depended on the overall selection intensity, the selection intensity in the various stages of the breeding scheme, and the ratio of the accuracies of selection in the various stages of the breeding scheme. When overall selection intensity was constant, reduction in response increased with increasing selection intensity in the first stage. The decrease in response was highest in schemes with lower overall selection intensity. Reduction in response was limited in schemes with low to average emphasis on first-stage selection, especially if the accuracy of selection in the first stage was relatively high compared with the accuracy in the final stage.
Closed nucleus breeding schemes in dairy cattle that use information on QTL were evaluated by deterministic simulation. In the base scheme, the selection index consisted of pedigree information and own performance (dams), or pedigree information and performance of 100 daughters (sires). In alternative breeding schemes, information on a QTL was accounted for by simulating an additional index trait. The fraction of the variance explained by the QTL determined the correlation between the additional index trait and the breeding goal trait. Response in progeny test schemes relative to a base breeding scheme without QTL information ranged from +4.5% (QTL explaining 5% of the additive genetic variance) to +21.2% (QTL explaining 50% of the additive genetic variance). A QTL explaining 5% of the additive genetic variance allowed a 35% reduction in the number of progeny tested bulls, while maintaining genetic response at the level of the base scheme. Genetic progress was up to 31.3% higher for schemes with increased embryo production and selection of embryos based on QTL information. The challenge for breeding organizations is to find the optimum breeding program with regard to additional genetic progress and additional (or reduced) cost.
Key Words: genetic evaluation • marker-assisted selection • quantitative trait locus • dairy cattle
Abbreviation key: MAS = marker-assisted selection.
This article has been cited by other articles:
|
|
 |
|
  M. Duangjinda, D. Buayai, V. Pattarajinda, Y. Phasuk, S. Katawatin, T. Vongpralub, and A. Chaiyotvittayakul Detection of bovine leukocyte antigen DRB3 alleles as candidate markers for clinical mastitis resistance in Holstein x Zebu J Anim Sci, February 1, 2009; 87(2): 469 - 476. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Neuner, R. Emmerling, G. Thaller, and K.-U. Gotz Strategies for Estimating Genetic Parameters in Marker-Assisted Best Linear Unbiased Predictor Models in Dairy Cattle J Dairy Sci, November 1, 2008; 91(11): 4344 - 4354. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Ansari-Mahyari, A. C. Sorensen, M. S. Lund, H. Thomsen, and P. Berg Across-Family Marker-Assisted Selection Using Selective Genotyping Strategies in Dairy Cattle Breeding Schemes J Dairy Sci, April 1, 2008; 91(4): 1628 - 1639. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. M. Dekkers Marker-assisted selection for commercial crossbred performance J Anim Sci, September 1, 2007; 85(9): 2104 - 2114. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Kearney, P. R. Amer, and B. Villanueva Cumulative Discounted Expressions of Sire Genotypes for the Complex Vertebral Malformation and {beta}-Casein Loci in Commercial Dairy Herds J Dairy Sci, December 1, 2005; 88(12): 4426 - 4433. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
