HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wiggans, G. R. Articles by Van Tassell, C. P. Search for Related Content PubMed PubMed Citation Articles by Wiggans, G. R. Articles by Van Tassell, C. P.

Calving Ease (Co)Variance Components for a Sire-Maternal Grandsire Threshold Model

G. R. Wiggans^*, I. Misztal and C. P. Van Tassell^*,

^* Animal Improvement Programs Laboratory and
Bovine Functional Genomics Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350
Animal and Dairy Science Department, University of Georgia, Athens 30602

Corresponding Author: G. R. Wiggans, e-mail:
wiggans{at}aipl.arsusda.gov.

Variance components for a sire-maternal grandsire (MGS) threshold model were estimated from subsets of the US calving ease (CE) database, which includes over 10 million calving records with CE scored 1 (no problem) to 5 (extreme difficulty). Selected records included sire and MGS among the 2601 most frequently appearing bulls. The data were further restricted by requiring at least 20 records in each herd year. Five mutually exclusive sample datasets of approximately 200,000 records each were created based on herd code. The model included random herd-year, sire, MGS, and residual effects and fixed year-season, parity-sex, and birth year of sire and MGS effects. Fewer than 50 iterations were required to reach convergence. The (co)variance component estimates from the five replicates were quite similar. The set of estimates (0.438, herd-year; 0.022, sire; 0.016, MGS; 0.009, sire-MGS) that yielded among the highest heritabilities (0.086, direct; 0.048, maternal) and a correlation of direct and maternal effects near the mean (-0.12) was selected for use in the implementation of a sire-MGS model for CE.

Key Words: calving ease • dystocia • threshold model

Abbreviation key: CE = calving ease, MGS = maternal grandsire

This article has been cited by other articles:

				G. R. Wiggans, J. B. Cole, and L. L. M. Thornton Multiparity Evaluation of Calving Ease and Stillbirth with Separate Genetic Effects by Parity J Dairy Sci, August 1, 2008; 91(8): 3173 - 3178. [Abstract] [Full Text] [PDF]

				J. M. Hickey, M. G. Keane, D. A. Kenny, A. R. Cromie, P. R. Amer, and R. F. Veerkamp Heterogeneity of Genetic Parameters for Calving Difficulty in Holstein Heifers in Ireland J Dairy Sci, August 1, 2007; 90(8): 3900 - 3908. [Abstract] [Full Text] [PDF]

				B. Heringstad, Y. M. Chang, M. Svendsen, and D. Gianola Genetic Analysis of Calving Difficulty and Stillbirth in Norwegian Red Cows J Dairy Sci, July 1, 2007; 90(7): 3500 - 3507. [Abstract] [Full Text] [PDF]

				J. B. Cole, G. R. Wiggans, P. M. VanRaden, and R. H. Miller Stillbirth (Co)Variance Components for a Sire-Maternal Grandsire Threshold Model and Development of a Calving Ability Index for Sire Selection J Dairy Sci, May 1, 2007; 90(5): 2489 - 2496. [Abstract] [Full Text] [PDF]

				E. L. de Maturana, E. Ugarte, J. Komen, and J. A. M. van Arendonk Consequences of Selection for Yield Traits on Calving Ease Performance J Dairy Sci, May 1, 2007; 90(5): 2497 - 2505. [Abstract] [Full Text] [PDF]

				R. L. Powell and H. D. Norman Major advances in genetic evaluation techniques. J Dairy Sci, April 1, 2006; 89(4): 1337 - 1348. [Abstract] [Full Text] [PDF]

				J. Jamrozik, J. Fatehi, G. J. Kistemaker, and L. R. Schaeffer Estimates of Genetic Parameters for Canadian Holstein Female Reproduction Traits J Dairy Sci, June 1, 2005; 88(6): 2199 - 2208. [Abstract] [Full Text] [PDF]

				J. B. Cole, R. C. Goodling Jr., G. R. Wiggans, and P. M. VanRaden Genetic Evaluation of Calving Ease for Brown Swiss and Jersey Bulls from Purebred and Crossbred Calvings J Dairy Sci, April 1, 2005; 88(4): 1529 - 1539. [Abstract] [Full Text] [PDF]

				M. Hansen, I. Misztal, M. S. Lund, J. Pedersen, and L. G. Christensen Undesired Phenotypic and Genetic Trend for Stillbirth in Danish Holsteins J Dairy Sci, May 1, 2004; 87(5): 1477 - 1486. [Abstract] [Full Text] [PDF]

				C. P. Van Tassell, G. R. Wiggans, and I. Misztal Implementation of a Sire-Maternal Grandsire Model for Evaluation of Calving Ease in the United States J Dairy Sci, October 1, 2003; 86(10): 3366 - 3373. [Abstract] [Full Text] [PDF]