VTechWorks staff will be away for the winter holidays starting Tuesday, December 24, 2024, through Wednesday, January 1, 2025, and will not be replying to requests during this time. Thank you for your patience, and happy holidays!
 

Model definition for genetic evaluation of purebred and crossbred lambs including heterosis

Simple item page
dc.contributor.authorJurado, Napoleon Vargasen
dc.contributor.authorNotter, David R.en
dc.contributor.authorTaylor, Joshua B.en
dc.contributor.authorBrown, Daniel J.en
dc.contributor.authorMousel, Michelle R.en
dc.contributor.authorLewis, Ronald M.en
dc.date.accessioned2023-05-25T19:07:39Zen
dc.date.available2023-05-25T19:07:39Zen
dc.date.issued2022-06en
dc.description.abstractBoth direct and maternal heterosis increase birth and post-natal weights in crossbred lambs. Estimates of these heterotic effects can be used as adjustment factors in multi-breed genetic evaluations. Crossbreeding is a common practice among commercial sheep producers to improve animal performance. However, genetic evaluation of U.S. sheep is performed within breed type (terminal sire, semi-prolific, and western range). While incorporating crossbred records may improve assessment of purebreds, it requires accounting for heterotic and breed effects in the evaluation. The objectives of this study were to: 1) describe the development of a paternal composite (PC) line, 2) determine the effect of direct and maternal heterosis on growth traits of crossbred lambs, 3) estimate (co)variance components for direct and maternal additive, and uncorrelated maternal environmental, effects, and 4) provide an interpretation of the estimates of random effects of genetic groups, and to use those solutions to compare the genetic merit of founding breed subpopulations. Data included purebred and crossbred records on birth weight (BN; n = 14,536), pre-weaning weight measured at 39 or 84 d (WN; n = 9,362) depending on year, weaning weight measured at 123 d (WW; n = 9,297), and post-weaning weight measured at 252 d (PW; n = 1,614). Mean (SD) body weights were 5.3 (1.1), 16.8 (3.9) and 28.0 (7.6), 39.1 (7.2), and 54.2 (8.7) kg for BN, WN (at the two ages), WW, and PW, respectively. In designed experiments, the Siremax, Suffolk, Texel, Polypay, Columbia, Rambouillet, and Targhee breeds were compared within the same environment. Estimates of heterotic effects and covariance components were obtained using a multiple trait animal model. Genetic effects based on founders' breeds were significant and included in the model. Percent estimates of direct heterosis were 2.89 +/- 0.61, 2.60 +/- 0.65, 4.24 +/- 0.56, and 6.09 +/- 0.86, and estimates of maternal heterosis were 1.92 +/- 0.87, 4.64 +/- 0.80, 3.95 +/- 0.66, and 4.04 +/- 0.91, for BN, WN, WW, and PW, respectively. Correspondingly, direct heritability estimates were 0.17 +/- 0.02, 0.13 +/- 0.02, 0.17 +/- 0.02, and 0.46 +/- 0.04 for BN, WN, WW, and PW. Additive maternal effects accounted for trivial variation in PW. For BN, WN, and WW, respectively, maternal heritability estimates were 0.16 +/- 0.02, 0.10 +/- 0.02, and 0.07 +/- 0.01. Uncorrelated maternal environmental effects accounted for little variation in any trait. Direct and maternal heterosis had considerable impact on growth traits, emphasizing the value of crossbreeding and the need to account for heterosis, in addition to breed effects, if crossbred lamb information is included in genetic evaluation. Lay Summary Crossbreeding is common in commercial sheep enterprises. It allows breeds with different attributes to be combined to generate crossbred progeny tailored to production environments and customer preferences. Additionally, crossbreds often benefit from heterosis, performing at levels above the average of their parental breeds. Over two decades, body weights were collected at birth and at pre-weaning, weaning, and post-weaning ages on purebred and crossbred lambs from semi-prolific (Polypay), western range (Columbia, Rambouillet, Targhee), and terminal sire (Siremax, Suffolk, Texel) breeds at the U.S. Sheep Experiment Station. When combined, the value of direct heterosis-that due to a lamb being crossbred-and maternal heterosis-that due to the lamb's dam being crossbred-increased birth (5%) and post-natal (up to 10%) weights in crossbred lambs. This highlights the value of crossbreeding to the U.S. sheep industry, especially in western range production systems. Genetic variation between and within breeds also was detected for the purebred parental breeds. Such heterotic and breed effects must be accounted for if crossbred performance is to be incorporated in genetic evaluation of purebreds. Therefore, these results provide the foundation for utilizing crossbred information in the evaluation and selection of purebred sheep in the United States.en
dc.description.adminPublic domain – authored by a U.S. government employeeen
dc.description.notesWe wish to thank the technical staff at the U.S. Sheep Experiment Station (Dubois, ID) for their contributions to the experimental program. This project was supported by the U.S. Department of Agriculture (USDA), Agricultural Research Service (Cooperative Agreement Number 58-2056-8-002). The USDA is an equal opportunity provider and employer. The mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA.en
dc.description.sponsorshipU.S. Department of Agriculture (USDA), Agricultural Research Service [58-2056-8-002]en
dc.description.versionPublished versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1093/jas/skac188en
dc.identifier.eissn1525-3163en
dc.identifier.issn0021-8812en
dc.identifier.issue6en
dc.identifier.pmid35696612en
dc.identifier.urihttp://hdl.handle.net/10919/115195en
dc.identifier.volume100en
dc.language.isoenen
dc.publisherOxford University Pressen
dc.rightsPublic Domain (U.S.)en
dc.rights.urihttp://creativecommons.org/publicdomain/mark/1.0/en
dc.subjectbody weighten
dc.subjectcrossbreedingen
dc.subjectheterosisen
dc.subjectlambsen
dc.subjectmultiple-trait animal modelen
dc.subjectparameter estimatesen
dc.titleModel definition for genetic evaluation of purebred and crossbred lambs including heterosisen
dc.title.serialJournal of Animal Scienceen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
skac188.pdf
Size:
6.12 MB
Format:
Adobe Portable Document Format
Description:
Published version
Download

Collections

Scholarly Works, School of Animal Sciences