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| Author(s): |
Erica Elias Baron
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2000-06-15 |
| Examining board members: |
Luiz Lehmann Coutinho;
Mario Luiz Martinez;
Luciana Correia de Almeida Regitano
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| Advisor: | Luiz Lehmann Coutinho |
| Abstract | |
Increased production in agribusiness has intensified the search for more efficient and competitive production systems. In animal production, advances are achivied primarily through sire selection. Genetic superiority of bulls for milk production cannot be directly measured in the animal; therefore, genetic value is measured by the milk production of its daughters by a progeny test. Selection of bulls by the progeny test could be considered an ideal method when the following characteristics are present: low hereditability, large productions and a large number of progenies. However, the method presents two drawbacks that limit its use: 1) high cost and 2) increase in generation intervals. Nevertheless, these obstacles can be overcome when a large number of progenies are obtained with artificial insemination (A.I.). Correct relationship among sires is essential for an efficient animal-breeding program. Many questions about relationship can be solved by conventional tests, such as blood type and serum proteins. In some cases these polymorphisms are not enough for accurate results; consequently, other methods are used such as microsatelitte molecular markers. This methodology has been described to determine and verify parentage including bovines with high efficiency due to its greater polymorphism and easily interpreted results. Microsatelitte markers BM8246, BMS963, TEXAN15, BMS483, CSFM50, INRA112 were used to investigate paternity. Paternity of nine Gir dairy sires participating in a progeny test was verified. The paternity error rate was calculated and its effect on estimation of the genetic value of the sires determined. Of the 74 daughters analyzed 27 were excluded, which corresponds to a 36% error in paternity identification. However, the change observed in bull classification due to correction of inaccurate paternity and consequent changes of genetic value of the sires was not significant when the two evaluations were compared by the correlation method of Spearman. (AU) | |