Summary

The National Association of Breeders and Researchers (ANCP) presents the Sire Summary – August 2021 for Nellore, Guzerá, Brahman and Tabapuã breeds. This publication aims to provide genetic and genomic evaluation of the sires with superior breeding values to be used as parents for the next generation.

The genetic evaluation of the Zebu breeds were performed by the Technical Center of Genetic Evaluation (CTAG), by means of mixed model methodology under animal model, which uses all available animal information (i.e., pedigree information, its performance data, and the performance data of its progenies and relatives). At present, ANCP´s database has around 3.8 million animals, and measures of 13.4 million body weights and 2.5 million scrotal circumferences.

Genomic Expected Progeny Differences were estimated for all the breeds using the singlestep genomic BLUP method (ssGBLUP), using a multi-trait animal model, which uses all available animal information, including molecular markers information. The Genomic technology increases the accuracy and the selection process efficiency. This summary informs the Expected Progeny Differences (DEP), Accuracies (AC) and the percentile rank (TOP) of evaluated traits in two sections, the Sires Summaries (Young Males, Young Sires and Sires) and the Trait Leaders Summaries, which gathers Age at First Calving (IPP), Precocious Calving Probability (3P), Maternal Ability (MP120), Pre-Weaning Growth (P120 or P210), Post- Weaning Growth (P450), Fertility (PE365), Stayability (STAY), Quantitative Carcass Trait (AOL and ACAB), Marbling (MAR), Hot Carcass Weight (PCQ), Retail Product Weight (PPC), Precocity at Yearling (PS), Muscling at Yearling (MS), Residual Feed Intake (CAR), Dry Matter Intake (IMS) and Age at Puberty in Males (IPM).

The DEPs for 3P and Stayabillity uses a threshold model, and interpretation of the two DEPs represents, in simple terms, probability of success. The DEPs for CAR, IMS, IPM and those of SAM were published only for genotyped or phenotyped animals, or for those with at least 10 genotyped or phenotyped progenies for the respective traits.

The Economic Total Genetic Merit (MGTe), a multi-trait economic selection index, was estimated for the Nellore, Guzerá, Brahman and Tabapuã breeds using the traits’ economic values, and was calculated using a bio-economic model.