Genealogical information analysis of Gyr and Nelore cattle from Costa Rica

ABSTRACT: The objectives were to analyze the genealogical information of Gyr (GY) and Nelore (NL) cattle from Costa Rica. Analyzed: pedigree integrity (GY, 13272; NL, 18153); number of complete, maximum traced and equivalent complete generations; inbreeding (FI); generation interval (GI) through four selection routes; average additive genetic ratio (AGR); effective number of founders (fe); effective number of ancestors (fa); effective population size (Ne). The analysis was performed with the ENDOG software. The maximum proportion of unknown parents, grandparents, and great-grandparents was 18.6%, 39.9%, and 59.3%, respectively. The average FI for NL was 8.87% and 2.85% in GY. The average consanguineous population (%) and FI was 53.9 and 16.5% in NL, 28.9 and 9.9% in GY. The average and maximum values of AGR for NL were 3.5 and 12.8, 1.4 and 5.6 in GY. The fe and fa for NL were 65.0 and 38.0, in GY 145.7 and 59.0. The Ne indicated increases in FI in the range of 1 to 2% in GY, for NL greater than 2%, with a status of care to monitor the evolution of F and AGR and their possible implications in genetic improvement. The GI ranged from 6.3 to 7.9 years with a general average of 6.9 years. These results show a summary of the genetic and reproductive management those breeders have carried out.

摘要：本研究旨在分析哥斯达黎加境内吉尔牛（Gyr, GY）与内洛尔牛（Nelore, NL）的系谱信息。本次分析涵盖以下指标：系谱完整性（吉尔牛群体规模13272头，内洛尔牛18153头）、完全世代数、最大追踪世代数与当量完全世代数、近交系数（FI）、基于4条选择路径的世代间隔（GI）、平均加性遗传比率（AGR）、奠基者有效数量（fe）、祖先有效数量（fa）以及有效种群大小（Ne）。本分析采用ENDOG软件完成。结果显示，未知亲本、祖父母与曾祖父母的最高占比分别为18.6%、39.9%与59.3%。内洛尔牛的平均FI为8.87%，吉尔牛为2.85%。内洛尔牛的平均近交群体占比与平均FI分别为53.9%与16.5%，吉尔牛则分别为28.9%与9.9%。内洛尔牛的AGR平均值与最大值分别为3.5与12.8，吉尔牛为1.4与5.6。内洛尔牛的fe与fa分别为65.0与38.0，吉尔牛为145.7与59.0。有效种群大小（Ne）分析结果显示，吉尔牛的FI增幅处于1%~2%区间，内洛尔牛的FI增幅则超过2%，当前需对近交系数（F）与AGR的变化趋势及其对遗传改良的潜在影响予以关注并监测。世代间隔的范围为6.3~7.9年，总体平均值为6.9年。上述结果总结了育种者所开展的遗传与繁殖管理实践。