Melhoramento e estrutura populacional em bubalinos da raça Mediterrâneo no Brasil

Abstract

O objetivo deste trabalho foi avaliar a estrutura populacional e os progressos genéticos, fenotípicos e ambientais de características de desenvolvimento ponderal, em bubalinos da raça Mediterrâneo. Foram utilizadas informações dos pesos ajustados aos 205, 365 e 550 dias de idade, de 6.243 bubalinos nascidos no período de 1974 a 2003, provenientes de quatro fazendas. As estimativas dos coeficientes de herdabilidade foram altas para os pesos ajustados nas três idades. Os rebanhos apresentaram ganho genético positivo quanto a essas três características, porém, aquém do possível, provavelmente em razão da seleção baseada somente no fenótipo, realizada pelos produtores. Para aumento nos ganhos genéticos, são necessários a redução do intervalo de geração, o aumento do tamanho efetivo, o uso de reprodutores avaliados com base nos valores genéticos preditos pelo BLUP e o controle dos acasalamentos de animais aparentados.

Variabilidade genética na raça bubalina Mediterrânea avaliada por meio de análise de pedigree

“…The generation intervals observed in this study were large but lower than those observed by MALHADO et al (2008) evaluating the population structure of Mediterranean buffaloes, when there was an average generation interval of 11.3±4.3 years. SANTANA JR. et al (2011) reported generation intervals lower than those found in this study, which were 7.38 (sire-son), 7.42 (sire-daughter), 6.60 (dam-son), 6.44 (damdaughter), with an average interval of 6.89 years.…”

“…The buffaloes are recognized for their long productive and reproductive life and the need for herd growth over the years allows some farmers to maintain the reproducing animals in the herd for longer periods, increasing the generation interval (MALHADO et al, 2008). The average generation interval is critical in a screening program, because it is directly related to the annual genetic gain of selected characteristics and to the economic return of the program (CARNEIRO et al, 2009).…”

“…In spite of few parameters estimated by MALHADO et al (2008) and MARCONDES et al (2010), the information about the population structure of Mediterranean breed raised in Brazil is scarce.…”

Tabapuã breed in Northeastern Brazil: genetic progress and population structure

“…Likewise, knowledge of the different factors that potentially interfere in the selection process and genetic progress, such as effective size, generation interval and genetics are of great importance for the feasibility of breeding programs (Malhado et al, 2008a). Yet, special attention should be given to the structure of populations under selection so as to preserve variability and allow greater responses to selection.…”

History of registered Gyr breed in Brazilian Northeast: population structure and genetic improvement of growth traits

“…Knowledge of genetic changes in a population is of crucial importance, not only as a guide for genetic interventions, but also to evaluate the results of the particular selection program adopted. However, it should also be noted that the success of genetic improvement programs is critically dependent on the knowledge of several factors that potentially interfere on selection, such as effective size of the population, generation interval and genetic variability (MALHADO et al 2008a). Moreover, knowledge of population structure combined with information on genetic change in the population can guide future management actions, allowing the development of strategies that promote the genetic improvement and adaptation of a breed in a particular region (MALHADO et al 2008b).…”