O presente estudo pretendeu identificar possíveis indicadores de rendimento, adstritos às ações de jogo, diferenciadores do resultado obtido no set em Voleibol. A amostra consistiu em 65.949 ações realizadas em 550 sets da Liga Mundial 2005, "adulto" masculinos. A coleta de dados teve como suporte instrumental o software "Volleyball Information System". Para testar as diferenças nos indicadores de rendimento, entre as equipes que vencem e perdem os sets, se utilizou o teste t de student de medidas independentes (p < 0,05). As observações cumpriram os requisitos de fidedignidade para serem utilizadas como ferramenta científica, tanto pela percentagem de acordos interobservador como pela estatística Kappa de Cohen. O presente estudo demonstrou que as equipes que vencem os sets obtêm melhores desempenhos em todas as ações de jogo (ataque, bloqueio, saque, defesa, levantamento e recepção), devido à maior frequência de ações ponto/excelente (com exceção do número de recepções excelentes) e à menor frequência de erros. As equipes que vencem os sets apresentam uma distribuição percentual dos pontos ganhos mais equilibrada entre as três ações terminais (ataque, bloqueio e saque) do que as equipes que perdem os sets. O ataque representa, para as equipes perdedoras, um maior peso no total de pontos ganhos através das ações terminais.
Summary
The present study investigated four restriction fragment length polymorphisms (RFLPs) in the leptin gene and five short tandem repeats (STRs) in its vicinity in 160 females from a synthetic beef cattle breed (5/8 Aberdeen Angus and 3/8 Nelore), and evaluated possible associations between these markers and reproductive performance. A high level of genetic diversity was observed, STRs being more variable than RFLPs. Heterozygosities ranged from 0.67 to 0.87 in STRs and from 0.12 to 0.49 in RFLPs, suggesting that the selective process applied to the Brangus‐Ibage cattle had not affected the total genetic diversity expected for crossbreeds. Two alleles (IDVGA51*181 and LEPSau3A1*+) seem to increase calving interval (CI) by about 79 and 81 days, respectively. Therefore, selection against carriers of these mutations could improve CI by at least 2 months, despite the seasonality of the mating period employed here. LEPSau3AI system seems to influence weight at first calving (WFC). Heterozygotes (LEPSau3AI*+/LEPSau3AI*−) had higher WFC than LEPSau3AI*−/LEPSau3AI*− homozygote. Selection for animals with this genotype could result in some advantages for post‐calving recovery. CI and WFC are indirect measurements of reproduction reflecting also animal body conditions, and therefore it is difficult to determine whether or not IDVGA51*181 and LEPSau3A1*+ alleles directly affect the reproductive system. Although further analysis of other herds should be performed to confirm these data, the association of genetic markers with better reproductive performance is a very interesting finding and could be used in marker‐assisted selection to improve reproduction in beef cattle.
Background: The aim of this study was to evaluate the distribution of sheep breeds in Brazil, correlate their occurrence with environmental factors and determine their risk for extinction.
Litter size (LS) in sheep is determined mainly by ovulation rate (OR). Several polymorphisms have been identified in the growth differentiation factor 9 (GDF9) gene that result in an increase in OR and prolificacy of sheep. Screening the databank of the Brazilian Sheep Breeders Association for triplet delivery, we identified flocks of prolific Ile de France ewes. After resequencing of GDF9, a point mutation (c.943C>T) was identified, resulting in a non-conservative amino acid change (p.Arg315Cys) in the cleavage site of the propeptide. This new allele was called Vacaria (FecG(v) ). A flock of half-sib ewes was evaluated for OR in the first three breeding seasons, and Vacaria heterozygotes had higher OR (P < 0.001), averaging 2.1 ± 0.1 when compared to 1.2 ± 0.1 in wild-type ewes. The OR was also influenced by age, increasing in the second and third breeding seasons (P < 0.001). In flocks segregating this allele, the LS was higher in mutant sheep (P < 0.001), averaging 1.61 ± 0.07 in heterozygotes and 1.29 ± 0.03 in wild-type ewes. Analysis of homozygote reproductive tract morphology revealed uterine and ovarian hypoplasia. Ovarian follicles continue to develop up to small antral stages, although with abnormal oocyte morphology and altered arrangement of granulosa cells. After the collapse of the oocyte in most follicles, the remaining cells formed clusters that persisted in the ovary. This SNP is useful to improve selection for dam prolificacy and also as a model to investigate GDF9 post-translation processing and the fate of the follicular cells that remain after the oocyte demise.
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