Identification of molecular markers on bovine chromosome 18 associated to calving interval in a Brangus-Ibagé cattle herd

Abstract

In the detection phase of a bovine marker assisted selection program, this paper investigated the genetic variability of three microsatellites on the chromosome 18 (BTA 18). The possible associations between genotypes or alleles of these markers versus weight at first calving and a lifetime calving interval (as indicators of reproductive performance) were evaluated in a beef cattle herd (5/8 Aberdeen Angus x 3/8 Nelore). Eleven alleles were detected in TGLA227 and ILSTS002 and three in BMS3004, the most frequent being TGLA227*79, ILSTS002*133, ILSTS002*135 and BMS3004*129. Polymorphic information content ranged from 0.41 to 0.84, while heterozygosity ranged from 49% to 86%, with an average value of 77%. The association analyses performed between genotype classes for the genetic markers versus weight at first calving indicated no significant result. Also, no correlation was observed between calving interval (CI) and TGLA227 genotypes. However, positive associations were detected between ILSTS002 and BMS3004 and CI. Animals carrying at least one ILSTS002*135 allele presented a CI about 39 days longer than the individuals with other genotypes; animals heterozygous for BMS3004 presented a CI about 35 days shorter than the homozygous. On these grounds, it can be concluded that these markers can be useful as an aid to fertility selection, in this herd.

Estudo de associação genômica de prenhez pós-parto em vacas de corte

“…In contrast to previous findings (ALMEIDA et al, 2003;DUARTE;OLIVEIRA et al, 2005;WEIMER et al, 2007), no association was found between reproductive performance and the BMS3004, BM4325, HEL05, AFZ1, and LEP Sau3/A1 markers. Therefore, these associations seem to be specific to the previous herds and might not be useful for MAS in other cattle breeds or herds.…”

“…Another association detected was a significant higher frequency of ILSTS002 137 in cows with lower reproductive performance (Table 2). In a previous study, Weimer et al (2007) reported that animals carrying at least one ILSTS002 135 allele have on average, longer calving intervals over the reproductive lifetime. Several reasons may explain the difference between the previous findings by and the present study.…”

“…Several reasons may explain the difference between the previous findings by and the present study. It would be highly unlikely to be due to an error in genotyping, since all genotype analyses were performed using a control sample supplied by Weimer et al (2007). This is also unrelated to the length of alleles, as there were no significant differences between short (127-137 bp) and long (139-145 bp) alleles.…”

“…Thus, genetic markers can improve animal selection by a methodology named marker-assisted selection (MAS) DENISE, 1998;DEKKERS, 2004). Previous studies described associations among reproductive performance (ALMEIDA et al, 2003;DUARTE;OLIVEIRA et al, 2005;WEIMER et al, 2007), STRs (short tandem repeats) and SNPs (single nucleotide polymorphisms) within leptin, IGF-1, FSH and LH receptors genes, however, not related to crossbred herds. Studies searching for associations among bovine superovulatory response, embryo production and the FSHR gene are described (AGUIAR, 2008;CORY et al, 2013).…”

Resposta reprodutiva de vacas de corte associada a marcadores moleculares relacionados à fertilidade

“…Oliveira et al (2005) relatam associações entre genótipos favoráveis para os marcadores HEL5 e AFZ-1 associados ao gene do receptor para o IGF-1 (IGF-1R) e desempenho reprodutivo. Weimer et al (2007) No presente trabalho, buscou-se uma associação entre a taxa de natalidade em vacas de corte Aberdeen Angus e marcadores moleculares e polimorfismos em genes relacionados à reprodução, como IGF1-R, LHβ, Leptina, FSHR e LHR.…”