Genetic relationships between scrotal circumference and female reproductive traits1

Martínez-Velázquez, Guillermo; Gregory, K. E.; Bennett, G. L.; Vleck, L.D. Van

doi:10.2527/2003.812395x

Cited by 86 publications

(58 citation statements)

References 34 publications

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“…However, Eler et al (2004) showed the importance of the inclusion of SC data to increase the accuracy of the prediction of genetic merit for HP, especially in the case of young bulls for which there is still no information regarding HP of the daughters. Martínez-Velá zquez et al (2003), in a study with 12 B. taurus breeds concluded that genetic response in the female reproductive traits through sire selection on yearling SC is not expected to be effective; and it is in agreement with Smith et al (1989), who reported non-significant relationships between age at puberty in heifers and SC of yearling males. The estimates of genetic correlation between SC-HP and SC-STAY obtained in this study show that there is no antagonism between these traits and permit us to infer that selection for SC leads to little or no improvement in reproductive traits of females and vice versa.…”

Section: Genetic Correlationssupporting

confidence: 78%

Genetic relationship between growth and reproductive traits in Nellore cattle

Júnior

Eler

Ferraz

et al. 2012

Animal

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The objective of this study was to evaluate the genetic relationship between postweaning weight gain (PWG), heifer pregnancy (HP), scrotal circumference (SC) at 18 months of age, stayability at 6 years of age (STAY) and finishing visual score at 18 months of age (PREC), and to determine the potential of these traits as selection criteria for the genetic improvement of growth and reproduction in Nellore cattle. The HP was defined as the observation that a heifer conceived and remained pregnant, which was assessed by rectal palpation at 60 days. The STAY was defined as whether or not a cow calved every year up to the age of 6 years, given that she was provided the opportunity to breed. The Bayesian linear-threshold analysis via the Gibbs sampler was used to estimate the variance and covariance components applying a multitrait model. Posterior mean estimates of direct heritability were 0.15 6 0.00, 0.42 6 0.02, 0.49 6 0.01, 0.11 6 0.01 and 0.19 6 0.00 for PWG, HP, SC, STAY and PREC, respectively. The genetic correlations between traits ranged from 0.17 to 0.62. The traits studied generally have potential for use as selection criteria in genetic breeding programs. The genetic correlations between all traits show that selection for one of these traits does not imply the loss of the others.

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Section: Genetic Correlationssupporting

confidence: 78%

Genetic relationship between growth and reproductive traits in Nellore cattle

Júnior

Eler

Ferraz

et al. 2012

Animal

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“…These heritabilities are within the range, from 0.20 to 0.67, of other estimates for age at puberty (Arije and Wiltbank 1971;Smith et al 1976;Laster et al 1979). Reported heritability estimates for scrotal circumference range from 0.39 to 0.75 (Lunstra et al 1988;Martinez-Velazquez et al 2003;Corbet et al 2009). Our result for puberty in bulls (AGE26) was closer to the higher end of that range (h 2 = 0.78).…”

Section: Discussionmentioning

confidence: 52%

Finding genes for economically important traits: Brahman cattle puberty

Fortes

Lehnert

Bolormaa³

et al. 2012

Anim. Prod. Sci.

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Abstract. Age at puberty is an important component of reproductive performance in beef cattle production systems. Brahman cattle are typically late-pubertal relative to Bos taurus cattle and so it is of economic relevance to select for early age at puberty. To assist selection and elucidate the genes underlying puberty, we performed a genome-wide association study (GWAS) using the BovineSNP50 chip (~54 000 polymorphisms) in Brahman bulls (n = 1105) and heifers (n = 843) and where the heifers were previously analysed in a different study. In a new attempt to generate unbiased estimates of singlenucleotide polymorphism (SNP) effects and proportion of variance explained by each SNP, the available data were halved on the basis of year and month of birth into a calibration and validation set. The traits that defined age at puberty were, in heifers, the age at which the first corpus luteum was detected (AGECL, h 2 = 0.56 AE 0.11) and in bulls, the age at a scrotal circumference of 26 cm (AGE26, h 2 = 0.78 AE 0.10). At puberty, heifers were on average older (751 AE 142 days) than bulls (555 AE 101 days), but AGECL and AGE26 were genetically correlated (r = 0.20 AE 0.10). There were 134 SNPs associated with AGECL and 146 SNPs associated with AGE26 (P < 0.0001). From these SNPs, 32 (~22%) were associated (P < 0.0001) with both traits. These top 32 SNPs were all located on Chromosome BTA 14, between 21.95 Mb and 28.4 Mb. These results suggest that the genes located in that region of BTA 14 play a role in pubertal development in Brahman cattle. There are many annotated genes underlying this region of BTA 14 and these are the subject of current research. Further, we identified a region on Chromosome X where markers were associated (P < 1.00E-8) with AGE26, but not with AGECL. Information about specific genes and markers add value to our understanding of puberty and potentially contribute to genomic selection. Therefore, identifying these genes contributing to genetic variation in AGECL and AGE26 can assist with the selection for early onset of puberty.

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“…Thus, selection of early-maturing B. indicus heifers as well as nutritional protocols to advance puberty have received a great deal of interest from the scientific community (Vargas et al, 1998;Martinez-Velazquez et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Leptin and hypothalamic gene expression in early- and late-maturing Bos indicus Nellore heifers

et al. 2008

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We investigated wether early-maturing or late-maturing Bos indicus Nellore heifers produced more leptin mRNA in adipose tissues and altered expression of hypothalamic genes related to leptin signaling. Six prepubertal and six pubertal heifers aged about 34 months and weighing 280 kg to 300 kg each were selected from a population of 100 Nellore heifers. Real-time PCR was used to quantify the expression of the leptin gene (LEP) in adipose tissues and the long isoform of the leptin receptor gene (Ob-Rb), the NK2 homeobox 1 hypothalamic marker gene NKX2-1, the suppressor of cytokine signaling 3 gene (SOCS-3), the neuropeptide Y genes (NPY) and the NPY G-protein coupled receptor genes NPY-Y1 and NPY-Y4 in the hypothalamus. Heifers attaining puberty earlier showed significantly greater LEP expression in adipose tissues (p < 0.05) and there was tissue interaction (p < 0.05). Hypothalamic expression of Ob-Rb, NKX2-1, NPY and SOCS-3 did not differ between groups, but in early-maturing heifers there was a tendency for lower expression of NPY-Y1 (8.3-fold less) and NPY-Y4 (14.3-fold less) compared to late-maturing heifers (p = 0.1). These results suggest that a combination of higher LEP expression, lower NPY-Y1 and NPY-Y4 expression could be a factor in regulating puberty in early-maturing B. indicus heifers.

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Genetic relationships between scrotal circumference and female reproductive traits1

Cited by 86 publications

References 34 publications

Genetic relationship between growth and reproductive traits in Nellore cattle

Genetic relationship between growth and reproductive traits in Nellore cattle

Finding genes for economically important traits: Brahman cattle puberty

Leptin and hypothalamic gene expression in early- and late-maturing Bos indicus Nellore heifers

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