Fertility

Quantitative genetic study of age at subsequent rebreeding in Nellore cattle by using survival analysis

M. H. Van Melis, Figueiredo, L. G. G., Oliveira, H. N., Eler, J. P., Rosa, G. J. M., Santana, Jr., M. L., Rezende, F. M., and Ferraz, J. B. S., Quantitative genetic study of age at subsequent rebreeding in Nellore cattle by using survival analysis, vol. 13, pp. 4071-4082, 2014.

The continuous trait age at subsequent rebreeding (ASR) was evaluated using survival analysis in Nellore breed cows that conceived for the first time at approximately 14 months of age. This methodology was chosen because the restricted breeding season produces censored data. The dataset contained 2885 records of ASR (in days). Records of females that did not produce calves in the following year after being exposed to a sire were considered censored (48.3% of the total).

Genetic correlations between heifer subsequent rebreeding and age at first calving and growth traits in Nellore cattle by Bayesian inference

A. A. Boligon, Baldi, F., and Albuquerque, L. G., Genetic correlations between heifer subsequent rebreeding and age at first calving and growth traits in Nellore cattle by Bayesian inference, vol. 11, pp. 4516-4524, 2012.

We estimated heritability for subsequent rebreeding (SR) of heifers and genetic correlations between this trait and weaning weight (WW), weight gain from weaning to yearling (WG), age at first calving (AFC), and mature cow weight (MW), in order to evaluate whether SR could be included as selection criterion in Nellore cattle. The SR of heifers was defined by attributing a value of 1 (success) or 0 (failure) to heifers that calved or not, respectively, given that they had calved once before. Records from 127,430 Nellore animals were analyzed.

Heritabilities and genetic correlations for reproductive traits in an F2 reciprocal cross chicken population

R. P. Savegnago, Buzanskas, M. E., Nunes, B. N., Ramos, S. B., Ledur, M. C., Nones, K., and Munari, D. P., Heritabilities and genetic correlations for reproductive traits in an F2 reciprocal cross chicken population, vol. 10, pp. 1337-1344, 2011.

Studies estimating genetic parameters for reproductive traits in chickens can be useful for understanding and improvement of their genetic architecture. A total of 1276 observations of fertility (FERT), hatchability of fertile eggs (HFE) and hatchability of total eggs (HTE) were used to estimate the genetic and phenotypic parameters of 467 females from an F2 population generated by reciprocal crossing between a broiler line and a layer line, which were developed through a poultry genetics breeding program, maintained by Embrapa Swine and Poultry, Concordia, Santa Catarina, Brazil.

Single nucleotide polymorphisms in the growth hormone and insulin-like growth factor-1 genes are associated with milk production, body condition score and fertility traits in dairy cows

M. P. Mullen, Lynch, C. O., Waters, S. M., Howard, D. J., O’Boyle, P., Kenny, D. A., Buckley, F., Horan, B., and Diskin, M. G., Single nucleotide polymorphisms in the growth hormone and insulin-like growth factor-1 genes are associated with milk production, body condition score and fertility traits in dairy cows, vol. 10, pp. 1819-1830, 2011.

The somatotrophic axis (GH-IGF) is a key regulator of animal growth and development, affecting performance traits that include milk production, growth rate, body composition, and fertility. The aim of this study was to quantify the association of previously identified SNPs in bovine growth hormone (GH1) and insulin-like growth factor 1 (IGF-1) genes with direct performance trait measurements of lactation and fertility in Holstein-Friesian lactating dairy cows.

Comparing data on the reproduction of Varroa destructor

M. H. Corrêa-Marques, Medina, L. Medina, Martin, S. J., and De Jong, D., Comparing data on the reproduction of Varroa destructor, vol. 2, pp. 1-6, 2003.

Varroa destructor reproductive success is considered an important character for determining the resistance of honey bees to this mite parasite. However, most of the published data are not comparable due to the different methods of ascertaining and reporting reproduction. A recently published technique that involves reconstructing mite families in older worker brood gives repeatable and reliable parameters. This methodology was used to compare various categories of reproduction of approximately 1,000 V.

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