Genetic parameters and relationships between fibre and type traits in two breeds of Peruvian alpacas

Cervantes, I.; Pérez-Cabal, María Ángeles; Morante, R.; Burgos, A.; Salgado, C.; Nieto, B.; Gutiérrez, Juan Pablo

doi:10.1016/j.smallrumres.2009.10.016

Cited by 29 publications

(27 citation statements)

References 9 publications

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“…The two alpaca ecotypes, Suri (SU) and Huacaya (HU), were analysed independently. The involved traits were those analysed by Cervantes et al (2010) and were grouped into two subsets: (a) those involving mean and variability of fibre diameter (FD); and (b) subjectively scored-type traits. The first group of traits were FD (in µm; FD), CV of FD, comfort factor (CF) and s.d.…”

Section: Datamentioning

confidence: 99%

“…The second group of traits included: density (DE), crimp (CR), scored only in HU alpacas, lock structure (LS), scored only in SU alpacas, head (HE), coverage (CO) and balance (BA). Details of definition and ways of scoring were reported by Cervantes et al (2010). All the alpacas were scored numerically by the same classifier, as a distance from that considered as the best performance for each trait, on a scale from poor (1) to excellent (5).…”

Section: Datamentioning

confidence: 99%

“…All the alpacas were scored numerically by the same classifier, as a distance from that considered as the best performance for each trait, on a scale from poor (1) to excellent (5). Some of these traits were already analysed by Gutiérrez et al (2009), and all of them were used to estimate genetic parameters by Cervantes et al (2010), but they have been reanalysed under the same model with the updated data set for both SU and HU ecotypes to improve the accuracy of the estimations of the genetic parameters, and Reference weights To simplify, only two sets of relative subjective weights will be considered for analysis in this study, those inspired by the ICAR suggestions with only FD and CV as traits of concern (ICAR, 2012), considered with identical importance, and those defined by PACOMARCA. However, the involved theory can be extended to any other set of weights and it should be easily extensible to any other population or specie under different genetic parameters provided they are known.…”

Section: Datamentioning

confidence: 99%

“…To discuss the relationship between expected and realized genetic gains, breeding values were obtained with the updated data set by fitting the model by Cervantes et al (2010) standardized to have a mean value of 100 and an s.d. of 20 and were averaged within years of birth and plotted.…”

Section: Datamentioning

confidence: 99%

“…their animals 2011;Morante et al, 2009;Cervantes et al, 2010;Pérez-Cabal et al, 2010;Paredes et al, 2013), and has implemented a strict genetic selection on their animals looking for a desired proportional improvement of some determined traits. As a consequence, success has been globally observed both in the performances and in the genetic trends, but this success has not been obtained in the expected proportionality.…”

Section: Proportional Expected Genetic Responsesmentioning

confidence: 99%

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Weighting fibre and morphological traits in a genetic index for an alpaca breeding programme

Gutiérrez

Cervantes

Pérez-Cabal

et al. 2014

Animal

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Nowadays, the fibre diameter (FD) is considered the main selection objective in alpaca populations all over the world. International Committee for Animal Recording recommendations define the FD and its CV as the first two traits to be considered in breeding programmes for this specie. In addition to these main criteria, other selection criteria of economic value used are comfort factor (CF) or standard deviation (s.d.); also other less important traits being used as selection objectives are these morphological traits: density (DE), crimp (CR) or lock structure (LS) for, respectively, Huacaya (HU) and Suri (SU) ecotypes, head (HE), coverage (CO) and balance (BA). The goal of this study was to establish how to implement a combined selection index starting from genetic parameters and to study the expected correlation between genetic trends by considering different alternative procedures of weighting all the involved traits, and the consequences of a wrongly proceeding way. Heritabilities and genetic and phenotypic correlations were estimated from the data set belonging to the PACOMARCA experimental farm for SU and HU. Two approaches were used to check the consequences of a set of subjective weights essayed. The coefficients of selection indexes were obtained for two sets of reference weights. In addition, equivalent weights were drawn if applied those reference values as coefficients of hypothetical selection indexes directly on phenotypes; relative expected genetic responses were computed in different cases. Results showed that almost in all cases for both ecotypes, the weight applied to CF should be surprisingly negative. Concerning genetic responses, only CO was compromised in some cases for the HU ecotype. The essayed methodology allowed explaining the differences between ecotypes in the genetic trends. The proposed methodology was shown to be effective to study the relative importance of the traits granted by the manager of a breeding scheme.

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Section: Datamentioning

confidence: 99%

Section: Datamentioning

confidence: 99%