The Effect of Birth Types on Growth Curve Parameters of Karayaka Lamb

Ulutaş, Zafer; Sezer, Metin; Aksoy, Yüksel; Şirin, Emre; Şen, Uğur; Kuran, Mehmet; Akbaş, Yavuz

doi:10.3923/javaa.2010.1384.1388

Cited by 25 publications

(22 citation statements)

References 11 publications

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“…According to parameter a, all models confirmed that males are heavier than females, which is consistent with the greater average weights of males at all ages of reference, as is evident in Table 1. This was also observed by several authors in the study of different species (Carneiro et al, 2009;Ulutas et al, 2010;Gbangboche et al, 2011).…”

Section: Resultssupporting

confidence: 70%

“…When conducting a t-test of homogeneity of means, it was concluded that, with a P < 0.001, the averages of the weights between sexes were heterogeneous, implying the need to infer the adjustments separately for each sex. This conclusion was also presented by McManus et al (2003), Ulutas et al (2010) and Gbangboche et al (2011), among others. Brown et al (1976), Bathaei and Leroy (1998) and McManus et al (2003) emphasized that the most important biological relationship in a growth curve is the relation between the parameters a and k. A negative correlation between these parameters indicates that early maturing animals tend to grow into animals with smaller mature weights.…”

Section: Resultssupporting

confidence: 67%

“…High values of the parameter k indicate that the animals reach maturity earlier (Brown et al, 1976;Carolino and Gama, 1993;McManus et al, 2003), and, as can be observed in Table 3, females have a higher rate of maturity (between 0.005 and 0.028) than males (between 0.003 and 0.027), as was also observed by Bathaei and Leroy (1998), Gbangboche et al (2008), Ulutas et al (2010), and, consequently, have a lower weight at maturity. The growth rates estimated by these models showed that females grow at a higher rate than males, although the differences between males and females were quite small, and always in favour of females, as reported in previous studies (Bathaei and Leroy, 1998;Gbangboche et al, 2006;Ulutas et al, 2010). The Brody model estimated the lowest growth rates for males and females, whereas the Verhulst model estimated the highest growth rates in both sexes.…”

Section: Resultssupporting

confidence: 50%

“…Growth, described as changes in volume, size or shape of an organism over time, is a very important characteristic of living organisms (Ulutas et al, 2010). Fitting growth curves to growth functions is an interesting method for assessing different management factors or for breeding purposes.…”

Section: Introductionmentioning

confidence: 99%

“…This information is important for research purposes and for recommendations regarding production, breeding and reproduction. The estimation of biologically interpretable parameters of a growth function, in association with the production characteristics of the animals, can be an alternative for selection programmes that seek precocity with higher weight and carcass quality (Souza and Bianchini Sobrinho, 1994;Ulutas et al, 2010). The main aims of these models are to describe and predict growth and make inferences based on an interpretation of growth parameters (Ratkowsky, 1983).…”

Section: Introductionmentioning

confidence: 99%

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Characterization of commercial and biological growth curves in the Segureña sheep breed

Lupi

Nogales

León³

et al. 2015

Animal

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Non-linear models were analysed to describe both the biological and commercial growth curves of the Segureña sheep, one of the most important Spanish breeds. We evaluated Brody, von Bertalanffy, Verhulst, logistic and Gompertz models, using historical data from the National Association of Segureña Sheep Breeders (ANCOS). These records were collected between 2000 and 2013, from a total of 129 610 weight observations ranging from birth to adulthood. The aim of this research was to establish the mathematical behaviour of body development throughout this breed's commercial life (birth to slaughter) and biological life (birth to adulthood); comparison between both slopes gives important information regarding the best time for slaughter, informs dietary advice according to animals' needs, permits economical predictions of productions and, by using the curve parameters as selection criteria, enables improvements in growth characteristics of the breed. Models were fitted according to the non-linear regression procedure of statistical package SPSS version19. Model parameters were estimated using the Levenberg-Marquardt algorithm. Candidate models were compared using the determinative coefficient, mean square error, number of iterations, Akaike information coefficient and biological coherence of the estimated parameters. The von Bertalanffy and logistic models were found to be best suited to the biological and commercial growth curves, respectively, for both sexes. The Brody equation was found to be unsuitable for studying the commercial growth curve. Differences between the parameters in both sexes indicate a strong impact of sexual dimorphism on growth. This can emphasize the value of the highest growth rate for females, indicating that they reach maturity earlier.Keywords: growth, models, sex, sheep, Zootechny ImplicationsNon-linear models can be an option to establish the mathematical behaviour of body development throughout the life of the Segureña sheep breed. These models require lower computational and faster convergence than other methods. Moreover, in genetic evaluation programmes with large data sets, non-linear models are more advantageous. The results showed a strong impact of sexual dimorphism on growth.

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Section: Resultssupporting

confidence: 70%

Section: Resultssupporting

confidence: 67%

Section: Resultssupporting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization of commercial and biological growth curves in the Segureña sheep breed

Lupi

Nogales

León³

et al. 2015

Animal

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Possibility of modifying the growth trajectory in Raeini Cashmere goat

Ghiasi

Mokhtari

2018

Trop Anim Health Prod

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The objective of this study was to investigate the possibility of modifying the growth trajectory in Raeini Cashmere goat breed. In total, 13,193 records on live body weight collected from 4788 Raeini Cashmere goats were used. According to Akanke's information criterion (AIC), the sing-trait random regression model included fourth-order Legendre polynomial for direct and maternal genetic effect; maternal and individual permanent environmental effect was the best model for estimating (co)variance components. The matrices of eigenvectors for (co)variances between random regression coefficients of direct additive genetic were used to calculate eigenfunctions, and different eigenvector indices were also constructed. The obtained results showed that the first eigenvalue explained 79.90% of total genetic variance. Therefore, changing the body weights applying the first eigenfunction will be obtained rapidly. Selection based on the first eigenvector will cause favorable positive genetic gains for all body weight considered from birth to 12 months of age. For modifying the growth trajectory in Raeini Cashmere goat, the selection should be based on the second eigenfunction. The second eigenvalue accounted for 14.41% of total genetic variance for body weights that is low in comparison with genetic variance explained by the first eigenvalue. The complex patterns of genetic change in growth trajectory observed under the third and fourth eigenfunction and low amount of genetic variance explained by the third and fourth eigenvalues.

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