Modeling of average growth curve in Santa Ines sheep using random regression models

Sarmento, José Lindenberg Rocha; Torres, Robledo de Almeida; Sousa, Wandrick Hauss de; Albuquerque, Lúcia Galvão de; Lôbo, Raimundo Nonato Braga; Sousa, José Ernandes Rufino de

doi:10.1590/s1516-35982011000200012

Cited by 7 publications

(3 citation statements)

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“…As the model utilized does not take the effects of permanent environment, they accumulate in the residue, inflating it and overestimating the environmental variance, which results in lower estimate of heritability. The same was observed by Sarmento et al (2011), when working with Santa Inês sheep, where the model that did not consider the effect of permanent environment presented heritability estimate higher than those which considered it.…”

Section: Resultssupporting

confidence: 71%

Genetic evaluation for egg mass in partial periods and complete period in meat quails

et al. 2012

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The objective of this study was to obtain estimates of genetic and phenotypic parameters for egg mass of meat quails and also to propose an optimal age for selection of birds through the egg mass. The data used in this study came from 3,503 female meat quails (UFV1: 1.811 quails; UFV2: 1.692 quails) of the Poultry Breeding Program from Universidade Federal de Viçosa. The traits examined were egg mass in partial periods until 77, 112, 147 and 182 days, and egg mass in the total period of 407 days by the use of single and bi-trait animal models. For the genetic group UFV1, the heritability values for the periods were high: 0.58, 0.59, 0.57, 0.59 and 0.24 (until 77, 112, 147,182 and 407 days, respectively). The values of genetic correlations were medium, ranging from 0.51 (77 and 407 days) to 0.61 (112 and 407, 147 and 407 days). For the genetic group UFV2, the estimates of heritability were of low magnitude: 0.05, 0.03, 0.04, 0.05, and 0.11 (until 77, 112, 147, 182, and 407 days, respectively). The values for genetic correlation ranged from 0.61 (112 and 407 days) to 0.93 (77 and 407 days). For the genetic group UFV1, the second partial period (112 days) for selection of meat quails using the egg mass trait is recommended, due to a higher value of heritability and a higher value of genetic correlation with the total and relative efficiency close to the unity in this period. In the genetic group UFV2, the first partial period (77 days) is indicated, since it had a higher estimation of genetic correlation and a higher relative efficiency. The choice of these partial periods reduces the generation interval, increasing the intensity of selection and an increase in genetic gain per unit of time

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Section: Resultssupporting

confidence: 71%

Genetic evaluation for egg mass in partial periods and complete period in meat quails

et al. 2012

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“…where, y ij is weight on the j th day of lamb i; F refers to a set of fixed effects consisting of contemporary group (1112 subclasses) and the covariate age of ewe at lambing (linear and quadratic effects); β m is the m th fixed regression coefficient for weight over the Legendre polynomial represented by a cubic function to model the average growth curve of the population, which was determined in a previous study (Sarmento et al, 2011); α im , γ im , δ im , and ρ im are direct additive genetic, maternal additive genetic, maternal permanent environmental, and animal permanent environmental regression coefficients, respectively, for lamb i; k a , k m , k q , and k c are the orders of fit of the corresponding Legendre polynomials, ranging from two to seven, which were used to determine the most appropriate order for each random effect; m φ is the m th Legendre polynomial function for standardized age (-1 < age < 1); and ε ij is the residual random effect.…”

Section: Methodsmentioning

confidence: 99%

Random regression models for the estimation of genetic and environmental covariance functions for growth traits in Santa Ines sheep

et al. 2016

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ABSTRACT. Polynomial functions of different orders were used to model random effects associated with weight of Santa Ines sheep from birth to 196 days. Fixed effects included in the models were contemporary groups, age of ewe at lambing, and fourth-order Legendre polynomials for age to represent the average growth curve. In the random part, functions of different orders were included to model variances associated with direct additive and maternal genetic effects and with permanent environmental effects of the animal and mother. Residual variance was fitted by a sixth-order ordinary polynomial for age. The higher the order of the functions, the better the model fit the data. According to the Akaike information criterion and likelihood ratio test, a continuous function of order, five, five, seven, and three for direct additive genetic, maternal genetic, animal permanent environmental, and maternal permanent environmental effects (k = 5573), respectively, was sufficient to model changes in (co)variances with age. However, a more parsimonious model of order three, three, five, and three (k = 3353) was suggested based on Schwarz's Bayesian information criterion for the same effects. Since it was a more flexible model, model k = 5573 provided inconsistent genetic parameter estimates when compared to the biologically expected result. Predicted breeding values obtained with models k = 3353 and k = 5573 differed, especially at young ages. Model k = 3353 adequately fit changes in variances and covariances with time, and may be used to describe changes in variances with age in the Santa Ines sheep studied.

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“…The polynomial regression function has also been used in previous research in sheep and dairy cattle. Previous researchers concluded that the order of four (cubic) provides a better fit and better reflects the reality of the changes (Sarmento et al 2011). It does not overestimate body weight measurement compare to the non-linear model (Vijayakumar et al 2020).…”

Section: Resultsmentioning

confidence: 98%

The Growth Performance and Costs of Rearing Friesian Crossbreed Dairy Young Stock in Malaysian Commercial Farm

Tong

Nor

Sithambaram

et al. 2021

jma

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The important elements in rearing dairy young stock are good farm management, proper growth and optimal costs of rearing. A survey on these important elements was conducted at two commercial farms in Johor and Sabah in 2019. The farm herd size is 214 heads and 2,221 heads with 163,682 litres and 4.2 mil. litres of milk production, in Johor and Sabah respectively. In addition, the body weight data of 188 dairy young stock was collected and analysed to determine the growth performance using polynomial growth function. The results showed the two farms have youngstock with different Friesian blood levels (60% and 70% in Johor, and 87.5% in Sabah) with different growth performance. The average weight of dairy young stock with 60%, 70% and 87.5% Friesian blood levels at birth were 21.31±3.70kg, 22.33±2.23kg and 26.55±2.68kg, respectively, while average weight at 3 months of age were 45.00±7.07kg, 55.57±8.36kg and 75.84±12.54kg, respectively. Heifers with 87.5% Friesian blood levels was bred at 15 months of age (444kg) while heifers with lower Friesian blood levels was bred 6 months later (250kg). The average rearing (feed) cost was RM4,932 (USD1,194)/heifer. The findings of this study can give awareness and insights in the performance and costs of rearing crossbreed dairy young stock in tropics.

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Modeling of average growth curve in Santa Ines sheep using random regression models

Cited by 7 publications

References 12 publications

Genetic evaluation for egg mass in partial periods and complete period in meat quails

Genetic evaluation for egg mass in partial periods and complete period in meat quails

Random regression models for the estimation of genetic and environmental covariance functions for growth traits in Santa Ines sheep

The Growth Performance and Costs of Rearing Friesian Crossbreed Dairy Young Stock in Malaysian Commercial Farm

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