• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.575-579
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• 2000

First lactation records of 683 Murrah buffaloes maintained at NDRI, Karnal which were progeny of 84 sires used for comparing the heritability estimates of age at first calving, first lactation milk yield and first service period under single and multiple trait models using restricted maximum likelihood (REML) method of estimation under an individual animal model. The results indicated that the heritability estimates may vary under single and multiple trait models depending upon the magnitude of genetic and environmental correlation among the traits being considered. Therefore, a single or multiple trait model is recommended for estimation of variance components depending upon the goal of breeding programme. However, there may not be any advantage of considering a trait with zero or near zero heritability and having no or very low genetic correlation with other traits in the model. Lower heritability estimates of part lactation yield (120-day milk yield) implied that there may not be any advantage of considering this trait in place of actual 305-day milk yield, whereas, comparable heritability estimates of predicted 305-day milk yield suggested that it could be used for sire evaluation to reduce the cost of milk recording under field conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.3
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• pp.305-308
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• 2004

The purpose of this study was to estimate the genetic parameters for backfat thickness at shoulder, mid back and loin and days to 90 kg using a derivative-free REML procedure. Data were collected from 6,146 boars and gilts of purebred Durocs, Landraces and Large Whites performance tested at breeding farms of National Agricultural Cooperatives Federation in Korea from 1998 to 2001. Estimated heritability for backfat measurements at shoulder, mid-back and loin and an average of those backfat measurements were 0.14, 0.32, 0.22 and 0.25 in Durocs, 0.34, 0.50, 0.42 and 0.46 in Landraces and 0.33, 0.52, 0.43 and 0.49 in Large Whites. Heritabilities of backfat measurements estimated were hightest in mid-back and lowest at shoulder. Phenotypic variances of backfat measurements estimated were largest at shoulder and smallest at mid-back. Estimated heritabilities for days to 90 kg were 0.37 in Durocs, 0.42 in Landraces and 0.54 in Large Whites. Genetic correlations among backfat measurements at shoulder, mid-back and loin and an average of those backfat measurements estimated were positive and very high. Genetic correlations of days to 90 kg with the backfat measurements estimated were _0.19 ~ _0.30 in Durocs, _0.04 ~ _0.17 in Landraces and _0.10 ~ _0.13 in Large Whites.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.19-24
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• 2007

Covariance components and genetic parameters of weekly live body weight from hatching to six weeks of age and age of sexual maturation were estimated in a laying type Japanese quail line. The univariate and bivariate animal model analysis included hatching group and sex as fixed effects. Each trait was analysed with animal as random effect to fit the additive direct effect. Additional random effects incorporated in the models were changed according to the trait examined. The best model for a trait was chosen based on a likelihood ratio test, comparing the models with and without maternal additive genetic and maternal permanent environmental effects. Heritability estimates of live-weight at hatch and one to six weeks of age with their standard errors were 0.22${\pm}$0.088, 0.39${\pm}$0.099, 0.31${\pm}$0.086, 0.38${\pm}$0.056, 0.46${\pm}$0.055, 0.50${\pm}$0.059, and 0.56${\pm}$0.062, respectively. Direct heritability value of age of sexual maturation was moderate (0.24${\pm}$0.055). The variances due to permanent environmental effect of dam after one week of age and maternal genetic effect after two weeks of age were not important sources of variation. The correlations between direct and maternal genetic effects were negative and ranged from high to moderate values (-0.21 to -0.83). Among the weekly live weights, genetic correlations were generally high between not only successive but also early and late weightings. It suggests that selection for final weight may be based on early weight records. Genetic correlations between age of sexual maturation and live weights were low, favourable but had high standard errors. These results indicate that selection for high weight will potentially result in lower age of sexual maturation only with accurate determination of breeding values.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.3
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• pp.302-307
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• 2010

The present study aimed to investigate the effects of maternal factors on body weight at hatching (day-old) and at six weeks of age in a commercial broiler line. A total of 6,765 records on body weight at day-old (BWTDO) and 115,421 records on body weight at six weeks of age (BWT6W), originated from a commercial broiler line during 14 generations, were used to estimate genetic parameters related to the effects of maternal traits on body weight of chicks immediately after hatch or six weeks thereafter. The data were analyzed using restricted maximum likelihood procedure (REML) and an animal model with DFREML software. Direct heritability ($h^{2}{_a}$), maternal heritability ($h^{2}{_m}$), and maternal environmental variance as the proportions of phenotypic variance ($c^{2}$) for body weight at day-old were estimated to be 0.050, 0.351, and 0.173, respectively. The respective estimated values for body weight at six weeks of age were 0.340, 0.022, and 0.030. The correlation coefficient between direct and maternal genetic effects for six-week-old body weight was found to be -0.335. Covariance components and genetic correlations were estimated using a bivariate analysis based on the best model determined by a univariate analysis. Between weights at hatching and at six week-old, the values of -0.07, 0.53 and 0.47 were found for the direct additive genetic variance, maternal additive genetic variance and permanent maternal environmental variance, respectively. The estimated correlation between direct additive genetic effect influencing weight at hatch and direct additive maternal effect affecting weight at six weeks of age was -0.21, whereas the correlation value of 0.15 was estimated between direct additive maternal effect influencing weight at hatch and direct additive genetic effect affecting weight at six-week-old. From the present findings, it can be concluded that the maternal additive genetic effect observed for weight at six weeks of age might be a factor transferred from genes influencing weight at hatch to weight at six-week-old.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.739-743
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• 2011

The aim of this paper was to estimate genetic parameters for body weight and five body measurements for an experimental population of Iranian Makooei sheep maintained at the Makooei Sheep Breeding Station at Makoo, Iran. To do this, yearling live weight (YW), and five body measurements, i.e., body length (BL), heart girth (HG), height at withers (HW), height at back (HB) and scrotal circumference (SC), were analyzed in a multi-trait animal model using the DXMUX program of DFREML software package. Heritability estimates were $0.22{\pm}0.08$, $0.11{\pm}0.06$, $0.21{\pm}0.07$, $0.17{\pm}0.06$, $0.17{\pm}0.06$ and $0.32{\pm}0.10$ for YW, BL, HG, HW, HB and SC, respectively. These estimates indicate that selection in Makooei sheep would generate moderate genetic progress in body weight and body measurements. Scrotal circumference, as an indicator of reproductive potential, exhibited the highest heritability. This trait, therefore, could successfully be used to increase productivity of males and, indirectly, female fertility. Genetic correlations between traits studied were all positive and ranged from 0.15 (YW/HB) to 0.99 (HW/HB). Phenotypic correlations were also positive and ranged from moderate (0.32, HW/SC) to high (0.94, HW/HB). Positive genetic and phenotypic correlations indicate that improvement in body measurements both at the genetic and phenotypic levels is expected through selection on body weight and vice versa.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.2
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• pp.167-170
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• 2017

Objective: The feed intake (FI) and feed efficiency are economically important traits in ducks. To obtain insight into this economically important trait, we designed an experiment based on the residual feed intake (RFI) and feed conversion ratio (FCR) of a random population Pekin duck. Methods: Two thousand and twenty pedigreed random population Pekin ducks were established from 90 males mated to 450 females in two hatches. Traits analyzed in the study were body weight at the 42th day (BW42), 15 to 42 days average daily gain (ADG), 15 to 42 days FI, 15 to 42 days FCR, and 15 to 42 days RFI to assess their genetic interrelationships. The genetic parameters for feed efficiency traits were estimated using restricted maximum likelihood (REML) methodology applied to a sire-dam model for all traits using the ASREML software. Results: Estimates heritability of BW42, ADG, FI, FCR, and RFI were 0.39, 0.38, 0.33, 0.38, and 0.41, respectively. The genetic correlation was high between RFI and FI (0.77) and moderate between RFI and FCR (0.54). The genetic correlation was high and moderate between FCR and ADG (-0.80), and between FCR and BW42 (-0.64), and between FCR and FI (0.49), respectively. Conclusion: Thus, selection on RFI was expected to improve feed efficiency, and reduce FI. Selection on RFI thus improves the feed efficiency of animals without impairing their FI and increase growth rate.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.981-986
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• 2010

Genetic parameters of growth traits were estimated in the German Angora rabbit reared in the sub-temperate region of India. Estimates of (co)variance components were obtained for body weights at weaning (42 days) and post-weaning at 84, 126 and 168 days. A total of 8,324 animal records were used for the analysis of these traits. The data were analyzed by restricted maximum likelihood (REML) fitting six animal models with various combinations of direct and maternal effects. A log likelihood ratio test was used to select the most appropriate univariate model for each trait. Direct heritability estimates were observed to be moderate for the traits under study. Heritability estimates for weaning (42 d), 84, 126 and 168 d weights obtained from the best models were $0.25{\pm}0.05$, $0.17{\pm}0.05$, $0.21{\pm}0.06$ and $0.12{\pm}0.05$. Maternal effects had higher importance at weaning, and declined with the advancement of age. Significant maternal permanent environmental effect on weaning and post-weaning weights was a carryover effect of maternal influences during pre-weaning age. The estimated repeatabilities of doe effects on body weights were 0.37, 0.22, 0.18 and 0.28 at weaning, 84, 126 and 168 d body weight, respectively. Results indicated that modest rate of genetic progress is possible for body weight traits of Angora rabbit through selection. Similarly, these growth traits could be included in selection criteria along with wool traits for early selection of the animals.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.591-599
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• 2009

Genetic parameters for growth-related traits were estimated in 9-month old of two Korean abalone subspecies, Haliotis discus hannai and H. discus discus, using multiple traits of animal model. The data were collected from the records of 3,504 individuals produced from 16 sires and 17 dams in H. discus hannai and 821 individuals produced from 3 sires and 4 dams in H. discus discus, which was evaluated at the Bukjeju branch, NFRDI, from May 20, 2004 to February 14, 2005. The heritability estimates obtained from restricted maximum likelihood (REML) method range from 0.29 to 0.31 for three growth traits (shell length, shell width and body weight) in H. discus hannai and from 0.22 to 0.28 in H. discus discus, respectively. The heritabilities for shell shape and condition factor were lower than others of growth traits such as ranging from 0.03 to 0.24 in H. discus hannai and from 0.06 to 0.11 in H. discus discus, respectively. Genetic and phenotypic correlations were >0.91 between shell parameters and weight in two abalone subspecies, respectively, indicating that breeding for weight gains could be successfully achieved by selecting for shell length.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1232-1236
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• 2002

Direct and service sire genetic parameters for total number of pigs born (TNB), number of pigs born alive (NBA), total pig weight at birth (TWB), and average pig birth weight (ABW) were estimated by DF-REML under a multiple trait animal model. Data on 3,078 litters of the Yorkshire from Jan, 1975 to Dec, 1998 at National Livestock Research Institute were obtained. The animal model included fixed contemporary group effects and random additive direct, service sire, and residual effects. Additive genetic relationships among animals were included. A separate relationship matrix for service sires and their sire was also included. Additive direct heritability estimates for TNB, NBA, TWB, and ABW were 0.19, 0.18, 0.25 and 0.39, respectively. Service sire heritability estimates for TNB, NBA, TWB, and ABW were 0.02, 0.01, 0.02 and 0.01, respectively. The genetic and phenotypic correlations of TNB with NBA estimated in this study were 0.81 and 0.81, respectively, and the genetic and phenotypic correlations of TNB with TWB estimated were 0.82 and 0.76, respectively. Results indicate that service sires account for 1 to 2% of the total variation for TNB, NBA, TWB, and ABW. Further investigation is needed to determine whether the service sire effect is primarily genetic or environmental.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.915-921
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• 2006

Various random regression models with different order of Legendre polynomials for permanent environmental and genetic effects were constructed to predict future milk yield of Holstein cows in Korea. A total of 257,908 test-day (TD) milk yield records from a total of 28,135 cows belonging to 1,090 herds were considered for estimating (co)variance of the random covariate coefficients using an expectation-maximization REML algorithm in an animal mixed model. The variances did not change much between the models, having different order of Legendre polynomial, but a decreasing trend was observed with increase in the order of Legendre polynomial in the model. The R-squared value of the model increased and the residual variance reduced with the increase in order of Legendre polynomial in the model. Therefore, a model with $5^{th}$ order of Legendre polynomial was considered for predicting future milk yield. For predicting the future milk yield of cows, 132,771 TD records from 28,135 cows were randomly selected from the above data by way of preceding partial TD record, and then future milk yields were estimated using incomplete records from each cow randomly retained. Results suggested that we could predict the next four months milk yield with an error deviation of 4 kg. The correlation of more than 70% between predicted and observed values was estimated for the next four months milk yield. Even using only 3 TD records of some cows, the average milk yield of Korean Holstein cows would be predicted with high accuracy if compared with observed milk yield. Persistency of each cow was estimated which might be useful for selecting the cows with higher persistency. The results of the present study suggested the use of a $5^{th}$ order Legendre polynomial to predict the future milk yield of each cow.