• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1129-1134
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• 1999

The rapid development of the sheep genetic linkage map over the last five years has given us the ability to follow the inheritance of chromosomal regions. Initially this powerful resource was used to find markers linked to monogenic traits but there is now increasing interest in using the genetic linkage map to define the complex of genes that control multigenic production traits. Of particular interest are those production traits that are difficult to measure and select for using classical quantitative genetic approaches. These include resistance to disease where a disease challenge (necessary for selection) poses too much risk to valuable stud animals and meat and carcass qualities which can be measured only after the animal has been slaughtered. The goal for the new millennium will be to fully characterise the genetic basis of multigenic production traits. The genetic linkage map is a vital tool required to achieve this.

• Animal Bioscience
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• v.34 no.4
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• pp.471-481
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• 2021

Objective: A comprehensive study was conducted to study the effects of partition of variance on accuracy of genetic parameters and genetic trends of economic traits in Vanaraja male line/project directorate-1 (PD-1) chicken. Methods: Variance component analysis utilizing restricted maximum likelihood animal model was carried out with five generations data to delineate the population status, direct additive, maternal genetic, permanent environmental effects, besides genetic trends and performance of economic traits in PD-1 chickens. Genetic trend was estimated by regression of the estimated average breeding values (BV) on generations. Results: The body weight (BW) and shank length (SL) varied significantly (p≤0.01) among the generations, hatches and sexes. The least squares mean of SL at six weeks, the primary trait was 77.44±0.05 mm. All the production traits, viz., BWs, age at sexual maturity, egg production (EP) and egg weight were significantly influenced by generation. Model four with additive, maternal permanent environmental and residual effects was the best model for juvenile growth traits, except for zero-day BW. The heritability estimates for BW and SL at six weeks (SL6) were 0.20±0.03 and 0.17±0.03, respectively. The BV of SL6 in the population increased linearly from 0.03 to 3.62 mm due to selection. Genetic trend was significant (p≤0.05) for SL6, BW6, and production traits. The average genetic gain of EP40 for each generation was significant (p≤0.05) with an average increase of 0.38 eggs per generation. The average inbreeding coefficient was 0.02 in PD-1 line. Conclusion: The population was in ideal condition with negligible inbreeding and the selection was quite effective with significant genetic gains in each generation for primary trait of selection. The animal model minimized the over-estimation of genetic parameters and improved the accuracy of the BV, thus enabling the breeder to select the suitable breeding strategy for genetic improvement.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.744-751
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• 2011

Meat production and quality traits in beef cattle are largely affected by genetic factors. Acetyl-Coenzyme A carboxylase-${\alpha}$ (ACACA) plays a key role in the regulation and metabolism of fatty acid biosynthesis in mammalian animals. The gene encoding ACACA enzyme was chosen as a candidate gene for carcass and meat traits. In this study, we investigated effects of single nucleotide polymorphisms (SNPs) in the ACACA gene on beef carcass and meat traits in Hanwoo (Korean cattle) populations. We have sequenced a fragment of intron I region of the Hanwoo ACACA gene and identified two SNPs. Genotyping of the two SNP markers (g.2344T>C and g.2447C>A) was carried out using PCR-SSCP analysis in 309 Hanwoo steers to evaluate their association with carcass and meat production traits. The g.2344C SNP marker showed a significant increasing effect on LW (p = 0.009) and CW (p = 0.017). Animals with the CC genotype had higher CW and LW compared with TT and TC genotypes (p<0.05). The g.2447A SNP marker was associated with higher MC (p = 0.019). Animals with the AA genotype had higher MC than animals with CC and CA genotypes (p<0.05). Although the degree of linkage disequilibrium (LD) was not strong between g.2344T>C and g.2447C>A in the LD analysis, four major haplotype classes were formed with two SNP information within the ACACA gene. We constructed haplotypes using the HaploView software package program and analyzed association between haplotypes and carcass traits. The haplotype of ACACA gene significantly affected the LW (p = 0.027), CW (p = 0.041) and MC (p = 0.036). The effect of h1 haplotype on LW and CW was larger than that of h3 haplotype. Animals with the h1 haplotype also had greater MC than did animals with h2 haplotype. Consequently, the ACACA gene could be useful as a DNA marker for meat production traits such as carcass yield and meat contents in Hanwoo.

• Animal Bioscience
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• v.34 no.8
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• pp.1303-1308
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• 2021

Objective: The objective of this study was to define a new composite trait for Holstein dairy cows and evaluate the possibility of joint improvement in milk and fertility traits. Methods: A data set consisting 35,882 fertility related records (days open [DO], calving interval [CI], and number of services per conception [NSC], and total milk yield in each lactation [TMY]) was collected from 1998 to 2016 in Polish Holstein-Friesian breed herds. In this study TMY, DO, CI, and lactation length of each cow was used to obtain composite milk and fertility traits (CMF). Results: Moderate heritability (0.15) was estimated for composite trait that was higher than heritability of female fertility related traits: DO 0.047, CI 0.042, and NSC 0.014, and slightly lower than heritability of TMY 0.19. Favourable genetic correlations (-0.87) were estimated between CMF with TMY. Spearman rank correlation coefficients between breeding value of CMF with DO, CI, and TMY were high (>0.94) but with NSC were moderate (0.64). Selection on CMF caused favourable correlated genetic gains for DO, CI, and TMY. Different selection indices with different emphasis on fertility and milk production were constructed. The amount of correlated genetic gains obtained for DO and total milk production according to selection in CMF were higher than of genetic gains obtained for DO and TMY in selection indices with different emphasis on milk and fertility. Conclusion: The animal selection only based on a composite trait - CMF proposed in current study would simultaneously lead to favourable genetic gains for both milk and fertility related traits. In this situation CMF introduced in current study can be used to overcome to limitations of selection index and CMF could be useful for countries that have problems in recording traits, especially functional traits.

• Animal Bioscience
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• v.34 no.4
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• pp.489-498
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• 2021

Objective: Milk production is one of the most desirable traits in livestock. Recently, the toll-like receptor (TLR) has been identified as a candidate gene for milk traits in cows. So far, there is no information concerning the contribution of this gene in milk traits in sheep. This study was designed to investigate the TLR 4 gene polymorphisms in Barki ewes in Egypt and then correlate that with milk traits in order to identify potential single nucleotide polymorphisms (SNPs) for these traits in sheep. Methods: A part of the ovine TLR 4 gene was amplified in Barki ewes, to identify the SNPs. Consequently; Barki ewes were genotyped using polymerase chain reaction-single strand conformation polymorphism protocol. These genotypes were correlated with milk traits, which were the daily milk yield (DMY), protein percentage (PP), fat percentage (FP), lactose percentage, and total solid percentage (TSP). Results: Age and parity of the ewe had a significant effect (p<0.05 or p<0.01) on DMY, FP, and TSP. The direct sequencing identified a missense mutation located in the coding sequence of the gene (rs592076818; c.1710C>A) and was predicted to change the amino acid sequence of the resulted protein (p.Asn570Lys). The association analyses suggested a significant effect (p<0.05) of the TLR genotype on the FP and PP, while the DMY tended to be influenced as well (p = 0.07). Interestingly, the presence of the G allele tended to increase the DMY (+40.5 g/d) and significantly (p<0.05 or p<0.01) decreased the FP (-1.11%), PP (-1.21%), and TSP (-7.98%). Conclusion: The results of this study suggested the toll-like receptor 4 (TLR4) as a candidate gene to improve milk traits in sheep worldwide, which will enhance the ability to understand the genetic architecture of genes underlying SNPs that affect such traits.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1813-1821
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• 2002

The aim of this study was to identify useful secondary traits for estimating genetic ability of milk production traits. We investigated the value of using plasma metabolites concentrations. Two hundred and nineteen cattle out of 271 had only milk production traits records (G1), 33 had only metabolites records (G2), and 19 had both milk production traits and metabolites records (G3). Fifty two calves with metabolites records (G2 and G3) were born from 1992 to 1997. Forty three calves (29 females, 14 males) were used from 10 to 90 d of age and the others (3 females, 6 males) from 10 to 60 d of age. A total of 566 records of milk yield, fat yield and protein yield for 240 to 305 d on 238 heads (G1 and G2) were collected The collected blood samples were divided into three age groups: AG1, 10 to 30 d; AG2, 40 to 60 d; and AG3, 70 to 90 d. Heritabilities of milk yield, fat yield and protein yield were $0.45{\pm}0.04$, $0.50{\pm}0.04$ and $0.38{\pm}0.04$, respectively. Heritability of plasma glucose concentration at AG1 was $0.45{\pm}0.08$. Genetic correlations between plasma glucose concentration and milk yield, fat yield and protein yield were -$0.35{\pm}0.28$, $0.64{\pm}0.24$ and $0.36{\pm}0.35$, respectively. When the plasma glucose concentration at AG1 was used to estimate genetic ability of these milk production traits, reliability of milk yield of animals without milk record increased 8.2%, fat yield increased 24.2% and protein yield increased 9.5%. Heritability of plasma total cholesterol concentration at AG3 was $0.83{\pm}0.04$. Genetic correlation between plasma total cholesterol concentration and milk yield, fat yield and protein yield were $0.58{\pm}0.21$, $0.42{\pm}0.20$ and $0.45{\pm}0.22$, respectively. When the plasma total cholesterol concentration at AG3 was using to estimate genetic ability of these milk production traits, reliability of milk yield of animals without milk record increased 19.0%, fat yield increased 9.6%, and protein yield increased 13.5%. The annual genetic gain is in proportion to the reliability of selection. These results show that the plasma metabolite concentrations would be useful for improvement of genetic ability for milk production traits in the genetic improvement in herd of cows, where half of the animals selected are from a herd without its own milk record.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.2
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• pp.182-187
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• 2010

The aim of this experiment was to evaluate the levels of hormones (progesterone, IGF-I and IGFBP-3) in blood plasma, growth, carcass traits and their interactions of sexually immature (n = 18) and sexually mature (n = 17) gilts. To calculate average daily weight gain (ADG), gilts were individually weighed at the beginning of the trial and at slaughter (110${\pm}$10 days old). Blood concentrations of progesterone, IGF-I and IGFBP-3 were determined by RIA. The right hot carcass sides were dissected and the individual basic parts from carcasses were weighed to record the carcass traits. IGFBP-3, ADG and carcass traits were not affected by pubertal maturation. Compared to sexually immature gilts, mature gilts had higher blood concentrations of progesterone and IGF-I. High correlations were noted between levels of some hormonal substances, productive performance and carcass traits of sexually immature and mature gilts.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.10
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• pp.1535-1541
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• 2018

Objective: In birds, three types of melatonin receptors (MTNR1A, MTNR1B, and MTNR1C) have been cloned. Previous researches have showed that three melatonin receptors played an essential role in reproduction and ovarian physiology. However, the association of polymorphisms of the three receptors with duck reproduction traits and egg quality traits is still unknown. In this test, we chose MTNR1A, MTNR1B, and MTNR1C as candidate genes to detect novel sequence polymorphism and analyze their association with egg production traits in Shaoxing duck, and detected their mRNA expression level in ovaries. Methods: In this study, a total of 785 duck blood samples were collected to investigate the association of melatonin receptor genes with egg production traits and egg quality traits using a direct sequencing method. And 6 ducks representing two groups (3 of each) according to the age at first eggs (at 128 days of age or after 150 days of age) were carefully selected for quantitative real-time polymerase chain reaction. Results: Seven novel polymorphisms (MTNR1A: g. 268C>T, MTNR1B: g. 41C>T, and g. 161T>C, MTNR1C: g. 10C>T, g. 24A>G, g. 108C>T, g. 363 T>C) were detected. The single nucleotide polymorphism (SNP) of MTNR1A (g. 268C>T) was significantly linked with the age at first egg (p<0.05). And a statistically significant association (p<0.05) was found between MTNR1C g.108 C>T and egg production traits: total egg numbers at 34 weeks old of age and age at first egg. In addition, the mRNA expression level of MTNR1A in ovary was significantly higher in late-mature group than in early-mature group, while MTNR1C showed a contrary tendency (p<0.05). Conclusion: These results suggest that identified SNPs in MTNR1A and MTNR1C may influence the age at first egg and could be considered as the candidate molecular marker for identify early maturely traits in duck selection and improvement.

• Korean Journal of Veterinary Research
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• v.53 no.1
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• pp.7-10
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• 2013

A study was conducted to determine the interdependence among the conformation traits of 28 "Pallaresa" cows using principal component analysis. Originally 21 body linear measurements were obtained, from which eight traits are subsequently eliminated. From the principal components analysis, with raw varimax rotation of the transformation matrix, two principal components were extracted, which accounted for 65.8% of the total variance. The first principal component alone explained 51.6% of the variation, and tended to describe general size, while the second principal component had its loadings for back-sternal diameter. The two extracted principal components, which are traits related to dorsal heights and back-sternal diameter, could be considered in selection programs.

• Journal of Animal Science and Technology
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• v.63 no.6
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• pp.1211-1222
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• 2021

Data of 651 lambs (68 Romanov, 49 Rahmani, 151 [♀1/2 Rahmani × ♂1/2 Romanov) and 383 (♀3/4 Rahmani and 1/4♂ Romanov]) were collected from Mehalet Mousa Farm, belonging to Animal Production Research Institute from the period of 2009 to 2016 to estimate phenotypic and genetic parameters. The traits studied were birth weight (BW), body weight at four week (BW4), body weight at eight weeks (BW8) and body weight at twelve weeks (BW12) or weaning weight. Least squares analysis of variance shows significance of the effects of breed groups, gender of lambs, birth type; month of birth and year of birth on all traits studied. Rahmani lambs had heavier BW, BW4, BW8 and BW12 while Romanov lambs had the lowest ones. The first generation (♀1/2 Rhamani × ♂1/2 Romanov) had heavier body weights than Romanov and the second generation (♀3/4 Rahmani × ♂1/4 Roamnov). Gender of lambs had highly significant effect on body weights. Males were significantly (p < 0.01) heavier than females for all traits studied. Least square means of BW, BW4, BW8 and BW12 for single lambs were 2.69, 10.43, 13.53 and 16.10 kg, respectively. Least square means of BW, BW4, BW8 and BW12 for twin lambs were 2.50, 9.37, 12.5 and 15.16 kg, respectively, while least square means of BW, BW4, BW8 and BW12 for triple lambs were 2.09, 7.86, 10.83 and 13.67 kg, respectively. Estimates of direct heritability measured by single trait animal model were 0.14, 0.23, 0.25 and 0.26 for BW, BW4, BW8 and BW12, respectively, and the corresponding measured by multi trait animal model were 0.17, 0.24, 0.32 and 0.36 for the same traits, respectively. All genetic and phenotypic correlations among different traits studied are positive and significant.