• Animal Bioscience
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• v.37 no.3
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• pp.451-460
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• 2024

Objective: The objective is to identify genomic regions and candidate genes associated with age to 105 kg (AGE), average daily gain (ADG), backfat thickness (BF), and eye muscle area (EMA) in Yorkshire pig. Methods: This study used a total of 104,380 records and 11,854 single nucleotide polymorphism (SNP) data obtained from Illumina porcine 60K chip. The estimated genomic breeding values (GEBVs) and SNP effects were estimated by single-step genomic best linear unbiased prediction (ssGBLUP). Results: The heritabilities of AGE, ADG, BF, and EMA were 0.50, 0.49, 0.49, and 0.23, respectively. We identified significant SNP markers surpassing the Bonferroni correction threshold (1.68×10^-6), with a total of 9 markers associated with both AGE and ADG, and 4 markers associated with BF and EMA. Genome-wide association study (GWAS) analyses revealed notable chromosomal regions linked to AGE and ADG on Sus scrofa chromosome (SSC) 1, 6, 8, and 16; BF on SSC 2, 5, and 8; and EMA on SSC 1. Additionally, we observed strong linkage disequilibrium on SSC 1. Finally, we performed enrichment analyses using gene ontology and Kyoto encyclopedia of genes and genomes (KEGG), which revealed significant enrichments in eight biological processes, one cellular component, one molecular function, and one KEGG pathway. Conclusion: The identified SNP markers for productive traits are expected to provide valuable information for genetic improvement as an understanding of their expression.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.95-99
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• 2005

A breeding plan was carried out on four commercial strains of silkworm (Bombyx mori L.) 101, 102, 103 and 104 to improve some important traits. Genetic gain or response to selection $({\Delta}G)$, heritability of cocoon shell weight (CSW) and specific combining ability effects were estimated to determine the strains that can be improved. Strain 101 had lowest heritabitity, ${\Delta}G$ and viability. Strain 102 was acceptable in selection response but its viability was low. Therefore these two strains were not suitable for more selection. As a result, only lines 103 and 104 were chosen for further improvement. Intra population selection based on independent culling level method practiced from third to sixth generation for both productive and viability traits simultaneously. While CSW and CW had increasingly enhanced during primary generations, they went slightly up after third generation. According to negative genetic correlation, viability decreased during primary generations, but after third generation that paid attention to balanced development of both productive and viability traits, viability increased so that the pupation rate reached to $91\%$ in 103 and $97\%$ in 104 for last generation $(G_8)$.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.57-63
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• 2012

The purpose of this study was to estimate genetic parameters for productive traits in Duroc breed. In this study, 40,657 records for productive traits and the pedigree data of 47,974 families were collected from 41 farms registered at the Korean Animal Improvement Association (KAIA) from 2004 to 2011. The REMLf90 program was used to analyze a multiple traits animal model with fixed effects of sex, contemporary group, parity and age at the end of the test as covariate and random effects of animal and residual error. The heritabilities of days to 90 kg (D90KG), average daily gain (ADG), backfat thickness (BF) and eye muscle areas (EMA) were estimated to be 0.334, 0.340, 0.335, and 0.200, respectively. The genetic correlation coefficients were -0.992 between D90KG and ADG, -0.142 between ADG and BF, -0.361 between ADG and EMA, and -0.243 between BF and EMA. Conversely, positive genetic correlations for D90KG with BF and EMA were 0.13 and 0.36, respectively.

• Animal Bioscience
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• v.35 no.8
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• pp.1151-1161
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• 2022

Objective: This study was conducted to estimate the association of age at first calving (AFC) with first lactation traits as well as lifetime performance traits in Murrah buffaloes. Methods: Data on first lactation and life time performance of Murrah buffaloes (n = 679), maintained at Indian Council of Agricultural Research-Central Institute for Research on Buffaloes, Hisar, India during the period 1983 through 2017, were deduced to calculate heritability estimates, genetic and phenotypic correlation of different first lactation and lifetime traits. The univariate animal model was fitted to estimate variance components and heritability separately for each trait, while bivariate animal models were set to estimate genetic and phenotypic correlations between traits under study. Results: The heritability was high for first peak milk yield (FPY, 0.64±0.08), moderate for AFC (0.48±0.07) and breeding efficiency (BE 0.39±0.09). High genetic correlations of first lactation total milk yield (FLTMY) with first lactation standard milk yield (FLSMY, 305 days or less), FPY, and first lactation length (FLL) was seen. Likewise, genetic correlation of AFC was positive with FLTMY, FLL, first dry period (FDP), first service period (FSP), first calving interval (FCI), herd life (HL) and productive days (PD). Significant phenotypic correlation of FLTMY was observed with HL, productive life (PL), PD, total lifetime milk yield (LTMY), standard lifetime milk yield (standard LTMY). Moreover, positive genetic and phenotypic correlation of FPY was observed with HL, PL, PD, total LTMY and standard LTMY. Conclusion: This study reports that AFC had positive genetic correlation with FDP, FSP, FCI, and unproductive days while, negative association of AFC was observed with FLSMY, PL, total LTMY, standard LTMY, and BE. This suggests that reduction of AFC would results in improvement of lifetime performance traits.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.11
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• pp.1511-1517
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• 2013

This study was performed to estimate the effect of age at first calving and first two calving intervals on productive life and life time profit in Korean Holsteins. Reproduction data of Korean Holsteins born from 1998 to 2004 and lactation data from 276,573 cows with birth and last dry date that calved between 2000 and 2010 were used for the analysis. Lifetime profit increased with the days of life span. Regression of Life Span on Lifetime profit indicated that there was an increase of 3,800 Won (approximately $3.45) of lifetime profit per day increase in life span. This is evidence that care of each cow is necessary to improve net return and important for farms maintaining profitable cows. The estimates of heritability of age at first calving, first two calving intervals, days in milk for lifetime, lifespan, milk income and lifetime profit were 0.111, 0.088, 0.142, 0.140, 0.143, 0.123, and 0.102, respectively. The low heritabilities indicated that the productive life and economical traits include reproductive and productive characteristics. Age at first calving and interval between first and second calving had negative genetic correlation with lifetime profit (-0.080 and -0.265, respectively). Reducing age at first calving and first calving interval had a positive effect on lifetime profit. Lifetime profit increased to approximately 2,600,000 (2,363.6) from 800,000 Won ($727.3) when age at first calving decreased to (22.3 month) from (32.8 month). Results suggested that reproductive traits such as age at first calving and calving interval might affect various economical traits and consequently influenced productive life and profitability of cows. In conclusion, regard of the age at first calving must be taken with the optimum age at first calving for maximum lifetime profit being 22.5 to 23.5 months. Moreover, considering the negative genetic correlation of first calving interval with lifetime profit, it should be reduced against the present trend of increase.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.153-157
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• 2005

Recently two breeding programs were carried out for isolation of new parental inbred lines in Iran. This study was undertaken in order to estimate the combining ability effects and heterosis of these lines. For this purpose an $8\times8$ diallel cross analysis including eight inbred lines of silkworm with four lines from each program were studied for their five quantitative traits. The results indicated that reciprocal effects appeared insignificant for most of traits. Japanese lines of 111 and 113 were best combiners for shell weight, cocoon weight and shell percentage traits. With respect to pupation rate, Chinese line 110 was the best and according to general combining ability (GCA) and specific combining ability (SCA) variances, it is superior in specific combinations. Hybrid $109\times110$ showed better characters for both productive and viability traits. Hybrids with high heterosis had high SCA too.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.747-753
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• 2001

In this study, the Italian milk recorded buffalo population from 1974 to 1996 was analysed with the purpose to estimate genetic and environmental variability and provide genetic parameters for the most important economic traits. High variability between herds was evident due to the poor knowledge of feeding requirements and husbandry technology in this species compared to cattle. Age at first calving was reduced by 57 days during the considered years following efforts made in better feeding and management from 1990; on the contrary, calving interval has increased by 17 days as a consequence of forcing buffaloes to calve in spring, in order to have the peak milk yield when milk is much better paid. Average milk yield increased by 1853 kg during these years, while lactation duration was reduced by 30 days. Season of calving has no effect on all traits. Calving order has a positive effect on milk yield especially because older cows produce more milk in shorter lactations. Heritability for the age at first calving and calving interval was 0.26 and 0.05 respectively. Heritability of productive traits, milk yield and duration of the lactation was 0.19 and 0.13 respectively, with repeatabilities of 0.40 and 0.26. Genetic trend for milk yield was 2.1 kg milk/year for the bulls and 1 kg for all population. The high genetic variability of milk production as well as duration of the lactation, indicates that there are good opportunities for genetic improvement when including these traits in a selection scheme. The low genetic trend registered over 15 years of recording activity can be explained by the fact that neither progeny testing was performed or selection schemes were implemented, due to the difficulties to use artificial insemination in buffalo.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.429-435
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• 2016

Heritability estimates for daily gain (g), backfat thickness (mm), days to 90kg (day), loin eye depth (mm) and meat percent (%) were 0.40, 0.44, 0.40, 0.25 and 0.48, respectively. Estimates of correlation between breeding value and rank for meat productivity traits by model 1 and 2 were 0.995 1.000 and 0.991 1.000, respectively and highly significant (p< 0.0001), and they were almost identical to the breeding values estimated by different farms. When top 5% and top 10% animals were selected by meat productive traits at different farms, markedly different animals were selected by farms since the selected improvement traits in each farm maintaining closed herds were different. Therefore, it seems to be desirable that superior pigs should be selected after the establishment of evaluation system for genetic performance at national level using the integrated data obtained from various farms.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.2
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• pp.93-97
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• 2007

A Silkworm breeding programme was designed to develop a robust but productive bivoltine silkworm hybrid of Bombyx mori L. suitable for rearing throughout the year in tropical climate by utilizing indigenous polyvoltine and productive bivoltine breeds. The breeding was carried out under high temperature ($36^{\circ}C{\pm}1^{\circ}C$) and low humidity ($50{\pm}5%$) conditions in the environmental chamber. By $F_{12}$, three oval and three dumbbell breeds were isolated with higher survival and productive merits. These breeds were utilized in the hybrid evaluation along with other popular breeds. Based on combining ability test results, the hybrid $SR_2{\times}SR_5$ was selected for large scale testing and evaluated in different seasons. The evaluation studies indicated that the hybrid has higher viability and productive merits and it is suitable to rear throughout the year. The hybrid $SR_2{\times}SR_5$ recorded a survival of 92.0%, cocoon shell weight of 0.417 g, cocoon shell percentage of 23.0 and a filament length of 1042 meters under hot and dry conditions of environmental chamber compared to the control thermo-tolerant hybrid $CSR18{\times}CSR19$.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.12
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• pp.1693-1702
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• 2009

Economic values of 14 production and functional traits for two Slovak dairy sheep breeds (Improved Valachian and Tsigai) were calculated. Semi-extensive production systems with one lambing per year were simulated using a bio-economic deterministic computer model. The marginal economic value of a trait was defined as the partial derivative of the profit function with respect to that trait. The relative economic value expressed the percentage proportion of standardized economic value (marginal economic value${\times}$genetic standard deviation) of a trait in the sum of the absolute values of the standardized economic values over all traits. Milk yield was of highest relative importance (26% and 32% in Improved Valachian and Tsigai) followed by productive lifetime and conception rate of ewes (16% and 15% in Improved Valachian and Tsigai, in both traits). Conception rate of female lambs and litter size had nearly the same relative economic importance in both breeds (9% to 11%). Survival rate of lambs at lambing and till weaning reached slightly lower economic values (4% to 7%). The economic importance of all remaining traits was less than 4%.