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Gowane G. R. Akram Najif Prince L. L. L. Prakash Ved Kumar Arun 《Tropical animal health and production》2017,49(4):867-873
Tropical Animal Health and Production - Enterotoxaemia (ET) is a fatal enteric disease of small ruminants attributable to a toxigenic type of Clostridium perfringens. The key strategy for... 相似文献
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Gopal R. Gowane Sang Hong Lee Sam Clark Nasir Moghaddar Hawlader A. Al‐Mamun Julius H. J. van der Werf 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2019,136(5):390-407
Reference populations for genomic selection usually involve selected individuals, which may result in biased prediction of estimated genomic breeding values (GEBV). In a simulation study, bias and accuracy of GEBV were explored for various genetic models with individuals selectively genotyped in a typical nucleus breeding program. We compared the performance of three existing methods, that is, Best Linear Unbiased Prediction of breeding values using pedigree‐based relationships (PBLUP), genomic relationships for genotyped animals only (GBLUP) and a Single‐Step approach (SSGBLUP) using both. For a scenario with no‐selection and random mating (RR), prediction was unbiased. However, lower accuracy and bias were observed for scenarios with selection and random mating (SR) or selection and positive assortative mating (SA). As expected, bias disappeared when all individuals were genotyped and used in GBLUP. SSGBLUP showed higher accuracy compared to GBLUP, and bias of prediction was negligible with SR. However, PBLUP and SSGBLUP still showed bias in SA due to high inbreeding. SSGBLUP and PBLUP were unbiased provided that inbreeding was accounted for in the relationship matrices. Selective genotyping based on extreme phenotypic contrasts increased the prediction accuracy, but prediction was biased when using GBLUP. SSGBLUP could correct the biasedness while gaining higher accuracy than GBLUP. In a typical animal breeding program, where it is too expensive to genotype all animals, it would be appropriate to genotype phenotypically contrasting selection candidates and use a Single‐Step approach to obtain accurate and unbiased prediction of GEBV. 相似文献
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Gowane Gopal R. Chopra Ashish Prakash Ved Arora A. L. 《Tropical animal health and production》2011,43(1):189-198
Data were collected over a period of 21 years (1988–2008) to estimate (co)variance components for birth weight (BWT), weaning
weight (WWT), 6-month weight (6WT), 9-month weight (9WT), 12-month weight (12WT), average daily gain from birth to weaning
(ADG1), weaning to 6WT (ADG2), and from 6WT to 12WT (ADG3) in Sirohi goats maintained at the Central Sheep and Wool Research
Institute, Avikanagar, Rajasthan, India. Analyses were carried out by restricted maximum likelihood, fitting six animal models
with various combinations of direct and maternal effects. The best model was chosen after testing the improvement of the log-likelihood
values. Heritability estimates for BWT, WWT, 6WT, 9WT, 12WT, ADG1, ADG2, and ADG3 were 0.39 ± 0.05, 0.09 ± 0.03, 0.06 ± 0.02,
0.09 ± 0.03, 0.11 ± 0.03, 0.10 ± 0.3, 0.04 ± 0.02, and 0.01 ± 0.01, respectively. For BWT and ADG1, only direct effects were
significant. Estimate of maternal permanent environmental effect were important for body weights from weaning to 12WT and
also for ADG2 and ADG3. However, direct maternal effects were not significant throughout. Estimate of c
2 were 0.06 ± 0.02, 0.03 ± 0.02, 0.06 ± 0.02, 0.05 ± 0.02, 0.02 ± 0.02, and 0.02 ± 0.02 for 3WT, 6WT, 9WT, 12WT, ADG2, and
ADG3, respectively. The estimated repeatabilities across years of ewe effects on kid body weights were 0.10, 0.08, 0.05, 0.08,
and 0.08 at birth, weaning, 6, 9, and 12 months of age, respectively. Results suggest possibility of modest rate of genetic
progress for body weight traits and ADG1 through selection, whereas only slow progress will be possible for post-weaning gain.
Genetic and phenotypic correlations between body weight traits were high and positive. High genetic correlation between 6WT
and 9WT suggests that selection of animals at 6 months can be carried out instead of present practice of selection at 9 months. 相似文献
4.
Estimates of (co)variance components and genetic parameters were calculated for birth weight (BWT), weaning weight (WWT), 6 month weight (6WT), 9 month weight (9WT), 12 month weight (12WT) and greasy fleece weight at first clip (GFW) for Malpura sheep. Data were collected over a period of 23 years (1985–2007) for economic traits of Malpura sheep maintained at the Central Sheep & Wool Research Institute, Avikanagar, Rajasthan, India. Analyses were carried out by restricted maximum likelihood procedures (REML), fitting six animal models with various combinations of direct and maternal effects. Direct heritability estimates for BWT, WWT, 6WT, 9WT, 12WT and GFW from the best model (maternal permanent environmental effect in addition to direct additive effect) were 0.19 ± 0.04, 0.18 ± 0.04, 0.27, 0.15 ± 0.04, 0.11 ± 0.04 and 0.30 ± 0.00, respectively. Maternal effects declined as the age of the animal increased. Maternal permanent environmental effects contributed 20% of the total phenotypic variation for BWT, 5% for WWT and 4% for GFW. A moderate rate of genetic progress seems possible in Malpura sheep flock for body weight traits and fleece weight by mass selection. Direct genetic correlations between body weight traits were positive and ranged from 0.40 between BWT and 6WT to 0.96 between 9WT and 12WT. Genetic correlations of GFW with body weights were 0.06, 0.49, 0.41, 0.19 and 0.15 from birth to 12WT. The moderately positive genetic correlation between 6WT and GFW suggests that genetic gain in the first greasy fleece weight will occur if selection is carried out for higher 6WT. 相似文献
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Estimates of (co)variance components and genetic parameters for growth traits of Avikalin sheep 总被引：2，自引：2，他引：0
Leslie Leo L. Prince Gopal R. Gowane Ashish Chopra Amrit L. Arora 《Tropical animal health and production》2010,42(6):1093-1101
(Co)variance components and genetic parameters for various growth traits of Avikalin sheep maintained at Central Sheep and
Wool Research Institute, Avikanagar, Rajasthan, India, were estimated by Restricted Maximum Likelihood, fitting six animal
models with various combinations of direct and maternal effects. Records of 3,840 animals descended from 257 sires and 1,194
dams were taken for this study over a period of 32 years (1977–2008). Direct heritability estimates (from best model as per
likelihood ratio test) for weight at birth, weaning, 6 and 12 months of age, and average daily gain from birth to weaning,
weaning to 6 months, and 6 to 12 months were 0.28 ± 0.03, 0.20 ± 0.03, 0.28 ± 0.07, 0.15 ± 0.04, 0.21 ± 0.03, 0.16 and 0.03 ± 0.03,
respectively. Maternal heritability for traits declined as animal grows older and it was not at all evident at adult age and
for post-weaning daily gain. Maternal permanent environmental effect (c
2) declined significantly with advancement of age of animal. A small effect of c
2 on post-weaning weights was probably a carryover effect of pre-weaning maternal influence. A significant large negative genetic
correlation was observed between direct and maternal genetic effects for all the traits, indicating antagonistic pleiotropy,
which needs special care while formulating breeding plans. A fair rate of genetic progress seems possible in the flock by
selection for all traits, but direct and maternal genetic correlation needs to be taken in to consideration. 相似文献
6.
Gowane GR Chopra A Prince LL Mishra AK Arora AL 《Tropical animal health and production》2011,43(2):299-303
The FecB gene of Garole sheep was introgressed into non-prolific Malpura sheep to evolve a new prolific sheep strain Garole × Malpura
(GM), suitable for semi-arid conditions. The present study was conducted to evaluate the impact of breeding program on production
profile of GM sheep and to estimate the genetic parameters for growth traits of GM sheep. Overall prolificacy increased significantly
in the new strain as compared to the native Malpura sheep. In the GM flock of F2 and F2 onwards generation 35.31% single,
55.83% twins, 8.16% triplet and 0.70% quadruplets were obtained during lambing. Over the years, prolificacy in the flock has
increased significantly. Over all least squares means for birth weight, 3, 6, 9, 12 month weight, pre-weaning gain (ADG1)
and post-weaning gain (ADG2) were 1.82 ± 0.03, 9.44 ± 0.18, 14.00 ± 0.24, 16.56 ± 0.33, and 19.32 ± 0.35 kg, and 84.08 ± 1.84
and 35.19 ± 0.99 g, respectively. Majority of the fixed effects had significant influence on the performance traits. The heritability
estimates for birth, 3, 6, 9, 12 month weight, ADG1 and ADG2 were 0.30 ± 0.11, 0.22 ± 0.09, 0.23 ± 0.10, 0.27 ± 0.10, 0.30 ± 0.11,
0.17 ± 0.08, and 0.17 ± 0.10, respectively. Modest rate of genetic progress seems possible for these traits under selection.
The genetic and phenotypic correlations among different body weights were moderate to high and positive. The genetic correlation
of pre and post-weaning daily gains with body weight traits were also high and positive. 相似文献
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Gopal R. Gowane Arun Kumar Chanda Nimbkar 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2019,136(5):329-338
Animal breeding in India has a long and chequered history. High pressure on agricultural land and increasing human population opened a new opportunity for the livestock and poultry sector as a promising food industry. Productivity of livestock in India is low due to less coverage of livestock under structured breeding programmes, inadequate nutrition and its entanglement with several socio‐economic issues. A bottom‐up approach to breeding policy formulation addressing local needs is required with assured flow of investments. Cattle slaughter is banned in India; hence, a legal policy to curb widespread indiscriminate mating is required which may incur substantial financial and infrastructural burdens for castration of stray males and strengthening of cow rehabilitation centres. Genetic evaluation of indigenous cattle with progeny testing (PT) requires substantial financial support, without affecting the already existing PT for exotic cattle breeds used in the local cross‐breeding programmes and PT of new genotypes obtained from crosses of exotic and local breeds of cattle and for purebred buffaloes. Small ruminants need special attention due to their socio‐economic importance in rural and often highly disadvantaged communities and because they are the second most important meat‐producing species after poultry. Genetic improvement of small ruminants should be accompanied by attention to shrinking grazing resources which would require strong political will together with financial support. The outreach of breeding programmes for small ruminants is currently limited; there is also a lack of linkage between the market and producers that discourages farmers from adopting clear breeding objectives like improvement in growth rate, as animals are seldom sold on weight basis. Apart from government agencies, involvement of private sector, non‐government organizations, local co‐operatives, self‐help groups and self‐sustainable community‐based breeding programmes can strengthen market linkages. Strengthening of the existing infrastructure along with technical input and skilled manpower is essential for achieving the breeding objectives. 相似文献
8.
Prince Leslie Leo L. Gowane G. R. Swarnkar C. P. Singh D. Arora A. L. 《Tropical animal health and production》2010,42(4):785-791
Genetic parameters for faecal egg count were estimated in naturally challenged Avikalin sheep developed and maintained at
Central Sheep & Wool Research Institute, Avikanagar, India, over a period of 4 years (2004–2007). The data on faecal egg count
for 433 animals descended from 41 sires, and 151 dams were used for the study. Genetic analyses were carried out using restricted
maximum likelihood, fitting an animal model and ignoring or including maternal genetic or permanent environmental effects.
Direct heritability for the trait was 0.149 ± 0.096 when maternal effects were ignored. In the model which takes in to account
direct genetic, maternal genetic and maternal permanent environment effect together, it was observed that maternal heritability
(m2) accounts for 0.6% of total variation whereas maternal permanent environmental effect (c2) accounts for 6.14% of total phenotypic variation. Effect of faecal egg count on the growth characteristics was observed
to be significant. It was seen that wherever FEC was high, body weight or average daily gain declined in active infective
stage. After termination of the infection, these effects were found to be non-significant. Result suggests that direct genetic
and maternal permanent environmental effects were important for this trait; thus, they need to be considered for improvement
in the trait. 相似文献
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