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| dc.contributor.author | Almaz Bekele | |
| dc.date.accessioned | 2021-08-16T06:39:14Z | |
| dc.date.available | 2021-08-16T06:39:14Z | |
| dc.date.issued | 2021-08-16 | |
| dc.identifier.uri | http://ir.bdu.edu.et/handle/123456789/12430 | |
| dc.description.abstract | Efforts to improve genetic quality of cattle through selection require information on genetic parameters of cattle breed population. Without estimation of genetic parameters, breeding program setting which could be used as a tool for breed improvement program seems hardly possible. With this fact data found at Metekel Ranch was used to analyze with the objectives of estimating genetic parameters of growth and reproduction traits of Fogera cattle and estimating the breeding value of sire. The implications of non-genetic/environmental effects on growth and reproductive performance of the Fogera cattle were assessed in relation to the effects of sex of the calf, season, year and parity of the dam. The OLM procedure of (SAS, 2004) was used to analyze the effects of these fixed effects. WOMBAT was used to estimate genetic parameters, sire breeding value and inbreeding levels of the population. The data set used for analysis consisted of5513, 3223 and 3223 recordsfor BWT, AWWT, and PADO respectively and 1008,1029,1250 and 1359 records for AFC, DO, OL and Cl respectively. Result offixed effect analysis revealed that all the fixed effects analyzed show a significant (p<0. 001) effect and cause variation in birth weight (BWT) and adjusted weaning weight (AWWT). Sex had no significant effect for pre weaning average daily gain (PADO) and for all reproductive traits. For age at first calving (AFC) only year has shown a significant (p<0.001) effect. Results of the analysis on non-genetic factors on growth and reproductive performance suggest that presence of inconsistency in management activity of the ranch. Four models (Modell (Y= Xb + Zia + e); Model2 (Y= Xb + Zia + Z3C+ e); Model3 (Y= Xb + Zia + Z2m + e; cov a,m = 0) and Model4 (Y= Xb + Zia + Z2m + Z3C + e; cov a,m = 0) were used to estimate genetic parameters and model 4 was the best model for all traits. Heritability value and additive variance for all traits were low. Estimates of direct heritability of growth performance traits from the best model ranged from 0.03 ± 0.02 for BWT to 0.06 ± 0.03 for A WWT and for reproductive traits ranged from 0.00 ± 0.03 for OL and Cl to 0.013 ± 0.03 for DO. The error variance (the variation due to temporary environment) was VI high for both growth and reproductive traits. The estimates confirmed the presence of high environmental effect among the study population. Given the low heritability estimates obtained, effective improvement in growth and reproduction performance of Fogera cattle could be achieved by improving the production conditions and through crossbreeding. The phenotypic correlation between growth ranged from -0.10 ± 0.02 for BWT and PADG to 0.99 ± O.Olfor AWWT and PADG and between reproductive traits rangedfrom 0.003 ± 0.034 for Cl and GL to 0.321 ± 0.041 for Cl and DO. Genetic correlation between growth traits were rangedfrom 0.5 ± 0.27 for BWT and PADG to 0.99 ± O.OOforA WWT and PADG, between growth and AFC ranged from 0.77 ± 0.24 for BWT and AFC to 0.87 ± 0.03 for PADG and AFC and between reproductive traits ranged from -0.94 ± 0.2 for DO and GL to 0.83 ± 0.579 for Cl and DO. The phenotypic and genetic correlation between BWT and GL were 0.026 ± 0.05 and -0.84 ± 0.013. The result of genetic correlation between considered traits were ranged from moderate to high and it indicates that selection for one trait would have a significant effect on the other traits not considered however selection must be done with caution. Estimated overall mean breeding values for BWT, AWWT and PADG were 0.046 ± 0.23 kg, 0.26 ± 2.4 kg and 0.0002 ± 0.009kg, respectively. The estimated inbreeding value (0.11%) was lower than the critical level (0.5%) and only 60 animals were found inbred. The trends of sire breeding values for all growth traits were negative. The hypothesis that selection based on phenotypic performance of animals will bring genetic progress in the herd was rejected and it is concluded that selection based on physical appraisal did not bring genetic progress. The selection method should be updated and must be based on genetic evaluation of individual animals. | en_US |
| dc.language.iso | en | en_US |
| dc.subject | ANIMAL GENETICS and BREEDING | en_US |
| dc.title | GENETIC PARAMETER ESTIMATION OF GROWTH AND REPRODUCTION TRAITS OF FOGERA CATTLE AT METEKEL RANCH, AMHARA REGION, ETHIOPIA | en_US |
| dc.type | Thesis | en_US |
