Saber Jelokhani-niaraki; Sholeh Ghorbani; Saeid Esmaeilkhanian
Volume 23, Issue 3 , September 2021, , Pages 313-324
Abstract
Monitoring the inbreeding rate of native chickens in breeding stations is of significant importance because of planned matings and lack of gene flow in the population. This study was undertaken to estimate the inbreeding coefficient, investigate the trend of inbreeding changes and evaluate the effects ...
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Monitoring the inbreeding rate of native chickens in breeding stations is of significant importance because of planned matings and lack of gene flow in the population. This study was undertaken to estimate the inbreeding coefficient, investigate the trend of inbreeding changes and evaluate the effects of inbreeding depression on the economic traits in Isfahan improved native chicken population. The studied traits were body weight, age at sexual maturity, weight at sexual maturity, egg number, mean egg weight and egg weight at first day. In the present study, data of 97272 birds recorded during 21 generations were included. In order to estimate the inbreeding coefficient of each bird and the effect of inbreeding on the traits, CFC and WOMBAT software were used, respectively. Pedigree analysis indicated that 79.48 percent of population were inbred. The estimated average individual and maternal inbreeding coefficients were 4.3 and 3.5 percent, respectively. According to results, for every one percent increase in inbreeding, rate of inbreeding depression for the traits including the body weight in 1 day, 8 weeks and 12 weeks, age at sexual maturity, weight at sexual maturity, egg number, average weight of eggs and egg weight at first day was -0.008, -2.52, -3.51, 0.23, -3/97, -0.13, 0/02 and 0.06, respectively. Based on the results of the present study, although in closed populations under genetic selection, the absence of inbred bird is almost impossible, but, the reduction of inbreeding can be achieved by controlling the matings, which prevents the adverse effects of inbreeding in the population.
Mokhtar Ali Abbasi; Sima Savar Sofla
Volume 17, Issue 1 , April 2015, , Pages 1-8
Abstract
This study was evaluated some strategies and determined the suitable selection index for Afshari sheep using simulated data. The relative importance of traits was determined based on the estimated economic values and consequently, the most benefit traits were applied to selection indexes construction. ...
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This study was evaluated some strategies and determined the suitable selection index for Afshari sheep using simulated data. The relative importance of traits was determined based on the estimated economic values and consequently, the most benefit traits were applied to selection indexes construction. The interest indexes were different combination of traits including ewe body weight (EBW), annual wools weight (AWW) and total weaning weight for each exposed ewe (TWWEE). The index 1 was included all three mentioned traits. The indexes two, three and four were included (AWW, TWWEE), (EBW, TWWEE) and (TWWEE), respectively. The results indicated that the aggregate genotype, selection index and economic progress increased by increasing in the population size and decreasing in ram ratio, but made reduction in inbreeding average, in all indexes. In more cases, the aggregate genotype decreased by removing a trait in the index. The comparisons among indexes indicated that the most suitable selection index for this breed is index 1 which included EBW, AWW and TWWEE. This index had a maximum selection index average, aggregate genotype and economic progress.
Ghasem Motaghinia; Homayoun Farhangfar; Mohsen Ahmadi Shahrakht; Abdolahad Shadparvar; Majid Jafari
Volume 16, Issue 1 , May 2014, , Pages 1-9
Abstract
Effects of lamb and parents coefficient of inbreeding (CI) on wool weight were studied using 10,868 wool records belonging to 3,244 Iran Black lambs (1,633 males and 1,611 females) representing 96 rams and 995 ewes collected during 1983-2006 from Animal Breeding Station of Abbas Abad. Year and month ...
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Effects of lamb and parents coefficient of inbreeding (CI) on wool weight were studied using 10,868 wool records belonging to 3,244 Iran Black lambs (1,633 males and 1,611 females) representing 96 rams and 995 ewes collected during 1983-2006 from Animal Breeding Station of Abbas Abad. Year and month of shearing, CI of lamb and dam, sex and birth type had significant affect on wool weight Among 3,244 pedigree animals, 3,005 heads (92.6 percent) were found to be inbred. Mean and standard deviation of CI of lamb, sire and dam in whole population were 8.1±6.1, 6.5±6.1 and 5.3±5.8 percent, respectively. The corresponding figures in inbred population were 9.0±5.7, 7.0±6.1 and 5.7±5.8 percent, respectively. Minimum and maximum CI of lamb was 0 and 36.4 percent, respectively. Increase of CI by one percent was accompanied with a decrease of 26.9 g (quadruplet male), 4.8 g (twin female), 4.3 g (triple female) and 13.1 g (quadruplet female) in wool weight. A decrease of 1.4 g in wool weight of lamb was observed as the CI of dam was increased by one percent. Statistically significant annual change trend were estimated to be 0.2±0.02 percent and 0.1±0.02 percent for whole and inbred populations, respectively. A controlled mating is needed to reduce deleterious effects of inbreeding.