Inbreeding and Inbreeding Depression on Body Weight in Iranian Shal Sheep

محورهای موضوعی : Camel

ز. پتی‌آبادی ¹ ( Department of Animal Science, Faculty of Agriculture, Razi University, Kermanshah, Iran )
ش. ورکوهی ² ( Department of Animal Science, Faculty of Agriculture, Razi University, Kermanshah, Iran )
س. ساور-سفلی ³ ( Animal Science Research Institute of Iran, Agricultural Research, Education and ExtensionOrganization (AREEO), Karaj, Iran )

تاریخ دریافت : 1378/09/09 تاریخ پذیرش : 1378/09/09 تاریخ انتشار : 1378/09/09

کلید واژه: growth traits, inbreeding depression, inbred population, regression coeffi-cients,

چکیده مقاله :

The aim of this study was to estimate amount of inbreeding coefficient in Shal sheep and its impact on growth performance. Pedigree information and body weight at different ages (birth weight, 3 month weight, 6 month weight, 9 month weight and 12 month weight) were used from 6692 lambs from 90 rams and 1007 ewes. Data were collected on Ghazvin sheep breeding station during 1997-2013. Estimation of inbreeding coefficient was done by CFC program and quantifying the individual inbreeding regression of traits was run by wombat software. Number of inbred animals at pedigree was 1616 lambs, equal to 24.15% of total population. The average of inbreeding coefficient on whole population and inbred population were 1.51% and 6.28%, respectively. Regression coefficients per 1% inbreeding for birth weight, 3 month weight, 6 month weight, 9 month weight and 12 months weight were estimated as -0.001, -0.017, -0.005, -0.019 and -0.019 kg, respectively. The highest inbreeding coefficient was 31.25% and most of inbred animals had inbreeding coefficients lower than 5%. These results confirmed the low level of inbreeding in the population. Annual trend of inbreeding coefficient on population average was 0.07 and non significant statistically. Applying a designed mating system like cross-breeding could be a suitable method to avoid inbreeding depression.

چکیده انگلیسی:

هدف از انجام این مطالعه برآورد مقدار همخونی و اثر آن بر عملکرد صفات رشد، در گوسفندان شال بود. برای انجام این پژوهش از اطلاعات شجره و وزن بدن در سنین مختلف (وزن تولد، 3 ماهگی، 6 ماهگی، 9 ماهگی و 12 ماهگی) 6692 رأس بره حاصل از 90 رأس قوچ و 1007 رأس میش که طی سالهای 1376 تا 1392 در ایستگاه پرورش و اصلاح نژاد گوسفند قزوین جمع­آوری شده بود، استفاده شد. برای برآورد ضریب همخونی از برنامه  CFCو برای محاسبه میزان تابعیت صفات از همخونی، از نرم افزار WOMBAT استفاده گردید. تعداد حیوانات همخون موجود در شجره 1616 رأس (15/24 درصد گله) بود. میانگین ضریب همخونی کل جمعیت و جمعیت همخون به ترتیب برابر 51/1 و 28/6 درصد برآورد گردید. مقدار تغییر در صفات به دلیل همخونی برای اوزان تولد، 3 ماهگی، 6 ماهگی، 9 ماهگی و 12 ماهگی به ترتیب برابر 001/0-، 017/0-، 005/0-، 019/0- و 019/0- کیلوگرم محاسبه شد. بیشترین مقدار همخونی 25/31 درصد و بیشترین حیوانات همخون را حیوانات با ضریب همخونی صفر تا 5 درصد تشکیل دادند که این نتایج، در حال حاضر میزان پایین همخونی در این گله را تأیید می­کند. روند تغییرات سالیانه ضریب همخونی 07/0 درصد و به لحاظ آماری غیر معنی­دار بود. بنابراین با مدیریت همخونی به صورت افزایش آمیزش­های دور در گله و استفاده از آمیزش نرهای مولد برتر در گله به صورت کنترل شده، می­توان از اثرات زیان­آور احتمالی، ناشی از افزایش بیش از حد همخونی جلوگیری نمود.

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