The Effect of Dams of Sire Path Management on Genetic and Economic Parameters in a Simulated Genomic Selection Program

محورهای موضوعی : Camel

س. عزیزیان ¹ , ع.ا. شادپرور ² , س. جوئزی-شکالگورابی ³ , ن. قوی حسین-زاده ⁴

1 - Department of Animal Science, Faculty of Agricultural Science, University of Guilan, Rasht, Iran
2 - Department of Animal Science, Faculty of Agricultural Science, University of Guilan, Rasht, Iran
3 - Department of Animal Science, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran
4 - Department of Animal Science, Faculty of Agricultural Science, University of Guilan, Rasht, Iran

تاریخ دریافت : 1393/12/04 تاریخ پذیرش : 1394/08/09 تاریخ انتشار : 1395/03/12

کلید واژه: Economic, genetic, Efficiency, Holstein, genomic selection,

چکیده مقاله :

A deterministic model based on the gene flow method, considering the features of Iranian Holstein cattle population, was implemented in this study to evaluate the effect of altering the number of age-classes in the dams of future sire (DS) path and the number of dams required for breeding a young bull (YB), to be evaluated as future sire, on genetic gain and resultant economic efficiency of a genomic selection program for milk production as a selection goal. Based on the simulation, changing the number of age-classes from 10 to 1 resulted in higher replacement rate of DS path (from 0.22 to 1) and shorter generation interval. Consequently, the economic efficiency of the program increased up to a maximum point and then a descending trend was observed. The maximum economic efficiency (25.68) was obtained when 7 age-classes in DS path was assumed. By chaining the number of dams required for breeding a YB from 7 to 1, the genetic gain in selection goal increased from 0.0232 to 0.0264 kg per dairy cattle and therefore, the economic efficiency rose from 25.42 to 28.52. The results revealed that a decrease in generation interval does not necessarily result in maximum economic efficiency and there is an optimum level for generation interval. Less number of required dams per YB could result in higher economic efficiency and therefore should be considered as an effective management strategy to improve the economic efficiency of a genomic selection program for milk production.

چکیده انگلیسی:

در این تحقیق یک مدل قطعی مبتنی بر جریان ژن با در نظر گرفتن مشخصات جمعیت گاو هلشتین ایران اجرا شد تا اثر تغییر تعداد گروه سنی مسیر مادران پدر آینده (DS) و تعداد ماده مورد نیاز برای تولید یک گاو نر جوان (YB) که قرار است به عنوان پدر آینده ارزیابی شود، بر رشد ژنتیکی و کارآیی اقتصادی حاصل از یک برنامه انتخاب ژنومی برای تولید شیر به عنوان یک هدف انتخاب بررسی شود. بر اساس شبیه سازی، تغییر تعداد گروه سنی از 10 به 1 منتج شد به نرخ جایگزینی بالاتر (از 22/0 به 1) و فاصله نسل کوتاهتر برای مسیر DS. متعاقب آن، کارآیی اقتصادی برنامه تا رسیدن به یک ماکزیمم افزایش یافت و پس از آن یک روند نزولی مشاهد گشت. حداکثر کارآیی اقتصادی (68/25) هنگامی حاصل شد که تعداد گروه سنی مسیر DS 7 فرض شد. با تغییر تعداد مادر مورد نیاز برای ایجاد یک YB از 7 به 1، رشد ژنتیکی در هدف انتخاب از 0232/0 به 0264/0 کیلوگرم به ازای هر رأس گاو شیری و در نتیجه کارآیی اقتصادی از 42/25 به 52/28 افزایش یافت. نتایج آشکار ساخت که کاهش فاصله نسل لزوما منتج به حداکثر کارآیی اقتصادی نشده و یک حد بهینه برای فاصله نسل وجود دارد. تعداد کمتر مورد نیاز به ازای هر YB می‪تواند به کارآیی اقتصادی بیشتر منجر شود و لذا به عنوان یک راهبرد مدیریتی مؤثر برای بهبود کارآیی اقتصادی برنامه انتخاب ژنومی برای تولید شیر باید مد نظر قرار بگیرد.

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