نوع مقاله : علمی پژوهشی- ژنتیک و اصلاح دام و طیور
1 گروه علوم دامی، دانشکده کشاورزی و منابع طبیعی، دانشگاه محقـق اردبیلی، اردبیل، ایران.
2 محقق اردبیلی
عنوان مقاله [English]
Introduction Improving animal performance should be sustainable and economically profitable, therefore economic selection indices have been used in most breeding programmes for livestock. For this purpose, economic weighting factors have to be estimated for all traits in the breeding objective.The best way to maximize profitability through genetic improvement is to use economic weights of the trait Involved. In this study, to estimate the economic values of production and reproduction traits, Costs, revenues and profit analysis in nomadic systems, determine the breeding objective for Moghani sheep. The human population is growing fast which it seems that in spite of the recent progresses in new issues and technologies, they are not enough to fulfill feed requirements of humankind. Planning a suitable breeding system would be an important practical method in using the production potential of local sheep flocks. Therefore, it is essential to estimate economic values of production traits in a one or multivariate selection scheme to evaluate the priority in-comes and costs of a breeding system. A bio-economic model was used to describe performance, revenues and costs and to calculate the economic values, economic values are determined from these models by simulating changes in the genetic level of a trait and noting the associated changes in overall economic outcome. As a first step in developing such a programme a suitable breeding goal for the cattle population has to be defined, giving emphasis to production as well as to functional traits in order to achieve a more sustainable production. For a sustainable production, traits that have been identified as important for selection are also functional traits. The economic value of a trait is defined as the increase in profit resulting from a unit genetic improvement in that trait, while all other traits in the breeding objective are kept constant in simple terms economic values are defined as the effect on the efficiency of production of a marginal unit increase in a trait, independent of changes in other traits. Economic efficiency of the production system was calculated as the difference between total revenues and total costs per cow and year at the stationary herd structure.
Materials and Methods In this study, production, reproduction, management and economic parameters resulted from recording of 5 flocks with 500 head of breeding ewes during annual cycle of production (August 2015 to August 2016) in extensive rearing system were used to determine the breeding objective and relative economic values.Traits included; fertility, pregnancy rate, weight lambs from birth to the end of period, survival rate of lambs, wool production weight, average daily gain and milk production. A bioeconomic model was written for rearing system and flock information, economic values using maximum profit orientation was calculated by partial derivative of the profit function by the MATLAB software. To calculate economic values, change in system profit per unit change in the trait while was kept the other characters in the average, and was considered the average change in profit as an economic value. To calculate the relative economic values, the absolute economic value of each trait divided by the absolute economic value of weight of wool.First all costs, revenues, profits and flock structure determined then intered input files and run the software.
Results and Discussion Economic analysis of system indicated that, costs, revenue, and profit per ewe per year were 9437617.88, 10637654.49, and 1200036.61 Rials, respectively.The results showed that live weight, milk yield, manure and wool yield accounted for 86.36 %, 9.64 %, 2.85 and 1.15% of total revenue, respectively. Feeding and management costs (variable costs) represented 73.65% and 26.35 % of total cost, respectively. The relative economic values for Carcass yield, Lamb live weight at 12-month , ewe survival, Post-weaning lamb survival, Pre-weaning lamb survival, Lamb live weight at 4-month, birth weight, conception rates ewes, , little size, Lambing frequency per year, Average daily gain yearlings, Wool weight, Milk yield of ewe, Average daily gain lambs, Replacement female weight, Adult weight of ewes were7.30,4.27, 3.08,2.85,2.44,2.35,2.01,1.85,1.54, 1.42, 1.05,1, 0.55, 0.34,- 0.06, and ( -1.81) respectively.
Conclusion Breeding objective in Moghani sheep breed were Carcass yield, Lamb live weight at 12-month, ewe survival, Post-weaning lamb survival, Pre-weaning lamb survival, Lamb live weight at 4-month, birth weight, conception rates ewes, little size, Lambing frequency per year, Average daily gain yearlings, wool weight, Milk yield of ewe, Average daily gain lambs, Replacement female weight and Adult weight of ewes respectively.
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