عنوان مقاله [English]
Introduction The aims of interbreeding for the first level in planning interbreeding programs are generally maximize the improvement in the economical efficiency of the production system by means of increase the average of characteristics. The purpose of this research was to estimate the economic values for milk production traits, fat percentage, protein percentage, and lifetime of native cows of Ilam province and also consideration of their sensitivity to any change in productive and economical parameters in the production system.
Materials and methods Using a deterministic bio-economical model and economic and production parameters of Native cow, was estimated economic values of milk yield, fat percentage, protein percentage, herd life at the Ilam province in 2013. The economic values of each trait was estimated with increase of one unit of average traits used for the amount of annual profit change, so that were constant the other traits. Calculation of Revenues and Costs: Estimation of economical factors needs explanation of production system, revenue and costs sources and their relationship with existing characteristics for the aim of interbreeding. Costs are expressed as fixed and current. Current costs are depending on the level of cattle production. Fixed costs are independent of production level and including building and installations, machinery and so on.to calculate the nutritional costs for each age group of animals, four different levels according to the life style were defined by order. These levels include: from birth to weaning (bull calf and heifer before weaning),from weaning to selling age (bull calves in 8-months year old and heifers in 17 months of age, from selling age till the age of first delivery (for replaced heifers)and regenerator cows(over two years old). According to the definition, economical factor of each characteristic is described as a change in the net profit of factory for a unit of addition in the average considered characteristic in a way that the average of other characteristics in the population doesn’t change. In this research to calculate the economical factors of characteristics while other characteristics are in between in the population, the average for the considered characteristic was increased once by one unit and the difference of earned and profit or base mode was considered as the economical factor of that characteristic.
Results and Discussion In the system of Native cows production, the economic values of milk yield, fat percentage, protein percentage, herd life were estimated 0.002079, 0.999782, 1 and - 0.000351 respectively. In the native cow's fostering system, revenue resources include annual sale of milk, bull calf, surplus heifer, annual, omitted regenerator cow and annual manure. Earned revenue out of annual milk sale equaled 43.54% of the total revenue which appropriated the greatest amount of revenue resources. Other revenue resources were including bull calf, surplus heifer and the sale of omitted cow that appropriated 11.23%, 32.37%, 10.04% and 2.81% of the revenues respectively. The costs were divided into two parts including annual fixed charge which contained the cost of building, installations, equipment and repairs. Annual current cost which contained nutritional costs, hygiene and reproduction, work force, cattle selling and transportation of manure from its place per each head of regenerator cow. Fixed annual cost per each head of regenerator cow equaled 4572556.56 Rial, which contained 14.44 percentage of the total costs .annual current cost per each head of regenerator cow equaled 27094514.46 Rials which appropriated85.56 percentage of the total cost. Among the current costs ,nutritional cost by 84.25% appropriated the most part .other current costs including workforce ,cattle sale and manure transportation from its place equaled 9.38% and costs of hygiene and reproduction appropriated 6.36% of the current costs.
Conclusion Thus estimated the annual avenue of production system for Native cows -1801718.005 Rials. The results showed that positive amount of an economical factor to produce milk; selection of an average for an increase in the characteristic causes an increase in profiting in native cow's production system. According to the importance of interval in calving as a characteristic and specifically its influence in the situation of limitation in systems, it is suggested that interbreeding should be done to decrease it.