جستجوی مقالات مرتبط با کلیدواژه « ارزش اقتصادی » در نشریات گروه « علوم دام »

The first step in designing livestock breeding programs is to decide on appropriate breeding objectives. The most significant factor in the inefficiency of livestock breeding programs is the undesired breeding goals, which causes the selection pressure to be applied to the wrong traits. The production system, market conditions, and flock competence cause the breeding goals to be different from each other. This research was conducted to investigate the production system and cost-benefit analysis of Kurdi sheep flocks in the mountainous regions of Kurdistan province under the conditions of village breeding, as well as estimate the economic values and relative importance of traits and determine the breeding goals of this breed.
In an entire production period, seven flocks of Kurdi sheep of the mountain type were covered and investigated to collect detailed information about the breeding system. The parameters required for analysis in the used model include flock structure, production variables, management variables, feed consumption variables, management costs, marketing costs, fixed costs, and prices gathered directly from the covered flocks, market, and scientific sources. The collected data were used to estimate the economic values, economic weights, and relative importance of the traits and determine the breeding goals. In this study, the economic value of traits was calculated using a deterministic static model, and the total annual profit of the flock was calculated by deducting the costs from the system's revenues under survey. The economic values of each trait were defined as a change in the profit obtained per one-unit increase in the desired trait while keeping other traits constant at the population average. The economic weights of traits were also calculated by multiplying the economic value of each trait by the genetic standard deviation of that trait. After determining the relative importance of the traits, the traits present in the breeding goals were determined in order.
The study of the dynamics of Kurdi sheep flocks, and their reproduction and survival characteristics in the conditions of rural farming showed that the survival rate of ewes, pregnancy rate, frequency of lambing, and litter size were 97%, 84%, 20%, and 1.08, respectively, and the rates of lamb survival until weaning and after that were 85% and 96%, respectively. In this way, the number of weaned and salable lambs per head of breeding ewe were 0.90 and 0.54, respectively. The cost-benefit analysis of sheep flocks showed that the costs of feeding, labor, veterinary services, fixed, transportation of animal feed, and marketing were 55.7%, 21.5%, 15.6%, 4.7%, 1.8%, and 0.7% of the total costs, respectively. Meat was the first with 99.5%, and wool with 0.5% was the second source of flocks’ income. The profit from each head of breeding ewe per year was 11313953 Rials, and the ratio of income to cost and the ratio of cost to income were 1.38 and 0.73, respectively. The absolute economic values were positive for all investigated traits except for the live weight traits of the replacements, and the culled mature ewes. Calculation of economic weight and relative importance of traits showed that reproductive traits, survival traits, and productive traits were important, respectively. The traits of pregnancy rate and litter size were the most important, and the live weight of replacements and wool production were the least important in increasing profitability or reducing costs.
The efficiency of each head of breeding ewe compared to costs was calculated as 38%, which has increased by about 3% compared to the last four years. These figures showed that the profit from each head of breeding ewe is noticeable, and the policy of freeing the price of livestock inputs in recent years has not had a significant effect on the profitability of Kurdi sheep breeding in rural conditions. Of course, the number of salable lambs per head of breeding ewe as the net reproduction efficiency in this study was low, and with its improvement, the economic efficiency will also be better.  By examining each trait, it was determined that the breeding goals of this breed, in order of importance, included pregnancy rate, litter size, lamb survival until weaning, lambing frequency, lamb survival from weaning to sale, lamb live weight at sale, ewe live weight at maturity (with a negative value), ewe survival, replacements’ weight (with a negative value) and wool production. This ranking should be considered in breeding programs. In an entire production period, seven flocks of Kurdi sheep of the mountain type were covered and investigated to collect detailed information about the breeding system. The parameters required for analysis in the used model include flock structure, production variables, management variables, feed consumption variables, management costs, marketing costs, fixed costs, and prices gathered directly from the covered flocks, market, and scientific sources. The collected data were used to estimate the economic values, economic weights, and relative importance of the traits and determine the breeding goals. In this study, the economic value of traits was calculated using a deterministic static model, and the total annual profit of the flock was calculated by deducting the costs from the system's revenues under survey. The economic values of each trait were defined as a change in the profit obtained per one-unit increase in the desired trait while keeping other traits constant at the population average. The economic weights of traits were also calculated by multiplying the economic value of each trait by the genetic standard deviation of that trait. After determining the relative importance of the traits, the traits present in the breeding goals were determined in order. The study of the dynamics of Kurdi sheep flocks, and their reproduction and survival characteristics in the conditions of rural farming showed that the survival rate of ewes, pregnancy rate, frequency of lambing, and litter size were (97%), (84%), (20%), and (1.08), respectively, and the rate of Lamb survival until weaning and after that were (85%) and (96%), respectively. In this way, the number of weaned and salable lambs per head of breeding ewe were (0.90) and (0.54), respectively. The cost-benefit analysis of sheep flocks showed that the costs of feeding, labour, veterinary services, fixed, transportation of animal feed, and marketing were (55.7%), (21.5%), (15.6%), (4.7%), (1.8%), and (0.7%) of the total costs, respectively. The meat was the first, with (99.5%), and produced wool, with (0.5%), was the second source of flocks’ income. The profit from each head of breeding ewe per year was (11313953) Rials, and the ratio of income to cost and the ratio of cost to income were (1.38) and (0.73), respectively. The absolute economic values were positive for all investigated traits except for the live weight traits of the replacements, and the culled mature ewes. Calculation of economic weight and relative importance of traits showed that reproductive traits, survival traits, and productive traits were important, respectively. The traits of pregnancy rate and litter size were the most important, and the live weight of replacements and wool production were the least important in increasing profitability or reducing costs. The efficiency of each head of breeding ewe compared to costs was calculated as (38%), which has increased by about (3%) compared to the last four years. These figures show that the profit from each head of breeding ewe is noticeable, and the policy of freeing the price of livestock inputs in recent years has not had a significant effect on the profitability of Kurdi sheep breeding in rural conditions. Of course, the number of salable lambs per head of breeding ewe as the net reproduction efficiency in this study was low, and with its improvement, the economic efficiency will also be better. By examining each trait, it was determined that the breeding goals of this breed, in order of importance, include pregnancy rate, litter size, lamb survival until weaning, lambing frequency, lamb survival from weaning to sale, lamb live weight at sale, ewe maturity live weight (with a negative value), ewe survival, replacements weight (with a negative value) and wool production. This ranking should be considered in breeding acts and programs.

In order to optimally use the inputs, the efficiency of economic units is of great importance. The purpose of this study is to investigate the technical efficiency and economic value of some traits of production, reproduction, survival and growth of Holstein cows in Pars agro-industry. For this purpose, required information including: manpower, cattle population, feed consumption and milk production quantities were collected from Pars Livestock Unit by documentary study, observation and face-to-face interview and their efficiency was calculated based on production and economic performance. The variables used in the research include herd size in terms of head, feed and concentrate in terms of weight, manpower in terms of men per day, health in terms of number of days per day, milk production and production of manure in terms of kilograms and incomes in Rials, which include Income from milk sales, Rial value of livestock manure produced, income from sales of voluntary and forced elimination of livestock, income from sales of bulls and heifers in dairy farms were examined. Deap 2.1 software was used for performance calculations. Optimal decision was calculated numerically by a iterative method using compecon toolbox in MATLAB program. Probability of pregnancy in the first, second, third and higher lactation periods based on data analysis and using logistic regression and GenMod procedure of SAS software Obtained, the results showed that the average of technical efficiency with constant efficiency compared to the scale was 0.83; the average efficiency with variable efficiency compared to the scale was 0.86 The scale efficiency of this company was estimated to be 0.96. The amount of technical efficiency in general was 0.83, allocation efficiency was 0.87 and economic efficiency was 0.72. This unit was efficient in March in terms of types of efficiency, which means that during this month, in addition to consuming a certain amount of product produced with a minimum of inputs, the minimum costs are also considered in the composition of inputs, so the unit in this month was technically, allocative, economically and economically efficient and has a constant return on scale. Also, the highest economic value in non-optimal conditions in survival, reproductive, productive and growth traits, and also for survival rate after weaning, first calving age, milk fat and body weight of adult animals was equal to 234297.30, -41835.16, 128664.12 and 454227.93 Rials, respectively. In optimal conditions, the highest economic value for survival, reproduction, production and growth traits was related to the set of traits of production lifespan, and the calving interval, milk fatproduction and daily weight gain before weaning were estimated at 4594.88,9084.67, 1582264.09 and -1464.87 Rials, respectively. The reason for the difference in economic values of traits in optimal conditions compared to non-optimal conditions is due to the application of optimal livestock replacement strategy, so that the farmer's policy in eliminating and replacing, affect herd profit.

In this study, production, population and economic parameters of 30 buffalo herds of Khuzestan province in two sale conditions during 2016-2017 were used to estimate the economic value for production, reproductive and survival traits. Economic value of the traits were estimated by one unit increase for each trait using the maximum profit trend. The average annual revenue, cost and profit per head of buffalo for milk and local cream condition were 60480817, 59270944 and 1209873 Rials, respectively, and for just milk sale condition were 59220881, 59270944, and -50062.7 Rials, respectively. In the milk and local cream sale condition, as a proper sale, the economic value of production traits including milk yield, fat percentage, fattening male calf weight and weaning weight were 16774, 178011, 16051 and -46070 Rials, respectively, the economic value of reproductive traits including conception rate, live birth rate, calving interval, buffalo heifer weight and age at first calving were 476142, 527296, 9504, -36668 and -76743 Rials, respectively, and the economic value of survival traits including survival rate of buffalo cow, survival rate of calf from birth to 4 months of age, survival rate of buffalo heifer from 4 months to parturition and longevity were 364946, 216406, 143588 and 72030 Rials, respectively, per head of buffalo in a year. According to the results, selection for increasing the average milk yield, fat percentage and fattening male calf weight would improve the economic condition of buffalo breeder. Considering the negative economic value of calving interval and the age at first calving, breeding in order to shorten them can increase the economic efficiency of the herd. Also, due to the superiority of milk and local cream sale condition compared to milk sale as well as taking into account that due to the lower milk production in buffalo raw milk selling was unprofitable, dairy products selling along with milk can be regarded to improve the economic efficiency.

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.
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.
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.
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.

The best way to maximize the profitability through breeding is using economical coefficients of characteristics with genetic assessment. One of the effective ways to increase profitability in animal husbandry is using livestock breeding. It is not possible to utilize breeding optimized method without considering relative importance of characteristics economically. On the other hand, the best way to determine the relative importance of characteristics is to calculate the economic coefficients. Economic Value of characteristic is the profit obtained from one unit genetic improvement of the average of a characteristic when other characteristics are held in their constant values. Bio-economic model is a set of equations which define the incomes and costs of the production system as a function of different characteristics. Simulation is a process in which a set of examinations are carried out by using a designed method on the basis of a real system in order to find out the system behavior and various approaches are assessed for its operation in a defined range.
The aim of the present study is to estimate the economic value of production and reproduction characteristics of dairy cows of Mohan cultivation, industry and animal husbandry based on collected data from 13000 dairy cows and market conditions in 2014 and by using a determined bio-economic model. The income factor included obtained incomes from milk sale, additional heifer sale, male calf, removed cows and fertilizer sale and the costs included nutrition, management and capital costs. The management costs included health and care, human forces and reproduction. Five different stages defined in animal life cycle. These stages including from birth to weaning, from weaning to the age calf sale (12th month), from weaning to the first insemination of female calf (18th month), from first insemination to first birth (alternative heifers) and productive cows more than two years old. The calculation of cost and revenue of the heifer per 18 months is carried out. The breeding period of calf, young cow and productive cow considered 12 months. In these herds, nutrition was done completely manually and in the place. Nutrition cost was calculated using energy requirements estimation equations AFRC (1991) by considering the consumed concentrate constant for productive cows, growing male and female calf and alternative heifers separately. In this system, artificial insemination is used for cows impregnate and reproduction cost considered as a function of interval of two births which indicates the number of insemination which resulted in impregnation. Health program included vaccination, deparasitation and quarantine. Male calf was sold based on each kilogram weight per each calf at a constant price. In present study, dairy cows in production system were categorized in seven different age groups of 2, 3, 4, 5, 6, 7, 8 and then revenues, costs, final profit and economic value of characteristics calculated for every age group separately. The studied characteristics include milk production, fat milk production, age of the first birth, calf birth interval, increasing daily weight before and after weaning, birth weight, matured calf weight and live rate before and after weaning. The bio-economic model designed based on breeding and information system of herd and economic coefficients calculated by matlab software. Economic value of each characteristic estimated based on the changes in annual profit of production system per one unit increase in the average of the considered characteristic while other characteristics are kept constant. First, all of the revenues and costs and profit and herd combination determined and the input files saved and the program ran.
Annual revenues and costs calculated based on different age groups and the annual profit was 15966572/69 Rials for each productive cow. Among revenue resources, 71% was for milk sale and its components, 10% for removed cow sale, 11% for male calf sale, 6% for additional heifer sale and 2% for fertilizer sale. Among variable costs 68% was for nutrition costs, 17% for work force cost and livestock sale and 10% for health and reproduction costs. Economic values of production and reproduction characteristics including milk production, milk fat production, age of first birth, calf birth interval, daily weight increase after and before weaning, birth weight, matured calf weight and live rate before and after weaning estimated 4718/59, 144757/8, -30756/52, -86789/17, 1284/45, 34/57, 9894/16, -1900/13, 5808 and 107521/9 Rials per each cow respectively. The highest relative importance related to production characteristics (54/37%) and after that reproduction (21.98%), durability (20/56%) and the least amount estimated for growth (3/07%). Characteristics can be divided into several groups based on the impact on revenues and costs. Economic values of production and reproduction characteristics including milk production, milk fat production, age of first birth, calf birth interval, daily weight increase after and before weaning, birth weight, matured calf weight and live rate before and after weaning estimated 4718/59, 144757/8, -30756/52, -86789/17, 1284/45, 34/57, 9894/16, -1900/13, 5808 and 107521/9 Rials per each cow respectively. The highest relative importance related to production characteristics (54/37%) and after that reproduction (21.98%), durability (20/56%) and the least amount estimated for growth (3/07%). Characteristics can be divided into several groups based on the impact on revenues and costs. A group of characteristics increase the revenue and cost of production system and also increase the profit compared with the initial state (initial value). Most of the production characteristics such as milk production, fat, increase of weight before and after weaning, birth weight and live rate before and after weaning are placed in these groups. However, by increasing one unit of matured cow weight, the revenue and costs are increased and but the obtained profit is decreased. Characteristics of the second group do not impact the revenue but the costs of production system increased by increasing its average which include the age of the first birth. The third group includes the characteristic of interval between two births and the revenue decreased, system costs increased and profit decreased by increasing its average.
Increase in the average unit production and reproduction traits have different effects on revenue, cost and profitability of production systems.

It has been estimated that feed is the major cost associated with commercial poultry production. Hence, inclusion of non-conventional feed resource becomes of primary importance in livestock production to maintain the productivity at a lower cost. Date palm fruit is one of the most important products of Middle East countries and its byproduct can help to lowering the feed cost in livestock nutrition.
There are a few studies about use of date palm byproduct in poultry nutrition and especially in laying hens diets, therefore, in this study, we considered the effect of different levels of date waste powder on laying hens performance.
Two independent experiments were conducted to determine the nutritional value of date waste powder (DWP) and its effects on performance and egg qualitative traits of laying hens. In the first experiment, AOAC method was used for determination of proximate analysis of DWP. In the second experiment, a total of 144 Hy-Line W-36 leghorn hens (at 46 wk old) were housed in cages and randomly allocated to 6 treatment groups for 6 weeks. Each group was divided in to 4 replicates. Feed and water were provided ad libitum. The hens received basal diet (corn and soy based diet with 15.00 % crude protein and 2820 kcal/ kg ME) that was formulated to meet the Hy-line W36 requirements recommended for nutrients. The diet did not have any antibiotics and coccidiostats. Treatments were included 0, 5, 10, 15, 20 and 25 percentage of date waste powder by expense of corn in basal diet. Experiment was designed in a completely randomized design. Egg weight (gr), egg production (%) and egg mass (gr/hen/day) were recorded daily. Feed consumption was measured weekly and feed conversion ratio (FCR) (grams of feed: grams of egg mass) was calculated weekly too. At the end of weeks 2, 4 and 6 of the experiment, two eggs from each replicate were randomly selected for measurement the egg qualitative traits.
The results of these experiments showed that gross energy (GE), crude protein (CP), ether extract (EE), crude fiber (CF), calcium and ash of DWP were 4663 (Kcal/Kg), 7.17 (%) 11.45 (%), 30.64 (%), 0.63 (%) and 2.06 (%) of dry matter, respectively. Feed intake, egg weight and feed conversion ratio of the laying hens were not affected by inclusion different levels of dietary DWP. Egg production and egg mass were highest in 25% of DWP inclusion. This result may be related to the high levels of vegetable oil in this diet to maintenance the energy level. Adding vegetable oil to the diet increase the palatability of the diet, reduce dust and improve food texture and consequently increased nutrient utilization. Dietary inclusion of 25% DWP significantly decreased haugh unit of eggs compared to the 5, 10 and 15% inclusion level. Low availability of amino acids in this level may reduce albumen height. Egg yolk color decreased significantly at 10 and 15 % DWP rather than control group and increased in higher levels of DWP. Plant oils contain carotenoids, which can increase yolk color. Therefore, based on the results of this experiment, it could be concluded that inclusion of DWP in 20 and 25% can improve egg production of laying hens, and economically, the cost spent for producing one Kg egg, when using high levels of DWP was comparable with conventional commercial diets.

In this study production, reproduction, management and economic parameters obtained from 7 flocks with 600 head of native sheep were used during annual cycle of production in village systems. The economic values of traits were estimated using maximizing profit, revenue per cost and minimizing cost method. The results showed that the average profit per sheep per year, revenue per cost ratio and cost per revenue ratio for this system were 3,211,391Rials, 1.40 and 0.713, respectively. Feeding and husbandry costs represented about 64% and 20% of total cost, respectively. In maximizing profit method, average economic values (relative) of traits were 7,550.139 (1.102) Rials for survival rate, 7,630.49 (1.1143) Rials for conception rate, 7,172.632 (1.0475) Rials for lambing frequency, 6,520.575 (0.95228) Rials for lambing rate, 7,969 (0.9164) Rials for lamb survival rate to weaning, 8,150.719 (1.1903) Rials for kid survival rate to yearling, 6,847.3565 (1.00) Rials for lamb live weight at sale, -2610 (-1.93) Rials for body weight of sheep. In revenue per cost method the average economic values of aforementioned traits in all systems were 0.677, 0,683, 0.646, 0.592, 0.711, 0.726, 0.566, -0.293 respectively. The sensitivity of economic values to changes in prices of input parameters was low and to changes of prices in output parameters was high. Since the input parameters used in this study were collected from a wide range of management and climates conditions, estimated economic values could be used for designing the appropriate selection index for Kordi sheep.

In this study, production, reproduction, population, management and economic parameters resulted from recording of 12 industrial dairy farms with herd size 20 to 250 and a total of 1240 head of Holstein cows in a cycle of reproduction, during 2010 to 2012 were used to determine the economic values of important traits. The traits of economic importance that appeared in profit equation were durability traits (including survival rate in cow, calf to 3 months of age and heifer from 3 mo to parturition; cow and heifer weight and longevity of cow), health and reproduction traits (including conception rate, live birth rate, calving interval, calving difficulty rate, and age at first calving) and production traits (including calf weaning weight, weight of male fatten calf, milk, fat and protein yield). The economic values and the relative emphasis of traits estimated using maximizing profit by increasing one genetic standard deviation of each trait. The results showed that the sum of relative emphasis of different group of traits for different milk production levels were 38.15 to 36.05 percent for durability traits, 34.80 to 36.59 percent for reproduction and health traits and 27.05 to 27.80 percent for production traits, respectively. The relative emphasis of durability traits and reproduction and health traits decreasing and increasing respectively, with increasing milk production. The estimated relative emphasis of different traits, could be used to construct multiple trait selection indices in dairy cattle breeding programs.

Economic values for production, reproduction, growth and functional traits in crossbred and Holstein cow production systems in Guilan province were estimated using a total of 16 herds consisting in average 12 and 30 cow, respectively, and a bio-economic model. Economic values were calculated in two production systems for 12 traits, classifying into four categories of production, reproduction, growth and survival. Economic value of each trait was estimated as the amount of change in the annual profit of production system by one unit increase in mean of the considered trait while the means of other traits were hold unchanged. Economic values, relative to the economic value for productive lifetime, for milk yield, fat yield, protein yield, age at first calving, calving interval, pre-weaning daily gain, post-weaning daily gain, birth weight, mature live weight, pre-weaning survival rate and post-weaning survival rate were, respectively 3.7, 0.003, -0.01, -7.26, -32.6, -4.35, -23.4, -46.55, -0.78, 4.26 and 68.68 for crossbred production system, and were 0.92, 0.001, -0.002, -6.72, -20.64, -1.10, -6.10, -11.82, 0.21, 30.49 and 25.29, for Holstein production system. The results showed, although the importance of some traits in two production systems were different, which was a reflection of overall difference in two production systems, the breeding objective of two population should be very close together, considering high similarity of economic values of traits

Economic values for milk production, growth, reproduction and functional traits were estimated using a bio-economic model and the information collected on the traditional and industrial rearing systems of dairy cattle. Rearing methods were divided according to management system into four types: pasture, migratory rearing methods and industrial rearing of crossbred and Holestain cows. Economic value of each trait was estimated as the amount of change in the annual profit of systems by one unit increase of mean of the trait while the means of other traits were constant. In traditional rearing methods, the economic values for traits related to growth, survival and milk production traits, except for milk protein, were positive and the economic values for reproductive traits and longevity were negative. In industrial rearing methods, the economic values for milk production, survival rate and productive life, were positive and the economic values for reproductive, growth traits, other than live weight in adult animals in Holstein rearing method, were negative. Results indicated that calf rearing system had the main role in variation of economic values for production and survival traits. On the other hand, the pricing system for surplus heifers is the main factor affecting economic values for growth and longevity traits. The sensitivity analysis of economic values to20% change in prices showed that the price of live weight was the most effective factor on economic values.

The objective of this study was to estimate the economic value of productive and reproductive traits in Holstein dairy cattle in the North West, based on data collected from eight large herds of three provinces (Ardabil, East Azerbaijan and West Azerbaijan) under sub-optimal and optimal manufacturing system based on market conditions in 2011, was based. In this study, economic values for some production and reproductive traits including milk, milk fat, birth weight, mature cow weight, age at first calving and calving interval, were calculated using a deterministic bio-economic model according and the weighted average revenues and costs of different age groups. Economic value of each trait was estimated as the amount of change in the annual profit of production system resulted by one unit increase in the mean of the trait while the means of other traits were hold constant. Economic values for these traits were 7297.86, 85301.68, -126286.29, -11785.38, -80752.14 and -197416.81 Rials, respectively. Production systems for the culling and replacement policies were assumed as optimal herd. Then calculation of the economic value of a trait by one unit increase of mean of the trait of the change of the system was re-optimized. System’s profit in optimal condition before and after the change was calculated from the difference between the obtained economic values. Economic values for some production and reproductive traits including milk, milk fat, birth weight, mature cow weight, age at first calving and calving interval, were 20833.51,147887.78,-53606.09,-5002.665,-34277.73,-6450.21 Rials, respectively. Sub-optimized production systems to estimate the economic value of the biased is therefore better estimate the economic values of the optimized systems.

In this research, economic value for production traits and reproduction traits of Afshari sheep were estimated using a deterministic bio-economic model. In production system of Afshari sheep, the variable costs comprised 99 % of total costs. Revenue sources consisted of meat, milk, wool and manure, where meat with 83.4 % of revenue had the highest effect. Economic value for a trait as the change in profit of production system by increasing one unit in the trait avrage, while avrage of other traits were constant was estimated.After that, milk, wool production and ewe survival were followed. Birth weight had negative economic value. The sensitivity of economic value of various traits to ±10 % changes in feed, non- feed costs and also to meat, wool and milk prices were examined, and the results showed the economic values of wool and milk productions were not sensitive to none of the costs. Also changes in the costs of rearing and marketing had no effect on the economic value for body weight in various ages of wool and milk production. By changing the price of meat, the economic values of all traits except birth weight, wool and milk production were changed, by increasing the price of meat results to increases in the economic values of those traits. Among various factors, meat price had the most effect on the economic value of traits.