جستجوی مقالات مرتبط با کلیدواژه « اهداف اصلاحی » 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.

The aims of the present study were to estimate economic values and to determine breeding goals of functional traits of Lori sheep in the rural development system with two strategies, one lambing per year and three births in two years. For this purpose, functional parameters, management and economics of 32 flocks (according to Cochran's sample size formula) under the cover of a livestock breeding plan with a capacity of 3000 generative ewes from 2013 to 2015 were analyzed for two production cycles using a bio-economic model. The performance data were obtained from Animal Breeding Center of Iran and management and economic data were collected through preparation of a questionnaire and interviews with farmers. The results showed profit per head of ewe in the strategy of one lambing per year and three births in two years was 1723376 and 3429140, respectively. In both strategies, feeding considered more than 75 percent of total costs and the sales of meat with 98.5% had the highest percentage of total costs and revenues. In addition, in both strategies, relative economic coefficient of the number of lambs born per ewe had the highest relative economic value and wool produced for per ewe had the lowest relative economic value. Litter size and conception rate were the most important traits in the breeding objective for ewe in village system. Birth weight, weaning weight, yearling weight and survival at 3 and 12 months of age were the most important traits in the breeding objective for ewe lamb in village system. The strategy of three lambings in two years was superior to one lambing per year strategy due to the increase in the number of lambs for consumer sales.

Increasing the profitability of each production unit, is the most important way to increase its competitiveness in all fields, including animal husbandry. The first step in designing livestock breeding programs is to decide on appropriate breeding goals and the Lack of precise breeding goal determination is the most important factor behind the inadequacy of livestock breeding programs. Therefore, the determination of the breeding objectives and economic values of the important traits in the Adani goat, which is one of the important livestock of the Persian Gulf coastal strip, will greatly help the breeding of this animal.
In this study, a deterministic static model which assumes no variation among animals for the important traits was used for calculation of economic values. In order to estimate the required parameters (demographic, productive, reproductive, managerial, and economic), for a whole year of production (from the 1st of September 2016 to the 1st of September 2017), seven flocks of Adani goats with 920 does were directly recorded. The economic values of the traits were calculated by generating profit equations and changing the traits by one percent or one unit, while the mean of other traits was constant at the average of the population. The economic weight of the traits was calculated for a genetic standard deviation of the increase in the corresponding trait while the other traits were maintained at a constant average. In order to correct comparison the economic values of the traits, their relative importance was determined.
The results of this study showed that the highest income was the share of kid sales and milk and the largest share of the cost was the management and labor contribution. The traits that were included in the objective goals of the Adani goat including kidding rate, number of kidding per year, litter size, the weight of the kid sales at 12 months, conception rate, survival of the kid to weaning, doe survival, survival from weaning to sales, milk production, mature doe weight, and twining rate were 22.7, 17.5, 12.8, 12.1, 10.1, 9.8, 9, 4.6, 1.9, -0.7 and 0.3, respectively.
Reproduction, longevity and production traits are the most important trait in Adani goats, respectively. According to the breeding conditions of this animal, number of kidding per year, kidding rate, litter size, the weight of the kid sales at 12 months, conception rate, survival of the kid to weaning, doe survival, kid survival from weaning to sales and milk production are the most important traits, respectively and must be regarded more in breeding programs for Adani Goats.

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, management and economic parameters resulted from recording of 4 flocks with 1155 head of breeding ewes during annual cycle of production (August 2011 to August 2012) in extensive rearing system were used to determine the breeding objective and relative economic values for Dalagh sheep. To calculate the economic values for traits, the level of each trait for the flock was increased by 0.1 standard deviation, while all other traits were held at their mean value and changes in profit was as sum of the absolute economic value for all traits. To calculate the relative economic values, absolute economic value of each trait was divided by sum of the absolute economic value of all of traits. In the base situation, live weight or carcass weight was accounted as 87.45% of revenue and wool and milk accounted for the remaining 12.55%. Feeding and management costs (variable costs) represented about 75.50% and 22.30% of total cost respectively. Relative economic values were 15.49 for conception rate, 12.26 for ewe survival, 9.81 for lambing frequency,9.14 for litter size, -12.5 for weight of ewe, -2.61 for replacement weight, 2.97 for weight of wool, 5.73 for weight of milk and 18.86 for 6-month live weight.

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.

In this study production, reproduction, management and economic parameters resulted from recording of 6 flocks with 1500 head of breeding ewes during annual cycle of production (August 2011 to August 2012) in extensive system were used to determine of the breeding objective and relative economic values of survival, production and reproduction traits for Zel breed of sheep. For deriving economic weights, change in profit by one percent increase in mean of a trait, while all other traits were fixed at their means, were calculated and then divided by amount increased in that trait. With analysis of cost and revenue for each of breeding ewe, the highest level of revenue and cost were for live weight and nutrition, respectively. The breeding goals of Zel sheep consist of relative economic values 15.47 for conception rate, 10.58 ewe survival, 10.79 for lamb survival from birth to 6 month, 8.04 for lambing frequency, 8.83 for litter size, -12.89 for weight of ewe, -4.32 for replacement weight, 6.11 for weight of wool, 1.68 for weight of milk and 21.25 for 6 month live lamb weight. The results showed that survival and reproduction traits are important for Zel sheep as well as body weight traits. So, precious registration of the data and implementation of these traits in breeding schemes of this breed is strongly recommended.

In this study production, reproduction, management and economic parameters resulted from recording 6 flocks with 1228 heads of breeding ewes during one year were used to determine the breeding objectives of Lori-Bakhtiari sheep in nomadic production system. A bio-economic model used to determine economic value for each trait in maximum profit, efficiency and minimum cost interests. For deriving economic weights, change in profit by one percent increase in mean of a trait, while all other traits werefixed at their means, were calculated and then divided by amount increased in that trait. To calculate the relative economic values, the absolute economic value of each trait was divided by the absolute economic value of the weight of wool. Sensitivity of economic weights to ±20 percentage changes in prices of costs and revenues were analysed. Economic analysis of system indicated that, costs, revenue, and profit per ewe per year were 1128200, 887255, and -240945 Rials, respectively. Labour costs with 55.7 % and revenue from live weight accounted for about 97.3 %, had the highest percentage of total costs and revenue, respectively. Feed and fixed costs represented about 36.9 % and 1.8 % of total costs, respectively. Lamb live weight at 5-month, litter size, lambing frequency, conception rate, lamb survival at birth, lamb survival from birth to 5 months, mature ewe live weight, fleece weight in ewes, ewe and replacement survival rate were represented in profit equation and accepted as breeding objectives. Relative economic values in maximum profit interest were, 2.64 for 5-month lamb live weight, 57.33 for litter size, 73.41 for lambing frequency, 97.88 for conception rate, 92.60 for lamb survival at birth, 113.96 for lamb survival from birth to 5 months, -0.067 for mature ewe live weight, 1 for weight of wool, 215.05 for ewe survival and 59.67 for replacement survival rate. It was concluded that litter size, lambing frequency, conception rate and survival rates, were the most important traits in breeding objectives. Sensitivity of economic weights with regard to meat price change was higher than the others.

In this study, production, reproduction, management and economic parameters deduced from recordings of 5 flocks with 720 heads of native goats during an annual cycle of production in transhumance, village and farming systems were employed to determine the trait's economic values. The economic values of the traits were estimated, using maximizing profit, revenue per cost as well as minimizing cost situations. The relative economic values of traits for transhumance system resulted from maximizing profit situation were 15.29 for survival rate in goat, 5.60 for conception rate, 4.92 for kidding frequency, 2.37 for kidding rate, 3.34 for kid survival rate up to weaning, 2.74 for kid survival rate to yearling, 1.00 for kid live weight at sale, -5.45 for body weight of goat and 13.37 for milk yield. In village system, these values were 8.30, 4.52, 4.16, 1.21, 1.55, 1.38, 1.00, -6.42 and 4.96, respectively. In farming system, these values were estimated as 1.73, 1.13, 0.73, 0.37, 0.53, 0.50, 1.00, -0.77 and 1.16, respectively. The absolute economic values of traits increased with improving economic efficiency from transhumance to farming systems, but the relative economic values decreased. Although, the calculated economic values from all the three situations were different numerically, but from the rank point of view of traits they ended up with apporoximatly similar results.

In this study, production, reproduction, managerial, and economic parameters obtained from data recorded for Lori-Bakhtiari flock of sheep (500 heads of breeding ewe) stationed at the sheep's Breeding Station, were employed to determine the relative economic values of and breeding objectives for an annual cycle of production, in village system in this breed of sheep. Economic value for a trait was estimated as the level of change in the profit of system as its mean increased by one unit, while the means of other traits being kept constant. The economic values were investigated in three approaches including a included to maximization profit to maximize economic efficiency and to minimize cost. The results show, live weight of (carcass weight) accounted for 94.51% while wool and manure for the remaining 5.49% of the revenue, respectivly. Feeding and management costs represented about 72.28 and 25.94% of total costs, respectively. Relative economic values for conception rate, litter size, mature ewe live weight, weight of wool, lamb survival at 6 months of age, 6-month live weight, carcass lean weight and carcass fat weight at 6 months of age were 60.52, 48.00, -0.05, 1, 56.55, 1.01, 4.61 and -0.92, respectivly for maximization of profit approach. Relative economic values from the three approaches were approximately the same. Litter size, conception rate and ewe live weight were the most important traits in the breeding objectives for ewe in the village system. Lamb survival at 6 months of age, carcass lean and fat weights were the most important traits in the breeding objectives for the lamb in the village system. Estimates of sensitivity analysis of relative economic values to changes in prices of input and output by? 20% indicated that the relative economic values of traits, relative to change in cost of input (feed and management), were of low sensitivity, while relative to change in output (carcass and carcass lean weight) indicated a relatively higher sensitivity.

Production، reproduction، management and economic parameters resulted from recordings of 5 flocks comprised of 720 heads of native goats during annual cycle of reproduction in transhumance، village and farming systems were employed to determine the performance of traits، cost-profit analysis as well as breeding objective. The overall mean for number of salable kid per goat in transhumance، village and farming systems were 0. 35، 0. 52 and 1. 20، respectively. The mean kid body weights in sale time were 22. 50، 28. 50 and 31. 86 kg، respectively. The mean milk salable shares per goat were 14. 50، 50. 50 and 60. 00 kg، respectively. The traits appeared in profit equation were survival rate in goat، conception rate، kidding frequency، kidding rate، kid survival rate to weaning، kid survival rate to yearling، kid live weight at sale، body weight of goat and milk yield (breeding objective). The average profit per goat per year were، estimated as 55427، 103162 and 733654 Rials for transhumance، village and farming systems. The economic efficiencies were calculated as 1. 10، 1. 09 and 1. 57، respectively. The highest and lowest profit occurred in farming and transhumance systems، respectively. The economic efficiency in village system was lower than in the transhumance system.

In this study were used production, reproduction, management and economic parameters resulted from recording of 7 flocks with 1133 head of breeding ewe during annual cycle of production in village system. The profit equation were evaluated for two situations: 1) current situation, that there is not any pay for grazing in range, 2) In this situation, assumed for grazing in range pay as same as grazing in pasture of residual crop and hay farm. To calculate the economic value for traits, the level of trait included in profit equation was increased by 0.1 standard deviation, while all other traits were held at their mean value and change in profit was as the absolute economic value for trait. To calculate the relative economic values, the absolute economic value of each trait divided by the absolute economic value of weight of wool. Sensitivity analysis of relative economic values to price levels of inputs and outputs was carried out. In the current situation, live weight or carcass weight accounted for 95.04% of revenue and wool and manure the remaining 4.96% Feeding and management costs (variable costs) represented about 73.97% and 23.68% (97.65%) of total cost respectively. For the current situation, relative economic values were 33.09 for conception rate, 43.27 for litter size, -2.67 for mature ewe live weight, 1.0 for weight of wool, 30.55 and 35.64 for lamb survival at 3 and 6 month of age, 15.71 for 6-month live weight, 10.87 for dressing percentage, -7.57 for proportion of fat-tail to carcass, 0.59 for fat-tail weight and 25.03 for carcass weight without fat-tail at 6 month of age. The relative economic values of considered traits for situation 2 were slightly less than current situation. Litter size and conception rate were the most important traits in a breeding objective for ewe in village system. Lamb survival at 3 and 6 month of age and carcass weight without fat-tail were the most important traits in a breeding objective for lamb in village system. Sensitivity analysis of relative economic values to changes in prices of input and output indicated that change in cost of input (feed and management) by ± 20% changed relative economic values of traits by equal to less than %2.4, while, change in output (carcass weight without fat-tail) by ± 20% changed these values more than %20.