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

The aim of this study was to estimate the economic values for residual feed intake and some production and performance traits in Iranian Holstein dairy cow. For this purpose, trait by trait or multiple traits of bio-economic modeling along with production and economic data were used. These data were collected from seven large herds of dairy cows in 2020. The economic values of the residual feed intake was calculated in four different age groups. The diets of different groups were formulated using CNCPS software. Index economic weights (multiplication of the economic values by discounted genetic expressions, in Rial and one cow per year) on average at the level of the studied farms were estimated to be IRR 14280 per kg of milk yield; IRR 291060 per kg of fat yield; IRR 232260 per kg of protein yield; IRR - 790860 per kg of residual feed intake; IRR 702588 per month of longevity and IRR- 113820 per day of days open. The sensitivity analysis showed that the price of concentrate ingredients has a greater effect on the economic value of the residual feed intake than of forage ingredients. In the genetic- economic analysis, the milk production with a relative emphasis of 50 percent was the most important trait in the breeding of Iranian dairy cows, while the relative emphasis on feed efficiency was only about 5 percent. The results of this research provide valuable information for economic values of traits that can be used to complete the national selection index and cost-benefit analysis.

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.

Economic data and performance records from 10 Iranian Holstein dairy cattle herds, as well as milk production and fertility records from Iranian Center of Animal Breeding and Animal Production Improvment were used to estimate the effect of calving difficulty on milk production, fertility and as well on the economic aspects of maternal and direct calving difficulty. Calving difficulty could be divided into 3 classes. Class 1: normal calving; Class 2: calving that needed help by one man worker, and Class 3: calving with serious damage to calf and mother. Milk production decreased about 46 kg and 323 kg in classes 2, and 3 of the calving difficulty incidences, respectively. Calving difficulty caused decreases in fertility performance by 0.22 more inseminations to be performed in class 2 and 0.35 more ones in class 3. Stillbirth was not affected as by class 2 but was intensified in class 3 by 5 percent. Total economic loss attributed to classes 2 and 3 of calving difficulties were $57.76 and $243.83, respectively. Estimated economic value for maternal and direct effect were $37 per unit change in liability per cow/year. Following a correction of the economic values by cumulative discounted expressions, the economic values for maternal and direct effects amounted to $22.79 for direct, and $8.54 for maternal difficulties.