مهراب فرجی نافچی

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 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, population, management and economic parameters resulted from recording of 12 industrial dairy farms in Chaharmahal-va-Bakhtiari province with herd size 20 to 250 and a total of 1240 head of Holstein cows in a cycle of production, during 2010 to 2012 were used for cost-benefit analysis and determination of the economical and biological efficiency values. Revenue was derived from milk, live weight, breeding animals and cull animals. Costs were included to feed, management and labor, health and veterinary, fuel and energy, interest rate and fixed. The results showed that the annually average profits per cow were ranged from 15206843 to 25921834 Rials (507 to 864 US$), revenue to cost ratio were 1.18 to 1.27 and biological efficiency ranged from 57.43 to 65.38 and all of them increased by milk production level. In general, the sale of milk yield, animal live weight and stock animal accounted the highest proportion of total revenue, respectively and the proportion of milk yield from total revenue increase by increasing milk level. The cost of feeding, interest rate, management and labor, health and veterinary, fixed and energy had the highest percent of total cost, respectively and the proportion of feeding cost increased with level of milk yield. The estimated cost- benefit analysis and efficiencies obtained in this study could be used to assist researchers, macro policy makers, determination of dairy cattle strategy and farmers in making decisions that will improve sustainability and also farm profitability.

Three hundred and sixty broiler chicks (Ross 308) were employed in an experiment from 6 to 49 days of age to evaluate the effect of replacing canola meal for soybean meal either with or without enzyme supplementation. Dietary treatments included 5 substitution levels (0, 25, 50, 75 and 100%) at two enzyme concentrations of: 0 and 400 g/ton in a 5×2 factorial layout experiment. The enzyme mixture contained mainly? -glucanase activity and to some extent xylanase activity. Data were analyzed in a completely randomized design. Body weight gain during 6 to 21d was significantly (P<0.05) reduced by raising of canola meal substitution level and while enzyme addition successfully restoring the situation so that main effect of enzyme addition was observed as significant (P<0.05). However, body weight gain during 6 to 49d was not affected by treatments (P>0.05). The effect of substitution level was significant with respect to feed intake during the starting (6-21d) and growing (21-42d) periods whereas it was not significant during the finishing (42-49d) period and the entire the experiment (6-49d). Feed conversion ratio was significantly (P<0.05) influenced by substitution level in all the feeding periods. Main effects and interaction of treatments were not found significant for carcass traits and plasma thyroid hormone concentrations. Feed cost per unit of gain was linearly reduced by increasing the proportion of Canola Meal (CM) at the cost of SBM in the diet. Enzyme addition did not significantly affect feed cost per unit of gain. The optimal substitution level in terms of feed cost per unit of gain was 100%.