محمود وطن خواه

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 estimate some population parameters in sheep flocks of Khuzestan province, information of 100 flocks from rural rearing systems with two breeds of Arabic and Lori-Bakhtiari sheep were used during the years 2017 - 2019. The data were collected through a questionnaire and interview with the farmers. Data was analyzed by SAS 9.1 software. The average of the number of breeding ewes, the number of breeding rams, duration of ram stay in the flock and ram to ewe ratio were achieved 173.67 heads, 9.56 heads, 5.96 years and 5.65%, respectively. Accordingly, the average of effective size and the rate of inbreeding of flocks were 34.9 heads and 3 percent per generation, respectively. In general, the results showed that the estimated effective size was less than the minimum size recommended by FAO (50 heads) for having less than 1 percent inbreeding per generation. So, it may result in having flocks with inbreeding rate which is 3 times more than the permissible rate. Increasing of inbreeding in the flocks can decrease production performance, reproductive performance and increase genetic abnormalities. Therefore, based on the estimated inbreeding rate for sheep flocks in the province (3 percent per generation), it is necessary to prevent further increasing in inbreeding rate and its negative consequences by training farmers about issues such as suitable ram to ewe ratio, supplying breeding rams from out of the flock and keeping rams in flock for a shorter period of time, as well as, using rotational mating scheme

All breeds of Irannians sheep except Zel has a fat tail, and despite their lower carcass fat percentage, male lambs have higher fat-tail weight. Using within breed genetic variation requires accurate and precise measuring of fat tail weight on candidates of selection. The aime of this study was comparision of artificial neural network (ANN) modeling and linear modeling methods to prediction of fat tail weight, using body weight and different tail dimensions. 32 lambs of Chal and Zandi breeds,crosses of Zandi×Chal,Zel×Zandi and Zel×Chal hybrids were used for modeling to an estimation of fat-tail weight. Inputs of the model was birth type, sex, breed, upper width , mid width and lower width of fat tail,fat tail height and body weight, output of the model was fat tail weight. body weight, genotype, and fat tail mid-width had the largest positive correlations with fat-tail weight,0.83,-0.82 and0.80,respectively. The adequacy parameters of the best artificial neural network model had a coefficient determination of 0.99 and a mean squared error(RMSE)of 70.3g. The values of these estimated parameters by the multiple linear model were 0.891 and 263.86, respectively. The results of the extension of the original study showed the complexity of the interactions between the model inputs. Present research approved to accurate and unbiased estimation of tail weight of different breeds and crosses using artificial neural network. Furthermore, present study showed that ANN model can be used for accurate and presise estimation of fat tail weight using measured traits on sheep,than linear model.

Crossbreeding is used in order to take advantage of the different and complementary strong points of two or more breeds and to utilize hybrid vigor. In this study the results of sheep crossbreeding have been reviewed from published over the last years in Iran. The results showed that much of the crossbreeding in the sheep industry in Iran due to incorrect selection of breeds was not suitable. The main disadvantages points of Iranian sheep are low reproduction performance, low longevity, insufficient growth rate, unsuitable carcasses composition and feed efficiency, respectively. While, in the most crossbreeding schemes have been done between Iranian breeds of sheep, focused on improve growth traits and reduced fat-tail weight, which created low and no significant changes in crossbreds for these traits, leading to reducing economical efficiency and unsustainable of rearing sheep in semi-intensive or village system over last years. Sustainability could been achieved by combining desirable characteristics from the indigenous breeds to keep fitness and marketability with those of specialist exotic breeds that had already demonstrated genetic potential for traits of economical importance for commercial production. However, research findings suggested that in well-planned efforts to create composite breeds (with minimum 50% native) using the prolific breeds (such as Romanov), with high mothering ability, low maturity age, suitable carcass composition and medium ewe body weight could increased productivity of sheep in village system in Iran.

One of the breeding programs for sheep is the nucleus breeding scheme (Kosgey and Okeyo 2007). The nucleus breeding system, including open or close nucleus, is a good start for genetic improvement in many populations. Unlike the close nucleus schemes, there is a reciprocal gene flow in open nucleus schemes, where the best animals from base layer could be transferred to the nucleus layer (Kosgey et al. 2006). In the original nucleus breeding scheme, a constant genetic variation was assumed for the trait of interest across different generations (Hopkins and James 1978). However, it is well realized that the additive genetic variance is decreased after several generations of intense selection. Thus, the actual genetic gain is likely less than the expected genetic gain. In other words, the outcomes of these breeding schemes are likely affected by the intensity of selection as well as the relative size of the nucleus population to the size of whole population. The aim of current study was to investigate the effect of relative nucleus size at three levels of 5, 10 and 15 percent and the effect of selection intensity in males and females at three levels of high (i.e. selection proportion in male and female candidates were 1 and 20 percent, respectively), moderate (i.e. selection proportion in male and female candidates were 5 and 50 percent, respectively) and weak (i.e. selection proportion in male and female candidates were 10 and 80 percent, respectively) on the amount of biasness of predicted genetic gain due to ignoring the effect of selection on genetic variance. An open nucleus breeding scheme was deterministically simulated using data from Lori Bakhtiari sheep breed, consisting a nucleus herd of 1005 ewes and a base herd of 4019 ewes (Vatankhah 2005). Birth weight was the breeding goal trait and selection was carried out using one individual performance record. The generation was assumed to be overlapped and three and six age groups were considered for males and females, respectively. The age of parents at first lambing was 2 years and 0.94 yearling lamb was produced per ewe. One ram was mated to 33 ewes. The additive genetic variance for breeding goal trait was 0.11 and its heritability was set to 0.30. For a given size of the nucleus and a constant rate of transferring ewes from base population to nucleus (x), there was an optimum rate of migration of nucleus rams into the base population (w), that maximized the expected genetic gain and minimized the genetic lag between nucleus and base populations, with or without accounting for the effect of selection on the genetic variance. By increasing the relative size of the nucleus, from 5 to 15 percent of whole population, the biasness of the predicted genetic gain was increased from 11.84 to 16.67 percent. At a given rate of x, the bias of genetic gain prediction which originated from ignoring the effect of selection, varied nonlinearly as the rate of w increased and had a minimum value at the optimal value of w. At a particular rate of w, increasing the rate of x, was associated with higher rate of bias. The rate of bias increased from 12.2 to 16.54 percent, as the intensity of selection increased. The reason could be the markedly reduction in the genetic variance of considered trait due to selection at high selection intensities. In open nucleus schemes, the amount of bias changed from 14.18 to 17.72, as a consequence of increasing the intensity of selection. Across all levels of selection intensity in open nucleus programs, the lowest bias was observed at the rate of 0.75 for w. Evaluation of joint effect of relative nucleus size and intensity of selection, showed that at high selection intensity and relative nucleus sizes higher than 10 percent, the amount of bias was not likely to be influenced by nucleus size. Ignoring the effect of selection on genetic variance could result in a biased prediction of genetic gain in the nucleus breeding schemes. However, the optimal ram transfer rate from nucleus to base population was independent from the effect of selection intensity. The lowest bias was observed for the scheme with optimum transfer rate. Results of the current study revealed that at weak selection intensity, the effect of selection could be ignored and the breeding program could be optimized for ram transfer rate from nucleus to the base populations. However, at high selection intensities, the ignorance of this effect might result in wrong conclusions.

In this study, to estimate some population parameters and inbreeding rate in Lori Bakhtiari sheep flocks, the data set of 81 flocks of sheep were recorded from farmer flocks under current systems during 2015 to 2016. Questionnaire survey was used to collect data from last year information, recorded information, direct recording during visit the farm and interview with the smallholder farmer. The results showed that in 68% of the studied flocks, the male replacements were selected from the within flock, the selection criterion for all of the flocks was visual apparent characteristics and the type of mating was random. The average generation interval, the number of breeding ewes, the number of breeding rams, the proportion of ram to ewe, the duration of the ram stay in the flock were 3.30 years, 98.6, heads, 4.5 heads, 4.6%, 3.4 years, respectively, and 34.57% the flocks had at least one lamb with a visual genetic abnormality. Accordingly, the effective size and the rate of inbreeding, regardless of family size variance were 17.2 and 4.9%, respectively, and with family size variance estimated as 9.8 heads and 7.5%, respectively. The effect of city and type of breeding system were significant on most of the studied population parameters and inbreeding rate (P< 0.05). Therefore, the mean of effective size in farmer flocks was lower than minimum recommended for maintaining genetic diversity and implementation of the improvement breeding program, and this fact has caused an inbreeding rate of more than 5 to 7 times the permissible limit.

In this study 429 smallholder dairy farms in 44 villages of the Zabol county included 1728 lactating cows and 3759 head of total herd during February 2015 to March 2016 were recorded to assess the estimate economic opportunities per cow. A questionnaire survey was used to collect data from last year information, direct recording during visit the farm and interview with the smallholder farmer. The number of 5 economic indices calculated using revenue and expense for each farm. The economic opportunity is the amount of additional revenue that could be obtained if farmers could improve various productivity indexes to meet reasonable targets. The economic opportunity estimated as the amount of difference between average herd and reasonable target multiplied by the value of one unit change in the variable in Rials. The sum of economic opportunities per cow per year estimated as 19.68 million Rails included 8.13 million Rails (37.73%) for average daily milk production per cow, 6.47 million Rails (32.51%) for average age at first calving, 3.58 million Rails (20.58%) for average lactation length, 0.82 million Rails (5.33%) for average calf production interval and 0.67 million Rails (3.85%) for average calf mortality, respectively. There was significant variation between different levels of season, breed, rearing system and herd size for the performance of economic opportunities indices. The results obtained in this study can be used in planning to improve the performance economic indices to improve productivity and economic efficiency in smallholder cattle farms.

An open nucleus breeding scheme consisting a nucleus herd of 500 ewes and a commercial herd of 4500 ewes was simulated deterministically using the information of the population of Lori Bakhtiari sheep to investigate the effect of heritability and nucleus size on the bias of estimates for genetic gain. The objective function was 9 months body weight and the selection was based on own record. Different values for heritability in nucleus and commercial herd and also different nucleus sizes were considered and the expected genetic gain was estimated by ignoring or accounting for the selection effect and from the ratio of these two estimates the amount of bias of estimates for genetic gain was obtained. The results showed that when the heritability of the nucleus and the commercial herd were equal, the highest bias (18%) occurred. Increasing the heritability in nucleus and commercial herd from 0.1 to 0.9 showed the amount of bias was directly related to heritability and ranged from 10 to 36 %. When the heritability in nucleus was fixed at a given value, and the heritability in commercial herd changed, the rate of bias altered, but only by 10 % indicating the amount of bias is not so sensitive to the heritability in the commercial herd. Results related to the changes in nucleus size indicated that the amount of bias changed between 10 to 20 %; therefore, effect of this factor on the bias is negligible. In general, the most important factor on the bias of genetic gain estimates, due to ignoring the effect of selection, is the heritability.

In this study 429 smallholder dairy farms in 44 villages of the Zabol county included 1728 lactating cows during February 2015 to March 2016 were used to assess the performance of smallholder farms. The performance of production traits were as 13.66, 7.82 and 7.24 kg for average total milk yield in farm, average milk sold in farm and average daily milk production per cow, respectively. The overall mean of reproductive traits and mortality rate were as 28.71 months for age at first calving, 14.17 months for calving interval, 232.66 days for average lactation length, 7.76% for calf mortality rate up to yearling age and 1.35% for mature cow mortality rate. The mean of daily feed consumption per cow was 13.36 kg, with 29.33% concentrate. The mean of daily feed intake expenses per cow and return from sale of daily milk per farm were 83 and 90 thousand rails, respectively. The value of milk income to daily feed intake expenses per cow, daily feed intake to average daily milk production and the kg milk price to kg feed intake ratio were 95.48%,2.20 and 1.97, respectively. The average total herd size was 8.76 head, included 30.57% lactating cows, 16.20% dry cows, 11.95% female milking calves, 11.79% male milking calves, 10.18% male growing calves, 10.03% female growing calves, 5.76% mature bulls and 3.52% pregnant heifer, respectively. There was significant variation between different levels of season, breed, rearing system and herd size all of the most traits.

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.

The aim of this study was to estimate inbreeding coefficient and its impact on wool performance in Lori-Bakhtiari sheep. In this research, wool weight records of 6234 lambs born from 273 rams and 1924 ewes were used. The data were collected at Shahrekord Sholi station during 1990-2010. In total pedigree, 1764 animals were inbred. Averages of inbreeding coefficient for total and inbred population were estimated at 1.02 and 2.32 respectively. The inbreeding effects reduced wool weight performance approximately 4.2±1 g for each percentage of increase in inbreeding. Increasing 1% of inbreeding coefficient of male and female lambs was respectively accompanied with decreasing 5±1 and 3±1 g in wool weight. This decreasing was 4.6±1 and 2±1 g for single and twine lambs respectively. Annual trend in inbreeding coefficient for total and inbred population were 0.098±0.01 and -0.72±0.1 kg respectively that was statistically significant (P

Information about mortality of 6426 lambs which were born from 223 rams and 1769 ewes from years 1991 to 2015 in Sarakhs’ Karakul sheep breeding station was used. The trait under study was lambs’ monthly cumulative survival rate from time of birth to one year of age. Frequency of mortality causes and survival distribution function were analyzed using Freq and Lifetest procedures of the SAS statistical software, respectively. The overall lambs' mortality from birth to yearling age was 14.57 percent. The most important mortality reasons were starvation, digestive and respiratory illnesses. The lambs’ cumulative survival rate was 85.4 percent in their first year of life. Regression coefficient of survival from lamb age showed that lamb's survival decreased 0.037% per day. Lambs’ mortality rates were 7.8, 4.06, 1.23 and 1.48 percent in the first, second, third and fourth triplet months of lambs’ life, respectively. The lambs’ highest mortality occurred in 1st, 2nd, 6th and 10th month of age. As mortality rate was highest in the first 3 months of lambs' life, it is suggested to apply better care and nutritional management for the ewes and lambs in this period to increase survival rate of lambs.

The aim of present study was to estimate genetic and phenotypic trends for body weight traits at some ages in Lori-Bakhtiari lambs. In this study a total of 7721 records on birth weight, 6462 records of one month weight, 7275 records of weaning weight 5745 records of 6 month weight, 3326 records of 9 month weight and 3088 records of 12 month weight of Lori-Bakhtiari sheep was used to reveal the genetic and phenotypic trend of growth traits. The data was collected in Shahrekord sheep breeding station during 1989-2010. The SAS statistical software was used to evaluate the effect of environmental factors. Wombat software was employed to estimate genetic parameters and animals breeding value. Environmental factors, like birth year, sex, birth type and the age of mother were significant factors as fixed effects (P

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.

The current experiment carried out to investigate the effect of fish oil and selenium supplementation in the ration on performanceand blood parameters in lambs. Sixteen male Lori Bakhtiyari lambs with the same mean weight (39.6±0.290)were randomly allotted to 4 treatments in completely randomized design. Dietary treatments were included of: 1) control (basal diet without any additives); 2) FO (basal diet +2% fish oil; 3) FO + Se (basal diet + 2% fish oil +0.2 mg/kg selenium; 4) Se (0.2 mg/kg selenium). In order to evaluate the blood metabolites, samples were taken on day 60 of the experiment to measure the serum triglyceride (TG), cholesterol (CHOL), high density lipoprotein (HDL), density lipoprotein (LDL) and glutation peroxidase (GPX). Results indicated FO + Se had no significant influence on performance (p>0/05). Moreover, this treatment led to decreased serum TG, CHOL, LDL and increased GPX and HDL‎‎(P<0.05). Therefore results show that however performance was not affected by dietary treatments, selenium as well as fish oil compared to the control group significantly affected blood parameters.

A study with 56 male lambs of Lori-Bakhtiari sheep breed was carried out to investigate the effect of selection to decrease fat on the fatty acids composition in the subcutaneous fat and fat-tail adipose tissue. Subcutaneous fat and fat-tail fat samples were obtained from the back of left side of carcass and fat-tail, respectively. Total 112 samples of subcutaneous fat and fat-tail adipose tissue were obtained from 56 carcasses at six month of age. The fatty acid composition of subcutaneous fat and fat-tail were analyzed after fat extraction by gas chromatography. Data were analyzed using SAS statistical program. Proportion of palmitic (C16:0) in fat tissue significantly (P<0.05) decreased and linoleic (C18:2) significantly increased at the end of the selection program.While body weight lambs was higher at the end of the selection program, unsaturated fatty acids was higher in carcass fat. Ratios of poly unsaturated fatty acids to saturated fatty acids were significantly higher incarcass fat at the end of the selection. Desirable fatty acids and ratio of (C18:0+C18:1)/C16:0 did not significant increase at constant weight. Proportion of palmitic (C16:0), stearic (C18:0)and total saturated fatty acids were significantly higher in subcutaneous fat but oleic fatty acid (C18:1)was significantly higher in fat-tail. Ratios of unsaturated fatty acids to saturated fatty acids, desirable fatty acids and ratio of (C18:0+C18:1)/C16:0 were significantly (P<0.05) higher in fat-tail than subcutaneous fat at constant weight. Inconcluded, selection for decreased carcass fat cause improve fatty acid composition of fat tissue.

The Lori-Bakhtiari sheep breed is one of the most common native breed in the south-western parts of Iran. The peri-parturition period (2 weeks before to, 2 weeks after parturition), is generally of critical importance regarding the health, production and profitability of the ewes. This study was carried out to compare the serum concentrations of glucose, non-esterified fatty acid (NEFA), β-hydroxybutyrate (BHBA), cholesterol, blood urea nitrogen (BUN) and calcium (Ca) during peri-parturition period in 30 single and 30 twin-bearing Lori-Bakhtiari ewes. All blood profiles were determined in healthy ewes on days 14, 7 prepartum, and days 7 and 14 postpartum. Serum glucose levels were lower in twin-bearing ewes, compared to single-bearing ewes on prepartum and day 7 after lambing. Serum NEFA, BHBA and cholesterol levels were higher in twin-bearing ewes compared to single-bearing ewes during the peri-parturition period. Lower serum Ca levels were recorded 7 days before and after parturition in twin-bearing ewes, compared to single-bearing ewes. The results showed that NEFA and BHBA recorded significant (p<0.05) changes during the peri-parturition period in twin-bearing ewes. These significant differences could be related to increased metabolic demands of the fetuses in twin-bearing ewes.

In this research 5633 records, which collected by Khojir Sheep Breeding Station of Tehran, during the 1994 to 2011 were used for estimate of (co)variance component and evaluation of inbreeding effects on birth weight (BW) and pre weaning mortality (PMW) in Zandi lamb. Genetic parameters were estimated using REML procedures. AIC criterion test were used to choose the most suitable model. The most suitable animal model for BW included direct additive genetic, maternal additive genetic, maternal permanent environmental and common litter effects, and suitable model for PMW were included direct additive genetic, maternal additive genetic and common litter effects. Also suitable threshold model was included sire additive genetic effects and litter effects, but the most appropriate sire model only including sire additive genetic effect. Direct and maternal heritability for BW was 0.11 and 0.08, respectively. Also, logit heritability and heritability obtained from threshold, animal and sire models were 0.14, 0.20 and 0.18, respectively. Genetic, environmental and phenotypic correlation between BW and PMW was -0.27, -0.23 and -0.28, respectively (p<0.05). The 27 percent of all animals in population were inbred. The mean of inbreeding coefficients in population and inbreed animals were 3.5 and 0.9 percent, respectively. The estimates of inbreeding depression were -3.5 g for BW and 0.1 percent for mortality, respectively (p<0.05).

In this study production، reproduction، management and economic parameters resulted from recording of 4 flocks with 600 head of breeding ewe during the annual cycle of production in village system were used to determine of the breeding objective، absolute economic values and relative emphasis for a Lori_Bakhtiari breed of sheep. To calculate the economic values of traits، the level of each trait for the flock was increased by 1 unit، while all other traits were held at their mean values and change in profit was as the absolute economic value (maximize profit، P)، the ratio of revenue to costs (maximize efficiency، Q) and the ratio of costs to revenue (minimize costs،) calculated for considerable trait. To calculate the economic weight and relative emphasis، the absolute economic value of each trait multiplied to the genetic standard deviation of trait in three ways. The results showed that annual profit per ewe، the ratio of revenue to costs and the ratio of costs to revenue were 667023 rials، 1. 16 and 0. 86، respectively. The breeding objective for Lori-Bakhtiari sheep in village system in order of relative emphasis were reproductive traits (Litter size، conception rate، number of parturition in each year); durability traits (in lamb up to sale and ewe); growth traits (lamb weight at sale time، weight of replacement، weight of mature ewe) and greasy fleece weight. The economic values of corresponding traits resulted from various ways were different in values and the sign of economic values from P was the same as Q but different to. The sum of relative emphasis for reproductive traits، durability traits، growth traits and greasy fleece weight resulted from P were 57. 09، 23. 39، 19. 32 and 0. 19; from Q were 55. 54، 22. 98، 21. 29 and 0. 19 and from were 55. 05، 23. 06، 21. 69 and 0. 19، respectively. Thus، the relative emphasis resulted from different ways for various traits were equal relatively and if the relative emphasis is used instead of absolute economic values، the result of each different ways could apply

In this study، the number of 1802 longevity records of ewes collected during 1989 to 2010 in Breeding Station of Lori-Bakhtiari sheep flocks were used to estimate of genetic، environmental and phenotypic trends for economic lifetime. The breeding values of a ewe’s lifetime were estimated by restricted maximum likelihood procedure under an animal model of univariate analysis. The best linear unbiased prediction of breeding values estimated and genetic trends were estimated as a regression coefficient of average breeding values on the birth year of ewes. The environmental and phenotypic trends estimated as a regression coefficient of average environmental deviation and phenotypic deviation (deviations of phenotypic values from overall mean) on the birth year of ewes. The results showed that، genetic trend of longevity was positive (0. 033 days) but insignificant from zero. While the environmental and phenotypic trends were equal to -27. 81 and -27. 78 days، respectively، and significantly different from zero (P<0. 05). Thus، selection for growth traits did not affect longevity traits as genetically and to exhibit negative phenotypic trend for longevity the environmental factors should improve firstly

The data set used in this study were 1082 records of ewe’s life length from 217 sires and 851 dams collected during 1989 to 2012, from the Lori-Bakhtiari flock at Shooli station in Shahrekord. The data were analyzed using Freq and Life test procedures of SAS. The results showed that the overall mean of ewe’s life length was 1774.37 days (4.86 years). The most important cause of culling was disease (51.22%), especially in the first three parity of the ewe. After disease cause, oldness, reproductive problems, low production, physical phenomenon, experimental slaughter, additional ewe and bad type causes accounted for remaining ewe culling, respectively. The conditional probability increases with age, while survival cumulative rate decrease with age of ewe. The hazard ratio of death increases with age up to 6 years of old steadily and then increases strongly. Thus, the longevity and survival rate of ewe can be improved first by farm management practices and improving environmental factors for preventing and treating of diseases.

For this study, a total of 6,326 records of wool weight obtained from 273 rams and 1,927 ewes of Lori-Bakhtiari sheep were used. The data were collected in Shahrekord sheep breeding station (Sholi) during 1990-2011. SAS statistical software was utilised to determine the effect of environmental factors, and MTGSAM software via Gibbs sampling was applied to estimate genetic parameters. Environmental factors such as birth year, sex, type of birth, and age of mother had significant effect on the trait. The interaction between age of mother and sex of lamb, and interaction between type of birth and sex of lamb were significant. Animal’s age at shearing and birth weight were taken into account as covariates in the models. Using the best model, direct and maternal heritabilities for wool weight were 0.31±0.02 and 0.06±0.01, respectively. Direct and maternal genetic trends were 3.23±0.24 and 0.3±0.04 gr per year,respectively and statistically significant. Phenotypic and environmental trends were found to be 0.003 and -0.001, respectively but non-significant. Genetic progress was considerable at different years which could be due to breeding programs targeted at these stations.

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.

To assess the economics of rural sheep production systems and estimation of economic values of important traits in Zandi breed, bio-economic approach was used. In order to estimate economical parameters for using in bio-economical equations and to calculate the EVs of traits, two farms with the flock sizes of 500 and 450 head of Zandi sheep breed in Varamin were studied since the beginning of September 2010 to September 2011. EVs (economic values) of six important traits including pregnancy rate (FE), litter size (LS), lamb weights at birth (BW0), 3 (weaning; BW3), 6 (BW6) months old and survival rate until the age of 6 months (SRL6) were estimated. To estimate the EV of each trait, the level of the trait was increased by both 1% of its mean value and 1 unit while all other traits were constant in their mean values and the amount of change in the profit of system was considered as the EV of the trait. The sensitivity of the EVs was investigated by changing prices of feed and live weight of animals by ±20%. The economic analysis results indicated that the average of feeding cost ratio to the overall costs; and also the average of management cost ratio to the overall costs of rural sheep production system were 64.5 and 33.2 percent respectively and the average annual profit of each breeding ewe in rural sheep production system was 1109594 Rials. The most important trait in this system was FE, followed by LS, BW6, SRL6, BW3 and BW0, respectively when used by 1% increase.