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

This study aimed to explore the current status and assess the risks faced by the Markhoz goat population in its breeding region. To achieve this objective, we gathered census data, population distribution information, and biological parameters, focusing on three key criteria: geographic, demographic, and genetic. We employed four risk assessment systems from reputable entities, namely the World Food Organization (FAO), the European Union (EU), the European Association of Livestock Products (EAAP), and private organizations (NGOs). In addition, we used Vortex version 10.5.5 to simulate past population dynamics, specifically investigating genetic changes. According to the latest census, 1297 goats were distributed across the primary region (50%), other areas (7%), and stations (43%). Notably, the region dedicated to goat breeding has experienced a significant reduction in size over recent years. Presently, 88% of the goat population in the region is concentrated within a circle with a radius of fewer than 6 kilometers in Armardeh, Baneh. The decline in population size, as well as breeding males and females in the Markhoz goat's breeding region, has led to a reduction in effective population size and an increase in the rate of inbreeding in recent years. Inbreeding in the last year of investigation was calculated at 0.1049, and its rate (∆F) had reached more than 0.5% in each generation since 2015. Our study's findings indicate that across all assessment systems and considering demographic, geographic, and genetic criteria, the Markhoz goat breed is currently at risk of extinction in its breeding region.

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

Sex allele homozygosity as an indicator of inbreeding could effects on the performance of honey bee colonies. Then sex allele homozygosity is essential to evaluate apiaries situation in the country, as well as designing breeding strategies. In order to investigation of sex alleles homozygosity percentage and number of allele in honey bee populations of West-Azerbaijan and Kurdistan provinces and its correlations with honey production and adult population, 320 honeybee colonies were used. Data analysis was performed using SAS software (Version 9.4). The results showed that sex alleles homozygosity and number were 12.7 % and 9.02 for West Azerbaijan province for apiaries of Kurdistan province were 13.82% and 8.15, respectively. The results of variance analysis showed that the province had significant (p<0.05) effect on all studied traits. The county in provinces had significant (p<0.01) effect just only honey production. The sex alleles number effects on colony population and honey production, and also effect of colony population on honey production were significant (p<0.01). The results of correlation analysis showed negative and significant (p<0.001) between sex alleles homozygosity percentage with sex alleles number (-0.92), honey production (-0.79) and colony adult population (-0.86). Also, regression analysis results showed that sex alleles homozygosity percentage had negative and significant (P<0.001) effect on colony adult population (-0.17) and honey production (-0.44). Thus, with an increase of one percent homozygosity, the colony adult population decreases about 0.17 frame (units), and honey production decreases about 0.44 units, or in other words, 440 grams. Therefore, only with attention of beekeepers on the homozygosity and number of sex alleles, it is possible to prevent a decrease in honeybee population and consequently a decrease in honey production in the countrychr('39')s apiaries.

The aim of this study was to design optimal selection index without the use of economic coefficients based on the expected genetic gains in economic traits. Random simulation with 5 replications was used to evaluate the results of the designed indices. Simulated traits include body weight at birth (BW1), eight weeks (BW8), twelve weeks (BW12), maturation (BWM), age at first laying (AFE), weight of first egg (EWM), the mean egg weight from 28 to 32 weeks (EW) and the egg number (EN). In three indices, BW12, EN and EW traits were in the selection target and all simulated traits were in the selection criterion. Indices with the aim of genetic gain for 5 g in EW, 20 in EN and the difference between the three indices of the first to third selection were related to the change in the expected values of 100, 200 and 300 gr in BW12. The results showed that all three selection indicators are able to create a uniform and desirable genetic gain in traits. However, the second index is able to achieve acceptable results in a smaller number of generations (304 gr, 25.3 and 6.4 gr genetic gain for BW12, EN and EW, respectively). The inbreeding after 5 generations of the implementation of the first to third indices was not desirable (approximately 0.02) and the difference in inbreeding between the indices was not significant (P> 0.4). It is suggested that the second index for 5 generations be used for the Yazd province native fowls breeding.

Inbreeding, which has been defined as the mating between relative animals, leads to increase homozygous genotypes and decrease heterozygous genotypes in a population. As a result, the progenies of such mating are inbred (Wakchaure and Genguly 2015). Reduction of the traits associated with physiological efficiency and reproductive potential are the most important impacts of inbreeding in the farm animals (Filho et al. 2015, Fleming et al. 2018). Traits in livestock have different heritabilities suggesting that they are not influenced by inbreeding in a similar pattern and that although animals’ fitness is generally deteriorated; the magnitude of inbreeding depends on the type of the trait (Roff 1998; Derose and Roff, 1999, Wright et al. 2008, Mikkelsen et al. 2010). Until now, all studies regarding effects of inbreeding on productive and reproductive traits of dairy cows have been focused on using the statistical models in which inbreeding coefficient was included as covariable (Behmaram et al. 2017) or as the classified variable (Amirzadeh 2012). As inbreeding coefficient is defined as a covariable in the model, only a regression coefficient is estimated describing average changes of the trait per increasing / decreasing inbreeding coefficient. As a matter of fact, inbreeding may unequally influence the shape of distribution of the trait. Based on this assumption, this research aimed to estimate inbreeding effects on some productive and reproductive traits of Iranian dairy cows using Quantile regression statistical method.     

The data set was provided by Animal Breeding Centre, Iran. Foxpro (version 2.6) and UEStudio (version 09) software were utilized for editing initial data. Final data consisted of 580,802 records belonging to 580,802 first-parity cows distributed in 1,185 herds (over 20 provinces of the country) and calved between years 1991 and 2015. The traits under consideration were lactation milk yield (TMILK), 305d, 2X milk yield (MILK3052X), average daily milk yield (ADM), lactation length (LL), and age at the first calving (AFC). The average of the traits in the final data set was 9,447 Kg, 7,792 Kg, 30 Kg, 315 d and 25.6 m, respectively. Holstein gene percentage (HGP) of the cows in the pedigree file was set to be in the range of 50 to 100 and AFC of the cows was set to be between 18 and 48 months. Inbreeding coefficient (IC) of individual animals was calculated by CFC software (Sargolzaei et al. 2006). Fitting a series of the Quantile regression models was conducted with the use of SAS (version 9.4) software. Quantile regression, which was introduced by Koenker and Bassett (1978), extends the regression model to conditional quantiles of the response variable, such as the 90th percentile. Quantile regression is particularly useful when the rate of change in the conditional Quantile, expressed by the regression coefficients, depends on the Quantile (Chen 2005). In all the models used in this research, fixed effects of province, year and month of calving, as well as linear co-variables of HGP, IC and AFC (except of the model for AFC as the trait) were included. For TMILK, lactation length was also included as linear co-variable. Moreover, in addition to the quantile models and for the sake of estimating usual regression coefficient, general linear model (GLM) was also fitted for each trait in which a single regression coefficient of the trait on IC was defined. Ordinary least-squares regression can be used to estimate conditional percentiles by making a distributional assumption such as normality for the error term in the model. The main advantage of Quantile regression over ordinary least-squares regression is its flexibility for modeling data with heterogeneous conditional distributions (Chen 2005).      

Based upon the analysis of main pedigree file, the total number of animals was 1,941,871 (16,169 sires and 895,376 dams) among which the number of base and non-base animals were 246,388 (3,936 sires and 120,287 dams) and 1,695483 (12,233 sires and 775,089 dams), respectively.Total number of inbred animals in the pedigree was 1,211,343. Average IC for total as well as inbred animals was found to be 0.9149% (minimum 0% and maximum 47.02%) and 1.4651% (minimum 0.00038% and maximum 47.02%), respectively. For the cows with records for all five traits, IC ranged from 0 to 38.45% with the average of 1.13% (SD=1.63%). Estimate of annual change of IC was found to be 0.017 (SE=0.005), which was statistically significant (P<0.01) indicating that there is a positive increase of inbreeding in Iranian dairy cows’ population over the time. Within each trait, different Quantiles were unequally influenced as animal’s IC increased. Vast majority of the estimated regression coefficients in different Quantiles were statistically significant (P<0.05). Based upon fitting Quantile regression model and the average estimated regression coefficients, it was found that TMILK, MILK3052X, ADM, LL, and AFC changed -5.5 (Kg), -2.6 (Kg), -18 (g), 0.35 (d) and 0.30 (d), respectively as the IC of the animal increased by 1%. Estimated simple regression coefficients based on fitting GLM models were found to be -9.83 Kg (SE=1.332 Kg), -6.9 Kg (SE=0.169 Kg), -32 gram (SE=4.2 gram), 0.2087 d (SE=0.08234 d) and 0.0158 m (SE=0.0024 m), respectively and all were statistically significant (P<0.05).     

This research indicated that different Quantiles of some productive and reproductive traits of Iranian dairy cows are not equally affected by inbreeding phenomenon suggesting that Quantile regression models are needed to be utilized in the future research for evaluating the impacts of inbreeding on the other traits, which are of great economic importance.

Genomic information offers new possibilities to control the level of progeny inbreeding. Traditionally, mating plans constrain the inbreeding of predicted progeny by using a matrix of relationships among individuals. In this study aims to improve genetic gain and restrict the inbreeding level of progeny, a founder population, with effective population size 1000 and 1000 generations, was simulated using the QMSim program to generate linkage disequilibrium. Thereafter, 500 males and 500 females were used to generate a secondary 10-generation population, with 1000 individuals per generation and its corresponding phenotype and genotype in SNP terms. Five hundred sires and 500 dams from generation 1010 were randomly selected to create generation G0 and a trait with heritability of 0.3 was simulated. The eight strategies consisting of two mating designs: minimum_inbreeding (minf) and random (rnd) and four relationship matrices as matrices of A, GRM, IBS and Weighted were used to estimate breeding value for ten generations. Comparison of strategies showed that type of mating designs and different relationship matrices had significant effect on amount of genetic gain, homozygosity and inbreeding (p < 0.05). The type of relationship matrix affected the accuracy of predictions. In strategies with weighted matrix (Gweighted), average of genetic gain during 10 generations was less than strategies using A, GRM and IBS matrices. In strategies with random mating, inbreeding rate had increasing trend. Accuracy of selection (0.63) in strategies with A matrix was lower than other strategies. In general,

The purpose of this study was investigated the genetic gain, increase of average inbreeding and accuracy of prediction using simulated data under different mating designs. Two level of heritability (0.1 and 0.5) and five maing designs including random mating (rnd), mating based on minimum inbreeding (minf), mating based on maximum inbreeding (maxf),positive assortative mating design based on phenotype (phen) and positive assortative mating design based on estimated breeding value (ebv) were considered. The genetic gain after ten generation in rnd, minf, maxf, phen and ebv mating designs for heritability 0.1 were 0.836, 0.747, 0.952, 0.877 and 1.023 units, respectively, and for heritability 0.3 were 2.979, 2.997, 3.016, 3.303 and 3.595 units, respectively. After ten generation increase of average inbreeding for heritability 0.1 was 0.084 in rnd, 0.038 in minf, 0.353 in maxf, 0.079 in phen and 0.215 in ebv, and for heritability 0.3 was 0.057 in rnd, 0.026 in minf, 0.356 in maxf, 0.092 in phen and 0.177 in ebv, respectively. The results shoewd that the genetic gain in minf design was greater than others mating designs per 1% increase of inbreeding, and minf design was better than other mating designs.

The aim of the study was to compare two strategies in Mazandaran native fowls using computer simulation.  Simulated traits included body weight at birth (BW1), at eight weeks of age (BW8), at twelve weeks of age (BW12), at maturation (BWM), age at sexual maturity (AFE), weight of first egg (EWM), mean egg weight from 28 to 32 weeks of age (EW28-32) and egg number (EN). The first strategy was to select cockerels based on breeding value of BW12 and hens based on a selection index with 4-traits including BW12, AFE, EW28-32 and EN. The second strategy was to select cockerels and hens using a selection index based on a 4-traits including BW12, AFE, EW28-32 and EN. After 10 generations, the first strategy improved BW1, BW12, BWM, EW28-32 and EWM to 1.49, 573.81, 397.58, 3.96, and 3.75 grams and AFE and EN to -3.51 days and 2.09 eggs, respectively. After 10 generations, the gain for traits in the second strategy for BW12, BWM, AFE and EN was 415.78, 218.74 grams and -9.77 days and 9.45 eggs, respectively. At the end of the tenth generation increase of inbreeding in the first and second strategies was 0.048 and 0.070, respectively.  The results showed that the first strategy was suitable for a breeder flocks with the aim of chickens suitable for broiler production and the second strategy was suitable for a dual-purpose flocks with the aim of producing egg and meat.

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.

Introduction Control and management of genetic diversity of breeds is necessary for their sustainable use in the future because a limited number of breeding animals will unavoidably lead to increased inbreeding and thus to a reduction in additive genetic variance, and maybe to inbreeding depression. Managing inbreeding is usually one of the major goals in conservation and selection programs of breeds. Some of descriptive parameters of population structure are the inbreeding coefficient, effective population size, effective number of founders, effective number of ancestors, effective number of founder genomes, effective number of non-founder genomes and average generation interval, which are indicative of genetic diversity levels in a population. In a breeding program, the inbreeding coefficient and the rate of annual inbreeding should be monitored because of their influence on production and on the estimation of genetic parameters. The Lori-Bakhtiari sheep is one of the most important native breeds of Iran. With more than 1.7 million head population are mostly kept on village or semi-migratory system in Chaharmahal and Bakhtiari province. This breed has the largest fat-tail size among all of sheep breeds in Iran. The objective of this study was to investigate genetic structure and genetic diversity of Lori–Bakhtiari sheep using pedigree analysis and the inbreeding depression of body weight traits was estimated.
Materials and methods The pedigree information of 7693 Lori–Bakhtiari lambs (2478 male and 5215 female) from 274 rams and 2006 ewes collected from 1990 to 2011, were used. The data were collected at Shooli sheep breeding station in Shahrekord, Chaharmahal and Bakhtiari province. Estimation of inbreeding coefficients was done by CFC software and Endog (v4.8) software was used to compute other pedigree analyses including mean coancestry, effective population size, probability of gene origin parameters and average generation interval. Parameters based on the probability of gene origin were used to describe genetic variability. To investigate the effect of inbreeding on body weight traits, the data of birth weights, weaning weights, weights at six months of age, weights at nine months of age and weights at 12 months of age were used. Inbreeding depression was estimated as the regression of these performance records on the individual inbreeding coefficients by fitting an animal model. WOMBAT software was used for estimating the inbreeding depression of body weight traits.
Results and Discussion Total number of founders, effective number of founders, effective number of ancestors, effective number of founder genomes and effective number of non-founder genomes were 506, 105, 90, 65, 181 heads, respectively. Average generation interval and effective population size were 4.23 years and 249 heads, respectively. The generation interval in the dam-progeny pathway was shorter than in sire-progeny pathway. Estimated average coancestry and inbreeding coefficient were 0.76 and 0.56, respectively. Animals with progeny were 29.7 % and those of without progeny 70.3 % of the total animals. Animals with both known parents and one unknown parent constituted 92 % of the population. Between all the registered animals, 28 % were inbred. The average inbreeding coefficient during the study period for inbred and all animals were 2 and 0.56 %, respectively. The most inbred animals, equivalent to 25% of the inbreeds, had inbreeding coefficients equal to or lower than 5 %. The regression coefficients for birth weight, weaning weight, weight at 6, 9 and 12 months of age on inbreeding were -11, -106.6, -259.7, -161.2 and -239.9 g, respectively.
Conclusion Considering the parameters obtained from the probability of gene origin analysis, the contribution rate of founders and major ancestors have been unbalanced due to the selection of animals that led to decrease of genetic diversity. Estimated inbreeding depression of body weight traits for this breed was higher than other sheep breeds of Iran and showed high degree of close mating in this herd. Due to the deleterious effect of inbreeding on body weight traits it is suggested that this breeding station should use a better breeding plan to avoid mating of close relative animals. At this study, the presence of inbreeding depression for body weight traits also confirmed reduction of genetic diversity in this population. The results of this study also indicate that genetic variability within this population has to be monitored constantly in order to prevent or minimize loss of founder alleles due to genetic drift or selection. The authors suggested that pedigree analysis should be done periodically in this breeding station. Doing this analysis would also prevent or control kinship in this breeding population.

Along with increase in genetic progress, maintaining genetic diversity in any population is very important to adapt with the economic and environmental changes in the future and ensure long-term response to selection for traits that are very important. Intensive use of a few breeding animals, where the selection intensity is high, could result in greater rates of inbreeding in the population. Therefore, a small number of seedstock, with a strong family relationship, is responsible for the maintenance of almost the whole genetic pool in the population. This is an aspect of great influence in the genealogical analysis of a population structure, because of its effect on the probability of genes lost between generations and the consequent reduction in genetic variability. The unavoidable mating of related animals in closed populations leads to accumulation of inbreeding and decreased genetic diversity. Measurement of the effect of inbreeding on these traits is important in order to estimate the magnitude of changes associated with increases in inbreeding although direct selection for lower maintenance requirements is difficult. Some populations may show a very pronounced effect of increased inbreeding for a trait, whereas others may not display much of an effect. The rate of inbreeding needs to be limited to maintain diversity at an acceptable level, so that genetic variation will ensure that future animals can respond to changes in the environment and to selection. Without genetic variation, animals cannot adapt to these changes. Commonly, negative inbreeding effects, or inbreeding depression, are thought to most frequently occur because of an increase in frequencies of recessive alleles that adversely affect the traits of interest. The increased frequency of recessive alleles leads to a larger number of individuals that are homozygous for the recessive alleles, whereas in non-inbred populations, the recessive allele would more frequently be masked by an advantageous dominant allele. Kleiber ratio (KR) allows us to identify efficient animals. This ratio, defined as growth rate/ metabolic weight (body weight0.75), was suggested for measuring growth efficiency. One of the most important breeds of Iranian sheep is Mehraban sheep which is reared in Hamedan province. This breed is adapted to harsh climate and rocky environments in the western regions of Iran. The Mehraban is a fat-tailed carpet wool sheep with light brown, cream or grey color, dark face and neck and primarily used for meat production. The objective of this study was to evaluate the inbreeding effects on daily weight gain and Kleiber ratio in Mehraban sheep.
Data and pedigree information used in this research were collected from 1994 to 2011 in Jihad Agriculture Organization of Hamedan province. Studied traits were average daily gains from birth to weaning (ADGa), average daily gain from weaning to 6 months (ADGb), average daily gain from weaning to 9 months (ADGc), average daily gain from weaning to yearling (ADGd) and corresponding Kleiber ratios (KRa, KRb, KRc and KRd). All animals were grouped into three classes according to their inbreeding coefficients: the first class included non-inbred animals (F=0) and the second and third classes included inbred animals (0 Significant regression coefficients ADGa, KRa, ADGb, KRb, ADGd and KRd on inbreeding of all lambs were observed for 1% increase of inbreeding. According to the birth type, the regression coefficient of all traits except KRc on inbreeding of single-born lambs and ADGa and KRa on inbreeding of twin-born lambs was significant for a 1%. increase in inbreeding. According to lamb sex, the regression coefficient of all traits except ADGd and ADGc on inbreeding of male lambs and ADGc and KRd on inbreeding inbreeding of female lambs was significant for a 1% increase in inbreeding.
The results showed both significant and non-significant effects of inbreeding on daily weight gain and kleiber ratio traits. The results of this study showed that inbreeding level of over 90% of animals was between 0 and 50%. These results indicate multiple use of a small number of sires in the herd, also the lack of use of mating programs designed for prevent high levels of inbreeding in Mehraban sheep.
The results showed positive and significant effects of inbreeding on average daily gains and Kleiber ratios in Mehraban sheep.

The Raeini Cashmere goat is one of the most important breeds among Iranian goat. This study was conducted to characterize genetic diversity and population structure of Raeini Cashmere goat using pedigree analysis, to identify factors affected the genetic variability of this breed. By knowing these kinds of parameters especially probability of gene origin parameters animal breeders could suggest good strategies to manage inbreeding and describing decrease in genetic variability in the population.
The information of 7264 goat from 293 fathers and 2057 mothers were used. The data were collected during 1990-2013 in Raeini Cashmere goat breeding station in Baft, Kerman. Estimation of inbreeding coefficient was done by CFC software. Endog (v4.8) software was used to compute other pedigree analyses including mean coancestry, mean relationship, effective population size, probability of gene origin parameters and average generation interval.
The mean generation interval was 3.93 years. The generation interval in the dam-progeny pathway was shorter than in sire-progeny pathway. The mean coancestry of this population was estimated 0.012 percent. Average inbreeding coefficients of the population and within inbred population were 0.08 and 3.5 percent, respectively. Inbred animals formed small part of the population and included about 2 percent of total animals. The maximum inbreeding coefficient was 25 percent and the majority of inbred animals were animals with inbreeding coefficient up to 5 percent. Increase in inbreeding was 0.004 percent per year and based on 3.9 generation interval inbreeding will increase about 0.015 percent per generation. The mean relationship was 0.24 percent. The relationship coefficients estimates between male and female animals are to predict the future level of inbreeding in population. The total number of founder animals, the effective number of founders, effective number of ancestors and effective number of founder genomes, were estimated 1227, 251, 232, 240 heads, respectively. Also, the effective population size was 191 heads.
The results of this study showed that the effective population size of this population decreased during the period of research. The effective population size in Raeini Cashmere goat was in good condition according to the FAO suggestion. An effective population size of 50 determined by FAO as a critical status for animal populations. But if this trend continues in the future, the effective size of the population will approach to critical levels. The results of this study indicated that, the contribution of the founders and major ancestors to the population has been unbalanced due to the selection of animals and the genetic variability of the population decreased compared to the founder population. In comparison to other breeds, the population under study has an acceptable level of genetic variability.

Effects of lamb and parents coefficient of inbreeding (CI) on wool weight were studied using 10،868 wool records belonging to 3،244 Iran Black lambs (1،633 males and 1،611 females) representing 96 rams and 995 ewes collected during 1983-2006 from Animal Breeding Station of Abbas Abad. Year and month of shearing، CI of lamb and dam، sex and birth type had significant affect on wool weight Among 3،244 pedigree animals، 3،005 heads (92. 6 percent) were found to be inbred. Mean and standard deviation of CI of lamb، sire and dam in whole population were 8. 1±6. 1، 6. 5±6. 1 and 5. 3±5. 8 percent، respectively. The corresponding figures in inbred population were 9. 0±5. 7، 7. 0±6. 1 and 5. 7±5. 8 percent، respectively. Minimum and maximum CI of lamb was 0 and 36. 4 percent، respectively. Increase of CI by one percent was accompanied with a decrease of 26. 9 g (quadruplet male)، 4. 8 g (twin female)، 4. 3 g (triple female) and 13. 1 g (quadruplet female) in wool weight. A decrease of 1. 4 g in wool weight of lamb was observed as the CI of dam was increased by one percent. Statistically significant annual change trend were estimated to be 0. 2±0. 02 percent and 0. 1±0. 02 percent for whole and inbred populations، respectively. A controlled mating is needed to reduce deleterious effects of inbreeding.

This study was conducted to estimate coefficient of inbreeding of Shirvan Kordi sheep based on molecular and pedigree information. Pedigree of 7170 lambs produced from 177 rams and 2182 ewes collected during 1989 to 2009 in Shirvan Kordi sheep breeding flock were used for calculating inbreeding coefficient. Average inbreeding coefficient of the flock on base year 1989 was estimated as 0.668%. Coefficient of inbreeding was also estimated in this population using 6 microsatellite markers (BM8125, BMS2361, BM6526, BM6438, BMS1004 and BM6444) and 100 blood samples. A total of 34 alleles with an average of 5.67 was observed for each locus. Within population inbreeding (FIS) in Shirvan Kordi sheep breeding flock ranged from -0.1859 for BM6526 to 0.3329 for BM6438. The FIS estimates were positive for BM6438 and BM6444 loci (0.3329 and 0.2287, respectively) and for the other loci were negative. Average inbreeding coefficient based on marker data was estimated as 0.2617%. Microsatellile loci used in this population showed a high polymorphism and can be used for future genetic studies in this population. These estimates may be closer to the true values using more number of genetic markers across the whole genome and higher sample size. Moreover, the results indicated that the estimates of genetic resemblance between individuals based on allelic contribution of a limited number of loci may not be very accurate for measuring the relationships and making breeding decisions in the flocks. Therefore, estimation of inbreeding coefficients using pedigree is suggested.

In this research، a total of 27،241 edited records from four distinct files of calving، pedigree، insemination and production collected by Iranian animal breeding center، from 1984 to 2007 were used to study effects of inbreeding، on various traits in 543 herds of Iranian Holsteins. The traits was age at first freshening، days of productive life، total milk، mean fat percent، mean calving interval، relative net income (lifetime profit) and RNI per day (profit per day of lifetime). Preparing and required edition of the data was undertaken by Foxpro and Excel software. For calculating the inbreeding coefficients، Pedigree software (Sargolzaee، 2000) was utilised. The overall average inbreeding coefficients was 1. 63%. Relative net income of per cow was calculated by Shadparvar equivalent (1999) based on the costs and incomes of 2007، from Sefidroud (first farm) and Maghan (second farm) farms. The effects of inbreeding on the traits were analyzed by a model (with inclusion of herd and first calving year) by Proc GLM of SAS program. In the model، herd and first calving year effects on all traits was highly significant (P<0. 001). Inbreeding effect on age at first freshening، total milk، RNI and RNIPD was highly significant (P<0. 001). This effect was not significant on productive life، mean fat percent and mean of calving interval. The result of this research showed that the average inbreeding coefficient in Iranian Holsteins was lower than the other populations، which could be the result of the avoidance of farmers from inbreeding and also because of incomplete or wrong information. This research also revealed that the price level of products and nourishment costs could affect the profitability of inbred cow such that an inbred cow is harmful in one herd but is useful on the other herd condition.