جستجوی مقالات مرتبط با کلیدواژه "صفات تولید مثلی" در نشریات گروه "علوم دام"

Reproductive efficiency is one of the most important factors influencing dairy cow performance. In the present study, relationship between the polymorphism in interleukin 2 (IL-2: exon 6) and interleukin 10 (IL-10: exon 5) genes with reproductive characteristics including days open, calving interval, days from calving to first duty, gestation period, Service result, stillbirth and calving ease was examined.

In the present study, the relationship between interleukin 2 and interleukin-10 as two candidate genes with some important reproductive traits in Holstein dairy cows was investigated by means of selective genotyping. Individuals were selected based on their open door residuals obtained from mixed models. In the model used, the effects of year of birth, year of calving, time of calving and lactation were taken into account as fixed effects, and the random effects of the animal and the covariate effect of milk yield were also included in the model. A total of 194 cows, 97 of which were individual cows, were selected from both tails of the residual value distribution. The DNA was extracted using a modified salting out procedure. Polymerase chain reactions (PCR) using specific primers were implemented to amplify fragments of 172 bp and 325 bp of IL-2 and IL-10, respectively. Different banding patterns were identified using the PCR-SSCP technique. The Cox test in SAS was used to examine the association between banding patterns with open days, calving interval, days from calving to first service, gestation duration. The logistics regression was implemented in SAS for service results, stillbirths and calving ease.

The results showed the existence of polymorphism for both loci studied. Four different band patterns in IL-2 and seven different band patterns in IL-10 were observed. At the IL-10 locus, striped patterns 5 and 6 had the highest frequency and pattern 3 showed the lower frequency in the individuals with residual values below the mean. In the second group with residual values above the mean, the highest frequency was observed for pattern 6, which also had the highest frequency in the total samples. For IL-2, patterns 1 and 2 showed the greatest and lesser frequency, respectively, in the individuals with residual values below the mean. Pattern 4 had the lower frequency in this locus. Statistical results showed the significant association of IL-2 on open days and length of gestation. In addition, IL-10 had the significant effect on open days.

Taking into account the polymorphisms in the studied regions for the population of Holstein dairy cows and the association of these polymorphisms with reproductive traits, following confirmation of the results using sequencing approach, these regions could be considered in animal breeding programs.

An experiment was carried out to evaluate the effect of different levels of dietary methionine on performance, blood parameters and reproductive traits of laying Japanese quail for 9 weeks(8-16 week of age). A total of 140 female Japanese quails were distributed in completely randomized experimental design with five treatments (56 days of age) with 4 replicates(7 birds in each replicate). Treatments including: 0.35, 0.40, 0.45, 0.50 and 0.55 % of methionine concentration in the diet. The results of study demonstrated that in first period (8-12 week), second period(13-16 week) and the whole period(8-16 week), methionine levels had a significant effect(P>0/05 (on egg production and egg mass(gr/bird/day) which the highest egg production and egg mass were related to birds fed on diets containing 0.45%, 0.50 % methionine, respectively. The comparison of treatments demonstrated that with increasing the methionine concentration, albumin and uric acid level were decreasing. The results of this study shows that the highest production performance and reproduction indicators in the first period (8-12 week), second period (13-16 week) are related to 0.45%, 0.50 and 0.55 % of methionine in diets and therefore these levels can be considered as requirements of layer Japanese quail in laying phase.

The best way to maximize the profitability through breeding is using economical coefficients of characteristics with genetic assessment. One of the effective ways to increase profitability in animal husbandry is using livestock breeding. It is not possible to utilize breeding optimized method without considering relative importance of characteristics economically. On the other hand, the best way to determine the relative importance of characteristics is to calculate the economic coefficients. Economic Value of characteristic is the profit obtained from one unit genetic improvement of the average of a characteristic when other characteristics are held in their constant values. Bio-economic model is a set of equations which define the incomes and costs of the production system as a function of different characteristics. Simulation is a process in which a set of examinations are carried out by using a designed method on the basis of a real system in order to find out the system behavior and various approaches are assessed for its operation in a defined range.
The aim of the present study is to estimate the economic value of production and reproduction characteristics of dairy cows of Mohan cultivation, industry and animal husbandry based on collected data from 13000 dairy cows and market conditions in 2014 and by using a determined bio-economic model. The income factor included obtained incomes from milk sale, additional heifer sale, male calf, removed cows and fertilizer sale and the costs included nutrition, management and capital costs. The management costs included health and care, human forces and reproduction. Five different stages defined in animal life cycle. These stages including from birth to weaning, from weaning to the age calf sale (12th month), from weaning to the first insemination of female calf (18th month), from first insemination to first birth (alternative heifers) and productive cows more than two years old. The calculation of cost and revenue of the heifer per 18 months is carried out. The breeding period of calf, young cow and productive cow considered 12 months. In these herds, nutrition was done completely manually and in the place. Nutrition cost was calculated using energy requirements estimation equations AFRC (1991) by considering the consumed concentrate constant for productive cows, growing male and female calf and alternative heifers separately. In this system, artificial insemination is used for cows impregnate and reproduction cost considered as a function of interval of two births which indicates the number of insemination which resulted in impregnation. Health program included vaccination, deparasitation and quarantine. Male calf was sold based on each kilogram weight per each calf at a constant price. In present study, dairy cows in production system were categorized in seven different age groups of 2, 3, 4, 5, 6, 7, 8 and then revenues, costs, final profit and economic value of characteristics calculated for every age group separately. The studied characteristics include milk production, fat milk production, age of the first birth, calf birth interval, increasing daily weight before and after weaning, birth weight, matured calf weight and live rate before and after weaning. The bio-economic model designed based on breeding and information system of herd and economic coefficients calculated by matlab software. Economic value of each characteristic estimated based on the changes in annual profit of production system per one unit increase in the average of the considered characteristic while other characteristics are kept constant. First, all of the revenues and costs and profit and herd combination determined and the input files saved and the program ran.
Annual revenues and costs calculated based on different age groups and the annual profit was 15966572/69 Rials for each productive cow. Among revenue resources, 71% was for milk sale and its components, 10% for removed cow sale, 11% for male calf sale, 6% for additional heifer sale and 2% for fertilizer sale. Among variable costs 68% was for nutrition costs, 17% for work force cost and livestock sale and 10% for health and reproduction costs. Economic values of production and reproduction characteristics including milk production, milk fat production, age of first birth, calf birth interval, daily weight increase after and before weaning, birth weight, matured calf weight and live rate before and after weaning estimated 4718/59, 144757/8, -30756/52, -86789/17, 1284/45, 34/57, 9894/16, -1900/13, 5808 and 107521/9 Rials per each cow respectively. The highest relative importance related to production characteristics (54/37%) and after that reproduction (21.98%), durability (20/56%) and the least amount estimated for growth (3/07%). Characteristics can be divided into several groups based on the impact on revenues and costs. Economic values of production and reproduction characteristics including milk production, milk fat production, age of first birth, calf birth interval, daily weight increase after and before weaning, birth weight, matured calf weight and live rate before and after weaning estimated 4718/59, 144757/8, -30756/52, -86789/17, 1284/45, 34/57, 9894/16, -1900/13, 5808 and 107521/9 Rials per each cow respectively. The highest relative importance related to production characteristics (54/37%) and after that reproduction (21.98%), durability (20/56%) and the least amount estimated for growth (3/07%). Characteristics can be divided into several groups based on the impact on revenues and costs. A group of characteristics increase the revenue and cost of production system and also increase the profit compared with the initial state (initial value). Most of the production characteristics such as milk production, fat, increase of weight before and after weaning, birth weight and live rate before and after weaning are placed in these groups. However, by increasing one unit of matured cow weight, the revenue and costs are increased and but the obtained profit is decreased. Characteristics of the second group do not impact the revenue but the costs of production system increased by increasing its average which include the age of the first birth. The third group includes the characteristic of interval between two births and the revenue decreased, system costs increased and profit decreased by increasing its average.
Increase in the average unit production and reproduction traits have different effects on revenue, cost and profitability of production systems.

The parturition is a very important stage in the longevity of cows and related to future animal health. The health parturition and avoid dystocia are main issues that needed to attention in farms. Prolonged or difficult parturition called dystocia and effects on the profitability of herds, animal welfare and admissibility of the production system of consumers. Dystocia is the main cause of stillbirth, death of cattle and calves and decreasing fertility, also have a negative effect on the reproductive traits (such as higher days open and number of inseminations per conception). This situation can also lead to increasing risk of infertility, the outbreak of diseases after parturition, culling probability and cost of veterinary. Although dystocia is one of the most important problems in dairy cattle production system and had major economic losses in the dairy industry. Thus, the objective of this study was to estimate genetic and environmental correlations between dystocia and production traits (milk, fat and protein production), reproduction (calving interval, calving to first service, fist service to conception) and birth weight in Holstein cattle of Iran with Bayesian linear- threshold model.
In this study, data collected by Animal breeding center of Iran during 1989 to 2012 were used. The dystocia was considered as traits for the mother and the service sire was fitted for this trait as an additional random effect. After edition of records, dystocia (threshold with 5 scores) with other traits (linear) were analyzed as bivariate analysis by Gibbs sampling method via DMU software. Gibbs chains with 300000 iterations were generated, with an initial discard of 20000 samples and a sampling interval of 120 iterations. Therefore, each analysis 2500 samples of (Co) variance components were obtained. The convergence checking of the chains generated by the Gibbs sampler was done using graphical analysis and diagnosis tests available in the Bayesian output analysis program (BOA).
Maximum frequency of dystocia was related to unassisted calvings (80.35%) and only 19.65 % of calving were performed with assistance. Among calving that require to assistance, the highest number was for assistance with no damage (11.43 %) and 8.22 % of calvings require a lot of assistance. The posterior mean of heritabilities for milk, fat, protein, calving interval, calving to first service, first service to conception, birth weight and dystocia were 0.175, 0.120, 0.126, 0.050, 0.040, 0.004, 0.128 and 0.012, respectively. According to the estimated heritability, the genetic selection for production traits and birth weight can be somewhat effective, but it will not observe appropriate response for reproductive traits and dystocia. The genetic correlation between dystocia with production traits were estimated low and negative (exception of fat). Low genetic correlations between traits showed that these traits were not influenced by same genes. The highest genetic correlation was estimated between dystocia and birth weight that showing similar genes affected for these traits and dystocia was increased due to increasing of birth weight. The genetic correlation between dystocia with calving to first service and first service to conception were obtained positive and negative, respectively, indicating that dystocia can be increase calving to first service and decreased first service to conception. Increasing of calving to first service interval can be created opportunity for improvement of anatomical conditions of the animal, thus first service to conception could be decreased due to the improvement of the conception rate.
Recent study showed that estimated heritability for production traits and birth weight were high and it was low for reproduction traits and dystocia. The results indicated that improvement of environmental conditions was necessary for the improvement of reproduction traits and dystocia. The highest genetic correlation between dystocia and birth weight suggested that improvement of birth weight increases dystocia. Increasing of calving to first service and reducing first service to conception after dystocia is expected due to genetic correlation estimates for these traits with dystocia.

Reproductive records of 5327 Zandi ewes were collected from a research flock at the Zandi sheep breeding from Varamin station during 1991-2011. Genetic parameters were estimated for main traits such as conception rate (CR), number of lambs born (NLB), number of lambs at weaning (NLW) and the composite traits including number of lambs born per ewe exposed, number of lambs weaned per ewe exposed, total litter weight at birth, total litter weight at weaning, total litter weight at birth per ewe exposed and total litter weight at weaning per ewe exposed. Year, age of ewe, breed of ewe on breeding were used as fixed effects. Direct and maternal genetic effects, permanent environmental effects of ewe and mate of ewe were considered as random effects in the model. The effect of environmental factors such as mating year and age of ewe at mating on all of reproductive traits were significant (P >0.01) exception CR, NLB¡NLB/EE, NLW NLW/EE, TLWB. Parametric and variance components were estimated by linear and threshold models. Estimates of heritability for animal genetic effects were mainly small and ranged from 0.0011 to 0.1 in linear model while the estimates resulting from thershold were ranged from 0.009 to 0.063. Estimates of heritability's for animal genetic and permanent environmental effects were low mainly due to the typical strong influence of environmental factors on reproductive traits. Estimates of repeatability's for animal permanent environmental effects were low to medium by linear analysis, and medium by threshold analysis.

The objective of this study was to study the current reproductive performance of Iranian Holstein dairy cattle. A total of 221, 501 records from heifers and cows of parity 1 to 5 calved in 60 herds collected by Bonyad Organization and Vahdat Cooperative Ltd., during 2001 to 2011, was used. The statistical analysis of data was conducted using generalized linear models and regression procedures of SAS software. In cows, means ± SD were for 405.7 ± 78.7 d. for calving interval, 127.5 ± 63.5 d. for open days, 75.4 ± 27.5 d. for days from calving to first insemination, 63.5 ± 52.1 d. for interval between first and last artificial insemination, 2.7 ± 1.8 for number of insemination per conception, 68.9 ± 28. 5 d. for duration of dry period and 37.6 ± 32.1% for conception rate. In heifers, number insemination per conception, age at first service and conception rate were 2.0 ± 1.4, 454.0 ± 37. 7 d., 63.0 ± 32.0 %, respectively. The linear regression coefficient of least square means for each trait of interest on calving year was defined as phenotypic trend. The trends for all studied traits were undesirable and statistically significant; conception rate for example showed a negative and significant trend of 1.3 ± 0.2 % in cows and 1.9 ± 0.2 % in heifers. Statistical analysis showed that increase in milk production had undesirable and significant effects on reproductive performance; for every 100 kg increase in milk yield, calving interval and open days for example, increased by about 0.5 and 0.4 d., respectively. Current situation emphasized that more attention to reproductive traits is required.

This study was designed to estimate the economic values for important economic traits of Lori goat in Lorestan. Finally the breeding objectives of this animal were determined. Phenotypic and production data for the study were collected from 6 flocks of goats raised under Lori goat breeding project. The questionnaire was designed and the goat rancher breeders were interviewed too. Statistics on revenues and costs were calculated based on the prices of years 2010-2011, according to mentioned questionnaires. Four traits including litter size, birth survival rates, replacement rates and the amount of milk in a lactation period were examined in this study. Also four growth traits including birth weight, weaning weight, daily growth from weaning to 6 months, and 6 months weight for kids were estimated in this research. A biological-economic model as an overall model and sub models for each of the above traits were designed. The corresponding coefficients for traits were estimated. Finally the production system was also analyzed. Based on this study the relative economic weights for litter size, survival rates, replacement rates and the amount of milk yield measured in two systems (one birth in year and 3 births in two years) were 361.89, 487.37, -1.38, 1, and 591.88, 799.75, -1.03 and 1 respectively. The relative economic weights for birth weight, weaning weight, daily growth from weaning to 6 months and 6 months weight in two mentioned systems were 4.96, 11.92, 92.28, 9.25 and 4.07, 18.97, 157.69 and 15.81 respectively. As a conclusion, the reproductive traits and growth rate have the highest economic coefficient, hence shoul be considered in Lori goat breeding programs under rural system.

In this study, records of 64220 first lactation dairy cows were used. Data were collected from 749 herds during 1996 to 2009 by the Animal Breeding Center of Iran. Data included of production (305 d milk yield, 305 d fat percentage, 305 d protein percentage and lactation length) and reproduction (dry days, age at first calving, calving interval and days open) traits. Data analysis was performed by restricted maximum likelihood procedure using DFREML software. The estimated heritabilities of milk yield, fat percentage and protein percentage and lactation length were 0.197, 0.282, 0.333 and 0.031, respectively. The estimated heritabilites of dry days, age at first calving, calving interval and days open were 0.015, 0.079, 0.035 and 0.036, respectively. Genetic correlations between production traits were from 0.52 for milk yield and fat percentage to 0.74 for fat percentage and protein percentage. Genetic correlations between reproduction traits were from 0.07 (age at first calving and calving interval) to 0.95 (dry days and calving interval). Estimated genetic correlation between production and reproduction traits were from -0.63 (milk yield and dry days) to 0.96 (lactation length calving interval). Considering negative genetic correlation between production and reproduction traits, planning of selection programs in dairy cows based on a combination of production and reproduction traits is recommendable.

The aim followed in the present research was to investigate the effect of nine generations of divergent selection on some reproductive and egg production traits in Japanese quail. The results indicated that selection for 4-week body weight، increased the age at sexual maturity of HW and of LW lines، in comparison with control، for about 7 and 3 days، respectively (P<0. 05). At the ages of sexual maturity، there weren’t significant differences observed within the selected lines (P<0. 05)، but these lines were significantly different from control. Body weight at sexual maturity was higher in HW line than in LW and in C. The differences between lines were significant (P<0. 05). Body weight at sexual maturity and average egg weight at different productive stages increased in HW in comparison with control (P<0. 05). This was while، percentage egg lying at the point of sexual maturity was higher in LW than in control (P<0. 05). Total number of eggs laid was higher in LW than in HW and in control while the difference being significant only with HW. The highest percentage of egg-laying was recorded within 3-6 pm in any of the three lines. Peak egg production occurred during the second month. It can finally be concluded that because of the interrelated response between body weight and reproductive traits، it’s important to consider the reproductive and safety traits beside growth traits in selection programs.

In the present research some reproductive traits in Holstein cows of Khoramdareh agro-industry were studied. The data set comprised of 10،891 records collected from 23 years (1988 to 2010) by animal breeding centre، Iran. The total number of animals in the pedigree file was 16/087. Genetic and phenotypic parameters using soft WOMBAT software and restricted maximum likelihood method under animal models and a multivariate trait was estimated. Genetic trend for each trait was estimated using SPSS programmer based upon regression of mean breeding value on year of calving. Phenotypic trend was also estimated based upon regression of phenotypic mean of the trait on year of calving. Levels of heritability from linear model for the traits age at first insemination (AFS)، age at first calving (AFC)، number of insemination resulted in conception (NSPC)، open days (OD)، pregnancy rate (PR)، calving interval (CI)، Non return rate to 90 days (NRR90) respectively 0. 037، 0. 016، 0. 01، 0. 032، 0. 021، 0. 051 and 0. 034، respectively. Maximum genetic correlation between traits and open days and pregnancy rates between insemination number of days open and pregnancy، respectively، leading to -0. 99 and 0/84 and the lowest genetic correlation between PR with NRR90 (0. 001) respectively. Open days and pregnancy rate with the open days and NRR9 respectively Olsen -0. 99 and 0. 00 the highest and lowest phenotypic correlation showed. Genetic trend for the reproduction traits was between -0/009 for NRR90 and -0/04 for CI respectively. Phenotype trend for the about traits has lower trend for (0/002) NRR90 and (-0/74) for AFS respectively. Lower among environmental trend (-0/007) for NSPC and upper among environmental trend for AFS (-6/52) respectively.

In the research the genetic investigation productive and reproductive traits and changes trend the traits in years, seasons and different lactation periods and genetic evaluation cows and bulls of 785 records for milk and 665 records for fat yield and reproductive information during years 1998 to 2003 of 207 dairy cows ghezlagh farm aboureyhan campus (university of Tehran) studied. The least square mean and standard error (LSM ± SE) of milk yield (3x, 305, ME) and fat yield were 6305.6 ± 87.7 and 206.1 ± 1.7 kg, respectively. The least square means (± SE ) of calving interval , open days ,dry days, age at first calving and gestation length were 403.2 (± 6.7 ), 117.5 (± 6.8 ), 86.8 (± 7.3), 760.3 (± 9.7 ), 278.1 (± 0.7 ), respectively and insemination rate was 1.8 (±0.04). The effect of environmental factors of lactation period on milk production, persistency and insemination rate; year of parturition on milk and fat production, calving interval, insemination rate and age at first calving, dry days; and calving season on milk production and insemination rate were significant. Estimated heritabilities and standard error for milk and fat yield using Repeatability Record Animal Model (RRAM), were 0.22 (± 0.12) and 0.29 (± 0.05), respectively. Genetic and environmental trend of production traits during years 1998 to 2003 were positive. The breeding value of the animals for production traits predicted with Animal Model method and the superior families were ranked

Autoselection is a kind of natural selection, that occurs in reproductive traits by inequality of offspring generation and therefore by virtue of the nature of its genes transmission to next generations. In this study, the effects of autoselection on heritability and selection response in reproductive traits by using univariate stochastic computer simulation in artificial selected and unselected populations were investigated. The results showed that, in autoselection and no artificial selection on litter size, additive genetic mean, phenotypic mean and threshold mean increased. Additive genetic variance and heritability had no changes. In autoselection and artificial selection for threshold phenotype on dams and in autoselection and artificial selection for threshold phenotype on dams and for sires base on their mother’s threshold phenotype, the results showed that in high heritability, observed selection response for per generations was more than last generation because with increasing threshold mean, the distribution of threshold phenotype in dam’s population and autoselection response depends to this distribution. Although, autoselection and artificial selection occurred additive genetic variance and heritability had decreased a little, because artificial selection base on threshold phenotype and autoselection prevent to decrease additive genetic variance. Analysis of threshold phenotypic data by MATVEC with threshold model, showed that estimated heritability was less than real underlying heritability and its estimation depends on real underlying heritability, proportion selected and paths of selection.