Serum protein profile could be considered as a useful indicator of physiological and pathological conditions, but several factors may interfere with the interpretation. This study was conducted to evaluate serum protein fractions in association with age, body weight, birth type and birth season in a meat-type sheep. Blood samples were randomly taken from 96 healthy Lori-Bakhtiari ewes in the Shooli breeding station in Iran. The sampled animals randomly belonged to different age, birth type, birth season and body weight groups. Total protein and other fractions were determined by Biuret and electrophoresis methods, respectively. IgG levels were measured by ELISA method. Total protein, albumin, total globulins, albumin/globulins ratio, α1, α2, β and γ globulins and IgG levels averages were 5.82, 2.35, 3.47, 0.69, 0.06, 0.42, 0.15, 2.82 and 1.56 g/dL, respectively. Total protein had high correlations with total and γ globulins, while albumin and IgG were almost independent from other fractions. Levels of serum protein fractions in adults were also independent from body weights at different ages. Serum protein profile was significantly affected by age and birth season (P<0.05), where by older ewes had lower levels of α2, γ and total globulins and higher albumin/globulin ratios. The winter-born ewes significantly had higher γ globulins levels and probably more immune system activities, compared to the spring-born ewes. Body weight and birth type did not have any significant effect on the studied serum protein fractions. This study suggested that the age and birth season should be considered for interpretation of the serum protein profiles. تفاصيل المقالة

Abortion is an important trait with noticeable impacts on economic profit of dairy herds. This study was conducted to estimate variance components and genetic, environmental and phenotypic trends for abortions in Iranian Holstein Friesian cows. The data used were 247230 calving and abortion records of 84421 Holstein cows, collected during years 1991-2016, from 51 herds in Iran. Variance components and genetic parameters were estimated using a logit link function, fitting an animal mixed model by ASReml software. In this model, parity and milk yield were fixed, while direct additive genetic, herd-year-season and permanent environment effects were considered as random factors. Genetic, phenotypic and environmental trends were estimated as weighted regression coefficients of breeding values, phenotypic values and environmental deviations averages on birth year, respectively and the number of observations was considered as the weighting factor. Generally, abortion risk in the first parity was lower than the later parities and in autumn was lower than the other seasons. Abortion risk also increased by increase in milk yield level. Heritability and repeatability estimates for abortion were both 0.165 ± 0.010. A significant positive genetic trend (0.038 rate/year) and a significant negative environmental trend (-0.033 rate/year) were estimated for abortion, which indicated significant increase of genetic predisposition to abortions and improvement of environmental conditions to prevent abortion incidence. A significant positive phenotypic trend (0.002 rate/year) was also estimated, which showed overall increase of abortion rate during the studied years. Overall, it could be concluded that genetic predisposition to abortion is increasing in Iranian Holstein cows, but inclusion of abortion risk in bull proofs and selection indices may help to reduce abortion incidence and increase economic profit of dairy cattle industry. تفاصيل المقالة

In the present study, the polymorphism of myostatin gene (MSTN) in native chickens of Western Azerbaijan Rearing and Breeding Institute was investigated. The blood samples were collected from eighty two randomly selected hens. Genomic DNA was extracted from blood samples and a fragment of myostatin including 599 bp in promoter and exon 1 was amplified using PCR method. Breeding values for body weight and carcass traits were predicted by univariate animal mixed model analysis, using WOMBAT software. The effects of different SSCP genotypes on breeding and phenotypic values of the studied traits were evaluated by general linear model analysis. Three different single strand conformational polymorphism(SSCP) genotypes as AA, AB and AC were identified, with frequencies of 0.244, 0.549 and 0.207, respectively. Shannon and Nei gene diversity indices and number of effective alleles in the studied population were 0.88, 0.53 and 2.2, respectively, which indicated a high diversity of the studied population. Moreover, the studied population was not in Hardy-Weinberg equilibrium. The effect of the SSCP genotypes on breeding and phenotypic values was significant only in the case of breeding value for body weight at 12 weeks of age, whereas, the AC genotype individuals, significantly (P<0.05) had the lowest breeding value for body weight at 12 weeks of age. Based on the results obtained, it could be concluded that the studied fragment of myostatin gene is polymorphic in native chickens of Azerbaijan and could be used for marker assisted selection. تفاصيل المقالة

The aim of the current study was to evaluate the replacement effect of soybean meal (SBM) at different levels (0 as D1, 33 as D2, 67 as D3 and 100% as D4 based on crude protein (CP) content) by guar meal (GM) on ruminal gas production kinetics, ruminal digestibility and fermentation characteristics of a fattening diet for lambs. Three experiments were conducted. The first experiment of 144-h incubations was aimed to determine comparatively the gas production kinetics of SBM and GM. The gas production kinetics and the ruminal digestibility and fermentation of the fattening diet, containing different proportions of SBM and GM, were also studied by the incubations of 144-h and 24-h in the second and last experiments, respectively. The results of the first kinetic experiment indicated a higher asymptote of gas production (a), half time to asymptote of gas production (T1/2) and metabolizable energy (ME) and a lower fractional rate of gas production (µ) for SBM than GM (P <0.001). Replacing SBM with GM had no effect on gas production kinetics of the fattening diet at any substitution levels in the second kinetic experiment (P>0.05). However, the gas produced after 24-h of incubation (GP24), in vitro true dry mater degradability (IVTDMD), in vitro true organic matter degradability (IVTOMD), partitioning factor (PF), microbial biomass production (MBP) and total volatile fatty acids (TVFA) concentration increased with D2 compared to D1 and D3 in the last experiment. The ammonia concentration decreased with D2 and D3 compared to D4 (P<0.05), nevertheless, the ruminal volatile fatty acids (VFA) pattern was not affected by the treatments (P>0.05). These results demonstrated that the protein from SBM might been replaced by that from GM in fattening diets for lambs at the levels up to 67%, but the 33% substitution is recommended because of its beneficial effects on ruminal digestibility and fermentation. تفاصيل المقالة

The aim of the present study was the estimation of (co) variance components and genetic parameters for body weight of Moghani sheep, using random regression models based on B-Splines functions. The data set included 9165 body weight records from 60 to 360 days of age from 2811 Moghani sheep, collected between 1994 to 2013 from Jafar-Abad Animal Research and Breeding Institute, Ardabil province, Iran. Random regression models were employed to analyze the data. Contemporary groups (year-season of birth -sex-birth type-dam age at the birth) and fixed regression of body weight on age were considered as fixed parts of the models. Random regressions of direct additive genetic, permanent environment, maternal additive genetic and maternal environment were random parts of the models. Linear and quadratic B-Spline functions with two or three coefficients were fitted for fixed and random regressions of the models. A heterogeneous structure of residual variance was considered in five age classes. Variance components were estimated by average information algorithm of restricted maximum likelihood (AI-REML). Different models were compared based on Akaike information criterion (AIC) and Schwarz Bayesian information criterion (BIC). According to both criteria, the best model was a model with quadratic B-Spline functions with 3, 3, 3, 2 and 2 coefficients for fixed regression and random regressions of direct additive genetic, permanent environmental, maternal additive genetic and maternal environmental effects, respectively. According to this model, low to moderate estimates of direct heritability (0.135 to 0.330) and moderate to high estimates of coefficient of permanent environmental effects (0.229 to 0.613) were obtained, while estimates of maternal heritability (0.05 to 0.14) and coefficient of maternal environment (less than 0.01) were low or negligible in all ages. تفاصيل المقالة

The periodic trimming of the long hairs growing at the distal end of the tail -switch trimming- is humane alternative of tail docking. The purpose of this study was to determine the influence of switch trimming on somatic cell count (SCC), California mastitis test (CMT) and udder cleanliness of lactating cows in a free-stall dairy farm. In the present study, 219 healthy, pregnant Holstein cows were enrolled. All cows were randomly allocated to either trimmed (T) (n=107) or control (C) groups (n=112) prior to entering the calving pen. The long hair in the tail switch of the cows enrolled in group T was removed completely by a hair clipper machine, while the tail hair of the animals enrolled in group C remained intact. After two months, all studied cows were evaluated for udder cleanliness and health. Udder cleanliness scores (UCS) were significantly associated with switch trimming of the tail (P=0.0129). Both trimmed and control cows showed significant difference in UCS of 2 and 3 (P≤0.05), though the difference in other UCS was not significant. No significant difference (P=0.41) in SCC between groups was identified. Comparing the CMT scores of front, rear, or all udder quarters showed that the frequency of a CMT score of 0 in group T was significantly higher than in group C (P≤0.05). Reversely, the frequencies of Trace and 2 scores of CMT for rear and all udder quarters in the control group were significantly higher than the group T (P<0.05). The results of this study show that switch trimming may be suggested to improve cleanliness and udder health of dairy cows in free-stall housing systems. تفاصيل المقالة