مجله تولیدات دامی
سال بیست و یکم شماره 4 (زمستان 1398)

The aim of current study was to evaluate the accuracy of genomic breeding values (GEBV) for two important economical traits of milk yield and somatic cell score using SNP markers and LD-based haplotype blocks (haploblocks) by two statistical methods of GBULP and Bayes B. The data set consisted of 1654 bulls genotyped with different marker densities. When SNPs were used, the accuracy of breeding values obtained by Bayes B was better than GBLUP. In other words, for milk yield and somatic cell score traits, the prediction accuracy of GBLUP was 0.54 and 0.44 and by Bayes B was 0.58 and 0.44,respectively. For milk yield, the prediction accuracy of using haploblocks in both statistical methods was higher than the prediction accuracy using SNPs, while for the somatic cell score, this increase was more pronounced when GBLUP was used. However, when Bayes B was used this superiority was only obtained when the r2 statistic used to build the haploblocks was higher than 0.2. The results showed that the optimum level of r2 for building haploblocks depends on the trait type and its heritability. As a result, using r2 statistic more than 0.2 for building haploblocks can increase the accuracy of breeding valuesfoe both traits compared to SNP markers.

The present study was conducted to evaluate the effect of Tribulus Tresstrise (TT) herb on sex ratio of semen in Arabic Khouzestan ram using real time-qPCR technique using 18 rams in a completely randomized design with 3 treatments. The SRY and PLP genes were amplified to isolate the specific fragments of Y- and X- chromosome sequences. The treatments included: i) the control group (0% TT), ii) Diet containing 15 g/kg TT, iii) Diet containing 30 g/kg TT. Sperm sampling was taken from all rams at 10 month of age and blood sampling was performed at 8 and 10 month of age. The results showed that expression rate of SRY gene increased with increasing TT level and rams that received 30 g/kg TT diet had the highest SRY gene expression and PLP gene expression decreased with increasing TT level (p-value =0.004). There was positive correlation between Testosterone concentration and SRY gene expression at 8 (0.65) and 10 (0.59) month of age, and the relationship between PLP gene expression and Testosterone concentration was negative and -0.61 and -0.66 at 8 and 10 month of age, respectively (p-value= 0.006). The results indicated that adding Tribulus Tresstrise herb to the ram diet increases the SRY gene expression and also sperm containing Y chromosome. In other words, it increases the sex ratio toward male gens in Arabic Khozestan ram by increasing the androgen hormones.

The objective of this research was to compare the growth patterns of commercial broiler chickens, native chickens and domestic pigeon raised in Iran. The growth curves and their parameters were estimated by the Richards function. Body weight data of mixed-sex of commercial broiler chickens (n=326000), native chickens (n=244000) and pigeon (n=4000) were used. Birds were fed ad libitum and weighed in alternating periods on their life. The accuracy of the curve fit was high in all species (R2 = 0.996 to 0.970). The y+/A ratios (weight at the inflection point over mature weight), which determine the shape of the growth curve, were 0.358, 0.379 and 0.352 in chickens, native birds and pigeons, respectively. The age at the inflection point confirmed the high early growth of pigeons (t+ = 10.2 d) and chickens(t+ = 36.6 d). The phenotypic correlations between the inflection parameters t+ and y+ were higher in commercial broiler chicken than native and pigeon. The inflection parameter t+ and y+ were positively associated with the maturing index k in all birds, in this way, the evolutionary aspects are discussed. In practical view, these results could be used to develop the production strategies for native chicken breed and domestic pigeon to positively affect the growth parameters, efficiency as well as conservation of local genetic resources.

The objective of this study was to consider biometric indices for distinguishing the difference between the Thoroughbred and the Turkoman horse breeds. Body conformation traits of 23 stallions and 23 mares of Thoroughbred and 26 stallions and 33 mares of Turkoman at the ages of two, three and four years , were measured for calculating of 12 indices. Then, the data were analyzed as a factorial of 2×2×3 under completely randomized design using R software. The considered factors included: breed (Turkoman and Thorughbred), sex (mare and stallion) and age (two, three and four years of age). This study showed that indices of withers to body length (P<0.05), metacarpus circumference to its length (P<0.01) and metatarsus circumference to its length in Thoroughbred breed were greater than Turkoman breed and index of head side neck width to withers height ratio in Turkoman breed was significantly (P<0.05)  greater than Thoroughbred breed. Age and sex had a significant effect on three different investigated indices. According to the significant effect of breed on some biometric indices, the indices in respect to sex and age can be used for breed identification.

The present study was conducted to determine the chemical composition of Echinophora sibthorpiana and Pulicaria dysenterica and the effect of dietary inclusions of these plants on in vitro ruminal fermentation parameters and digestibility. Chemical composition of the experimental plants was determined using standard methods and different levels of each plant were included in the diet. In vitro gas production technique was performed with seven treatments (control diet, diets containing 15, 30 or 45 percentage of Echinophora and diets containing 15, 30 or 45 percentage of Pulicaria) and three replicates. Results indicated that crude protein and organic matter digestibility (OMD) of Echinophora (10.4 and 61.8 percentage, respectively) were higher than Pulicaria (7.85 and 52.5 percentage, respectively) (P<0.05). Inclusion of Echinophora in the diet increased OMD and metabolizable energy, while using Pulicaria reduced these parameters (P<0.05). Ruminal ammonia decreased with inclusion of Echinophora in the diet (P<0.05), but it was not affected by Pulicaria. Dietary inclusions of Echinophora and Pulicaria decreased protozoa population and methane production (P<0.05). The ruminal antioxidant capacity was improved by inclusions of Echinophora and Pulicaria in the diet (P<0.05). Based on the results, theuse of Echinophora up to 45 percentage and Pulicaria up to 30 percentage of diet dry matter is recommended in ruminants. However, the forage to concentrate ratio should be reduced when feeding Pulicaria in high-performance animals. On the other hand, using Echinophora and Pulicaria improves ruminal antioxidant capacity and reduces methane release to the environment.

The aim of the present experiment was to determine the effect of using the vitex agnus-castus (vitex) leaves as an alternative for alfalfa hay in the diet of fattening male goat kids on the performance, ruminal fermentation, digestibility of the nutrients and some blood parameters. The experimental treatments were 1) control (without vitex) and 2) replacement of vitex leaves with 60% alfalfa hay in the control diet(equal to 18% of diet). Sixteen fattening male goat kids with the average weights of 18 ± 2 kg and ages of 4.5 months were randomly assigned to the two treatments and eight replications for 60 days. Feed consumption, weight changes and feed conversion ratio were measured every 15 days. Dry matter intake, digestibility of nutrients, daily weight gain and feed conversion ratio were not affected by theexperimental treatments in the entire experiment period. Compared to the control diet, concentrations of blood urea nitrogen (P =0.08) and cholesterol (P =0.07) tend to decrease whereas blood glucose concentration (P=0.08) tend to increase in the kids fed with the diet containing vitex leaves. Ammonia nitrogen concentration and pH of the rumen liquor in treatment containing vitex leaves were significantly lower compared to the control group (P <0.05). Consequently, the vitex leaves can be used up to 18% of diet in the feeding of fattening male goat kids as an appropriate replacement for 60% of alfalfa hay without having the negative effects on their digestion and performance.

This study aimed to evaluate the buffering capacity of some buffer mixtures and the effect of their inclusion in the diet on in vitro ruminal fermentation parameters. For this purpose, five buffer mixtures were prepared as: 1) containing 15% sodium bicarbonate + 15% magnesium oxide + 35% magnesium carbonate + 35% sodium bentonite; 2) containing 35% sodium bicarbonate + 35% magnesium oxide + 15% magnesium carbonate + 15% sodium bentonite; 3) containing 20% sodium bicarbonate + 40% magnesium oxide + 20% magnesium carbonate + 20% sodium bentonite; 4) containing 40% sodium bicarbonate + 20% magnesium oxide + 20% magnesium carbonate + 20% sodium bentonite; and 5) containing 16% sodium carbonate + 35% magnesium oxide +22% magnesium carbonate + 5% sodium bentonite and 22% monobasic potassium phosphate. Buffering capacity and buffer value index were measured. Then the effect of buffer mixtures on gas production potential, pH, ammonia nitrogen concentration and in vitro dry matter disappearance (IVDMD) was investigated. Bufferingcapacity and buffer value index of buffer mixture 2 was higher than other buffer compounds (P<0.05). Buffer mixture 4 increased gas production (P<0.05). IVDMD was the same between the buffer mixtures and only buffer mixture 4 and 1 were different (P<0.05). The use of buffer mixture 2 increased the pH of the batch culture (P<0.05). Overall, the results of this experiment showed that the use of buffer mixture2 could have an effective role in preventing pH drop and consequently reducing acidosis.

The aim of this research is to estimate the methionine requirement of Japanese quails (Coturnix coturnix japonica) from 7 to 21 d of age using linear and quadratic broken-line regressions under chronic heat stress. A total of 480 quails were distributed according to a completely randomized design in 6 experimental treatments (diets containing 0.40, 0.45, 0.50, 0.55, 0.60 and 0.65% of methionine), with 4 replicates of 20 birds each. The basal diet was based on the corn-soybean meal and was formulated in mash form. Supplemental DL-methionine was added to the basal diet at the expense of corn starch to create experimental diets. The birds were fed a standard diet up to d 7, and then were weighed and randomly allotted to the experimental treatments. Birds exposed to chronic heat stress from 8 d of age for 6 h daily (37 ± 0.8°C from 10 AM to 16 AM). The optimal amounts of methionine for body weight gain, feed conversion ratio, and breast meat yield were obtained with 0.55, 0.57, and 0.60% of the diet as estimated by linear broken-line regression. However, based on the quadratic broken-line regression, the corresponding values were estimated at 0.58, 0.59, and 0.62% of the diet, respectively. According to the findings of this study, It seems that amounts of methionine higher than the usual recommendations are needed for Japanese quails to achieve optimal performance under chronic heat stress.

Effect of different levels of hydroalcoholic extract of Allium hirtifolium and flavophospholipol antibiotic on growth performance, carcass characteristics, meat quality, and immune responses was studied using 200 day-old chickens, Ross 308 broilers with five treatments, four replicates and 10 chickens per each replicate with completely randomized design. The experimental treatments were included basal diet withno additives (control group), and the basal diet containing hydroalcoholic extract of Allium hirtifolium (150, 300, 450 ml/kg diet) and flavophospholipol antibiotic (500 mg/kg diet). During the experimental period, birds fed with diet containing 450 ml/kg Allium hirtifolium extract had a higher weight gain than control birds (P<0.05). The effect of treatments on carcass characteristics was not significant. Themalondialdehyde value of legs muscles in birds fed with different levels of Allium hirtifolium extract was lower than the control group (p<0.05). The meat water holding capacity and drip loss in chickens fed with diet containing 450 ml per kg of Allium hirtifolium extract were higher and lower than birds receiving antibiotic respectively (p<0.05). The antibody titer against sheep red blood cells in chickens fed withdiet containing 450 ml per kg diet of Allium hirtifolium extract was higher than control birds or birds receiving antibiotic (p<0.05). According to the results of the present experiment, using 450 ml/kg diet of Allium hirtifolium extract could improve performance, meat quality and immune responses of broiler chickens, and can be used as a good replacement for antibiotic growth promoters.

This experiment was carried out to investigate the effect of different inclusion levels of free and microencapsulated essential oil of Ajowan (EOA) herb in broilers diet on growth performance and some ileal bacteria population. A total of 320 one-day-old chicks were distributed in a completely randomized design with 2×4 factorial arrangement. The dietary factors were 2 different forms of EOA (free and encapsulated) and 4 dietary inclusion levels of EOA (0, 50, 100 and 150 mg/kg). Growth performance parameters were recorded throughout the experiment, and intestinal organs weight and ileal microbial population were measured on 42 day of age. Broilers fed encapsulated EOA in diet had higher body weight gain and lower feed conversion ratio during 1 to 21 day of age than those fed free EOA (P<0.05). Higher relative weight of liver (% of live weight) was achieved in broilers fed diets supplemented with encapsulated EOA (P<0.05). There was a significant interaction between the form and dietary levels of EOA on E. coli count (P<0.05). As a general conclusion, use of encapsulated EOA led to an improvement in body weight gain, FCR, and European Production Index, in the first three weeks of growth and in the whole period of growth phase, respectively.

The effects of high stocking density and threonine (Thr) supplementation on performance and immunity in broiler chickens was evaluated. In this experiment 495 male Ross-308 broiler chickens were allocated to 4 treatments with 5 replicates in a completely randomized design. The dietary treatment consisted of: 1) basal diet as control with low density (10 birds/m2), 2) high density group (15 birds/m2 which fed basal diet) and 3 and 4) high density group which fed diet containing 10 and 20 percent Thr higher than requirment, respectively. The results showed that high stocking density decreased feed intake, body weight and feed conversion ratio at different period of production and increased European production efficiency factor (EPEF). Thr supplementation also reduced growth performance parameters (P < 0.05).Dietary treatments deseased antibody titer against NewCastle, but avian influenza virus, cell mediated immunity against phytoheamaglutinin, blood metabolites, blood cell count, and serum spartat aminotransferase and malondialdehyde concentration did noy change significantly. Serum alanine aminotransferase concentration in broiler chickens fed diet containing 20 percent Thr higher than requirment was higher than the others (P < 0.05). In conclusion, under the condition of this study (15 birds/m2), Thr supplementation (both of the levels) did not improved broiler chickens performance and immunity and more research is needed in this subject.

This experiment carried out to determine the nutritional value of 18 sorghum forage varieties and to introduce superior cultivars using multicriteria decision-making technology. They sow in early June and harvested in mid-November. Random samples were taken from the center of each experimental plot in a way that ten plants were cut from 10 cm above soil. These samples were cut into 3 to 5 cm pieces, eachcultivar had three samples, in total 54 samples were collected. Yield and nutrient contents such as, crude protein, crude ash, ADF, NDF, water-soluble carbohydrates, starch and lignin measured in the experimental cultivars. The metabolizable energy of sorghum cultivars estimated by gas test method using the amount of gas produced in 24 hours and the amount of crude protein contained in it. Sorghumcultivars ranked based on 11 integrated traits. Among the domestic cultivars, Spidfeed ranked fifth among all varieties, followed by KFS-18 ranked seven and pegah ranked 10th and KFS-2 ranked 12th with moderate quantitative and qualitative performance. Overall, based on the results of the multi-criteria decision-making method, it was found that the top three sorghum cultivars are Siloking, FGCSI12 and PHFS-27, respectively, which are recommended for sorghum forage production and silage for dairy farmers.

This experiment was conducted to identify the ovarian activity throughout the year and determine the length of estrus cycles of Sanjabi sheep. Accordingly, blood serum samples were collected weekly and daily (12th of September to 11th of November) from 14 non-pregnant Sanjabi ewes at Mehregan livestock research station in Kermanshah for one year and the progesterone concentration was measured using the radioimmunoassay. The daily evaluation of progesterone secretion proceeding showed that there were four estrus cycles during the period from September 11 to November 12. The average length of the first to fourth estrus cycles was 6.30±2.41, 8.33±1.90, 9.17±2.50, and 16.08±3.11 days, respectively, and the mean time interval between estrus cycles was 6.47±2.46 days. The highest progesterone concentration mean in 61.54 percent of ewes was observed in November and in 38.46 percent of ewes was observed in spring, especially in April. In total, 78.57, 78.57, 71.43 and 78.57 percent of the ewes in June, July, February, and March, respectively, were in perfect anestrus conditions, but all of the ewes had the active ovarian cycle in November. The average length of ovarian activities and in contrast perfect anestrus were estimated 215 ± 38 and 150 ± 48 days per year, respectively. The results showed that Sanjabi ewes had an active ovarian cycle about 60 percent of the time of the year; so, there is naturally applicable of a three-time lambing program in two years in this sheep.

To examine the effect of glycyrrhizic acid on lipid peroxidation and vital parameters of Holstein bull sperm after freeze-thawing process, semen samples were collected from four mature Holstein bulls twice a week using artificial vagina. Ejaculates were pooled in order to eliminate the individual effects of bull. Semen samples were divided into four equal groups (8 reps) including Zero (control), 20, 30 and 40 mg/ml of glycyrrhizic acid along with diluents based on egg yolk-citrate. Following cooling and equilibration stage, semen samples were stored in nitrogen tank for 30 days. After thawing procedure, level of malondialdehyde in sperm samples were measured by ELISA. Also, membrane integrity, motility and viability of sperm were examined. Statistical analysis was carried out using one-way ANOVA and post-hoc Tukey tests (p<0.05). According to the results, membrane integrity, motility and viability of sperm samples treated with concentration of 20, 30 and 40 mg/ml glycyrrhizic acid dose dependent manner significantly increased and level of malondialdehyde dose dependent manner significantly decreased ccompared to control groups (p<0.05). Therefore, use of glycyrrhizic acid in bull semen diluent can improve sperm vital parameters and decreases lipid peroxidation of sperm after freeze-thawing process.