نشریه علوم دامی (پژوهش و سازندگی)
پیاپی 135 (تابستان 1401)

This study was conducted to evaluate the effects of dietary supplementation of guanidine acetic acid and mating management current methods on the performance of Ross 308 broiler breeders. This experiment was done in a completely randomized design and factorial methods with three levels of GAA (0. '0.12 and 0.16 g/kg of diet) and three mating management methods (without management, spiking and intra-spiking methods) with 6 replicates (experimental unit) and 8 hens and one rooster in each (totally 486 bird). During this period, adjectives performance (egg production percentage, egg mass weight (g/hen/d) and feed conversion ratio) were measured. Dietary inclusion of GAA at levels of 0.12 and 0.16 g/kg of diet had negative effects on the above traits (P<0.05). In addition, the use of different methods of mating management did not have a significant effect on performance traits .The interaction effects of GAA and mating management methods were not significant on egg production, egg weight, egg mass weight and feed conversion ratio. Dietary supplementation of GAA, mating management method and their interactions on fertility and hatching percentage were not significant (P>0.05). The effect of GAA level on nitric oxide concentration was significant (P<0.05). The highest concentration of nitric oxide was observed at the level of 0.12 g/kg diet, The dietary inclusion of GAA at levels of 0.12 and 0.16 g/kg of diet and the application of mating management methods could not improve production and reproduction performance of Ross 308 broilers breeders.

This research was conducted to investigate the possibility of using visual machine technology in measuring the body dimensions of Sistani cows. For this purpose, the record of body dimensions including length, shoulder height, hip height and chest circumference of 179 heads of livestock in Zahak Sistani cow breeding station, were measured at different time points, using a tape meter. At recording time, digital images were taken using the canon camera from the lateral view of cattle from distance of 2 meters. Digital image processing and feature extraction were performed using Graphical Unit Interference of MATLAB software. The feature of digital images as input and different body dimensions of cows as output of Artificial Neural Network(ANN) were used in the training and modeling phase. The results showed that, out of 22 features extracted from the images of Sistani cows, the 15 effective features, such as Equivalent Diameter, Major Axis Length, Minor Axis Length, Bounding Box, Convex Area, Filled Area, Area, Perimeter, and the number of white pixels of image (NNZ) had a significant correlation with the body dimensions of the Sistani cow(p<0.01). Body dimensions of Sistani cows including body length, shoulder height, hip height, and chest girths were estimated with accuracy of 0.98, 0.97, 0.97and 0.98%, by the ANNs model, respectively. The results of the present research showed that Artificial Intelligence Technology can act as a suitable alternative to biometric evaluation of Sistani cows and save time and relevant costs.

An experiment was conducted to study growth traits and fattening potential comparison of two Iranian camel ecotypes (Kalkouhi and Turkmen) in enclosed breeding conditions. The project was carried out using 32 young male camels with an average age of 151±31 days and an average weight of 141.77±29.55 kg (in light, medium and heavy groups) during 9 months. Initial weights as covariate and monthly weight of camels as repeated measures were considered in the analyzing model. Least square mean of growth traits were calculated. The fix and random effects on growth traits with Mixed model procedure of SAS, 2004 software were included. Measurement of feed intake/residuary was recorded in group and daily, measurement of weight gain was recorded individually and monthly, as well as for all period. Results showed that the effects of breed (P<0.01), initial weight and weight categories on feed intake, growth performance and feed conversion ratio of young camels were significant (P<0.05). The average daily feed intake, daily weight gain and feed conversion ratio for Kalkouhi ecotype were 3.83±1.01, 0.379±0.11 kg and 9.94±1.57 and for Turkmen ecotype were 4.31±1.05, 0.430±0.10 kg and 9.83±1.08 respectively. Mean total weight gain of Kalkouhi and Turkmen was 102.33±5.03 and 116.01±8.84 kg respectively (P<0.05). In conclusion, growth performance, fattening potential and feed efficiency of Turkmen ecotype was better than Kalkouhi ecotype and could be advised.

Reducing the population size of Sistani cattle due to the multi various reasons during the last years, was the motivation of the current study. Therefore, the aim of this study was to investigate the factors of population decline and strategies to increase the population and revive this breed. For this purpose, a questionnaire was developed using the Delphi method. Questionnaire was included 21 reasons and 18 strategies related to the situation of Sistani cattle population. Based on the breeders’ insight, drought in the Sistan region during last three decades was considered as the most important factor in reducing the population of Sistani cattle, and for both groups, the least important factor affecting population decline is the uneconomic importance of Sistani cattle (P < 0.05). Both groups were agreed that climatic factors are the most important in reducing the population of Sistani cattle and almost no differences in this regard were observed between the two groups (P > 0.05). From the breeders' point of view, economic support for Sistani cattle breeders is the most important way to support the Sistani cattle population, while experts believe that the most important way is to rehabilitate Hamoun Wetland. In general, the results of this study showed that due to the changing and varying climate of Sistan region, attention to economic issues and support for breeders can largely compensate for the problems caused by unfavorable climatic conditions in the rehabilitation of Sistani cattle population.

The aim of this study was to discover QTL for body weight traits on chromosome 3 of Japanese quail in a four-generation design based on diallel crosses. For this purpose, four strains of Wild, AandM Texas, Italian and Tuxedo Japanese quail were crossed in reciprocal and diallel pattern. The first generation of hybrid birds was then used to produce the next generations, including the second, third, and fourth generations. Phenotypic data included body weight gain from hatching to 45 days with an interval of 5 days in the offspring of the selected fourth generation parents. Third and fourth generation parents and all offspring of selected fourth-generation parents (369 birds) were genotyped for three microsatellite markers on chromosome 3. Marker effects and variance components were estimated using three models for additive, dominant, and additive-dominant markers using GVCBLUP software For marker effects estimation, the point with the highest F statistic was considered as the QTL position. The results of this study indicate the presence of at least one QTL with additive effects related to body weight traits at 5, 10, 20 and 40 days at the beginning of the chromosome and for hatching traits, 15, 25, 30, 35 and 45 days at the 38cM of chromosome 3. Significant QTLs were also found in the dominance model for most traits, except for 25 and 35 days at the beginning of chromosome 3. The percentage of changes due to additive and dominance effects of markers in the phenotypic expression ranged from 1.3 to 8.7%.

In this study, the effect of probiotic supplements (Protexin® (PR) and Multi Behsil® (MB)) and oxytetracycline antibiotic was evaluated on performance, egg and carcass quality, immune response and acidity of the small intestine contents of laying Japanese quails from 7 to 13 weeks of age. A total of 240 laying Japanese quails were used in a completely randomized design with 6 treatments, 4 replications and 10 birds in each replication. The experimental treatments included 1- basal diet without additive (negative control; NC), 2- basal diet+ 50 mg/kg Oxytetracycline (positive control; PC), 3 and 4 were basal diet+ 50 and 100 mg/kg of MB probiotic, and treatments 5 and 6 were basal diet+ 50 and 100 mg/kg PR probiotic, respectively. The results showed that the diets containing MB and PR probiotics improved feed conversion ratio (2.96 and 2.77 vs. 3.05), feed intake (29.49 and 29.13 vs. 30.56 gr) and egg mass (10.47 and 10.66 vs. 10.37 gr), respectively in comparison to NC treatment (P<0.05). The utilization of PR probiotics decreased the feed cost per each kilogram of egg when compared with NC treatment (P<0.05). The treatment containing 100 mg/kg PR probiotic had the maximum shell thickness (P<0.05). The utilization of probiotic had no significant effect on immune response and pH of small intestine and cecum contents of laying quails (P>0.05). Generally, the use of probiotic in the diet of laying quails was able to show the ability to compete with Oxytetracycline growth promoter antibiotic by improving performance and egg qualitative traits.

In this study, the economic evaluation of broiler farms in Fars province was performed based on some characteristics of farms and managers, measuring and analyzing the productivity of producing factors and comparing the current consumption of these factors with the optimal situation. Using stratified random sampling method, 86 poultry farms were selected and the necessary data were collected through interviews and completing a questionnaire. Based on the results, the effect of feed cost, day-old chickens, labor, vaccines, drugs and fuel cost variables on live chicken production is positive and significant. The average productivity of the consumed feed and conversion ratio for the sample are equal to 0.51 and 1.96, respectively. An average of 22,740 kilograms of live chicken is produced per worker in each production period. According to the calculated final productivity values, the amount of consumed feed is more than the optimal limit and the used labor force is less than the optimal limit. The mean, minimum and maximum productivity values of the total production factors calculated in the selected sample are 2.35, 1.38 and 3.26, respectively. Based on the results reforming the market structure at the slaughterhouse level, optimal use of feed inputs and labor, reducing breeding periods and increasing the number of hatcheries per year, can improve producers' incomes compared to costs and affect productivity of producing factors, and recommended.

This experiment was conducted to investigate the effect of using vitamin C and aspirin on the performance of broiler turkeys during different weeks, the European performance efficiency factor, and economic analysis of the rearing period in normal conditions.288 male turkey chickens, BUT6 strain, were used as a 3×3 factorial experiment (three levels of 0, 250, and 500 mg/kg vitamin C, and three levels of 0, 75, and 150 mg/kg aspirin) ina completely randomized design with nine experimental groups, 4 replications and 8 birds per replication. The results showed that vitamin C and aspirin have no effect on body weight, daily weight gain, feed intake, and feed conversion ratio of broiler turkeys during different weeks of rearing (P>0.05). However, only in the ninth week of rearing, chickens fed the combination of aspirin and vitamin C in levels of 75 and 250 mg/kg showed a higher daily weight gain than the control group (P<0.05). The feed conversion ratio of chickens in this group was lower than that in other groups in the ninth week (P<0.05). On the other hand, the European performance efficiency factor was not affected by the experimental groups. Economic analysis of the rearing period showed that vitamin C and aspirin supplementation have no effect on total feed cost/bird, feed cost/Kg body weight, sale bird, and net return. In conclusion, the use of vitamin C and aspirin does not recommend in turkey chickens under normal conditions.

This experiment was conducted to evaluate the effects of adding different levels of water to the total mixed ration on growth performance, nutrients intake, digestibility and feeding behavior of fattening lambs. For this purpose, 28 Lori male lambs with120 ± 6 days old and 33.4 ± 3.4 kg of live weight were used in completely randomized design experiment with 4 treatments and 7 lambs per treatment. Experimental diets containing levels 10 (control), 20, 30 and 40 % moisture were fed to the lambs for 56 days. Results showed that dry matter (DM), organic matter (OM), crude protein (CP) and neutral detergent fiber intakes were elevated linearly when dietary moisture content increased up to 30 % (P<0.05). Total weight gain, average daily gain and chewing activity traits including rumination and chewing were improved linearly (P<0.05) with increasing dietary moisture content up to 30%. Increasing the level of dietary moisture up to 30% linearly increased DM, OM and CP digestibility (P<0.05). In conclusion, increasing the dietary moisture of fattening lambs up to 30% improved feed intake and growth performance of fattening lambs.

This study was conducted to investigate the effect of adding 0, 10 and 15% levels of wheat straw and the use or non-use of Lactobacillus buchneri microbial additive on the quality of fodder beet silage (FBS) in polyethylene bags in a 3×2 factorial statistical design. For each treatment, 4 bags and a total of 24 bags of 25 kg of fodder beet silage with different composition were prepared and transferred to storage at room temperature and after 75 days, all bags were opened and their pH, temperature and silage quality were immediately determined. A sample of each bag was used for chemical laboratory evaluation including DM, CP, Ash, NDF, ADF and ammonia nitrogen (AN). The results showed that adding 10 and 15% levels of wheat straw improved silage quality and reduced pH compared to the control (P<0.01). Addition of wheat straw had a significant effect on chemical composition and silage stability (temperature and pH) during opening (P<0.01), Addition of wheat straw reduced watery loss and increased silage quality (P<0.01). In general, the most suitable mixture of the silage was control + 15% wheat straw, which had a higher quality and longer shelf life.