مجله تحقیقات دام و طیور
سال چهارم شماره 2 (1394)

In order to study the effect of pistachio by-product (PB) in diets with or without canola seed on digestibility and plasma metabolites in Baluchisheep, four Baluchi rams (40±2 kg body weight) were used in a duplicated 4×4 Latin square design with 4 periods. Each period included 14 days of adaptation and 7 days of sample collection. Treatments were: 1) 30% alfalfa- 20% straw- 50% concentrate, 2) T1+5/5% canola seed in concentrate 3) 30% PB-20% straw- 50% concentrate 4) T3+ 5/5% canola seed in concentrate. Apparent digestibility of DM, OM, NDF and ADF, blood glucose concentrations, total protein and activity of liver enzymes were not significantly affected by the treatments, but CP digestibility and blood urea nitrogen (BUN) concentrations were lower in diets containing PB. Blood triglyceride was significantlyhigher in canola seed diets. The results demonstrated that 30% PB in sheep diet although shows negative effect on CP digestibility, because of no significant effect on other nutritional parameters, it could be replaced with part of diet alfalfa.

In this study, barley straw was irradiated with doses of 100, 200 and 300 KGy to evaluate the effects of electron beam on the chemical composition, ruminal degradability parameters and ruminal-postruminal digestibility of its dry matter (DM). Initially, using nylon bag technique, an amount of 5 g of grounded samples (with 6 replicates) was incubated for 0, 2, 4, 8, 16, 24, 48 and 72 h in the rumen of two fistulated Holstein heifers and then parameters of DM ruminal degradability were estimated. Then ruminal digestibility and post ruminal digestibility of DM were determined by incubating of feed samples in rumen for 16 h and in Daisy digester apparatus, respectively. Statistical analysis of the data was performed using SAS statistical software. The results indicated that acid detergent fiber (ADF) in irradiated samples was numerically reduced, while NDF reduction of irradiated samples was statistically significant (P<0.05). Effective degradability of DM increased significantly (P<0.05) by irradiation at 200 KGy. Post-ruminal and total tract digestibility of DM increased significantly (P<0.05). The results of this experiment showed that electron beam irradiation had an effective role in improving the nutritive value and digestibility of barley straw, but regarding the absence of a dose related effect, the dose of 200 kGy is recommended.

To study the effect of calving month on occurrence probability of atypical lactation curve, a number of 751,099 test day records belonging to 85,641 first parity Holstein cows calved during 1997-2009 in 156 herds in six provinces were used. Logistic generalized linear mixed model using GLIMMIX procedure of SAS software was fit to the data. In the model, fixed effects of province, herd production level, calving year, calving month, age at first calving, sperm type, cow type, interval of first recording from calving, number of total test day records for each cow, determination coefficient of Wilmink fitted to each cow, as well as random effect of sire were included. Dependent variable was defined as a binary (0 for typical and 1 for atypical lactations) in the model. Maximum and minimum probabilities were found for the cows calving in April (0.3435) and December (0.2348), respectively so that cows calving in the former one was expected to have 70.5 % more chance of atypical lactation as compared to the cows calving in the latter one. Based upon the findings it can be concluded that the shape of the lactation curve in Iranian dairy cows is influenced by the seasonal variations.

Based on the experiences of different countries, application of technical and advanced knowledge in manufacturing section will form the basis of the agricultural sector development. In this regard, this study estimates the total factor productivity index to investigate the factors affecting the productivity of the industrial farms in Mazandaran province. For this purpose, information from 50 dairy farms in Sari, Ghaemshahr and Babol Counties was collected. Based on the results obtained from the city of Sari, factors such as education and extension courses, working with cooperatives and price per unit of milk had significant effect on total productivity of production factors and factors such as education level and the number of dairy cows on total productivity of factors of production was not significant. Also in addition to the factors affecting productivity in the city of Sari, in Ghaemshahr and Babol city both education level and the number of dairy cows had significant effect on total factor productivity.

One of the most common causes of the death over the world is the cardiovascular and atherosclerosis diseases. However, in the last decades there has been continuing accumulation of evidence that trans fatty acids and omega-6 fatty acids have potential harmful action in blood lipid metabolism, atherosclerosis development and cardiovascular disease. Among the most important of fat sources in ration of human are meat and fat of broiler and edible oil. Therefore, the aim of this study was to determine the fatty acid profiles of broiler's meat and abdominal fat and edible oil in South Khorasan Province. In this descriptive and analysis study, 10 samples of meat (MB) and abdominal fat (FB) from the Birjand broiler's abattoir were collected at 3 consecutive days and 5 samples of each butter oil (B), solid oil (S), margarine (M) and liquid oil (O) were gathered from shopping around province. The samples were frozen in -80o freezer. Then, the oils were separated and methylated. The type and of each fatty acids were designated with compare to the retention time in the standard peak. The quantity of fatty acids was determined from internal standard method. Analysis of the data were revealed that the sum of SFA were 31.84, 51.92, 50.03, 24.43, 35.57 and 30.67 in B, S, M, O, FB and MB respectively. The highest and lowest amount of saturated fatty acid were observed at S, M and O respectively (P<0.05). The percentage of MUFA in B, S, M, O, FB and MB were 37.9, 14.98, 17.15, 31.95, 37.97, 39.96 % respectively. The omega-6 fatty acids were higher at liquid oil and the least amount were in FB (P<0.05). The amount of omega-3 fatty acids in BM and B were higher than other. The percentage of trans fatty acids in MB and FB were lower than 2% and in B were equal to 2.7%. The amount of trans fat acid were 10.5 and 9.82% in margarine and solid oil respectively. Therefore, the fat and meat of broiler had lower SFA and trans fatty acid and higher omega-3 fatty acids and these had lower effect on cardiovascular disease and better source for supplying their requirement.

In this study, the effect of white rot fungus Trametes versicolor on chemical composition and rumen degradability of rapeseed (Brassica napus) straw was investigated. Rapeseed straw was inoculated with fungus mycelium and kept in plastic bags for 21 and 40 days. Then straw was dried and milled. Chemical compositions of treated and untreated samples were measured by standard methods and their rumen degradability was estimated using the nylon bag technique by 3 rams. The results showed that the loss of organic matter (OM) only in treated rapeseed straw for 40 days was significant, compared with control (P<0.05). Crude protein (CP) content in treated rapeseed straw for 21 days was significantly higher than control and was not significant with increasing days of fermentation to 40. After treatment with fungus for 40 days, the amount of neutral detergent fiber (NDF), hemicellulose and lignin (ADL) reduced (P<0.05). Total phenolic compounds and tannins in treated straw for 21 days decreased and thereafter at day 40th was not changed (P<0.05). Amount of chitin/dry matter in treated rapeseed straw for 40 days increased, compared with day 21th (P<0.05). According to degradability parameters of dry matter, total degradability (a+b) of rapeseed straw showed a significant increase after 40 days treatment (P<0.05). As well as rumen degradability of cell wall constituents in treated rapeseed straw for 40 days was enhanced considerably. The findings showed that treated rapeseed straw by Trametes versicolor has the potential to be a valuable feed source for ruminants.