مجله پژوهش در نشخوار کنندگان
سال سوم شماره 1 (بهار 1394)

This research was conducted to investigate the effects of electron beam (EB) (150 and 200 kGy), hydrogen peroxide (H2O2) (132 ml/kg DM), hydrobromic acid (HBr) (60 g/kg DM) and their combination on the gas production parameters and in vitro digestibility of vetch wastes. Processing increased gas production potential (P<0.05). The highest amount for this trait was observed in HBr, EB (150 and 200 kGy) and their combination. Except for HBr+ EB (150 and 200 kGy) (P>0.05), the other treatments increased gas production rate (P<0.05). In vitro digestibility of the dry matter (DM) and organic matter (OM) of samples was increased by EB, chemical compounds (H2O2 and HBr), and their combination (P< 0.05). Estimated parameters, including metabolizable energy (ME), net energy (NE) and short chain fatty acids (SCFAs) were increased by processing (P<0.05). The highest increase was observed for HBr and EB (200 kGy) treatments. Ammonia nitrogen (NH3-N) concentration was greater in HBr+ EB (150 kGy) than other treatments (P<0.05). Except for the EB (150 kGy) and HBr (P>0.05), the other treatments led to an increased partitioning factor (PF) and efficiency of microbial mass production (P<0.05). Overall, the processing improved the nutritional value of vetch wastes. In this case, treatments of EB, HBr and their combination had greater effect on the studied traits.

The purpose of this study was to evaluate the effects of 2 different feeding regimens of zilpaterol hydrochloride (ZH) and 3 different dietary protein levels (DPL) on growth performance, carcass characteristics and blood metabolites in Lori-Bakhtiari feedlot lambs. The lambs (n=42; IBW= 47±4.4 kg) were assigned to one of six treatments (7 lambs/treatment) based on IBW and were fed with a diet content of 14%, 15.5% and 17% protein and supplemented with 0.2 mg/kg of live weight d-1ZH. The continuous feeding of ZH for 28 days and intermittent 1 d feeding ZH followed by 1 d of withdrawal for 42 days were employed as the different regimens. Blood samples were taken via the jugular vein from 6 lambs in each treatment on d 0 and d 42 and analyzed for plasma metabolites. ZH regimen and DPL had no significant effect on dry matter intake and feed efficiency. DPL had a significant effect on Final BW, average daily gain and total weight gain, with high protein having the higher (p< 0.05) values for these performances. Lambs fed high protein had higher carcass weight and larger LM area (p< 0.001). There were no ZH and DPL interaction for lambs growth performance and carcass traits (P>0.05). Overall, the main effects of protein improved growth performance and carcass traits, but the interaction effects of ZH supplementation methods with different dietary protein levels did not affect these parameters.

In order to evaluate the effect of organic chromium on performance of twin-bearing ewes, 16 pregnant Afshari ewes (91.8 ±4.5 kg BW and 116.9 ± 1.7 d in pregnancy) were used in a completely randomized design and were individually assigned to one of two diets where one of them contained no chromium and another on contained 1 mg/ kg DM of organic chromium. Ewes were fed a TMR diet twice a day. Dry matter intake, blood metabolites, ewe’s BW, lamb’s BW and average daily gain were measured during experiment. Despite the fact that prepartum DMI was not different between treatments, postpartum DMI tended to be higher for chromium fed ewes (P<0.1). Although there was no difference in BW of prepartum treatments, chromium fed ewes numerically had lower BW loss after lambing compared to control group. Despite the lack of difference in birth BW of lambs, average daily gain was greater in control group compared to chromium fed group on day 10 after birth (P<0.05), whereas there was no difference between treatments on d 30 and 60 after lambing. Average daily gain between day 0 to10 in control group tended to be higher (P<0.06), and in chromium group between day 30 to 60 was higher. Organic chromium supplementation did not influence prelambing blood metabolites, but post lambing total protein (P>0.05) and albumin (P<0.05) and triglyceride (P>0.05) was higher in chromium fed ewes compared to control group. The obtained results from the current study show that chromium supplementation in twin-bearing pregnant ewes during preparturient period, which is a critical and vital period in terms of ewes and their lamb's performance and health, can improve the post lambing performance by positively affecting blood metabolites and increasing post partum dry matter intake.

The aim of this study was to evaluate the effect of use of different levels of Citrus Limon powder on blood metabolites concentrations, rumen fermentation and apparent total tract digestibility of nutrients in male Makuii sheep. This study were conducted using Three male Makuii sheep, each fitted with a permanent rumen cannula (average body weight 55 ± 5 kg) that received experimental diets including control without additives, control with 5, 10 and 15 mg/d Citrus Limon powder and control with 30 mg/d monensin in a change-over complete randomized block design with 5 periods of 17 days. The effect of treatments was not significant on digestibility of dry matter, organic matter, acid detergent fiber, ether extract and crude protein. But neutral detergent fiber digestibility of control treatment were more than the other treatments (P<0.05). Results of this experiment showed that different levels of Citrus Limon powder decreased acetate, ammonia N, acetate to propionate ratio and increased propionate concentration (P<0.05). Also concentration of total volatile fatty acid was different in experimental treatments. There was no significant difference between the treatments in valerate, iso-valerate and butyrate concentration and pH values. Effect of different of experimental treatments on blood metabolites such as glucose, cholesterol, triglyceride were significant. In conclusion, results showed that utilization of Citrus Limon powder in high levels could improve ruminal fermentation.

In this research, chemical composition and effect of feeding mixed corn silage with different levels of tomato pomace on performance of Holstein dairy cows were investigated. Nine multiparous Holstein cows (DIM 65±19 d and 31.3±3.5 milk production Kg/d) were allocated in a 3*3 change over design. The experiment was consisted of three periods of 21 days and each experimental period was consisted of 14 days for adaptation and 7 days of sampling. Treatments were 1) control (containing corn silage without tomato pomace, 2) containing corn silage with 7.5% tomato pomace, 3) containing corn silage with 15% tomato pomace. Dry matter intake was not affected by treatments. The addition of tomato pomace to corn on ensiling decreased apparent digestibilities of crude protein and NDF (P<0.05). Digestibility of dry matter, organic matter, ADF, rumen pH, BUN and blood glucose were not affected by treatments. However, blood total protein were different between treatments (P<0.05). Also, by increasing the level of tomato pomace in corn silage, milk production, milk protein and fat percentages, MUN and milk NPN and milk production efficiency were not affected by treatments. In conclusion, adding tomato pomace up to 15% to corn on ensiling, due to its nutritive value, decreases the costs of production without any negative effect on dairy cattle performance.

To study the effects of barley silage particle size and concentration levels on feed intake, nutrient digestibility and ruminal parameters, four 14 months Kermani male lamb with an average weight of 35 ± 2 kg were used in change over design in 2×2 factorial arrangement with the four periods of 21 days. For the preparation of silage, 1200 kg of whole plant of barley was chopped with coarse and fine particle size and ensiled for 45 days in nylon bags. Experimental diets were: 1) 40% coarse barley silage and 60% concentrate, 2) 60% coarse barley silage and 40% concentrate 3) 40% fine barley silage and 60% concentrate and 4) 60% fine barley silage and 40% concentrate. Geometric mean of coarse and fine barley silage particle size were 13.95 and 10.83 mm, and pH was lower in fine barley silages (P=0.03). The results showed that DM feed intake was higher in 40% concentrate and diets (P<0.001), but the highest DM and OM digestibility were in 60% fine barley silage and 40% concentrate diet (p<0.05). Rumen pH value was higher in coarse silage diets four hours after feeding (p=0.005), but rumen ammonia nitrogen concentration was not affected by experimental diets. Microbial protein synthesis was the greatest in 60% fine barley silage and 40% concentrate diet (p<0.044). Reducing the level of concentrate and barley silage particles size, was caused the highest DM and OM digestibility, because of improved rumen conditions and increased surface area of silage particles.

This study was conducted to investigate the effect of additional of two medicinal plants Peppermint or Thymus vulgarise on chemical composition and quality parameters of Sanjabi finishing lambs. Eighteen male lambs with average body weight of 21.6±1.5 (kg) in a completely randomized design with 3 treatments were used in a 90 days finishing period. Treatment include: control diet (with no additive), control diet congaing either 3 percent Peppermint (Pep) or Tymuse Vulgarise (Thy). The ratio of concentrate: forage was 70:30. Diets were isocaleric and isonitrogen. At the end of experimental period, animals were slaughtered and meat samples were taken for meat quality measurements. The average daily weight gain and final body weight in Peppermint and Thymus vulgarise was higher than Control (P<0.05). Finishing diet with Peppermint or Thymus vulgarise had no significant effect on the chemical component (DM, CP, E.E., and Ash) the mean of protein and ether extract were 21.67 and 2.84% respectively. The quality characteristics such as pH, water holding capacity, cooking loss, shear force and tenderness were similar., There were no significant difference in sensory-taste properties and tonality on 0, 4 and 7 days (P>0.05). The results of this study showed that, Peppermint or Thymus vulgarise containing natural antioxidants at 3 percent level in diet of finishing lambs had no effect on any of the meat quality parameter measured. The results of this study, the use of powder, peppermint and thyme herbs can be used as a supplement to increase feed intake and daily gain in the finishing lambs.

This study was conducted to examine the effect of dietary inclusion of sucrose with or without crushed sunflower seeds on ruminal fermentation, blood metabolites and performance in early lactating dairy cows. Eight Holstein dairy cows in a replicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments were assigned to following experimental diets; 1) low sugar diet without added sunflower seeds and sucrose, 2) low sugar diet supplemented with sunflower seeds (8 percent of dry matter), 3) high sugar diet supplemented with sucrose (4 percentage of dry matter), and 4) high sugar diet supplemented with sucrose and sunflower seeds. Sucrose and sunflower seeds were substituted with corn grain in the diets. Dry matter intake, milk production yield and milk concentrations of protein, lactose and solid non-fat were not affected by the treatments. Dietary inclusion of sucrose increased milk fat (P<0.01) and milk corrected fat (P<0.05). Although, there were no differences between treatments for the ruminal concentration of ammonia nitrogen, total volatile fatty acids, propionate, butyrate, isovalerate, and valerate concentrations, feeding sucrose to dairy cows increased rumen concentration of acetate (P<0.01), rumen pH (P<0.01) and acetate to propionate ratio (P<0.1). Feeding dairy cows with diet containing eight percent of sunflower seeds increased plasma concentration of triglyceride (P<0.05) and cholesterol (P<0.01) in comparison with the diets without oil seeds. The current study showed that replacing corn grain with sucrose increased milk fat yield and milk corrected fat and modified ruminal fermentation pattern in dairy cows.

In this study, in order to multivariate analysis of genetic and phenotypic correlations of productive and reproductive traits in Iranian Holstein dairy cows, 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. The studied traits were productive (305 days milk yield, 305 days fat percentage, 305 days protein percentage and lactation length) and reproductive (dry days, age at first calving, calving interval and open days). Animals breeding values were predicted using a single trait animal model. A canonical correlation analysis using CANCORR procedure of SAS software was carried out to examine the relation between sets of productive and reproductive traits. Analysis indicated that first canonical correlation between first canonical variate pair for phenotypic and breeding values were 0.999 and 0.996, respectively (P<0.0001). Considering high and undesirable genetic correlation between sets of productive and reproductive traits, for long term profitability, designing selection programs based on a combination of these traits is recommendable.