JWSS - Journal of Water and Soil Science

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Two experiments were conducted to investigate the effect of dietary energy levels on the performance of Arian broiler chicks. Trial 1 was performed in summer and trial 2 in fall. Both experiments were accomplished in 5×2 factorial designs, involving 5 levels of dietary metabolizable energy and two sexes. Each of the 10 resulting treatments was replicated 4 and 3 times in trials 1 and 2, respectively. The metabolizable energy contents in diets number 1 to 5 were 2800, 2900, 3000, 3100 and 3200 Kcal/kg for starter (0-4 weeks) period and 2900, 3000, 3100, 3200 and 3300 Kcal/kg for grower (4-7 weeks) period, respectively. The ratios of energy to each nutrient were the same for all diets in each stage of the experiments.

In both experiments, body weight gain and feed conversion ratio improved significantly (P<0.01) when diets with higher levels of energy were consumed. Feed intake was affected (P<0.01) by the dietary energy content only in summer (trial 1) resulting from the reduced intake of chicks fed with the lowest energy level. Abdominal fat percentage was decreased (P<0.01) in chicks fed with the lowest energy diet in summer. In both experiments, the cost of the feed per unit of live body weight was reduced (P<0.01) in accordance with the reduction in diet density. As expected, body weight gain, feed conversion ratio, abdominal fat and cost of the feed per unit of live body weight for male chicks were significantly better than the same values for females (P<0.01).

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Rice bran is the most important by-product of rice milling. It is a valuable source of edible oil in most rice producing countries. Rice bran oil is used in babyfood, biscuit, poultry, fish and farm animal feeds. The storage of rice bran without 'heat processing will result in hydrolysis and auto-oxidation of lipids, and to its decreased physicochemical, organoleptic and nutritional quality. Rice bran is rich in carbohydrates, free amino acids, lipids and different enzymes. The enzymes have destructive effects on the quality of rice bran components. Heat processing is an effective method to reduce the microbial and enzymatic activity of bran. This study was carried out using a factorial experiment by completely randomized design with three replications to investigate the effect of heat treatment and storage time on rice bran crude oil properties.

The parboiling treatment was effective on the rice kernel strength. The bran produced from parboiled rice milling had lower endosperm components. This type of bran had a lower starch but a higher oil percentage. The results of color of rice bran oil samples determined by Lovibond showed that the oil from parboiled rice bran before and during storage had better color than the other samples. Iodine value of bran oil from parboiled paddy decreased during the storage period. The results from studies on fatty acid composition of oil samples determined by gas chromatography (G.C.) showed that the quantitative trend of fatty acids of the control sample remained the same as that in the rice bran samples with the treatment process.

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A ruminal in situ experiment using three fistulated ewes was conducted to determine dry matter (DM) and crude protein (CP) degradation of steam–flaked broomcorn (SFBr), ground broomcorn (GBr) and ground barley (GB). Grain samples were suspended in the rumen of sheep for 0, 2, 4, 8, 16, 24 and 48 h. Nylon bags were washed with tap water after removal. Effective degradability of DM at outflow rates of k = 0.05 and k = 0.08 h^-1 was significantly higher for SFBr than for GBr (59 and 53% vs. 43 and 35%). SFBr has considerably higher soluble DM than GBr and GB. Insoluble DM of SFBr was lower than that of GBr and GB. Solubility of CP in broomcorn grain was significantly decreased by steam–flaking, but degradation rate of insoluble CP was not altered. Results from this study showed that SFBr supplies the major source of availabe nutrients for rumen microorganisms compared with GBr. In other words, using the most efficient processing method for ruminants will be necessary.

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Improvement of feed efficiency in dairy farming economically has a great importance. In this study, the genetic parameters of net energy efficiency and its relationships with milk yield, 3.2% fat corrected milk, body weight, gross income and income over feed costs were investigated, by the 2589 monthly records collected from the 723 lactating cows in the 3 herds. The different requirements of energy were estimated, by the National Research Council (NRC) models. A general linear model was employed for determining significant factors affecting each trait. The genetic parameters were estimated by a multivariate analysis with the derivative free approach of restricted maximum likelihood algorithm. The animal models contained the fixed effects of herd-year-season, parity number and stage of lactation, the regression coefficients of each trait on the dietary levels of rumen undegradable protein and metabolizable energy, and the random effects of animal additive genetic, permanent environment and residuals. The heritability of milk yield, 3.2 percent fat corrected milk, body weight, net energy efficiency, gross income and income over feed cost, were estimates 0.31, 0.32, 0.30, 0.34, 0.24 and 0.29 respectively. The results of this study indicated that the direct selection for net energy efficiency might genetically improve the feed efficiency. It also seems that the selection for fat corrected milk may be effective for the indirect improvement of feed efficiency and economic performance of dairy cows.

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  Blast, caused by Magnaprthe grisea, is often an important fungal disease in the production of rice in temperate and tropical areas including Iran. To determine reaction of rice cultivars against blast disease, 40 rice genotypes from Iran and other sources from Asia were selected. Four blast isolates from different races were used to test all rice genotypes in different greenhouse tests. In blast nursery, experiments were conducted in a Randomized Complete Block Design (RCBD) with three replications. In different experiments inoculated plant materials were evaluated for Infected Neck Number(INN), Neck Lesion Size(NLS), Infection Type(IT), Diseased Leaf Area(DLA), Area Under the Disease Progress Curve(AUDPC), Lesion Number(LN), and Sporulating Region Diameter(SRD). Most of the Iranian traditional cultivars together with CO-39 and C104-PKT showed susceptible reaction for AUDPC, IT, INN and NLS. Performance of improved cultivars from Iran, IRRI and NILs (except C104-PKT) was resistant. Some cultivars including Fujiminori, Onda , Hassan saraii were moderatly susceptible to leaf blast in blast nursery. All components of resistance in both growing stages in greenhouse and nursery tests were significantly correlated. In some cases such as cultivar Haraz different reaction was observed in seedling and flowering stages, indicating that genetics of resistance in two stages could be different.

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  Two hundred fifty seven bacterial isolates were collected from colza root and rhizosphere in Golestan, Mazandaran, Guilan and Tehran provinces. Antagonistic effect of bacterial isolates on Rhizoctonia solani, the causal agent of colza damping off, was studied using dual culture method. The results showed that, 60 isolates had the ability to inhibit the growth of R. solani on PDA medium. On the basis of the biochemical, physiological and morphological tests, isolates P1, P2 and P3 were identified as Pseudomonas fluorescens. Biocontrol mechanism studies showed that isolates produced antibiotics and volatile metabolites prevented the mycelial growth of the fungus. The isolates produced some of antimicrobial metabolites including hydrogen cyanide, protease and siderophore. Isolate P3 was more effective to inhibit the growth of the fungus in-vitro. The effect of isolates on disease reduction in comparison with control was significantly different. None of the isolates were able to prevent disease occurrence completely. Isolates applied as soil treatment had a significantly higher disease control as compared to seed treatment method. Isolate P3 had considerable effect on reduction disease in the greenhouse conditions. All isolates were capable of colonizing canola roots and so increased canola growth in free-causal agent conditions.

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24 Holstein cows and 16 Holstein heifers in close-up period were used to evaluate the effects of ground wheat grain in prepartum diets on health and performance of dairy cows. Cows were blocked based on parity (three groups) and then randomly assigned to two experimental diets. Study rations included a treatment containing wheat with 1.62Mcal/kg NEL, 14.8%CP, 42.1%NFC, and –64meq/Kg DCAD and another treatment was composed of barley and wheat bran with 1.59Mcal/kg NEL, 14.8%CP, 38.2%NFC, and –48meq/Kg DCAD. Cows were fed experimental diets in group, on average 24%4 days prior to parturition, and they were fed the same ration up to day 21 postpartum. Average feed intake prior to confining, milk yield and composition, blood metabolites, feeding and chewing activity, urine and feces pH, placenta weight and time of its omitted, pregnancy duration, parturition status, body weight and BCS, and metabolic disorders were evaluated in this research. Average feed intake for wheat treatment was more than barley and wheat bran treatment (11.56 in contrast to 10.74, Kg DM), but it was not statistically significant. Milk production in wheat treatment had no significant increase. Milk fat yield in wheat treatment had a higher value compared to barley and wheat bran treatment (P<0.025). Blood calcium in wheat treatment was significantly higher (P<0.005), and blood glucose in wheat treatment was significantly higher than barley and wheat bran treatment (P<0.011). Changes in body weight and BCS, pregnancy duration and parturition status were not significantly different between treatments. Urine pH in wheat treatment had a significant decrease in the last week prior to parturition (P< 0.003).

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Information on animal requirements for determination of rangeland grazing capacity is essential. Animal requirements depend on its live weight, age, physiological condition and quality of available forage. There are more than 20 sheep breeds with different body sizes grazing in various climatic zone's rangelands of Iran, so animal unit equivalent of each breed should be determined independently. In this research, live weight of animal unit of Fashandy sheep based on average live weight of 3 and 4 year old ewes was determined. Three herds with more than 100 Fashandy ewes among existing herds in Taleghan region were selected. In each herd, 15 three year old ewes, 15 four year old ewes, 5 three year old rams, and 5 four year old rams were selected. They were weighed three times including at the time of beginning of grazing in highlands, end of grazing season in highlands, and once in winter. In each herd, also 5 three month old lambs in the beginning of grazing season and 5 six month old lambs at the end of grazing season were weighed. The amount of daily forage requirement according to live weight and energy requirement of animal unit equivalent for maintenance condition was calculated using NRC (1985) tables and MAFF (1984) formula. It was multiplied by 1.5 because of mountainous condition of rangelands and distances from watering points and villages. The SAS statistical software was used for data analyses according to factorial experiment in the form of completely random design. According to the results, the live weight of animal unit of Fashandy breed was 60.7 Kg. The average live weight of 3 and 4 year old rams were 80.3 and 85.3 kg, respectively. Live weights of 3 and 6 month old lambs were 21.4 and 37.8 kg, respectively. Therefore, animal unit equivalents for rams, 3 and 6 month old lambs were 1.36, 0.35 and 0.62 respectively. According to NRC tables, daily metabolisable energy requirement was 13.8 Mj, and based on MAFF formula it was 11.8 Mj (including that multiplied by 1.5).