JWSS - Journal of Water and Soil Science

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Effects of the β-adrenergic agonist metaproterenol were studied daily gain, carcass composition and feed consumption of Varamini female lambs were studied. Thirty lambs were randomly assigned to a randomized complete block design with three groups (treatments) and two blocks (live weight). The ration was similar for all groups (ME: 2.6 MCal/kg, CP: 14.9%) and lambs were fed ad libitum. Metaproterenol was injected subcutaneously at 0 (control), 7 (low dose) and 14 (high dose) µg kg^-1 w⁷⁵. Lambs were weighed at 20-day intervals.

Mean daily weight gain and feed conversion ratio improved significantly by metaproterenol (P<0.05), but feed intake was not affected. Hot carcass weight, carcass weight minus fat-tail, dressing percentage and longissimus muscle characteristics were different among the three groups (P<0.01). Physically separated fat from several depots and fat-tail weight significantly reduced in the metaproterenol groups. Carcass fat content decreased but carcass protein content increased in metaproterenol treated lambs.

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Three levels of urea (0, 0.5 and 0.75% on fresh weight basis) were added to whole corn plants to investigate their effects on the chemical composition, and digestibility in 16 Ghezel male lambs using a completely randomized design. Rumen degradability and nutritive values were also evaluated.

 pH, total nitrogen and ammonia-N concentration of silages increased (P<0.05) with the addition of urea. Total nitrogen apparent digestibility was higher (P<0.05) with the urea addition. Nitrogen balance in ruminal fluid increased (P<0.05) with the addition of 0.5% urea. pH and ammonia-N concentration increased (P<0.05) with the addition of urea until 1.5 hr post feeding. Blood serum urea nitrogen concentration was higher (P<0.05) with the addition of urea until 6 hr post feeding. Potential degradability of dry matter and organic matter was higher at 0.5% urea level. Average daily gain increased with the urea addition and was highest (212.88 gr) at 0.75% urea. Subcutaneous fat depth was significantly (P<0.0l) lower for the sheep fed with 0.5% urea-treated silage as compared to other treatments. The results indicated that feed efficiency may be improved by urea addition and that the addition of urea (0.5% on fresh weight basis) may be recommended in order to increase the feeding value of whole corn plants.

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The effect of adding two urea levels (0.5 and 0.75% on fresh basis) to whole-crop barley (WCB) on chemical compositon and digestibility in Ghezel rams was studied. The effect of including these silages in the ration of fattening Ghezel and Mehraban rams was also investigated. Urea supplementation of WCB silage resulted in an increase in pH, total nitrogen level, and ammonia-nitrogen concentrations (P<0.05). Apparent digestibility coefficients of dry matter, organic matter, acid detergent fiber, and neutral detergent fiber of WCB silage were not affected by urea treatment (P>0.05), but apparent digestibility coefficient of total nitrogen was higher for 0.5% urea-WCB silage. Apparent digestibility coefficients of total nitrogen and nitrogen balance were higher for 0.5% urea-WCB silage than for 0.75% urea-WCB silage, but the differences were not significant. Ruminal fluid pH at 2.5 h, and ammonia-nitrogen concentration at 4 h post-feeding were higher for 0.75% urea-WCB silage than for 0.5% urea-WCB silage (P<0.05). BUN levels (<20 mg per dl) in sheep fed with a mixture of alfalfa hay and silages were not affected by the treatment. The potential and effective degradabilities of dry matter and crude protein were higher for 0.75% urea-WCB silage. Feed performance and carcass characteristics were not significantly different amongst diets. The results showed that urea supplementation at 0.75% fresh basis, at the time of ensiling, may have a beneficial effect on feeding value of WCB silage.

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An experiment was carried out to determine the effect of substituting alfalfa hay (Medicago sativa) with Gundelia tournefortii hay (a range forage in Fars Province) in the ration of fattening lambs. Alfalfa hay was substituted with Gundelia tournefortii harvested at the final stages of flowering at various ratios (0, 25, 50, 75, and 100% dry matter basis) in the ration of fattening lambs. The rations (iso-nitrogenous and iso-energetic) were pelleted and each ration was fed for 75 days to 12 Shirazi Grey ram lambs with an average age of 136 days. The lambs were slaughtered and their feedlot performance and carcass characteristics were measured. Substituting alfalfa hay with Gundelia tournefortii hay did not significantly affect the mean daily weight gain, feed consumption, feed conversion ratio, dressing percentage, internal fat weight, carcass meat content, or meat DM and CP contents (p>0.05). However, backfat depth was significantly different among various rations (p<0.01). At present costs, the inclusion of Gundelia tournefortii in the ration of fattening lambs seemed to be cost-effective the cost of one kg DM of ration was 1266, 1155, 1050, 924, and 787 Rials for rations 1 to 5, respectively.

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The aim of this research was to study the effect of treatment with oyster mushroom (Pleurotus sajor-caju) on digestibility of Glycyrrhiza glabra L. pulp. Pleurotus sajor-caju was inoculated on sterilized wheat grains. Two weeks after growth at 25 °C it was added to the sterilized Glycyrrhiza glabra L. pulp in nylon bags. After two weeks (at 25 °C), mycelia grew on the pulp and were used for treatment. Digestibility coefficients were measured in 12 Ghezel rams. Dry matter, crude protein (CP) and nitrogen free extract (NFE) increased, but ash content, cell wall (NDF) and lignin (ADL) decreased significantly in fungal-treated as compared with non-treated pulps. Crude fiber (CF) and ADF contents were not significantly affected by the treatment. There was a tendency for crude fat (EE ether extract) to decrease by fungal treatment (p=0.08). Mean dry matter intake and digestibility coefficient of dry matter were higher in sheep which were fed the fungal-treated pulp compared with the control group. Digestibility coefficients of CP, CF, organic matter (OM), EE, NFE, NDF, ADF and ADL were significantly greater in fungal-treated pulp than in control group. Treatment with P. sajor-caju increased the nutritive value and digestibility of Glycyrrhiza glabra L. pulp (P<0.05), but culture of this fungus was not possible on non-sterilized pulp, which hinders its field application.

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An experiment was carried out to investigate the effects of different levels of energy (2700, 2900 and 3100 kcal/kg) and protein (13, 14.5 and 16 %) on laying performance of Fars native hens during the first phase of production. Two hundred and sixteen 25-week-old native pullets were put into fifty four groups of similar live weight (994 ± 169 gr) of four chickens, which were randomly allocated to nine experimental diets. Each treatment was replicated six times in factorial CRD design (3×3). At each level of energy, three diets were formulated to contain three levels of protein (16, 14.5 and 13%). The diets were fed ad libitum for a period of 20 weeks (week 25-45). The treatments 1 with 3100 kcal/kg ME and 16% protein and 3 with3100 kcal/kg ME and 13% protein had less daily feed consumption than treatment 7 with 2700 kcal/kg ME and 16% protein (90.50 and 87.30 vs 101.20 gr respectively, P<0.05). The effect of energy levels on daily feed and energy consumption and feed conversion ratio was significant (P< 0.05). Feed conversion ratio for energy level of 3100 kcal/kg was significantly different from 2700 kcal/kg (2.85 vs 3.08 respectively). The effect of protein levels on uric acid content of excreta and daily protein consumption was significant (P< 0.05) and protein level of 16% was significantly differed from protein level of 13% (11.40 vs 10.50 gr respectively). The results of this experiment showed that it is preferable to use the energy level of 2700 kcal/kg and protein level of 13% during the first phase of production of Fars native hens.