Seasonal Variations in Voluntary Intake and Apparent Digestibility of Forages in Goats Grazing on Introduced Leymus chinensis Pasture
The nutrient composition of pasture, voluntary intake and digestibility of diet ingested by goats grazing on an introduced Leymus chinensis pasture were measured across spring (May), summer (July), autumn (October) and winter (March). In each season, 12 Inner Mongolian Cashmere goats (6 wethers and 6 does with an average live weight of 22.2±1.3 kg and 19.5±0.8 kg, respectively) were used to graze on a 2 hectares size paddock. Diet selection was observed and the plant parts selected by grazing goats and whole plant L. chinensis were sampled simultaneously. The alkane pair C32:C33 and C36 were used to estimate intake and digestibility, respectively. The results showed that the plant parts selected by goats had higher crude protein (CP) and lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) than the whole plant, especially in the autumn and winter. The voluntary intake of dry matter (DM), CP, ADF, NDF, and metabolizable energy (ME) by goats was highest in summer (p<0.05). The goats ingested more CP, ME, and less ADF in spring than in autumn (p<0.05). The intakes of DM, CP, and ME were lowest in winter (p<0.05). There were significant differences in nutrient intake between wethers and does in each season, except for the ADF and ME intake per metabolic weight (LW0.75). The nutrient digestibilities were higher in spring and summer, and decreased significantly during the autumn and winter (p<0.05). Goats, especially wethers, had a relative constant NDF digestibility across seasons, however, the apparent digestibility of CP in both wethers and does, decreased to negative values in winter. The grazing goats experienced relatively sufficient nutrients supply in spring and summer, and a severe deficiency of CP and ME in winter.
Comparison of Feeding Value of Some Popular Tree Fodders for Goats in the Mid-hill Region of Nepal
Large numbers of species of tree fodder are being used as green roughage source for goats in several farming systems. A study was carried out at Goat Research Station, Bandipur, Nepal in order to compare the feeding value of commonly used tree fodder leaves in mid-hills of Nepal. Altogether five treatments; tree fodder leaves of Ficus semicordata, Shorea robusta, Ficus glaberrima and Ficus lacor and mixed fodder as the conventional practices of the farmers were evaluated in Randomized Complete Block Design (RCBD) with three replications. Total of 30 male goats were used for the experiment in five groups, 6 for each treatment. The subsequent experiment was carried out to determine the nutrient digestibility of the tree fodder leaves by using fecal collection method. Nutrient composition, voluntary intake and nutrient digestibility of the fodder leaves and growth performance of goats were monitored. Crude protein (CP), total ash (TA), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), hemicelluloses and cellulose proportion were better for F. glaberrima and F. lacor leaves, whereas the digestibility of those nutrients were better for F. semicordata leaves and moderate for F. glaberrima and S. robusta. Voluntary fodder dry matter intake was highest for F. glaberrima and least for mixed fodders. Growth performance of goats was higher for F. lacor and F. glaberrima than other tree fodder leaves and mixed fodders. The leaves of F. lacor and F. glaberrima had shown better feeding value than the conventional practices of farmers, mixed fodders. The leaves of S. robusta and F. semicordata were observed similar with the mixed fodders for their feeding value.Int. J. Appl. Sci. Biotechnol. Vol 5(4): 442-448
The role of dissolved oxygen in supercritical water in the oxidation of ferritic–martensitic steel
Abstract To assess the role of dissolved oxygen in supercritical water on the growth processes of oxide scales, a marker experiment of ferritic–martensitic steel was performed by exposing to supercritical water (H 2 16 O) containing marked 18 O 2 at 600 °C under 25 MPa. The oxide scale was analysed by using Secondary Ion Mass Spectrometry (SIMS). The oxygen isotope profile shows that dissolved oxygen and supercritical water react with metals simultaneously. Dissolved oxygen changes the oxidation/reduction potential of supercritical water leading to an increase in the oxidation rate. The oxidation rate increases with increase in dissolved oxygen content in supercritical water. The mechanism of the effect of dissolved oxygen on oxidation is discussed.