There was no consistent difference in the botanical composition or nitrogen content of the diet selected by lambs and yearling sheep grazing annual or perennial pastures in the spring. On the annual pasture, where the grass and clover content was similar, selection by the animals appeared to be random with no particular species being favoured. On the perennial pasture, where the clover content remained below 20 per cent, the mean percentage of clover in the diet selected by the lambs increased from less than 5 per cent when they were seven weeks old to over 50 per cent at 16 weeks of age. Over the same period, the mean percentage of clover in the diet selected by the yearlings increased from less than 10 per cent to over 40 per cent.
As part of a programme to develop sustainable diets for macroalgivores, a 3‐month experiment was conducted to determine the effects of konjac glucomannan–xanthan gum (KX) binder configuration on formulated feed stability, feed palatability and growth performance of juvenile, hatchery‐reared, Haliotis discus hannai. This study was conducted in a recirculation facility in which four KX binder configurations were evaluated in a series of isonitrogenous experimental feeds and freshly harvested Laminaria digitata was included as a natural feed type. Dry matter leaching of the experimental feed treatments was assessed with no significant difference in the dry matter leaching between treatments observed. No differences (P > 0.05) were found in percentage survival, daily food consumption (DFC) and linear growth rate (LGR) between treatments. Food conversion efficiency (FCE), specific growth rate (SGR) and body weight/shell length (BW/SL) ratio were significantly higher when offered L. digitata. Trends showed that the best performing KX feed in terms of FCE, LGR, SGR and BW/SL ratio was produced with the 2% KX; 1 : 1 binder.
Three sheep in pens were fed cut white clover (Trifolium repens L.). On six separate days samples were collected through oesophageal fistulas and the length of the extruded pieces was taken as a measure of the amount of chewing and was related to the quantities of nitrogen and soluble carbohydrate released. Correlation coefficients of 0.84 and 0.77 were found between the amount of chewing and the release of nitrogen and soluble carbohydrate respectively.
Length, weight, branching and chemical composition of roots of barley grass (Hordeum leporinum) and subterranean clover, (Trifolium subterraneum), the main components of a non-irrigated pasture were measured in the fourth year of an experiment on pastures grazed by Corriedale wethers. The grazing treatments were in a factorial design (2 x 2 x 3) replicated three times, with three stocking rates, two levels of nitrogen fertilizer and two methods of management. Grass and clover density was reduced progressively as stocking rate was increased from 10 to 12 to 17 wethers ha-1 but the surviving plants at maturity had vigorous root systems. This performance of annual species contrasts with that of perennial pasture species where root development and root branching may be expected to decline with increase in grazing pressure. Applications of nitrogen fertilizer annually at rates of 0 or 67 kg ha-1 had little effect on density of grasses or clovers but clover roots were lighter and had fewer rhizobia nodules where nitrogen fertilizer had been applied. The management of pasture by deferment of grazing during regeneration was beneficial to clover plants in that their root structure was larger at maturity; similar effects were not evident in grass roots.
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