The relative intake of grazing ewes was estimated from faecal organic matter output, using chromic oxide marker, or as organic matter intake using chromic oxide plus faecal nitrogen. The ewes were grouped as: good teeth (mean age 2.9 years); medium or sound teeth (mean age 4.6 years); and poor teeth (broken-mouth or gummy ewes, mean age 8.2 years). They were grazed on a series of pastures-long grass of high feed availability to very short pasture of very low feed availability. The medium-teeth ewes were able to consume the same amount of pasture as those with good teeth on long grass, but only 90% as much on short grass. The corresponding figures for the poor-teeth ewes were 74% on long grass and 60% on short grass. Organic matter intakes indicated that on long grass the good-and medium-teeth ewes ate 2-3 times maintenance and the poor-teeth ewes I! times maintenance, but on the short grass the relative intakes were 0.7-1.2, 0.6-1.0, and 0.4-0.8 times maintenance respectively.
The quantity and quality changes of pasture in an all grass wintering system on a high country station, Central Otago, were studied at the end of the 1981 winter after an autumn of good pasture growth and during the 1982 autumn and winter after poor growth in the autumn. Higher levels of green herbage survived after the winter in 1981 compared with poor survival in 1982. Less than half of the green herbage present at the beginning of June was utilised during grazing, and losses of green herbage by frosting or senescence during June 1982 ranged from 35 to 70%. Green percentage of herbage was a good predictor of digestibility when values of 100% green and 100% dead material analyses were added to those of mixed herbage samples, with an average of 89% of variation in herbage digestibility being accounted for by the regressions of in vitro digestibility and % green. Prediction of digestibility from % green of mixed herbage samples alone was not as good (r 2 = 0.53 for June and 0.67 for July). Digestibility of 100% green herbage was high (82% mean) and varied little, whereas that of standing dead fluctuated, and was low (40% mean). Little, if any, dead herbage was eaten, and presence of dead herbage was of no advantage in autumn-saved pasture. There were no differences between clovers, grasses, or other species in winter survival or in digestibility of green herbage.
Sheep distributions on a 590 ha part of a 6200 ha summer range were observed for 3 years before and 3 years after an unfenced 44 ha part was oversown with white clover and topdressed with fertiliser. Treatment of the unfenced area attracted sheep from unimproved parts of the study area, but not from more distant parts of the summer range. Grazing pressure (stock units/t herbage) showed a seven-fold increase on the developed area compared with the undeveloped area in the last two postoversowing and topdressing seasons. Grazing pressure was halved for the whole study area, compared with pre-oversowing and topdressing (OSTD) levels, leading to accumulation of un utilised herbage on all vegetated areas that remained undeveloped. Higher grazing pressures on developed areas were accompanied by an increase in herbage quality on offer and improvement in diet selected. Partial area improvement attracted sheep from the higher altitude areas in a similar proportion to that from all the other undeveloped land units. Sheep densities were apparently very low on the higher altitude areas in both the pre-and post-OSTD periods and there might be little benefit to such higher environments from fencing them off or from attracting sheep away from them. The improved pastoral regime might itselfbetter justify the costs of land development.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.