The effect of the quantity and quality of pasture available to sheep on their grazing behaviour

1960 ◽  
Vol 11 (6) ◽  
pp. 1034 ◽  
Author(s):  
GW Arnold

During the spring of 1969 four originally similar plots of a Phalaris tuberosa subterranean clover pasture were grazed at different stocking levels to produce a range in levels of pasture availability. The plots were subsequently grazed at 12, 16, 20, and 24 sheep per acre in a 4 x 4 Latin square design. On these pastures, as the amount of pasture available decreased, there was a significant increase both in the nitrogen content of available material and in the diet selected by oesophageal-fistulated sheep grazing them. These differences in the quantity and quality of available pasture produced significant changes in the grazing behaviour of sheep. Grazing time showed a linear increase with decreasing pasture availability, but the rate of increase in grazing time was insufficient to maintain liveweight. Ruminating time was significantly reduced as pasture availability declined. There were considerable differences between sheep in their ability to increase their grazing times as pasture availability decreased. These differences could be of considerable practical implication.

1972 ◽  
Vol 12 (56) ◽  
pp. 240 ◽  
Author(s):  
KFM Reed ◽  
RW Snaydon ◽  
A Axelsen

Young sheep were rotationally grazed, at two stocking rates, on pasture sown to combinations of two legume species (lucerne or subterranean clover) and two grass species (a mixture of annual and biennial ryegrass or phalaris) at Canberra. Liveweight gains were 45 per cent greater, and wool production was 10 per cent greater, on the lucerne dominant pasture (87 per cent lucerne) than on the grass dominant subterranean clover pasture (8 per cent subterranean clover). The differences were maximum during summer, but also occurred during spring. Mortality and supplementary feed requirement on grass dominant pasture was double that on lucerne pasture. Liveweight gains were 13 per cent greater on pasture sown to ryegrass than on pasture sown to phalaris. Sheep mortality was eight times greater on the phalaris than on the ryegrass pasture, and survival feed requirements at least double. The superior animal production from lucerne pasture was due mainly to the ability of lucerne to grow during periods of low rainfall and to maintain a high production of legume in the pasture.


1955 ◽  
Vol 6 (4) ◽  
pp. 456 ◽  
Author(s):  
WH Southcott

Field trials in 1951 and 1952 confirmed previous observations on the evacuation of adult Oesophagostomum columbianum Curtice from sheep which graze continuously on green oats. Ingestion of phalaris-subterranean clover or red clover pasture also resulted in the evacuation of some O. columbianum but was much less effective in this regard. Evacuation of O. columbianum from sheep on green oats was not complete and was associated with softening, and lowering of the pH, of the faeces. The phenomenon occurred both with and without a considerable increase in liveweight. Some of the factors associated with oat-grazing which may influence removal of O. columbianum are discussed.


1959 ◽  
Vol 10 (2) ◽  
pp. 237 ◽  
Author(s):  
HE Fels ◽  
RJ Moir ◽  
RC Rossiter

Estimates of the intake of pasture organic matter by grazing sheep were made for two types of pasture, clover-dominant and grass-dominant, at three growth stages. These estimates were made from faecal nitrogen index equations which were derived from data on penned sheep. One of the equations was found to be remarkably close to Lanoaster's (1954) regression of feed/faeces ratio on percentage faecal nitrogen content. The dry mature clover pasture was anomalous, and a separate "local" regression was derived for it. Organic matter intakes for grazing sheep of about 110 lb body weight ranged from 900 to 1300 g/day, except on dry clover pasture, where the intake was only about 700 g/day. Contrary to common belief, subterranean clover was eaten at least as readily as grass during the growing season. Evidence is presented that sheep grazing on pastures with a total nitrogen content of 2 . 5 per cent. or less select material of higher than average nitrogen content, whereas if the nitrogen content of the pasture exceeds 3.5 per cent. there is no such selection. The anomalous characteristics of the dry mature clover are discussed in some detail, and further evidence is given suggesting that the material was of poorer digestibility than usual.


1980 ◽  
Vol 20 (107) ◽  
pp. 695 ◽  
Author(s):  
DG Hall ◽  
RD FitzGerald ◽  
EC Wolfe ◽  
BR Cullis

During 1976 and 1977 in southern New South Wales, diet samples were obtained at approximately 3-week intervals from oesophageally fistulated steers grazing a lucerne (Medicago sativa) and subterranean clover (Trifolium subterraneum) pasture (LC) and a subterranean clover (C) pasture. On LC, green lucerne was the predominant diet component for much of the 2 years. On C, the diet consisted mainly of dry material during a drought in autumn-winter 1976, green wireweed (Polygonurn aviculare) until late autumn 1977, green clover and grass in winter and spring 1977, and finally dry material again. During 1976 and early 1977, diets on LC had a higher digestibility (61.7% vs 49.4%) and nitrogen content (2.55% vs 2.04%) than those on C. This difference was due to the contribution of lucerne on LC, and also because the wireweed on C was of very low quality, even when green. During the latter part of 1977, LC and C had equivalent digestibility and nitrogen levels. The information on the diets helped explain changes in liveweight and the incidence of bloat of cattle grazing the plots.


1966 ◽  
Vol 17 (4) ◽  
pp. 543 ◽  
Author(s):  
GW Arnold ◽  
J Ball ◽  
WR McManus ◽  
IG Bush

The diet of grazing sheep was studied by using animals with oesophageal fistulas. Seasonal changes in the botanical and chemical composition of the diet when grazing Phalaris–annual grasses–subterranean clover pasture are described. The effect of grazing intensity on diet is considered. A comparison was made of diets on seven pasture species. None of the species examined had a useful qualitative superiority over Phalaris either in winter or in summer, when the digestibility of this species declines considerably. Relations between botanical and chemical composition of the diet and the pasture are discussed. Significant relations were established between the nitrogen and soluble carbohydrate contents of diets and their digestibility.


1967 ◽  
Vol 7 (28) ◽  
pp. 426 ◽  
Author(s):  
GW Robards ◽  
JH Leigh ◽  
WE Mulham

The diet selected by Merino sheep grazing a Danthonia caespitosa Gaudich. grassland was determined by analysing extrusa from Merino wethers fitted with oesophageal fistulas. Visual assessments were combined with hand clipped samples to determine the amount of forage available. In spring a large proportion of the diet consisted of annual species. In summer, when the range of species present in the pasture was low, Danthonia caespitosa made up the bulk of the diet. Under heavy grazing the amount of dry material and burrs of Medicago polymorpha L. in the diet increased as the supply of Danthonia caespitosa decreased. Nitrogen content and in vitro digestibility, both of the pasture and of the forage eaten during spring, decreased as forage availability decreased under heavy grazing. These values were lower in summer than in spring, but showed little change under increasing grazing pressure. The quality of the pasture, as assessed by nitrogen content and digestibility, would have been sufficient, even in the dry summer experienced during this study, to enable sheep to increase in body weight. Because of the lack of drought-resistant species capable of producing appreciable amounts of forage in the summer-autumn period, it is improbable that any system of management based on deferred or rotational grazing can be devised that will increase animal production from this pasture type.


Author(s):  
S. Ates ◽  
R.J. Lucas ◽  
G.R. Edwards

The effect of stocking rate (8.3 (low) and 13.9 (high) ewes + twin lambs/ha) and time of closing in spring on lamb liveweight gain, pasture production and subterranean clover seedling densities was monitored over 2 years for a dryland cocksfoot-subterranean clover pasture in Canterbury. Keywords: cocksfoot, Dactylis glomerata, closing date, liveweight gain, seedling density, sheep grazing, stocking rate, subterranean clover, Trifolium subterraneum


1963 ◽  
Vol 14 (6) ◽  
pp. 796 ◽  
Author(s):  
ER Watson

Under a subterranean clover pasture on a light-textured soil at Kojonup, Western Australia, soil nitrogen accumulated at a fairly steady rate of 42 lb/acre/year over a 5 year period. The increase in soil nitrogen accounted for differences in wheat production following the clover ley whether measured as total dry weight, yield of grain, or uptake of nitrogen. The clover treatments had little effect on the percentage of nitrogen in the grain or on the baking quality of the flour. Each additional year of clover gave an additional yield of 120 lb of wheat grain per acre for the first crop. Yields for second crops were considerably lower than the first but residual effects were evident. A practical implication of the results is that short leys of 1 to 2 years' duration followed by a single cereal crop could be a suitable cropping practice for the Kojonup area.


1972 ◽  
Vol 52 (4) ◽  
pp. 681-687 ◽  
Author(s):  
R. J. BOILA ◽  
T. J. DEVLIN

Four dairy steers were allotted to four lysine infusion levels in a 4 × 4 latin square design and fed an 11.5% crude protein (90% dry matter (DM)) diet continuously (10-min intervals every 24 hr). Lysine hydrochloride equivalent to 0.0, 3.0, 6.0, and 9.0 g lysine per day was infused per abomasum. When 9 g lysine were infused per day, the percent of absorbed nitrogen (N) retained was significantly (P < 0.05) reduced; urinary N excretion as a percentage of N intake and plasma-free lysine were increased significantly compared with the other three infusion treatments. The infusion of 9 g lysine per day apparently exceeded the body tissue requirements for this amino acid and the excess N was excreted in the urine. A possibility of lysine being limiting (0.28% lysine of a 100% DM diet) was apparently offset by the synthesis of lysine by rumen microorganisms, which increased the dietary lysine two- to threefold. Increased levels of infused lysine did not result in a linear increase of lysine in the abomasum. With 3 g per day lysine infusion rumen ammonia and N retentions were high. However, a smaller amount of N reached the abomasum with steers on this treatment.


1972 ◽  
Vol 79 (1) ◽  
pp. 99-103 ◽  
Author(s):  
A. M. Raven

SUMMARYA 6 x 6 Latin Square balance experiment was carried out using six Friesian steers, each of which initially weighed about 304 kg. The six treatments studied were an all-hay diet and five other diets containing 20,40,60,80 and 100 % of rolled barley fortified with mineral and vitamin supplements, accompanied by correspondingly reduced proportions of hay. Each diet was fed at an estimated maintenance level of feeding.The progressive increase in the proportion of concentrate gave a significantly linear increase (P < 0·001) in both digestible and calculated metabolizable energy. The actual increase in digestible energy was from 2·62Mcal/kg dry matter (59·3% of the gross energy) on the all-hay treatment to 3·42 Mcal/kg dry matter (79·5% of the gross energy) on the all-concentrate treatment. Use of the determined digestible energy values for the all-hay and fortified barley diets to calculate the digestible energy of the four mixed diets gave results in reasonably good agreement with the determined values, the maximum difference being 0·12 Mcal/kg dry matter, which represented 3·83 % of the determined value. The losses of energy in the urine expressed as percentages of the gross energy of the diets showed a small but significantly linear decrease (P < 0·01) with increase in proportion of barley in the diet. The molar proportions of steamvolatile acids in samples of rumen fluid taken from two animals on each treatment indicated that increase in the proportion of concentrate was associated with tendencies for increase in acetic acid, decrease in propionic acid and little change in butyric acid. The mean digestibility of the organic matter was 62·6 % on the all-hay treatment and 81·8 % on the all concentrate treatment. The progressive increase in the proportion of concentrate gave a significantly linear increase (P < 0·001) in digestibility of the organic matter. Although intakes of nitrogen decreased with increase in the proportion of concentrate due to a decrease in the amount of dry matter fed, the weights of nitrogen retained were well maintained and when expressed as percentages of intake showed a significantly linear increase (P < 0·01).


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