Herbage intake of grazing sheep in South-western Australia

1959 ◽  
Vol 10 (2) ◽  
pp. 237 ◽  
Author(s):  
HE Fels ◽  
RJ Moir ◽  
RC Rossiter
Keyword(s):  
Organic Matter ◽  
Nitrogen Content ◽  
Subterranean Clover ◽  
Growth Stages ◽  
Common Belief ◽  
Local Regression ◽  
Herbage Intake ◽  
Faecal Nitrogen ◽  
Grazing Sheep ◽  
Clover Pasture

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.

The estimation of the intake of grazing sheep II. Application of faecal nitrogen regressions to a group of grazing sheep

1962 ◽  
Vol 59 (3) ◽  
pp. 349-353 ◽  
Author(s):  
G. R. Pearce ◽  
J. E. Vercoe ◽  
D. E. Tribe
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
General Pattern ◽  
Live Weight ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Lolium Rigidum ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Grazing Sheep

1. Recordings of faecal organic matter (O.M.), faecal N% (O.M. basis) and live weight, were made over 52 consecutive weekly periods on ten Corriedale wethers grazing a pasture consisting mainly of Wimmera rye-grass (Lolium rigidum Gaud.) with some subterranean clover (Trifolium subterraneum) in a Mediterranean-type environment. The amount of available O.M. and its N% were also recorded.2. By applying regressions of (i) the ratio of O.M. feed intake to O.M. faecal output on faecal N% and (ii) the N% in the O.M. intake on faecal N%, to the above observations it was possible to estimate the following quantities: O.M. and digestible organic matter (D.O.M.) intake, N and digestible N intake and O.M. digestibility percentage.3. The patterns of O.M. and D.O.M. intake, and N and digestible N intake are described. Similar patterns exist for each of these quantities. Two maxima, a large one in the spring and a smaller one in the autumn, and two minima, one in the summer and one in the winter, are exhibited. The values for these various maxima and minima are presented in the text.4. Attention is drawn to variations from the general pattern for these quantities and factors which could influence these patterns are mentioned.

The estimation of the intake of grazing sheep I. Establishment of faecal nitrogen regressions

1962 ◽  
Vol 59 (3) ◽  
pp. 343-348 ◽  
Author(s):  
J. E. Vercoe ◽  
G. R. Pearce ◽  
D. E. Tribe
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Regression Equations ◽  
Lolium Rigidum ◽  
Faecal Output ◽  
Rye Grass ◽  
Faecal Nitrogen ◽  
Grazing Sheep

1. Regression equations for the ratio of organic matter (O.M.) feed intake to O.M. faecal output on faecal N%, and the N% in the O.M. intake on faecal N% were established over a 52-week period by feeding caged Corriedale wethers on pasture cut from a Wimmera rye-grass (Lolium rigidum Gaud.), subterranean clover (Trifolium subterraneum) sward in a Mediterranean-type environment.2. The regression equations and their application to grazing sheep together with the relation between O.M. intake and faecal N, are discussed.

Studies on the nutritive value of the diet selected by grazing sheep IV. Variation in the diet selected by sheep differing in age, breed, sex, strain and previous history

1969 ◽  
Vol 11 (3) ◽  
pp. 369-378 ◽  
Author(s):  
J. P. Langlands
Keyword(s):  
Nitrogen Content ◽  
Nutritive Value ◽  
Previous History ◽  
In Vitro Digestibility ◽  
Sheep Grazing ◽  
Faecal Nitrogen ◽  
Grazing Sheep ◽  
Grazing History

SUMMARYThe ability of two groups of six Merino wethers aged 6 and 66 months to digest a lucerne ration was examined in order to detect possible biases in the use of faecal nitrogen as a faecal index substance. Earlier work with this technique had indicated a difference in selectivity between young and older sheep. No difference in ability to digest the ration was observed and it was concluded that the earlier observation was not an artefact in the faecal nitrogen technique. Oesophageal fistulae were prepared in 120 sheep differing in breed, sex, age, strain and previous history. Determinations were made of the nitrogen content, and in one experiment of the in vitro digestibility of the diet selected by sheep grazing various pastures. Significant differences in the nitrogen content of the diet selected by sheep varying in breed, age and previous grazing history were recorded on some pastures on some occasions but not on others. No significant differences were observed between sheep varying in strain or sex. No reason could be suggested for the occasional differences between groups in the nitrogen content or digestibility of the diet selected, but it appeared unlikely that it would be a major source of variation in the productivity of the different groups at pasture.

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
Keyword(s):  
Nitrogen Content ◽  
Practical Implication ◽  
Latin Square ◽  
Subterranean Clover ◽  
Linear Increase ◽  
Sheep Grazing ◽  
Rate Of Increase ◽  
Clover Pasture ◽  
Grazing Behaviour

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.

Studies on the nutritive value of the diet selected by grazing sheep V. Further studies of the relationship between digestibility estimated in vitro from oesophageal fistula samples and from faecal and dietary composition

1969 ◽  
Vol 11 (3) ◽  
pp. 379-387 ◽  
Author(s):  
J. P. Langlands
Keyword(s):  
Nitrogen Content ◽  
Nutritive Value ◽  
Live Weight ◽  
Faecal Output ◽  
Faecal Nitrogen ◽  
Grazing Sheep ◽  
Predicted Values ◽  
Stocking Rates ◽  
The Relationship

SUMMARYDigestibility was estimated in vitro from a total of 167 oesophageal fistula samples collected over a period of 16 to 24 months from adult sheep grazing eight Phalaris tuberosa-Trifolium repens pastures stocked continuously at rates of from 2·5 to 37·1 sheep per ha. Corresponding estimates of the nitrogen content of the faeces and of the fistula samples, the live weight and faecal output of the sheep, and of the herbage availability of the pasture were obtained.The observations were stratified on the bases of stocking rate, digestibility, month of the year, herbage availability or organicmatter intake. Relationships between digestibility estimated by the fistula technique and faecal nitrogen content (model B) and between digestibility and faecal nitrogen content, nitrogen content of the dietary dry and organic matter, and faecal output per unit live weight (model A) were calculated for each stratum.There were significant differences between relationships derived for the various stocking rates, levels of digestibility, times of year, levels of intake and levels of herbage availability; predicted values of digestibility for given values of the independent variables differed by as much as 20 units of digestibility. Model A was substantially more precise than model B.Differences between estimates of digestibility, derived by the fistula technique and by a general faecal nitrogen—digestibility relationship, established by Lambourne and Reardon (1963a) were calculated. The differences were related to digestibility and to herbage availability.The implications of these results are discussed and it is concluded that faecal nitrogen content is not a satisfactory index of the digestibility of the diet selected by grazing sheep.

The effect of cereal concentrate supplementation on the digestibility of herbage-based diets for lactating dairy cows

1986 ◽  
Vol 106 (3) ◽  
pp. 581-592 ◽  
Author(s):  
C. M. Arriaga-Jordan ◽  
W. Holmes
Keyword(s):  
Organic Matter ◽  
Dairy Cows ◽  
The Other ◽  
Free Access ◽  
Concentrate Supplementation ◽  
Lactating Cows ◽  
Lactating Dairy Cows ◽  
Herbage Intake ◽  
Faecal Nitrogen ◽  
Faecal Indicators

SummaryTwo experiments were conducted, one with seven and the other with eight lactating cows, to measure the effect of supplementation with a cereal concentrate on the digestibility of fresh herbage and to provide equations relating digestibility of herbage to faecal indicators. Cattle were housed with free access to fresh herbage from individual Calan–Broadbent gates for recording feed intake, and faecal output was estimated by the use of chromic oxide. In both experiments a cereal supplement depressed herbage organic matter digestibility by 8 g/kg for each kg of fresh concentrate provided within the range 1–6 kg. The depression was associated with reduced digestibility of cellulose. Herbage digestibility was significantly related to faecal nitrogen and faecal cellulose. Herbage intake was depressed by concentrate supplementation and the response in milk yield to supplementation was small.

Comparing estimates of herbage digestibility from faecal nitrogen and in vitro determinations

1980 ◽  
Vol 31 (1) ◽  
pp. 57-62
Author(s):  
H. A. Birrell
Keyword(s):  
Organic Matter ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Feeding Trials ◽  
Grazing Sheep ◽  
Organic Matter Digestibility ◽  
Image Position ◽  
Stocking Rates

ABSTRACTIn a grazing experiment, the organic matter digestibility of herbage selected by sheep grazing at two stocking rates was determined at monthly intervals over a 9-month period by (i) the in vitro determination of organic matter digestibility of the material collected from sheep fitted with an oesophageal fistula, and (ii) derivation from the prediction of digestible organic matter intake with a faecal nitrogen regression. A comparison of the two techniques confirms the view of other workers that faecal nitrogen indices based on pen feeding trials of green herbage are unreliable for predicting digestibility of green herbage in the field. The bias which is produced by faecal nitrogen regression appears to be associated with the time spent grazing by the animal each day. Relating organic matter digestibility directly to nitrogen content of faeces of grazing sheep (N, g nitrogen/100 g faecal organic matter) and their grazing time (T,h) yielded the following equation:The expression has standard errors (±2·6) similar to those involved in an in vitro determination. It provides a simple technique for estimating digestibility of herbage eaten by grazing sheep, but this may only be applicable to the particular sward conditions.Field estimates of digestibility over summer and autumn by this equation were found to be similar to estimates by a faecal nitrogen expression established from hand feeding sheep with dry summer herbage.

Soil acidification under clover pasture

1980 ◽  
Vol 20 (106) ◽  
pp. 561 ◽  
Author(s):  
CH Williams
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Phosphorus ◽  
Chemical Properties ◽  
Subterranean Clover ◽  
Titratable Acidity ◽  
Exchange Capacity ◽  
Early Years ◽  
Total Soil ◽  
Clover Pasture

Long-term changes in some chemical properties of yellow podzolic soils under subterranean clover pastures were studied near Binda, New South Wales. The rate of decrease in pH of the surface 10 cm of soil was greatest in the early years following pasture establishment, and decreased with time. Over 50 years the decrease in pH was approximately one unit, resulting in current soil pH values of about 5.0. The increased acidity had led to increases in CaCI,-extractable manganese and exchangeable aluminium. Although the build-up of soil organic matter under a 32- year-old subterranean clover pasture was largely confined to the surface 10 cm, the decrease in pH extended to a depth in excess of 30 cm. Total soil nitrogen increased gradually throughout the 50-year period, reflecting increases in the soil organic matter. There were associated increases in cation exchange capacity and titratable acidity. Total soil phosphorus also increased with time and was correlated with the decrease in pH. This reflected the accumulation of organic and inorganic residues from phosphate fertilizers, but it seems unlikely that the acidity of the superphosphate contributed directly to the increase in soil acidity although it is essential for the establishment and maintenance of the legume, the main source of the increase in soil organic matter. It seems likely that the area of pasture soils adversely affected by acidity problems will increase in the future.

The energy requirements of sheep for maintenance and gain. II. Grazing sheep

1962 ◽  
Vol 58 (2) ◽  
pp. 187-199 ◽  
Author(s):  
I. E. Coop ◽  
M. K. Hill
Keyword(s):  
Organic Matter ◽  
White Clover ◽  
Energy Cost ◽  
Climatic Factors ◽  
Live Weight ◽  
Maintenance Cost ◽  
Weight Changes ◽  
Rye Grass ◽  
Faecal Nitrogen ◽  
Grazing Sheep

The intake of grazing sheep in terms of digestible organic matter, DOM, has been measured by faecal index methods, employing chromic oxide to measure faecal output and faecal nitrogen for digestibility of pasture. A regression equation for the prediction of digestibility from faecal nitrogen (organic matter basis) was developed from several series of digestibility trials with pasture, the equation beingdigestibility of organic matter = 30·84 + Four trials to measure maintenance and gain were conducted, as follows:(i) Thirty-eight sheep, comprising twelve wethers of mean weight 112 lb., thirteen small or thin Romney ewes of mean live weight 110 lb. and thirteen large or fat Romney ewes of mean live weight 166 lb. were grazed all together for 17 weeks on a rye-grass-white clover sward at an intensity such that live weight was just maintained. Corrections to intake were made for small live-weight changes.Daily DOM intake (lb.) for maintenance = 0·062 maintenance for a 100 lb. sheep becomes 1·48 ± 0·08 lb. DOM/day.(ii) Thirty-six weaned Romney ewe lambs of mean initial live weight 56 lb. were grazed for 8 weeks on a rye-grass-white clover pasture and allowed to gain in weight. Regression of intake on gain gave the equationdaily DOM intake (56 lb. lamb) = 0·93 (±0·07) + 0·90 gwhere g = gain in lb./day. Combining this lamb data with that of the previous trial yields the equationDOM intake (lb.) for maintenance = 0·052 (iii) Forty ewes, comprising eight Southdowns, twelve Romneys, eight Border Leicesters and twelve Border-Romney crossbreds were grazed together on short pasture (rye-grass-white clover) for 12 weeks. The ewes were of widely differing live weight and the mean gains or losses of the groups over the period varied from + 1·5 to −4·5 lb.Daily DOM intake (lb.) for maintenance = 0·061 which for a 100 lb. sheep becomes 1·63 ± 0·13 lb. DOM.(iv) Seven Romney ewes were grazed in high and eight ewes in low intake groups for 8 weeks. Regression of intake on gain gave the equationdaily DOM intake (130 lb. ewe) = 1·58 (±0·06) + 1·98 g.For a 100 lb. sheep this becomes 1·36 (± 0·06) lb. DOM/day for maintenance.The three estimates of maintenance of a grazing sheep of 100 lb. live weight 1·48, 1·63 and 1·36 lb. DOM/day are greatly in excess of the estimate of 0·92 lb. DOM/day for pen-fed sheep. It is believed that this difference is outside experimental error and represents a true increase in energy cost due to grazing. It is suggested that the cause of this derives from the energy costs of walking and harvesting the pasture together with climatic factors wind, cold and rain. The exponent of live weight agrees well with the estimates of other workers based on pen-fed animals. The energy cost of gain is less than that of pen-fed sheep and it is suggested that this is due to the maintenance cost decreasing with increasing availability of pasture and with increasing gain.

Studies on the nutritive value of the diet selected by grazing sheep. II. Some sources of error when sampling oesophageally fistulated sheep at pasture

1967 ◽  
Vol 9 (2) ◽  
pp. 167-175 ◽  
Author(s):  
J. P. Langlands
Keyword(s):  
Nitrogen Content ◽  
Nutritive Value ◽  
Diurnal Changes ◽  
Sources Of Error ◽  
Minute Period ◽  
Coefficients Of Variation ◽  
Significant Difference ◽  
Free Grazing ◽  
Grazing Sheep ◽  
Clover Pasture

Some possible sources of error when sampling oesophageally fistulated sheep at pasture were examined in eleven trials. Samples collected from sheep asted for varying periods of up to 22 hours did not differ significantly in nitrogen content from samples collected from unfasted sheep. There was no significant difference between the nitrogen content of extrusa collected at the start of a 30-minute period and that of extrusa collected at the end of the period. Sheep transferred from a perennial ryegrass/clover pasture to a native pasture for three months ingested herbage containing 3·80% nitrogen when returned to the original pasture. Control sheep which had remained on the ryegrass/clover pasture selected material containing 3·33% nitrogen. In a further trial sheep transferred from a ryegrass/clover pasture to a Phalaris/ clover pasture consumed herbage with an organic matter digestibility of 70·8 % which contained 3·44 % nitrogen. The material consumed by similar sheep which had grazed the Phalaris/clover pasture for 18 months was 71·5% digestible and contained 3·63% nitrogen.Diurnal changes in the digestibility and nitrogen content of the diet of free-grazing sheep were observed in two trials. Diurnal changes in nitrogen content were similar on different days but changes in digestibility were relatively smaller and less repeatable between days.Consistent differences in the composition of the diet selected by individual sheep and selected on different days were observed in a further five trials. Variation between sheep and between days in the nitrogen content of the diet was ±5·6% and ±7·4% respectively, both estimates being expressed as coefficients of variation. Corresponding estimates for digestibility, calculated as standard deviations, were ±1·6 and ±1·3 units. The implications of these results when sampling oesophageally fistulated sheep at pasture are considered.

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