Maintenance energy requirement of grazing sheep in relation to herbage availability. II.* Observations on grazing intake

1972 ◽  
Vol 23 (1) ◽  
pp. 77 ◽  
Author(s):  
BA Young ◽  
JL Corbett
Keyword(s):  
Energy Requirement ◽  
Grazing Pressure ◽  
In Vitro Digestibility ◽  
Consistent Manner ◽  
The Mean ◽  
Maintenance Energy Requirement ◽  
Calorimetric Studies ◽  
Maintenance Requirements ◽  
Biased Estimates

Grazing pressure on three pastures was adjusted so that the mean liveweights (W) of three groups of 10 Merino wethers, initially uniform, were kept at nominally 45, 35, and 25 kg (groups H, M, and L respectively). Grazing intakes of each sheep were estimated over eight 7-day periods during 6 months. The organic matter (OM) content of the faeces decreased to less than 40% with dccreasing W, but concentrations of nitrogen (FN) and chromium sesquioxide (Cr2O3) in the OM increased. Sheep in groups M and L re-ingested with herbage, Cr2O3 they had previously excreted on their pastures. Faecal Cr2O3 concentrations were adjusted for this recycling, which otherwise would have resulted in underestimation of faecal OM outputs by up to 10% (group M) or 15% (group L). The digestibility in vitro was determined of herbage grazed from each pasture by a sheep with an oesophageal fistula. The values obtained for group H showed some differences, but not in a consistent manner, from those predicted from FN. For groups M and L, the in vitro digestibility values were consistently lower than those predicted from FN, on average by 12.5 percentage units with a maximum discrepancy of 18.5 units. It is shown that when sheep graze sparse pastures, as did groups M and L, the ingestion of large amounts of soil can lead to biased estimates of digestibility from FN, resulting in gross overestimation of digestible OM intakes. It is suggested that this bias may account for the apparently high maintenance feed intakes reported by other workers for sheep in these conditions, and that the calorimetric studies made on groups H, M, and L reported earlier gave more reliable estimates of maintenance requirements. ___________________ *Part I, Aust. J. Agric. Res., 23: 57 (1972)

Maintenance energy requirement of grazing sheep in relation to herbage availability. I. Calorimetric estimates

1972 ◽  
Vol 23 (1) ◽  
pp. 57 ◽  
Author(s):  
BA Young ◽  
JL Corbett
Keyword(s):  
Energy Requirement ◽  
Grazing Pressure ◽  
Metabolizable Energy ◽  
Constant Infusion ◽  
Entry Rate ◽  
Energy Expenditures ◽  
Climatic Environment ◽  
Maintenance Energy Requirement ◽  
Maintenance Requirements ◽  
Made In

Grazing pressure on three pastures was adjusted so that the mean liveweights (W) of three groups of 10 Merino wethers, initially uniform, were kept at nominally 45, 35, and 25 kg. Daily rates of energy expenditure were calculated by measuring the respiratory gaseous exchanges of tracheostomized sheep in each group, and from estimates of CO2 entry rate determined during constant infusion with NaH14CO3. These measurements were made during a period of 3 weeks when the sheep had been at constant W for 9 months, and during a further 3 weeks beginning 30 days after the sheep were shorn. Further measurements were made in two periods of 7 days after animals had been interchanged between groups so that W was increasing in some animals and decreasing in others. Maintenance requirements of all sheep, indicated by the energy expenditures during the periods at constant W, were described by the equation M = 45.1 W + 256, where M is the estimated metabolizable energy requirement in kilocalories per 24 hr. Similar results were obtained during the two periods when W was changing. The requirements were in general 60–70% greater than those for housed sheep of similar W and are discussed in relation to the climatic environment, the condition of the sheep, and the availability of herbage.

scholarly journals Faecal endogenous loss of calcium in young sheep

1989 ◽  
Vol 61 (1) ◽  
pp. 59-65 ◽  
Author(s):  
J. S. Chrisp ◽  
A. R. Sykes ◽  
N. D. Grace
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Research Council ◽  
Agricultural Research ◽  
Energy Requirement ◽  
Energy Requirements ◽  
Maintenance Energy ◽  
Agricultural Research Council ◽  
The Mean ◽  
Maintenance Energy Requirement

1. Two groups of eight 6–7-month-old wether lambs were offered either a frozen ryegrass (Lolium perenne L.)-white clover (Trifolium repens L.) pasture or a ryegrass-white clover hay, containing 12.1 and 6.4 g calcium/ kg dry matter (DM) respectively. Within groups the amounts offered to individual sheep ranged from 0.5 to 2.0 times the estimated maintenance energy requirements.2. A single intravenous injection of 150 μCi 45Ca as CaCl2. 2H2O, and stable balances were used to determine absorption, faecal endogenous loss and balance of Ca.3. Faecal endogenous loss of Ca increased by 1.2 mg/kg body-weight (W) per d with each g/kg W per d increase in DM intake regardless of the diet. At any DM intake the mean faecal endogenous loss was 5.5 mg/kg W per d higher in the sheep offered the frozen herbage diet when compared with those on the hay diet. At any Ca intake the mean faecal endogenous loss was 6.9 mg/kg W higher in sheep offered the hay diet compared with those on the frozen herbage.4. At feeding levels of about 1.5–2 times the estimated maintenance energy requirement the observed faecal endogenous loss of Ca ranged from 35 to 50 mg/kg W per d, which is two- to threefold greater than the present estimate of the Agricultural Research Council (1980) of 16 mg/kg W per d.5. A simple model to explain the variation in faecal endogenous loss of Ca between the present study with young sheep and that with lactating ewes (Chrisp et al. 1989) also offered herbage diets is developed, which incorporates the concept of a true endogenous loss related to DM intake and a net endogenous loss reflecting the extent of re-absorption of Ca endogenous losses within the gastrointestinal tract.

Diet selection and intake by sheep and cattle grazing together on stubbles of wheat, oats or barley

1977 ◽  
Vol 17 (85) ◽  
pp. 224 ◽  
Author(s):  
JG Mulholland ◽  
JB Coombe ◽  
WR McManus
Keyword(s):  
Plant Material ◽  
Dry Matter ◽  
Crop Residues ◽  
Diet Selection ◽  
Green Plant ◽  
In Vitro Digestibility ◽  
The Mean ◽  
Cereal Residues ◽  
Daily Intakes

Single plots of wheat, oats and barley stubbles were grazed by sheep and cattle in common on a 19 day rotation for 76 days. Initially the stubbles contained 600-1200 kg dry matter ha-1 of green weeds and 3300-4800 kg dry matter ha-1 of cereal residues. Serial estimates were made of diet selection, in vitro digestibility and intake by both species. Sheep consistently selected a diet with a higher proportion of green material than did cattle, but neither species utilized the crop residues to any extent. The overall mean digestibilities of the diet were 68 and 54 per cent fop sheep and cattle respectively (P < 0.01) ; the mean N concentration in the faeces of sheep was 0.64 percentage units higher than for cattle (P < 0.01). Differences in selection by the animals were greatest at the lowest level of green plant material. Estimates of the mean daily intakes of DOM (g kg-1) per unit of metabolic liveweight (W0.9) were 32 and 15, and of dead plant material dry matter (g kg-1) 4.2 and 13.2 for sheep and cattle respectively. There were no differences in selection between stubble species. The results are discussed in relation to maximizing the use of cereal stubbles for animal production.

EFFECTS OF NITROGEN APPLICATION ON BARLEY, OATS AND TRITICALE GROWN AS FORAGE

1975 ◽  
Vol 55 (1) ◽  
pp. 49-53 ◽  
Author(s):  
H. G. NASS ◽  
H. T. KUNELIUS ◽  
M. SUZUKI
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Stem Elongation ◽  
In Vitro Digestibility ◽  
Hordeum Vulgare L ◽  
Whole Plant ◽  
The Mean ◽  
Triticosecale Wittmack ◽  
X Triticosecale Wittmack

A 3-yr study was conducted to determine the effects of high rates of N fertilizer (NH4NO3) on whole plant dry matter yields, crude protein and NO3-N concentrations and in vitro digestibility of dry matter of oats (Avena sativa L.), barley (Hordeum vulgare L.) and triticale (X Triticosecale Wittmack) harvested at early dough stage. Dry matter (DM) yields of barley only were significantly increased by N applications over the zero N rate every year. Split applications of N at seeding and stem elongation did not generally result in higher DM yields than the corresponding single applications of N at seeding. The crude protein concentration ranged from 5.1 to 12.1% in the zero N check plot and from 7.1 to 14.9% in the N-fertilized plots. The NO3-N concentration in tissue was generally less than 0.10%, although NO3-N concentrations up to 0.34% were recorded in oats at 200–300 kg N/ha rates. For barley and triticale, the mean in vitro digestibility of DM was 57.2 and 58.3%, respectively, while the mean in vitro digestibility of DM for oats was much lower at 46.9%. In vitro digestibility of DM was affected very little by rates of N. The limitations in using cereals for forage are discussed.

An evaluation of pasture quality with young grazing sheep. II. Chemical composition, botanical composition and in vitro digestibility of herbage selected by oesophageal-fistulated sheep

1966 ◽  
Vol 66 (1) ◽  
pp. 113-119 ◽  
Author(s):  
R. C. Grimes ◽  
B. R. Watkin ◽  
J. R. Gallagher
Keyword(s):  
Tall Fescue ◽  
Crude Protein ◽  
Management Systems ◽  
In Vitro Digestibility ◽  
Botanical Composition ◽  
Pasture Quality ◽  
Quadrat Method ◽  
The Mean ◽  
Point Quadrat

1. In a grazing experiment with sheep, cocksfoot, rye-grass and tall fescue were grown with and without white clover, under ‘short’ and ‘long’ management systems.2. One sheep on each plot was fitted with an oesophageal fistula, from which herbage samples were collected at fortnightly intervals. The botanical composition of samples from the mixed swards was estimated by an optical point quadrat method. Samples were analysed for crude protein and cellulose, and digestibility was estimated in vitro.3. Treatment difference within the mixed swards were not significant in terms of botanical composition. The mean proportions selected were 73% grass, 9% clover and 18% dead matter. The proportion of clover selected did not differ significantly between sample collections.

Comparative aspects of copper metabolism in silage-fed sheep and deer (Cervus elaphus)

1987 ◽  
Vol 108 (1) ◽  
pp. 1-7 ◽  
Author(s):  
D. O. Freudenberger ◽  
A. S. Familton ◽  
A. R. Sykes
Keyword(s):  
Liver Biopsy ◽  
Cervus Elaphus ◽  
Energy Requirement ◽  
Copper Metabolism ◽  
Basal Diet ◽  
Cu Content ◽  
Linear Relationships ◽  
Rate Of Increase ◽  
The Mean ◽  
Maintenance Energy Requirement

SummaryTen yearling red deer stags (Cervus elaphus) and ten yearling Coopworth wether sheep were housed in individual pens and offered ryegrass-white clover silage, containing 9–10 mg Cu, 1·4–1·7 mg Mo and 2·4 g S/kg D.M., in amounts close to maintenance energy requirement. For six animals of each species the diet was enhanced with 4·8 mg Mo and 3 g S/kg D.M. Liver biopsy samples were obtained during weeks 1, 6 and 12. The animals were then re-randomized and five of each species offered the basal diet and the remainder the basal diet supplemented with 4 mg Cu/kg D.M. Liver biopsy samples were obtained after a further 4½ weeks. Plasma samples for estimation of total and trichloroacetic acid-soluble Cu were taken weekly.The mean liver Cu concentration in sheep was 11-fold greater than in deer. Both diets induced liver Cu depletion, though there was a trend for a greater rate of depletion on the Mo- and S-enhanced silage. The rate of depletion (mg Cu/kg liver D.M./day) was 7-fold greater in sheep than in deer, although it was not possible to determine whether this reflected a species-, as opposed to a Cu status-induced effect. In both species highly significant linear relationships were observed between initial liver Cu concentration and rate of liver Cu depletion. This was interpreted to indicate that endogenous loss was directly proportional to liver Cu content in both species. Individual estimates for the minimum rate of endogenous loss of Cu (μg/kg W/day) ranged from 0·2 to 2·71, mean 1·43, and from 2·83 to 14·75, mean 8·35 in deer and sheep, respectively.During repletion the rate of increase of liver Cu in supplemented groups tended to be greater in sheep than in deer and calculated minimum values for availability of Cu were 0·061 and 0·037, respectively.Liver Cu concentrations of less than 20 mg/kg D.M. were maintained in deer for several weeks without apparent symptoms of deficiency.

Relationships between the diet selected by grazing sheep and the herbage on offer

1973 ◽  
Vol 24 (2) ◽  
pp. 271 ◽  
Author(s):  
BA Hamilton ◽  
KJ Hutchinson ◽  
PC Annis ◽  
JB Donnelly
Keyword(s):  
Plant Material ◽  
Green Plant ◽  
Perennial Grasses ◽  
Grass Species ◽  
In Vitro Digestibility ◽  
Sheep Grazing ◽  
Significant Difference ◽  
The Mean ◽  
Highly Correlated

Oesophageal extrusa samples were collected from sheep grazing monospecific swards of four temperate perennial grasses. The in vitro digestibility and the proportion of green plant material in the extrusa samples were related exponentially to the yield of herbage on offer. The digestibility of ingesta was highly correlated with the yield of green herbage. When the yield of green herbage exceeded c. 550 kg/ha the sheep selected a diet more digestible than the mean of the green plant material on offer, and when there were low amounts of green herbage available the ingesta was less digestible than the green plant material on offer because of the low proportion of green plant material eaten. A relationship between the proportion of green plant material in extrusa samples and the green herbage yield was determined for each species, and no significant difference in regressions between species was found. It is suggested that the pooled relationship obtained in this study may be used to predict the proportion of green plant material in the ingesta of sheep over a range of grass species and yields.

scholarly journals IN VITRO DIGESTIBILITY OF RANGE FORAGE PLANTS OF THE FESTUCA SCABRELLA ASSOCIATION

1962 ◽  
Vol 42 (4) ◽  
pp. 692-697 ◽  
Author(s):  
L. M. Bezeau ◽  
A. Johnston
Keyword(s):  
Native Species ◽  
Nutritive Value ◽  
Phleum Pratense ◽  
In Vitro Digestibility ◽  
Forage Plants ◽  
Browse Species ◽  
Regional Adaptation ◽  
The Mean ◽  
Digestible Protein

The in vitro digestibility of cellulose was determined for 20 grasses, 6 f orbs, and 6 miscellaneous browse species of the Festuca scabrella association of southwestern Alberta. From this was calculated the "Nutritive Value Index" (N.V.I.) and percentage of digestible protein. The mean N.V.I. and the mean digestible protein of the four cultivated grasses, Bromus inermis, Elymus junceus, Festuca rubra, and Phleum pratense, at each stage of growth, was higher than the respective mean of the native species of grasses. However, Bromus pumpellianus, a native species, had a higher mean N.V.I. for all stages of growth than any of the other grasses studied. The forbs as a class were equal or superior to the grasses in N.V.I. and percentage of digestible protein. It is suggested that other factors such as palatability, toxicity, and regional adaptation should be considered before a species is adequately evaluated as a range forage.

Selection of diet by sheep grazing semi-arid pastures on the Riverine Plain. 4. A grassland (Danthonia caespitosa) community

1967 ◽  
Vol 7 (28) ◽  
pp. 426 ◽  
Author(s):  
GW Robards ◽  
JH Leigh ◽  
WE Mulham
Keyword(s):  
Nitrogen Content ◽  
Grazing Pressure ◽  
In Vitro Digestibility ◽  
Sheep Grazing ◽  
Resistant Species ◽  
Heavy Grazing ◽  
Visual Assessments ◽  
Selection Of

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.

scholarly journals Severe below-maintenance feed intake increases methane yield from enteric fermentation in cattle

2020 ◽  
Vol 123 (11) ◽  
pp. 1239-1246 ◽  
Author(s):  
J. P. Goopy ◽  
D. Korir ◽  
D. Pelster ◽  
A. I. M. Ali ◽  
S. E. Wassie ◽  
...  
Keyword(s):  
Feed Intake ◽  
Energy Requirement ◽  
Latin Square ◽  
Live Weight ◽  
Enteric Fermentation ◽  
Nutrient Partitioning ◽  
Gross Energy ◽  
Maintenance Energy Requirement ◽  
Maintenance Requirements ◽  
The Relationship

AbstractThe relationship between feed intake at production levels and enteric CH4 production in ruminants consuming forage-based diets is well described and considered to be strongly linear. Unlike temperate grazing systems, the intake of ruminants in rain-fed tropical systems is typically below maintenance requirements for part of the year (dry seasons). The relationship between CH4 production and feed intake in animals fed well below maintenance is unexplored, but changes in key digestive parameters in animals fed at low levels suggest that this relationship may be altered. We conducted a study using Boran yearling steers (n 12; live weight: 162·3 kg) in a 4 × 4 Latin square design to assess the effect of moderate to severe undernutrition on apparent digestibility, rumen turnover and enteric CH4 production of cattle consuming a tropical forage diet. We concluded that while production of CH4 decreased (1133·3–65·0 g CH4/d; P < 0·0001), over the range of feeding from about 1·0 to 0·4 maintenance energy requirement, both CH4 yield (29·0−31·2 g CH4/kg DM intake; P < 0·001) and CH4 conversion factor (Ym 9·1–10·1 MJ CH4/MJ gross energy intake; P < 0·01) increased as intake fell and postulate that this may be attributable to changes in nutrient partitioning. We suggest there is a case for revising emission factors of ruminants where there are seasonal nutritional deficits and both environmental and financial benefits for improved feeding of animals under nutritional stress.

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