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.

A model for calculation of the energy requirements of the pregnant ewe

1979 ◽  
Vol 29 (3) ◽  
pp. 339-355 ◽  
Author(s):  
Pamela A Geisler ◽  
C. Merryl Jones
Keyword(s):  
Growth Curve ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Gestation Length ◽  
Foetal Growth ◽  
Pregnant Ewe ◽  
Maintenance Requirements ◽  
Weight Carrying ◽  
Made In

ABSTRACTA computer program is described which allows the calculation throughout pregnancy of the energy requirements of a ewe of any weight carrying any number of foetuses. The calculations rely on a prediction of potential lamb birth weight, from which a foetal growth curve of weight against time from conception is generated. Tied to the foetal growth curve are the growths of the placenta and fluids, while growth of the uterus is related to the ewe's weight at mating. Weights are converted to energy through energy density curves applicable through pregnancy for each component. An efficiency factor converts this energy requirement into a metabolizable energy requirement. With assumptions on the maintenance requirements for the ewe-foetus system, the total requirement for energy during pregnancy is calculated.Predictions from the model are compared with other estimates of energy requirements available in the literature. The sensitivity of the predictions of energy requirements for the pregnant ewe to variations in the assumptions made in the construction of the model is discussed. The most important assumptions are those on the maintenance requirements for the ewe-foetus system. Effects on the predicted energy requirements of varying either the efficiency for foetal growth or the gestation length are also discussed.

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)

Net utilization of roughage and concentrate diets by sheep

1976 ◽  
Vol 35 (2) ◽  
pp. 201-209 ◽  
Author(s):  
P. I. Wilke ◽  
F. J. Van Der Merwe
Keyword(s):  
South African ◽  
Energy Requirement ◽  
Experimental Period ◽  
Energy Gain ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Maintenance Energy ◽  
Energy Retention ◽  
Maintenance Energy Requirement ◽  
Body Energy

1. Two diets, an all-roughage diet and a high-concentrate diet, were fed at two levels, a low level of estimated 1.5 times maintenance energy requirement and a higher level of estimated two times maintenance energy requirement, to South African Mutton Merino castrated male sheep, aged 13 months and in fairly lean condition at the start of the 93 d experimental period..2. Body composition and energy retention were determined using the comparative slaughter technique and two series of digestibility and balance studies were done during the course of the experiment. Metabolizability of each diet was estimated and corrected for fermentation heat using the fermentation balance approach..3. Although there were significantly different rates of energy gain on different diets and feeding levels, fat energy gained (% total energy gained) was similar for the four groups, i.e. 78–80..4. Regression of energy gain v. corrected metabolizable energy (ME) intake indicated that the maintenance energy requirements of sheep used in this experiment were 310.2 and 302.3 kJ ME/kg body-weight0.75 per d and the values for net utilization of ME for body energy gain were 0.411 and 0.479 with the roughage and concentrate diets respectively..5. It was concluded that the estimated maintenance energy requirements of sheep obtained in this study are realistic values and that the efficiency of utilization of surplus ME for the two diets did not differ significantly.

scholarly journals Energy and nitrogen intake, expenditure and retention at 20° in growing fowl given diets with a wide range of energy and protein contents

1990 ◽  
Vol 64 (3) ◽  
pp. 625-637 ◽  
Author(s):  
M. G. Macleod
Keyword(s):  
Energy Intake ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Retention Efficiency ◽  
Protein Nitrogen ◽  
Body Protein ◽  
Wide Range ◽  
Energy Retention ◽  
Maintenance Energy Requirement ◽  
Diet Induced Thermogenesis

Heat production (HP) and the intake and retention of energy and nitrogen were measured at 20° in growing female broiler fowl given diets with metabolizable energy (ME) contents ranging from 8 to 15 MJ/kg at each of two crude protein (nitrogen × 6.25; CP) contents (130 and 210 g/kg). ME intake was partially controlled by the birds, but increased by 30% over the range of dietary ME concentration. CP intake varied directly with dietary CP:ME ratio, indicating that control of energy intake took priority and that food intake did not increase in order to enhance amino acid intake on low-CP diets. Maintenance energy requirement and fasting HP were not affected by diet. Although the HP of fed birds was significantly affected by dietary energy source, there was no evidence for regulatory diet-induced thermogenesis as energy intake increased. Total energy retention doubled on the higher-energy diets as a result of increased intake and retention efficiency in the absence of any compensation by diet-induced thermogenesis. The proportion of energy retained as fat was negatively correlated with dietary CP:ME ratio. It was concluded that the growing female broiler fowl responded to large differences in energy intake and dietary CP concentration not by changes in rate of energy dissipation as heat but by changes in the quantity of energy retained and in the partition of retained energy between body protein and body fat.

Seasonal energy requirements of wapiti (Cervus elaphus) for maintenance and growth

1994 ◽  
Vol 74 (1) ◽  
pp. 97-102 ◽  
Author(s):  
Z. Jiang ◽  
R. J. Hudson
Keyword(s):  
Energy Balance ◽  
Cervus Elaphus ◽  
Energy Requirement ◽  
Field Trials ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Energy Needs ◽  
Native Pastures ◽  
Metabolizable Energy Intake ◽  
Maintenance Requirements

Seasonal energy intakes of 6- to 14-mo-old wapiti hinds were determined in energy balance trials under pen and field conditions in winter, spring and summer. Six animals grazed native pastures supplemented with alfalfa hay when pasture availability declined in winter. Another six were penned and fed alfalfa-barley pellets to maximize growth throughout the year. Season and diet-specific metabolizable energy requirements for maintenance and liveweight gain were determined from regression of metabolizable energy intake on gain. Daily maintenance requirements of penned wapiti ranged from (mean ± SE) 473 ± 35 kJ kg−0.75 in winter to 728 ± 78 kJ kg−0.75 in summer. On spring and summer pasture, daily ecological maintenance requirements ranged from 900 ± 26 to 984 ± 37 kJ kg−0.75. Energy requirements for gain were the same in pen and field trials, ranging from 25 ± 6 to 33 ± 5 kJ g−1 in winter and from 40 ± 6 to 43 ± 12 kJ g−1 in spring and summer. This study provides basic information on the metabolizable energy needs of wapiti and insights into how their seasonal requirements can be optimally met. Key words: Elk, metabolizable energy requirement, growth, physiological maintenance, ecological maintenance, seasonality, energy balance

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.

The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig

1978 ◽  
Vol 40 (3) ◽  
pp. 423-431 ◽  
Author(s):  
W. H. Close ◽  
L. E. Mount ◽  
D. Brown
Keyword(s):  
Environmental Temperature ◽  
Body Weight Gain ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Growing Pig ◽  
Body Weights ◽  
Energy Retention ◽  
Four Levels ◽  
Maintenance Energy Requirement ◽  
Environmental Temperatures

1. Measurements of energy and nitrogen balances were made on thirty-eight individually housed pigs (initial body-weights 21–38 kg) at environmental temperatures of 10, 15, 20, 25 and 30° with four levels of feeding at each temperature. Values for energy retention (ER), protein (P) and fat (F) deposition and body weight gain (δW) were calculated at each temperature at metabolizable energy (me) intakes equivalent to once (M; 440 kJ/kg0.75 per d), twice (2M), three (3M) and four (4M) times the thermoneutral maintenance energy requirement.2. ER at each plane of nutrition increased with temperature to maximal values between approximately 20 and 25° ER was negative at four of the five environmental temperatures at M.3. P increased significantly with increase in me intake but was dependent on environmental temperatures only at intakes of M and 2M. The increase in P per unit increment in me intake decreased from 0.16 at 10° to 0.12 at 30°. The net efficiency of protein utilization also decreased with increase in environmental temperature from 0.54 at 10° to 0.39 at 30°.4. F increased significantly with increase in me intake, but was more temperature-dependent than P, increasing to maximum values estimated to be between 20 and 25° at each level of intake; F at 30° was less than that at 25°. The increase in F per unit increment in me intake decreased from 0.63 at 10° to 0.51 at 30°.5. The optimum temperature for ΔW was dependent upon me intake, varying from above 30° at M to less than 20° at 4M. The reduction in ΔW per 1° at 15° was also dependent upon the level of intake decreasing from 1.63 g/kg0.75 per d at M to -0.09 at 4M.6. For a 35 kg pig the reduction in P, as a result of a 1° decrease in temperature at 15° at an intake corresponding to 2.5M, was equivalent to a 4 g/d reduction in food intake; the corresponding equivalent for F was 28 g/d.

scholarly journals The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig

1978 ◽  
Vol 40 (3) ◽  
pp. 413-421 ◽  
Author(s):  
W. H. Close ◽  
L. E. Mount
Keyword(s):  
Critical Temperature ◽  
Heat Loss ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Maintenance Energy ◽  
Growing Pig ◽  
Extra Food ◽  
Four Levels ◽  
Maintenance Energy Requirement ◽  
Energy Balances

1. The heat losses and energy balances of thirty-eight individually housed pigs (initial body-weights 21–38 kg) were measured continuously for periods of 14 d when they were maintained at environmental temperatures of 10, 15, 20, 25 or 30°. At each temperature four levels of feeding were given approximating to once, twice and three times the maintenance energy intake and the ad lib. level. The minimal maintenance energy requirement (M) was calculated to be 440 kJ metabolizable energy (me)/kg0.75 per d at 25°.2. me intake at the ad lib. level decreased from 1965 kJ/kg0.75 per d at 10° to 1202 at 30°.3. Heat loss calculated from multiple regression analysis decreased to minimum levels between 20 and 25° 30° was within the hyperthermic zone at each plane of nutrition.4. The partition of heat loss into its sensible and evaporative components showed that evaporation increased from 25% at 10° to 78% at 30°.5. Critical temperature was dependent upon food intake and decreased from 23.1° at M to 20.7° at 2M, 18.0° at 3M and 16.7° at 4M.6. The extra food required to meet extra thermoregulatory heat production per 1° below the effective critical temperature was 0.65 g/kg body-weight per d.

MAINTENANCE ENERGY REQUIREMENT OF THE ROOSTER AND INFLUENCE OF PLANE OF NUTRITION ON METABOLIZABLE ENERGY

1970 ◽  
Vol 50 (2) ◽  
pp. 363-369 ◽  
Author(s):  
J. GUILLAUME ◽  
J. D. SUMMERS
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Maintenance Energy ◽  
Maintenance Requirement ◽  
Average Value ◽  
Maintenance Energy Requirement ◽  
Energy Maintenance

Arnould’s method can be applied to the adult rooster to estimate the energy maintenance requirement, although estimation of the weight gain requirement is inaccurate with this method. The average value obtained of 117 kcal metabolizable energy per kg body weight per day for maintenance requirement agrees well with previously reported estimates but is higher than values reported for the laying hen. Maintenance requirement for energy appears to be very variable, the coefficient of variation being 13% which equals that found for basal metabolism. Maintenance requirement is correlated neither with body weight nor with endogenous N excretion. It is concluded that metabolic and endogenous energy should be taken into account for correcting metabolizable energy values when food intake is close to maintenance requirement, especially with adult birds.

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