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. 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.

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 Protein and energy requirements for maintenance of indigenous Granadina goats

1990 ◽  
Vol 63 (2) ◽  
pp. 155-163 ◽  
Author(s):  
C. Prieto ◽  
J. F. Aguilera ◽  
L. Lara ◽  
J. FonollÁ
Keyword(s):  
Energy Balance ◽  
Heat Production ◽  
Energy Requirement ◽  
Open Circuit ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Total N ◽  
A Value ◽  
Maintenance Requirements ◽  
Fasting Heat Production

Sixteen adult castrated male goats of the Granadina breed, with initial live weights ranging from 26.0 to 33.3 kg were used in two experiments to determine their protein and energy requirements for maintenance. Digestibility, nitrogen and energy balance measurements were made during the experiments. Two diets, which were based on pelleted lucerne (Medicago sativa) hay alone or on this forage and barley, were individually given at about maintenance level once daily. Gas exchange was measured using open-circuit respiration chambers. Fasting heat production was also determined. By regression analysis endogenous urinary N and maintenance requirements for N were estimated to be 119 mg/kg body-weight (W)0.75 per d and 409 mg total N/kg W0.75 per d respectively. Fasting heat production was 324 kJ/kg W0.75. The energy requirement for maintenance was calculated by regression of energy balance on metabolizable energy (ME) intake and a value of 443 kJ/kg W0.75 per d was found. The overall efficiency of utilization of ME for maintenance was 0.73.

An equation, suitable for computer use, based on the ARC feeding system to determine the energy requirements of growing and fattening cattle

1972 ◽  
Vol 14 (1) ◽  
pp. 17-23 ◽  
Author(s):  
C. A. Zulberti ◽  
J. T. Reid
Keyword(s):  
Weight Gain ◽  
Computer Use ◽  
Agricultural Research ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Energy Concentration ◽  
Feeding System ◽  
Agricultural Research Council ◽  
Forward Calculation

SUMMARYBased on the Agricultural Research Council's feeding system, equations were developed that allow the calculation of the metabolizable energy requirements for maintenance and weight gain by cattle, separately or combined. A general equation was developed for the straight-forward calculation of the total metabolizable energy requirements of growing and fattening cattle for any combination of body weight, rate of weight gain, age, level of muscular work, and metabolizable energy concentration of the diet. The estimates of energy requirement made by the use of this equation are in excellent agreement with those made by the Agricultural Research Council using an iterative method.In addition to avoiding the awkward iterative process, the equations proposed are readily adaptable to computer use.

A note on energy requirements for maintenance of lean and fat Angus, Hereford and Simmental cows

1984 ◽  
Vol 39 (2) ◽  
pp. 305-309 ◽  
Author(s):  
C. L. Ferrell ◽  
T. G. Jenkins
Keyword(s):  
Metabolizable Energy ◽  
Energy Requirements ◽  
Maize Silage ◽  
Weight Gains ◽  
Maintenance Requirements ◽  
Different Levels

ABSTRACTMature Angus (A), Hereford (H) and Simmental (S) cows (16 each) that had been randomly assigned and fed a maize silage-based diet at different levels of intake during lactation were selected.Lean and fat A, H and S cows were fed the maize silage-based diet individually to provide metabolizable energy (ME) intakes of 542, 506; 476, 437; and 624, 597 kj/kg0.75 per day respectively for 84 days. Daily weight gains of lean cows were greater than those of fat cows (0·40 v. 0·11 kg/day) even though daily ME intakes were less (55·2 v. 62·4 MJ/day). Theoretical estimates of ME requirements for maintenance were less for lean than for fat cows, and maintenance of A and H cows tended to be less than those of S cows.These results suggest that cow maintenance requirements increased in association with fatness that resulted from the previously imposed nutritional regimes and tended to differ among cow breeds.

A model for the effects of energy nutrition on the pregnant ewe

1979 ◽  
Vol 29 (3) ◽  
pp. 357-369 ◽  
Author(s):  
Pamela A Geisler ◽  
Heather Neal
Keyword(s):  
Previous Analysis ◽  
Optimal Growth ◽  
Energy Requirements ◽  
Maternal Weight ◽  
Model Predictions ◽  
Daily Energy ◽  
Computer Based ◽  
Pregnant Ewe ◽  
Energy Surplus ◽  
Made In

ABSTRACTA computer-based model of the response of the ewe to energy nutrition during pregnancy is described, based on a previous analysis of energy requirements. A ewe of specified weight and body condition 30 days from conception, carrying a known number of lambs, is predicted to grow them to an optimal weight if the nutritional regime allows. Daily energy requirements of the ewe-foetus system are calculated as the sum of requirements for maintenance and for growth and are compared with the daily energy supplied.If the feed provides energy surplus to requirements, the ewe herself gains weight; otherwise, the ewe mobilizes her own reserves, within limits, to protect the foetus. If this does not produce the energy required for optimal growth, foetal growth is reduced.Published experimental results are compared with predictions of the model when run under similar conditions; in general, predictions of total maternal weight at the end of pregnancy are within 5 % of those observed in the experiments. Model predictions of the effects of some particular nutritional regimes during pregnancy are presented and the sensitivity of the predictions of the model to certain of the assumptions made in its construction are discussed.

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.

Stochastic simulation of growth in pigs: protein turn-over-dependent relations between body composition and maintenance requirements

1996 ◽  
Vol 63 (3) ◽  
pp. 549-561 ◽  
Author(s):  
P. W. Knap
Keyword(s):  
Body Composition ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Body Protein ◽  
Population Means ◽  
Protein Deposition ◽  
Proportional Increase ◽  
Input Variables ◽  
Maintenance Requirements ◽  
Turn Over

AbstractA dynamic model for simulation of growth in pigs, that was extended by a module to describe protein turn-over, was made stochastic in order to simulate groups of pigs with among-animal variation in the maximum daily protein deposition (Pdep, maxK in the minimum lipid to protein deposition rate (Ri/pimin), and in the distributionof body protein over protein pools (muscle, connective tissue, and other proteins). As a result, these simulated pigs show among-animal variation in body protein content and composition. This in turn leads to among-animal variation in energy requirements for protein turn-over and this causes among-animal variation in maintenance metabolizable energy requirements (MEmaint)as a result of variation in body composition.Simulated population means for PieVimax were varied in seven steps from 100 to 250 g/day, with an among-animal variation coefficient of 0·10; the feeding level was also varied in seven steps. Dependent on the levels of these input variables, 100-kg pigs showed within-population standard deviations in body protein and lipid content of 0·31 to 0·54 kg and 1·22 to 2·17 kg, respectively. ME showed a protein-turn-over-related, within-population coefficient of variation of 0·014 to 0·02. Comparisons over populations suggests that a 1·50 proportional increase in Pdep, max (from 100 to 250 g/day) would increase protein-turn-over-related MEmaint by 11 to 15%, from between 470 and 486 to 541 k] ME per kg body weight0'75 per day. The inferences that can be made from this with regard to experimental design are discussed.

scholarly journals ENERGY REQUIREMENTS OF YOUNG EWES FED GUINEA GRASS (PANICUM MAXIMUM) FOR MAINTENANCE AND GAIN

2021 ◽  
Vol 7 (2) ◽  
pp. 117-121
Author(s):  
T. A. Adegbola ◽  
A. A. Adeleye ◽  
Y. D. Yoila
Keyword(s):  
Organic Matter ◽  
Weight Gain ◽  
Energy Requirement ◽  
West African ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Panicum Maximum ◽  
West African Dwarf ◽  
Digestible Organic Matter ◽  
Guinea Grass

Energy requirement for maintenance and weight gain of non-lactating, non-pregnant West African Dwarf ewes were determined by using equation of the form DOMI           = aw0.75 + bG........ (1) where, DOMI = Digestible Organic matter intake (kg/day), W = Liveweight of ewe (kg), G = Liveweight gain of ewe (kg/day), a = DOMI requirement per kg of Wkg0.75,  b = DOMI requirement for each kilogram liveweight gain. The regression equation obtained was DOMI = 0.0385Wkg 0.75 + 1.54G........(2). The values of DOM required per kilogram of Wkg0.75 and for each kilogram of liveweight gain, were 0.0385 and 1.54kg respectively. In terms of Metabolizable energy (ME) equation (2) can be written as follows: ME = 523.50Wkg0.75 + 20940.92G........(3) Values of ME required per kilogram of Wkg0.75 and each kilogram of liveweight gain were 523.5 and 20940.92 KJ from equation 3. These results are comparable to those obtained for other breeds of sheep of both temperate and tropical origin.

scholarly journals Maintenance requirements for energy in cross-bred cattle

1975 ◽  
Vol 33 (2) ◽  
pp. 127-139 ◽  
Author(s):  
B. R. Patle ◽  
V. D. Mudgal
Keyword(s):  
Energy Balance ◽  
Multiple Regression ◽  
Heat Production ◽  
Regression Line ◽  
National Research Council ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Net Energy ◽  
Respiratory Gases ◽  
Maintenance Requirements

1. Twenty-seven energy and protein balances were done using nine cross-bred (Brown Swiss × Sahiwal) mature bullocks in a series of three balance trials. The bullocks were fed 75, 100 and 125 % of the metabolizable energy (ME) and digestible crude protein standard values recommended by the (US) National Research Council (1966). Heat production was estimated by indirect calorimetry, by collection and analysis of respiratory gases2. Utilization of energy for maintenance and fat production was estimated by computing regression of energy balance v. digestible energy (DE) and ME separately on a metabolic body size (kg body-weight (W)0·75) basis. Maintenance energy requirements and efficiency of utilization of ME for lipogenesis were estimated using multiple regression of ME intake, also. Heat production (and thus energy balance) was corrected for excess nitrogen intake3. An attempt was made to measure basal heat production of bullocks so that the net energy requirements for maintenance could be estimated. Extrapolation of the regression line of energy balance v. ME intake below maintenance on a W0·75 basis gave a basal metabolism of 348·09 kJ/W0·75 per d4. Energy requirements for maintenance were (kJ/kg W0·75 per d): 539·43 DE, 448·81 ME and 348·09 net energy. The results of multiple regression gave a requirement of 432·15 kJ ME/kg W0·75 per d for maintenance5. The efficiency of utilization of ME for maintenance was 81·34% while for lipogenesis it was 54·5 %.

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