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Articles 181 - 210 of 12002

Full-Text Articles in Physical Sciences and Mathematics

Influence Of Spring Grazing Management On Summer Autumn Production Of Dairy Pastures, S C. Da Silva, C Matthew, P.N P. Matthews, J Hodgson Sep 2024

Influence Of Spring Grazing Management On Summer Autumn Production Of Dairy Pastures, S C. Da Silva, C Matthew, P.N P. Matthews, J Hodgson

IGC Proceedings (1993-2023)

Three grazing treatments were allocated at random within e11ch of five 2.6 ha paddocks of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) pasture. The treatments involved variation i'n the timing and degree of control of ryegrass reproductive growlh in two successive pasture growth seasons (1990-91 and 1991- 92). In 1990-91, swards in which reproductive growth was controlled at anthesis (20 November; LHC) produced 4330 kg OM/ha between 18 December and 11 April, compared with 3980 kg DM/ha for swards controlled on 18 December (VLHC) and 3210 kg OM/ha for swards controlled on 9 October …


Pasture Composition, As Affected By Grazing Management, And Its Effects On Milk Production By Grazing Dairy Cows, C W. Holmes, C J. Hoogendoorn, V R. Rugambwa, M P. Ryan, A.C P. Chu Sep 2024

Pasture Composition, As Affected By Grazing Management, And Its Effects On Milk Production By Grazing Dairy Cows, C W. Holmes, C J. Hoogendoorn, V R. Rugambwa, M P. Ryan, A.C P. Chu

IGC Proceedings (1993-2023)

Prcgrazing herbage mass was controlled al higher or lower levels by grazing management (intensity or frequency). Three of the experiments used ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) swards, while the fourth included Grasslands Matua prairie grass (Bromus willdenowii Kunth.) and white clover swards. The high mass swards generally contained higher proportions of dead matter and stem, and the herbage from these swards was always less digestible. When offered a common daily herbage allowance, cows grazing on the high mass swards produced less milk than those on the low mass swards. The data suggest …


Defoliation Of Grass (Cut Or Grazed) And Its Effect On Forage Quantity, H C. Hughes Sep 2024

Defoliation Of Grass (Cut Or Grazed) And Its Effect On Forage Quantity, H C. Hughes

IGC Proceedings (1993-2023)

All grassland farmers should try to optimise their grassland output during the growing season. Grassland farmers would improve their production results if they paid more attention to plant defoliation processes. Careful management of the grass ley will increase outputs by more than one third, without needing further inputs. Most grassland farmers need to have this improvement with no additional cost, especially in the present world economy.


Role Of Mixed Animal Type Grazing In Range Preservation And Increasing Animal Product Output, T Nolan, J Connolly, C Sall Sep 2024

Role Of Mixed Animal Type Grazing In Range Preservation And Increasing Animal Product Output, T Nolan, J Connolly, C Sall

IGC Proceedings (1993-2023)

fhe work was part of a research programme to a) evaluate the role of mixed animal type grazing in increasing production, b) explain any; benefits obtained and c) develop improved whole grazing ecosystems in temperate and semi-arid areas. Its specific ai was to improve domestic food production from range grazing livestock and to preserve or improve native range resources. This paper discusses some recent results from the Senegalese Sahel related to· animal preferential and differential selection, animal performance and the role of mixed grazing in improving the relationships between them to secure the objectives stated. The use of these results …


Pasture Botanical Changes And Steer Gains On Continuously Stocked Hay-Type And Grazing-Tolerant Lucerne Cultivars At Three Grazing Pressures, Carl S. Hoveland, M A. Mccann, J H. Bouton, N S. Hill Sep 2024

Pasture Botanical Changes And Steer Gains On Continuously Stocked Hay-Type And Grazing-Tolerant Lucerne Cultivars At Three Grazing Pressures, Carl S. Hoveland, M A. Mccann, J H. Bouton, N S. Hill

IGC Proceedings (1993-2023)

Alfagraze (grazing-tolerant) and Apollo (hay-type) lucerne (Medicago sativa L.) cultivars were stocked continuously with beef steers at 3 grazing pressures (GP) for 3 years In central Georgia, USA. Lucerne stands declined at the highest GP, Apollo stand density being only 23% of that of Alfagraze in grass-free areas at the end of 3 years. Rapid encroachment by volunteer bermudagrass (Cynodon dactylon (L.) Pers,) at high GP resulted in greater stand loss in Apollo than Alfagraze. Steer average daily'gain on both cultivars declined from 0.95 kg at low GP to 0.76 kg at medium GP with a further …


Effect Of Grass-White Clover Mixtures On Steer Performance And Sward Characteristics In Atlantic Canada, H T. Kunelius, P Narasimhalu Sep 2024

Effect Of Grass-White Clover Mixtures On Steer Performance And Sward Characteristics In Atlantic Canada, H T. Kunelius, P Narasimhalu

IGC Proceedings (1993-2023)

Pasture production in winter cold regions such as Atlantic Canada is limited by the availability of winter hardy and productive grass and legume species, Perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca prarensis Huds.) and timothy (Phleum pratense L.) grown in binary mixtures with white clover (Trifolium repens L.), and naturalised pasture consisting of Poa spp., Agrostis spp. and white clover, were compared under grazing, Steers were used to graze the swards from 16-26 cm down to 8 or 11 cm post-grazing surface heights, Dry matter intake was higher for natural pasture than for sown pastures, …


Range Management: Optimizing Forage Production And Qualityy, J E. Danckwerts, N M. Tainton Sep 2024

Range Management: Optimizing Forage Production And Qualityy, J E. Danckwerts, N M. Tainton

IGC Proceedings (1993-2023)

Range management involves optimising forage production and quality, both in the short term and in the long term. In the short term, temporal climatic variability, stocking rate, grazing system, fire, animal type. and spatial variability, inter alia, strongly, influence forage production and quality. On the other hand, long-term optimisation requires prevention of range deterioration. The nature of this process seems to be profoundly different between humid and arid rangelands, at least in tropical and subtropical zones. In the former, changes are relatively predictable, overgrazing resulting in gradual deterioration. In the latter, change is event driven, providing the grazier with …


An Ecological Approach To Forage Management, J L. Brock, R.J M. Hay Sep 2024

An Ecological Approach To Forage Management, J L. Brock, R.J M. Hay

IGC Proceedings (1993-2023)

The principles of defoliation management for maximum production of quality herbage are well researched, namely the manipulation of frequency and severity of defoliation, but their impact on the various levels of ecological organisation in pastures is nol fully understood or their interpretation appreciated. Using grazed ryegrass-white clover pasture as; example, detailed sward studies have suggested the following model. Defoliation frequency and severity interact lo produce varying levels of physiological stress and morphological adaptation which affecl the survival rate and size of individual growth units, the lowest level of organisation. Increasing frequency of defoliation reduces organ size but increases survival rate …


Land Use In Non-Affluent Countries As Determined By Social Infrastructure And Population Patterns, Bore Motsamai Sep 2024

Land Use In Non-Affluent Countries As Determined By Social Infrastructure And Population Patterns, Bore Motsamai

IGC Proceedings (1993-2023)

Tenure of land in most developing countries is predominantly communal, with a mixture of introduced systems of individual ownership. Since nations attained independence structural- changes have been made in order to introduce land reform. Countries are caught up in a dilemma of having to provide social justice and greater equity through land reform, but face increasing population and landlessness. For example, Lesotho's landless rural people increased from 7.2% in 1950 to 38.5% in 1987, and 17.2% are without land and livestock. Employment opportunities fall short of satisfying the labour mBrket. With limited land resources and high population pressure, rational and …


The Future Of Sustainable Agriculture In The United States, Dennis R. Keeney Sep 2024

The Future Of Sustainable Agriculture In The United States, Dennis R. Keeney

IGC Proceedings (1993-2023)

In the United States, sustainable agriculture remains complicated and controversial as a concept, particularly to define and apply in terms of practices and policies to achieve sustainability. Many consider current agricultural practices to be sustainable in the near term with regard to the dependable, affordable supply of food and fibre, but unsustainable in terms of environmental quality and social costs. Production agriculture hos been linked to soil erosion and water pollution, and the emphasis on efficiency has contributed to the loss of many farmers and increasing instability in rural communities. Many of agriculture's dilemmas can be linked to policies of …


Livestock Production Systems In The Cameroon Sahelo-Sudanian Region, E Tedonkeng Pamo, R D. Pieper Sep 2024

Livestock Production Systems In The Cameroon Sahelo-Sudanian Region, E Tedonkeng Pamo, R D. Pieper

IGC Proceedings (1993-2023)

The Sahelo-Sudanian region of Cameroon extends from 7° to 13° N. The region receives 400-1000 mm rainfall and is covered by a complex mosaic of. vegelation and plant communities. Animal production has always been a cornerstone of the economy of this region. The range use system of the region is extensive. The major problem faced by pastoralists has been a compression of their range not only by the northward-moving cultivation, but also by the southward moving desertification. Various grazing melhods have been suggested but none have yet been implemented, and nomadism and transhumance remain the major production systems. Analysis of …


Runoff Studies In Different Cropping Systems And Preliminary Results For Nitrogen Leaching, Ragnar Eltun Sep 2024

Runoff Studies In Different Cropping Systems And Preliminary Results For Nitrogen Leaching, Ragnar Eltun

IGC Proceedings (1993-2023)

A cropping system project was started at Apelsvoll Research Station in 1990, with the aim of developing cropping systems to minimise nutrient leaching and maximise food quality and economy. The experiment involves cash crop and forage crop systems with conventional, integrated and organic farming. This paper presents the experimental layout and preliminary measurements of nitrogen leaching. Both drainage water concentrations and runoff results shows that nitrogen leaching is less from cropping systems dominated by forages than from cash crop systems with cereals and potatoes.


Land Subdivision In The Falkland Islands, O W. Summers, W.J R. Haydock, A Kerr Sep 2024

Land Subdivision In The Falkland Islands, O W. Summers, W.J R. Haydock, A Kerr

IGC Proceedings (1993-2023)

The Falkland Islands agricultural industry depends mainly on wool production. This paper reviews the structure of an induslry which has changed radically in the last 10 years. Lord Shackleton completed his economic survey of the Falkland Islands in 1976 when there where only 36 fanns, most of which were owned by companies based mainly in the UK, and an absentee-landlord system prevailed. Shackleton advocated that the Falkland Islands Government should purchase large fanns and split them into smaller family units for sale to local people. Presently (1991-92) there are 92 farms and most of the Islands is in local ownership. …


Disparities In The Utilization Of Nambia's Grassland: A Need For Adjustments In The Beef Industry, Helmke Sartorius Von Bach, Johan Van Zyl Sep 2024

Disparities In The Utilization Of Nambia's Grassland: A Need For Adjustments In The Beef Industry, Helmke Sartorius Von Bach, Johan Van Zyl

IGC Proceedings (1993-2023)

Extensive beef production, Namibia's life-line in agriculture, depends entirely on natural pastures. Socioeconomic and environmental disparities, namely (a) the· traditional smallholder communal sector versus the commercial sector and (b) areas in the vicinity versus distant from centralised abattoirs, are analysed by' using econometric analysis of time-series data on the regional influence of prices and· access to markets on beef numbers. This is particulary relevant because Namibia is in a process of structural adjustment, and in view of the beef sector's importance in the Namibian economy. The results accentuate the role of access to markets and productive opportunities for beef production …


Comparison Between Fodder Cropping Rotations Carried With Or Without Meadow In The Intensive Farming System Of The Po Valley Plain (Italy), Mario Onofrii, Cesare Tomasoni, Lamberto Borrelli Sep 2024

Comparison Between Fodder Cropping Rotations Carried With Or Without Meadow In The Intensive Farming System Of The Po Valley Plain (Italy), Mario Onofrii, Cesare Tomasoni, Lamberto Borrelli

IGC Proceedings (1993-2023)

Pour fodder cropping rotations were compared at different degrees of crop intensification: (RI) a I-year continuous monoculture of Italian ryegrass (Loll111n multij/orum Lam.) +silage maize (Zea mays L.); (R3) a 3-year rotation of Italian ryegrass+silage maize - barley (Hordeum vulgare L.)+silage mai1:e - grain maize; (R6) a 6-year rotation of Italian ryegrass+silage maize for 3 years followed by meadow for 3 years (Trifolium repe11s L. + Festuca ari111di11acea Schreb,): (PM) a monoculture of permanent meadow. The most efficient rotation for dairy cattle feeding, on sandy-loam soils, was the I-year rotation of Italian ryegrass, followed by silage maize, with 22 9S0 …


Cadmium In Soil, Pasture And Grazing Ruminants, J Lee, N D. Grace, A D. Mackay, M J. Hedley, J R. Rouce Sep 2024

Cadmium In Soil, Pasture And Grazing Ruminants, J Lee, N D. Grace, A D. Mackay, M J. Hedley, J R. Rouce

IGC Proceedings (1993-2023)

Cadmium, present in New Zealand hill country pastures rrom Cd­amended phosphatic fertiliser use, is assimilated by grazing ruminants. Concentrations of Cd in plasma from sheep grazing pastures containing low (0.1-0.2µglg dry weight) or high (0.8-1.4 µgig dry weight) levels of Cd were 0.15±0.04 nglg and 0,35:1:0.15 ng/g, respectively (P<0.08). Cadmium in pasture was highly correlated (P<0,001) with soil O.IM HCl-extractable Cd (log10 Soiled= -0.98+0.26 Plantcd).


Nitrogen Dynamics In Three Contrasting Grassland Systems: Implications For Pasture Productivity And The Potential For Environmental Pollution, B E. Ruz-Jerez, R E. White, P Roger Ball Sep 2024

Nitrogen Dynamics In Three Contrasting Grassland Systems: Implications For Pasture Productivity And The Potential For Environmental Pollution, B E. Ruz-Jerez, R E. White, P Roger Ball

IGC Proceedings (1993-2023)

Nitrogen (N) dynamics were compared in 3 contrasting grassland systems (2 legume-based and I receiving fertiliser N) in a cool temperate region of New Zealand. The study was concentrated on the various N transfers that occurred during and after grazing. Critical periods for N loss by different processes have been identified, allowing a more comprehensive understanding of the role of N in the productivity of different types of pasture, and the potential for environmental pollution, Calculation of N inputs and outputs for the three pastures indicated that the two legume-based systems were more or less in balance, but in the …


Reduction Of Nutrient Losses For Dairy Farms, With Emphasis On Nitrogen, W Luten, D J. Den Boer Sep 2024

Reduction Of Nutrient Losses For Dairy Farms, With Emphasis On Nitrogen, W Luten, D J. Den Boer

IGC Proceedings (1993-2023)

Recently the Dutch government presented several policy papers in which standards are given for maximum allowed emissions to air, groundwater and surface water. Depending on the farm situation an optimum combination of measures in relation to housing, slurry storage, slurry and fertiliser application, and composition of the ration can be taken. In general a better use of nutrients from animal manure by applying slurry with low emission techniques in the growing season and a reduction of the stocking rate by a higher milk production per cow are the most effective and cheapest measures to reach these targets. There is a …


Use Of Pasture As A Receivers For Swine Lagoon Effluent, J P. Mueller, J C. Barker, J P. Zublena, M H. Poore, R W. Harvey, J T. Green Sep 2024

Use Of Pasture As A Receivers For Swine Lagoon Effluent, J P. Mueller, J C. Barker, J P. Zublena, M H. Poore, R W. Harvey, J T. Green

IGC Proceedings (1993-2023)

Swine waste management-cattle grazing systems were monitored on 2 North Carolina farms from 1990-1992, Farmers co-operated directly in the project by furnishing land, labour, equipment and cattle and by maintaining records of grazing and waste applications. Local county agricultural extension agents helped with management decisions, record­keeping and co-ordinating activities among project participants. On a fann where waste was applied to pastures for 5 years, soil N in the upper l m averaged from 230-500 kg/ha, NO3 -N in the forage remained above 10 g/kg for the grazing season and 2 of 4 test wells recorded NO3 levels above 10 mg/I. …


Pastoral Systems Of Central Himalaya: How Long Will They Survive?, K S. Rao, K G. Saxena Sep 2024

Pastoral Systems Of Central Himalaya: How Long Will They Survive?, K S. Rao, K G. Saxena

IGC Proceedings (1993-2023)

Pastoral systems of Central Himalaya are very old and until recent time were in balance with environment, Recent changes in socio­political setup have drastically altered the status of these systems. The change of political power in trans-Himalayan Tibetean plateau has resulted in closure of international boarders, thus taking away the mercantile aspects of pastoralists and reducing pastoral area. Increased human disturbances on fragile Himalayan marginal lands and excessive onslaught on forests for fuel and fodder by the sedentary population has resulted in degradation and non-productive grasslands which do not help pastoralists sustain existing systems. Changes in relations between migratory pastoralists …


A Preliminary Discussion Of The Management And Administration Of Yunwu Mountain Natural Grassland Reserve In China, Zhao Zhiyi, Yang Ailian Sep 2024

A Preliminary Discussion Of The Management And Administration Of Yunwu Mountain Natural Grassland Reserve In China, Zhao Zhiyi, Yang Ailian

IGC Proceedings (1993-2023)

The advantages and problems encountered in the establishment of a grassland reserve are described. The conflicts between local farmers' requirement to feed and water livestock and the conservation strategy of natural grassland are discussed.


Effect Of Sewage Sludge On The Mineral Composition Of Corn, Arthur E. Peterson, P E. Speth, P L. Schlecht Sep 2024

Effect Of Sewage Sludge On The Mineral Composition Of Corn, Arthur E. Peterson, P E. Speth, P L. Schlecht

IGC Proceedings (1993-2023)

For the past 12 years, digested sewage sludge from the Milwaukee Metropolitan Sewerage District has been applied to a Plano silt loam (prairie) soil near Elkhorn, Wisconsin, and corn raised as the indicator crop. The corn has been harvested as silage and fed to dairy cnttle. The amounts of macro-, micro-, and heavy metals contained in this forage were compared with the amounts contained in the untreated areas, and in the forage produced by a sustainable agriculture study on the same experimental station. None of the heavy metals have moved out of the plough layer (lop 25 cm). The uptake …


Sustainable Direction For Resource Management An Assessment Of The Regional Council Role, Allan Lohrey Sep 2024

Sustainable Direction For Resource Management An Assessment Of The Regional Council Role, Allan Lohrey

IGC Proceedings (1993-2023)

The 1980s has seen an increased world awareness of the concept of sustainability. In 1991 New Zealand enacted the Resource Management Act (RMA) which reflected society's concern for a need to consider future generations when making decisions relating to the use of natural resources. Regional councils have been allocated the role within the Act to promote sustainable management at the regional level. The short term challenge to regional councils is to manage resources in manner which strikes a pragmatic balance between the ongoing needs of society and the need to provide resources for future generations. Regional councils will know they …


Application Of Dairy Manure On Alfalfa, Stephen J. Herbert, Jayarm Daliparthy, P L.M Veneman Sep 2024

Application Of Dairy Manure On Alfalfa, Stephen J. Herbert, Jayarm Daliparthy, P L.M Veneman

IGC Proceedings (1993-2023)

Applying dairy manure to alfalfa (Medicago sativa L.) as ,in alternative 10 excess application to· corn (Zea mays L.) may reduce nitrate pollution of groundwater. Field experiments were conducted at 2 sites in Massachusetts, USA, lo study the impact or dairy manure application to alfalfa on forage yield, weed infestation· and nitrate movement. Treatments were an unfertilized (no N) check.· plot, low and high manure (112 and 336 kg N/ha/year equivalerit), and low and high N fertiliser (112 and 336 kg N/ha/year from NH4NO3),'. Liquid dairy manure was applied 10 • alfalfa immediately· after 1st· cutting during spring …


Kentucky Surficial Geologic Map Compilation Database (Version 1), Matthew Massey Sep 2024

Kentucky Surficial Geologic Map Compilation Database (Version 1), Matthew Massey

Research Data--KGS

The Kentucky Geological Survey (KGS), a state-supported independent research center within the University of Kentucky, is committed to providing accurate and unbiased geologic information on natural resources, environmental issues, and natural hazards in Kentucky. While Kentucky boasts complete coverage by 1:24,000-scale geologic bedrock maps, surficial materials have been largely overlooked, except in regions with thick deposits obscuring the bedrock. Given the increasing trends in economic development and urbanization, detailed surficial geologic mapping has become crucial for supporting geotechnical planning, environmental management, and hazard assessment. In response, KGS has prioritized new, detailed surficial geologic mapping since 2004, specifically targeting areas anticipated …


Foraging Strategies Of Ruminant Livestock On Intensively Managed Grasslands: Potential And Constraints, I J. Gordon, C Lascano Aug 2024

Foraging Strategies Of Ruminant Livestock On Intensively Managed Grasslands: Potential And Constraints, I J. Gordon, C Lascano

IGC Proceedings (1993-2023)

All grazed swards exhibit heterogeneity in the spatial (horizontal and vertical) dispersion of species/biomass. A herbivore foraging at random within such a heterogeneous environment would ingest less nutrients than wou Id one which exploited the heterogeneity on offer through selective grazing. The suite of decision-making processes involved in the selective grazing we observe is termed the animal's foraging strategy. On first observation, intensively managed sown swards appear to offer little opportunity for a herbivore to exhibit a foraging strategy; however, opporlunities do exist and there is empirical evidence that herbivores foraging on sown swards tend to have a diet higher …


Comparative Foraging Strategies Of Grazing Ungulates In African Savanna Grasslands, N Owen-Smith, D H.M Cumming Aug 2024

Comparative Foraging Strategies Of Grazing Ungulates In African Savanna Grasslands, N Owen-Smith, D H.M Cumming

IGC Proceedings (1993-2023)

We review the evolutionary (species-specific) and ecological (individual behavioural) strategies of African grazing ungulates. The contexts considered are free-ranging wild ungulates, traditional livestock pastoralism and extensive commercial ranching. Particularly successful are (1) buffalo, able to digest grass fibre effectively in mesic grasslands; (2) wildebeest, exploiting semi-arid grasslands through migration; (3) megaherbivores (elephant, hippopotamus and white rhinoceros) utilising a wide range of vegetation components. Species-specific adaptations include body size and metabolic rate, digestive efficiency and passage rate, oral and dental anatomy, water dependence and detoxification capacity. Species overlap in grass species se'lected, with dietary differences apparent in grass height favoured, and …


Comparison Of Animal Gains Using Perennial Pastures Exclusively Or Combined With Chicory-Oats-Clover Temporary Winter Pastures, J A. Josifovich Aug 2024

Comparison Of Animal Gains Using Perennial Pastures Exclusively Or Combined With Chicory-Oats-Clover Temporary Winter Pastures, J A. Josifovich

IGC Proceedings (1993-2023)

The increment of winter forage availability using short-rotation pastures could be an interesting way to increase winter carrying capacity. The producer could make good use of higher spring grass production. Sowing oats, rye or chicory alone is quite common in the Argentine Pampa. to evaluate the efficiency of these short-rotation winter pastures a 3 year trial was carried out at Pergamino Experiment Station. The treatments were: a) perennial pastures, 100% of the surface, b) perennial pastures 75%, and chicory-clover 25%, with 2 replications of 3 ha each. The pastures were, for. class II soils, fescue (Festrlca aru11dinacea Schreb.) cv. El …


Influence Of Climatic Factors On Animal Production In The Humid Pampa Of Argentina, J D. Josifovich, E Frutos Aug 2024

Influence Of Climatic Factors On Animal Production In The Humid Pampa Of Argentina, J D. Josifovich, E Frutos

IGC Proceedings (1993-2023)

For any' pasture grazing area it is important lo know the relationship among the climatic parameters, rainfall and temperature, with carrying capacity and minimal gains. The availability of pasture to adjust stocking rates and make provisions for hay or supplementary feed needed for periods of shortage can be estimated from these data. Seven years of monthly rainfall and medium average temperature; and 25 years of forage digestibility and average daily gains were related to cattle i: carrying capacity; Analysis was made using the stepwise regression method. Carrying capacity was evaluated considering animal units (AU) for a 400 kg head gaining …


A New Theory Of Feed Intake Regulation In Ruminants And Its Implications For Forage Quality Research, J.J M.H Ketelaars, B J. Tolkamp Aug 2024

A New Theory Of Feed Intake Regulation In Ruminants And Its Implications For Forage Quality Research, J.J M.H Ketelaars, B J. Tolkamp

IGC Proceedings (1993-2023)

The low voluntary intake of many roughages is commonly explained by a limited physical capacity of ruminants to process fibrous feeds. Recently, we developed a new theory of feed intake regulation assuming feed consumption to create both benefits for the animal (represented by the intake of net energy for maintenance and gain) and costs (represented by the total oxygen consumption of the feeding animal). For non­reproducing ruminants we have shown that voluntary intake of roughages is close to the optimum feed intake level, i.e., the level at which for the animal the ratio between benefits and costs becomes maximum. According …