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Influence Of Feeding On Health And Productivity Of Ruminants, Alexander Sommer

IGC Proceedings (1977-2023)

As to the utilization of plant matter not suited for direct consumption by man, ruminants are of outstanding importance. This fact is related with the function of their specific stom­ach system. The paper discusses the microbial protein synthesis from NPN compounds. When 50 per cent of digestible crude protein required by fattening cattle were replaced, daily live weight gains of 997 g were reached; beef quality was not affected. Similarly favourable results were obtained with dairy cows when replacing by NPN compounds 50 to 100 per cent of extracted meals. Further on, the problem of crude-fibre diges­tion in connection with …

Impact On Energy Budgets In Grassland Production And Conservation Of Possible Production Of Energy From Biomass Crops, R J. Wilkins

IGC Proceedings (1977-2023)

There is commonly a conflict between output/unit of area of land and output/unit of support-energy (SE) input. The possibil­ity of using a proportion of the total land area for biomass energy production suggests an approach for calculating grassland out­put/ha unconfounded with differences in SE input. Output can be calculated for an area of land that is devoted to grassland and biomass energy crops in proportions that result in a net demand for SE of zero. Outputs of utilized metabolizable energy (UME) are related to inputs of SE for (1) grazed grass with high application of nitrogen (N) fertilizer and (2) …

Efficiency Of Dairying Under Contrasting Feeding And Management Systems In North America, Israel, Europe, And New Zealand, J.D. J. Scott

IGC Proceedings (1977-2023)

Four different systems of feeding and managing dairy cattle are seen in major milk-producing countries. These are (1) feeding purchased roughages and concentrates to zero-grazed, intensively penned cows; (2) home growing of roughages and most con­centrates for zero-grazed animals; (3) feeding concentrates with conserved pasture and other roughages in winter and reduced concentrates to grazed cattle in spring-summer; and (4) feeding cattle on grazed pasture and conserved pasture throughout the year. The following data on the four systems were obtained from examples in southern California, Wisconsin, England/Wales, and New Zealand. Average fat-corrected milk (FCM)/cow is approximately 7,140, 5,300, 4,670, and …

Potential Contribution Of White Clover To The Economics And Support-Energy Inputs Of Grass-Based Beef-Production Systems, T A. Stewart, R E. Haycock, A S. Laidlaw

IGC Proceedings (1977-2023)

Biological output, gross margins, and efficiency of support-energy usage in an 18-month beef-production system on grass-white clover swards receiving either 50 kg N/ha stocked at 3.3 head/ha (low N) or 300 kg N/ha stocked 4.5 head/ha (high N) were compared. To date, two production cycles (1977-1979 and 1978-1980) at two sites have been completed. Mean live-weight and carcass gains/ha were, respectively, 17.5% and 14% higher from the high-N than from the low-N system. Gross margin/head was higher from the high-N system in the first production cycle but not in the second. In the low-N system as com· pared with the …

An Evaluation Of The Black Walnut- Tall Fescue Pasture-Management System, H E. Garrett, W B. Kurtz

IGC Proceedings (1977-2023)

The economic and biological feasibility. of a black walnut-livestock-grazing multicropping-management regime bas been evaluated for comparison with a similar livestock-management regime conducted in the open. Pure tall fescue plots were established under open and black walnut-shade conditions. Forage yields on a dry-weight basis were estimated for a 3-year period. A concurrent grazing trial was co􀀌ducted on similar sites using 1.2-ha plots. Black walnut seedlings were planted within the plots on a 3 x 12-m spacing and protected from grazing animals by electric fencing. The economic analyses of the alternate grazing systems were based on their respective present net worth and …

Economic Analysis Of The Impact Of Management Decisions On Production And Use Of Silage For A Dairy Enterprise, A J. Corrall, H D. St. C Neal, I M. Wilkinson

IGC Proceedings (1977-2023)

The aim of this work was to examine the influence of variations in grass management and methods of ensiling on the economics of milk production for autumn-calving cows. A simulation model was developed to combine knowledge of plant and animal responses and their interactions in order to calculate the effects of management options on economic balances. Input data were compiled for herbage production from cut­ting strategies that gave herbage at four digestibilities, at two levels of applied nitrogen, and in three climates. Experimental evidence was also collated to construct matrices of loss of dry matter and changes in digestibility and …

Effective Training For International Students, G W. Thomas

IGC Proceedings (1977-2023)

The observations made in this paper are based upon contacts with international students, both in the U.S. and in many other countries. Two of the most serious problems in increasing world food production in the developing world are (1) lack of trained people, and (2) technology transfer. A third constraint, inadequate research, is also critical but not of the magnitude of the other two, since there is a great amount of research information available that is not being adequately ut:ilized. Training needs fall into two general categories in which deficiencies are obvious: (1) graduate-level programs, particularly in the applied fields …

West Virginia University Allegheny Highlands Project: A Ten-Year Experiment In Technology Transfer, B S. Baker, P E. Lewis, E K. Inskeep, R H. Maxwell

IGC Proceedings (1977-2023)

West Virginia's livestock industry is characterized by relatively small units located predominantly on rough terrain not suited to highly mechanized or intensive agriculture. As a result of changes in West Virginia agriculture during the last 40 years, there has been a reduction in support from agribusiness, marketing alternatives, and profitability. Some agriculturalists contend that if present technology were adopted, beef and sheep farms in mountainous regions could be profitable and could contribute to the local economy. The objective of the Allegheny Highlands Project (AHP) was to test the effectiveness of a method for delivering technological information to farmers to promote …

Grassland Societies In Manitoba, G Bonnefoy

IGC Proceedings (1977-2023)

Farmers with forage and livestock problems were organized into grassland societies and cooperated with extension staff sup­plied by 􀀇anitoba Agriculture. The purpose of the grassland societies is to improve by demonstration the traditional manage­ment practices used by livestock producers for pastures and forage production for beef and dairy herds. Results over 5 years were clearly positive. Significant improvements were noted in both field and animal husbandry practices. The experience confirmed the principles of the diffusion-adoption process and its application to adult extension education.

Pasture Demonstrations For Beef: Agronomic Considerations, N P. Martin, P R. Hasbargen, R L. Arthaud, G J. Sullivan

IGC Proceedings (1977-2023)

Beef cattle supply a major portion of farm income of northern Minnesota, but the major resource supporting this enterprise, forage, is vastly underutilized. A 5-year on-the-farm demonstration was conducted by the Agricultural Extension Service of the University of Minnesota and the Upper Great Lakes Regional Commission to improve income in this area by improving man­agement of the beef enterprise.

We compared one or two improved pasture systems with an unimproved permanent grass pasture composed predominantly of Kentucky bluegrass (Poa pratensis L.), system A, on each of six ranches. Improved systems included use of a cool-season grass fertilized with 138 kg …

Optimizing The Use Of Grazed Dryland Pasture In Western Oregon, T E. Bedell

IGC Proceedings (1977-2023)

When they are properly fertilized, western Oregon dryland pastures of subterranean dover with grasses such as perennial rp:g:rass, tall fescue, and resident annuals produce total annual dry-matter yields averaging 6,500 kg/ha. Some sites are capable of over 9,000 kg/ha. Optimum use of this forage is complicated by its highly seasonal availability. Over 50 % of the total growth occurs from late April to mid-June. Only about 10% takes place during autumn-early winter, and virtually none occurs during summer. Research shows livestock weight gains from 300 to over 700 kg/ha can be expected depending upon pasture mixture and kind of grazing …

Growing Beef Cattle On Native Pasture Oversown With The Legume Fine-Stem Stylo In Subtropical Australia, K G. Rickert, G M. Mckeon, J H. Prinsen

IGC Proceedings (1977-2023)

Fine-stem stylo (FSS), Stylosanthes guianensis var. lntermedia, is a perennial legume suitable for sowing into native Heteropogon contortus pastures on well-drained soils in southeastern Queensland. A grazing system is described that aims to maintain a productive FSS pasture and grow steers to 480 kg live weight at 27 months of age. This goal requires gains of 300 kg/steer in 20 months after weaning. Results from a short-term field study of the system were analyzed for long-term repeatabil­ity using a simple model that predicted animal production from stocking rate and weather records. The system was studied near Gayndah, Queensland, on 11.3 …

Development Of Legume-Based Pastures For Beef Production In Dry Tropical Areas Of Northern Australia, J G. Mcivor, R J. Jones, C J. Gardener, W H. Winter

IGC Proceedings (1977-2023)

A program designed to select pasture legume species suitable for beef cattle grazing in the 500-1,500 mm annual rainfall zone of northern Australia is described. A detailed study of members of the genus Stylosanthes, involving spaced-plant studies and small-scale cutting trials at a number of sites, identified a number of persistent, high-yielding accessions. Animal-production studies have shown that the introduction of a legume into native pasture generally results in an increase in carrying capacity, although production/head may not increase unless superphosphate is applied. The Stylosanthes accessions can produce moderate to high yields without superphosphate, and only small applications of superphosphate …

Development Of A Pasture Research Program For The Tropical Savanna Region Of Brazil, D Thomas, C P. Moore, W Couto, R P. De Andrade, C.M C. Da Rocha, D T. Gomes

IGC Proceedings (1977-2023)

The tropical savannas (cerrados) of west central Brazil contain almost 40% of the nation's cattle population. However, the low productivity and nutritive value of the native pastures is a serious limitation to cattle production. To improve the nutrition of the grazing animal, a research program has been developed with emphasis on the integrated use of cultivated pastures. The program aims (1) to select species adapted to the cerrados, (2) to determine their nutrient requirements, and (3) to develop methods of establishment and utilization. The program is being conducted at the Cerrados Agricultural Research Center (CP AC) at lat 15°S. Rainfall …

Advances In Pasture Research And Development In Santa Cruz, Bolivia, R T. Paterson, C R. Horrell

IGC Proceedings (1977-2023)

Cattle production is important in Santa Cruz but is low in productivity, due in part to low grazing value of natural pastures, particularly in the dry season. Other constraints to cattle production include low land values, poor management, high cost of in­puts, and relatively low product prices. This program is aimed at providing higher-quality, low-cost pastures for complemen­tary use within traditional grazing systems. Improved introduced species were identified for five agro-ecological zones, and commercial seed production of the following was encouraged: Petri guineagrass (Panicum maximum), Brachiaria decumbens, buf­felgrass (Cenchrus ciliaris), glycine (Neonotonia wightii, formerly Grycine wightii), Archer axillaris (Macroryloma axillare), …

Pasture Research Results In The Brazilian Amazon, E.A S. Serrao

IGC Proceedings (1977-2023)

Natural upland savanna grasslands are represented mainly by well-drained savannas, with the cerrado type predominant, and by poorly drained savannas with the campo alto-type being the most common. The main limitations are low forage­production potential and, especially, low forage quality. About 3 million ha of rain forest has been replaced by improved pastures of guineagrass (Panicum maximum, 80% ), jaraguagrass (Hyparrhenia rufa, 10% ), and Brachiaria spp. and other grasses (10% ). During the first few years after establish­ment, pastures are productive. However, with time, a gradual decline of productivity occurs, especially in P. maximum pastures. About 0.5 million ha …

Pasture Research Project In The Brazilian Amazon, H M. Saito, H W. Koster, E.J A. Khan, D F. Winslow, A M. Hollick, P M. Paollichi, A C. Costa, F A. Rolim

IGC Proceedings (1977-2023)

The procedure for pasture establishment in the Brazilian Amazon has been to cut down and burn forest and then to seed guineagrass (Panicum maximum L.). Under normal management, animal production has dropped significantly as pastures have deteriorated and have been invaded by weeds. A dearth of knowledge of climate, soils, and plant species; the manner in which pastures have been planted and managed; and a complete absence of fertilization have led to overgrazing and complete degrada­tion of the pastures. This study was undertaken to identify soil problems, adapted forage species, pasture-management practices, and ways of regenerating pastures. Two regions …

Animal Production From Brazilian Tropical Pastures, G L. Rocha, V.B G. Alcantara, P B. Alcantara

IGC Proceedings (1977-2023)

This review deals with the potential for beef production from nitrogen- and legume-based pastures in tropical Brazil. Possibilities for impr􀀞ving the beef industry supported by grass-legume pastures are very promising. According to the literature examined, legume-based pastures produced an annual average of 329 kg gain/ha, and nitrogen (N) fertilization resulted in 4.56 kg gain/ha. Phosphorus (P) was the main fertilizer utilized in addition to N, followed by potassium (K), lime, and micronutrients. An­nual rainfall averaged 1430 mm. Grasses used were of the genera Melinis, Hyparrhenia, Panicum, Cenchrus, Digitaria, Cynodon, Brachiaria, and Pennisetum, and the legumes were of the genera Macroptilium, …

Hemarthria Altissima: A Pasture Grass For The Tropics, K H. Quesenberry, W R. Ocumpaugh, O C. Ruelke

IGC Proceedings (1977-2023)

Limpograss (Hemarthria altissima [Poir] Stapf. et C.E. Hubb), introduced into the U.S. in 1964, has been evaluated for use as a pasture grass. Under Florida conditions it has shown yield potential equal to or greater than other tropical pasture grasses. The cultivar Bigalta has higher in-vitro organic-matter digestion (IVOMD) than other tropical grasses at comparable growth stages. Early evaluations of limpograss involved only three clones, but additional genotypes were collected and introduced during the late 1960s and early 1970s, and an evaluation scheme for this germ plasm was undertaken. Our objectives were to evaluate rapidly the available germ plasm of …

A Comparative Evaluation Of Six Ryegrass Cultivars Under Grazing And Conservation Managements, M Ryan

IGC Proceedings (1977-2023)

Meat and dairy products command overriding importance in the Irish agricultural economy. They are derived primarily from Irish grasslands, which occupy 89% of the arable land area. Use of improved grass cultivars is probably the best means of increasing grassland output once the basics, optimal fertilizer use, and high stocking rates have been met. Objective identification of superior cultivars is the responsibility of state agencies. A recommended list, published annually in Ireland, presently contains 47 ryegrass (Lolium perenne) cultivars. There is some doubt, however, that results from small-plot cutting trials can be extrapolated to equivalent performance by grazing …

Potential Grass Production In Ireland, A J. Breeton

IGC Proceedings (1977-2023)

Variation in weather geographically and between years can have a significant impact on intensive animal production systems dependent on grass as feed. This work was undertaken to quantify the effect of weather variations on grass production. The first objective was to relate grass growth quantitatively to radiation and temperature. These relationships are obscured by large changes in sward growth potential within the season, which are related to changes in the physiological status of the crop. Therefore, it was necessary to quantify this physiological effect. Production data were drawn from production experiments, and weather data were drawn from the published records …

Production Of Big Trefoil On Acid, Low-Fertility Soils In New Zealand, R S. Scott

IGC Proceedings (1977-2023)

On undeveloped, acid (pH< 5.0) soils in New Zealand, growth of the conventional legumes white clover (Trifolium repens L.), red clover (T. pratense L.), and alsike clover (T. hybridum L.) is limited by acidity. The objective of this research was to identify an alternative legume species better adapted to both acidity and low inputs of phosphorus (P) and to examine grazing management. Big trefoil (Lotus pedunculatus Cav.) cv. Grasslands Maku and birdsfoot trefoil (L. rorniculatus L.) cv. Maitland were examined. Seed was inoculated with appropriate strains of rhizobia and sown into undisturbed tussock grasslands on acid soils of low P status at altitudes of 550-880 m. Lime and phosphorus …

Animal Production With Controlled And Fixed Stocking And Managed Stocking Rates, R E. Blaser, J T. Johnson, F Mcclaughterty, J P. Fontenot, R C. Hammes Jr, H T. Bryant, D D. Wolf, D A. Mays

IGC Proceedings (1977-2023)

Grazing experiments were conducted to implement and improve animal-grazing-management systems. The primary objec­tives were (experiment 1) to investigate animal production with fixed and controlled stocking and (experiment 2) to study animal production and canopy characteristics with three managed stocking rates. Live-weight gains/head for the grazing season were similar for fixed and controlled stocking; during a summer period, gains/head were higher for controlled stocking. Gains/head were not associated with available herbage. The canopies with fixed stocking had 28% to 82% more forage than those with controlled stocking, the former being high in dead tissues and stems. Controlled stocking gave 61 % …

Influence Of Sward Structure Upon Herbage Intake Of Cattle Grazing A Perennial Ryegrass Sward, M H. Wade, Y.L P. Le Du

IGC Proceedings (1977-2023)

To examine the influence of structural distribution of herbage within a sward on intake by grazing animals, two swards of contrasting structure were established at two periods in the grazing season by either infrequent mowing (C) or hard sheep graz­ing (G) of a perennial ryegrass (Lolium perenne) pasture. The plots were then allowed to grow undisturbed for about 5 weeks before being grazed by young cattle for periods of 2 weeks at two levels of herbage allowance, 30 and 60 g dry matter/kg live weight/day, in July (1) and in September (2). Detailed measurements of sward structure were …

A Mathematically And Conceptually Unified Approach To Grazing-Management Terminology, D L. Scarnecchia, M M. Kothmann

IGC Proceedings (1977-2023)

Expressions such as "stocking density," "stocking rate," "grazing pressure," "herbage allowance," "grazing intensity," "stock­ing intensity," and "stocking pressure" have long been used to describe animal-pasture systems. In general, these expressions describe relationships among the basic variables of animal demand, forage quantity, pasture area, and grazing duration. Our objective was to develop a conceptually dynamic mathematical framework of expressions summarizing all of the meaningful relationships among these variables. Elementary differential and integral calculus were used to develop this dynamic approach. The resulting expressions are dimensionally valid and are capable of accurately describing dynamic animal-pasture systems. Adoption of this system would standardize …

Screening Perennial Forages By Mob-Grazing Technique, P Mislevy, G O. Mott, F G. Martin

IGC Proceedings (1977-2023)

Mob-grazing allows the study of forage response to severe defoliation by grazing animals on a limited land area. This tech­nique was used to evaluate two Digi,taria spp., one Paspalum sp., and 13 Cynodon spp. at grazing frequencies of 2, 3, 4, 5, and 7 weeks. Average dry-matter (DM) yield generally increased as grazing frequency decreased from 2 to 7 weeks. Decreasing the grazing frequency from 4 to 7 weeks resulted in a DM yield increase of 50% to 75% for most entries. Grazing at 4-and 5-week intervals resulted in the highest (42%) and lowest (22%) weed contamination, respectively, when compared …

Grazing Techniques For Evaluating Quality Of Forage Cultivars In Small Pastures, A G. Matches, F A. Martz, D A. Sleeper, R L. Belyea

IGC Proceedings (1977-2023)

Because plant beeders have few laboratory analyses of forage quality that are good predictors of animal performance when grazing pasture, • we studied the feasibility of grazing small pastures with cattle in order to detect possible forage-quality dif­ferences among cultivars of tall fescue (Festuca anmdinacea Schreb). Kentucky 31, Kenmont, Fawn, and Missouri 96 tall fescue cultivars and Kenhy, a Lolium-Festuca derivative, were grown in 0.47-ha pastures and grazed in separate periods ranging from 35 to 68 days during the spring, summer, and autumn of 1974-1976. Between grazing periods, cattle grazed a reserve pasture of the same cultivar. All test pastures …

Using A Dynamic Model Of Fiber Digestion And Passage To Evaluate Forage Quality, D R. Mertens, L O. Ely

IGC Proceedings (1977-2023)

Assessing forage quality depends not only upon the characteristics of the plant and animal, but also upon the dynamic interac­tion of the forage, rumen microorganisms, and animal. Although static variables, such as composition or 48-hour in-vitro fermentation, are important for characterizing feeds and predicting in-vivo responses under standard conditions, they provide little information that can be used to assess forage quality in dynamic situations. Dynamic properties, such as rates of digestion and passage, can be used to predict digestion under varied circumstances but require an appropriate mathematical model. Our objectives were to describe a dynamic model of fiber digestion and …

Methodology For Determining Pasture And Animal Response Differences In Unbalanced Experiments With Intercorrelations Among Treatments, J C. Burns, R W. Harvey, F G. Giesbrecht

IGC Proceedings (1977-2023)

Conventional statistical analyses require balanced data sets. Unbalanced data can be analyzed using regression procedures, but excessive adjustments may be needed for some treatment means. The objective of this paper is to evaluate an analysis of grazing-trial data using generalized least squares. The data was obtained from a 6-year study involving 12 treatments with not all treatments being made in all years. The analyses involved estimating variance components due to years, fields, and random error and then using these estimates to obtain adjusted treatment means. Variance-component estimates for the complete data set were similar to estimates from two balanced subsets …

Effect Of Experimental Methods On Results Of Voluntary Intake Experiments With Grass Cultivars, U Simon, P Daniel

IGC Proceedings (1977-2023)

The amount of forage eaten by farm animals when forage is offered ad libitum is a major factor in the nutritive value of forage grasses. It is influenced by a number of internal and external factors. Experimental results of studies on the subject :reported in the literature are often contradictory, partially because, perhaps, of the methods of evaluation employed. We studied whether and to what extent different experimental procedures influenced the results of intake experiments in grass cultivars. Four cultivars of Lolium perenne differing in ploidy level and precocity were fed to sheep ad libitum, and voluntary intake was assessed …