Plant Pathology Commons^™

Adaptation And Forage Quality Of Grasses Grown Under Shade, K D. Kephart, D R. Buxton

IGC Proceedings (1977-2023)

The three fundamental environmental factors which influence plant growth are water, temperature, and light. Light may be separated into photoperiod - and irradiance - related factors. Grasses adapt to reduced irradiance regimes by increasing leaf area and stem length and by decreasing leaf thickness and plant dry weight. Leaf thickness in grasses is alte­red by changes in cell size (Cooper and Tainton, 1968). These morphological and anatomical adjustments to irra­diance regime may affect cell-wall concentration and forage quality. Adaptation to reduced irradiance has resulted in lower soluble carbohydrate concentration and increased total-nitro­gen concentration (Deinum and Dirven, 1972; Wong and Wilson, …

Differences In Nutritive Value Of Lecerne Cut In Morning And Afternoon Hours, F Plhak

IGC Proceedings (1977-2023)

Beside crude fibre and protein, the photosynthetic products - nonstructural carbohydrates - are further important substances of digestible dry matter in lucerne fodder. They par­ticipate in dry matter by 15 %. In contrast to crude fibre and protein, the content of photosynthates changes expressively during the day (Plhak, 1984). The changes reach in leaves by 20 %, in stems 5 % of dry matter. The changes depend on the length and intensity ofsolar irradiance (Plhak, 1981) and cause specific weight alteration of leaves (Chatterton et al., 1972). Such variations in photosynthates content can cause some changes in dry matter digestibility …

Productivity And Nutritive Values In Three Ecotypes Of Trichloris Crinita, Native Forage Grass Of The Arid Zones Of Argentina, J Silva Colomer, J B. Cavagnaro, J Lemes, M Medero

IGC Proceedings (1977-2023)

Livestock activity in the arid and semiarid regions of the west central part of Argentina is mainly based on native grasses. On the plain areas of Mendoza province, the most important grasses are perennial, warm-season species, adapted to water stress, high temperature and high irradiance conditions (Cavagnaro, 1988). Mean rainfall of the area reached at 264 mm during the growing season. Trichloris crinita is one of the outstanding species in many areas of the mentioned region. In order to preserve genetic variability of natural popula­tions, IADIZA (Instituto Argentino de Investigacion de Zonas Aridas) initiated a germplasm bank of native forage …

Evaluating Maturity And Preservation Method Of Alfalfa On Optimum Rations For Lactating Dairy Cattle Based Upon Neutral Detergent Fiber Concentration Of The Total Diet, R W. Hintz, D R. Mertens, K A. Albrecht

IGC Proceedings (1977-2023)

Previous research has shown that formulating rations based upon neutral detergent fiber (NDF) concentration of the total diet can be an effective means of maximizing the performance of lactating dairy cattle (Mertens, 1982). Results of these studies indicated that ration formulation using NDF is a robust procedure, but that differences in the optimum NDF level may exist between forages conserved in different manners. To deter­mine if the method of forage preservation affects the optimum NDF concentration of diets, a study was designed to compare the response of lactating dairy cattle to diets of identical NDF concentration formulated using third-crop alfalfa …

Animal Performance As Effected By Herbage Availability And Quality In Semi-Arid Southern African Grassland, J E. Danckwerts

IGC Proceedings (1977-2023)

Rotational grazing with beef cattle is widely advocated and practised under commercial pastoralism in semi-arid grassland in southern Africa. Since animal performance is largely a func­tion of the quality and quantity of forage ingested, changes in herbage quality and availability in these situations are likely to have an important influence on animal production. The objective of this paper is therefore to quantify changes in the quality of herbage ingested by beef cattle at different times of the year and as grazing pressure increases within periods of occupation on rotationally grazed semi-arid grass­land in southern Africa. The effect of these changes …

The Intake And Digestibility Of Dry Mature Subterranean Clovers, G B. Taylor, R C. Rossiter, D B. Purser, W J. Collins

IGC Proceedings (1977-2023)

Although sheep grazing dry subterranean clover (Trifolium subterraneum L.) pasture may maintain body weight for the early part of summer, they usually lose weight during late summer and autumn, with consequent adverse effects on pro­ductivity (Purser, 1980). A decline in the digestibility of clover during plant senescence (Hume and Purser, 1975) is believed to be an important component of the reduced nutritive value of this dry feed. In a survey of dry mature stem material from a range of early flowering subterranean clover genotypes, Taylor et al. (1987a) found that in vitro digestibility ranged between 41 and 62 % …

Forage Production And Nutritive Value Of Cynodon Spp. Under Grazing In Puerto Rico, L E. Tergas, Y Q. Cabrera, A Sotomayor Rios

IGC Proceedings (1977-2023)

Livestock production in the tropics is highly dependent on forages to meet the nutritional requirements of grazing cattle. However, seasonal fluctuations on dry matter production and nutritive value are limiting factors affecting animal perform­ance and production. Stargrass Cynodon nlemfuensis var. nlemfuensis is a highly productive grass recommended for intensive management in the humid tropics of Puerto Rico (Vicente-Chandler et al., 1974). Bermuda Cynodon dactylon and Stargrass produced high yields of quality forage and persisted under intensive grazing in the humid northern coastal plains of Puerto Rico; however, the average production of both grasses was related to rainfall distribution, decreasing during …

Prediction Of The Yield Of Nutritive Matter In Some Autumn Cut Forage Catchcrops, K Kastelic, J A. Nikolic, A Pavlicevic, T Stupica, J Cizec

IGC Proceedings (1977-2023)

Arable land often lies fallow for a time, which provides an opportunity for growing fodder catchcrops between two main crops. This practice should improve the soil structure, conserve soil moisture, eliminate many weeds, maximise land use and enable easier preparation for the subsequent main crop. More­over, subsequent cereal yields may be increased by preceding forage legume crops (Papastylianou and Samios, 1987). The aim of present investigation was to determine the concentration of promising autumn cut catchcrops (D-value) and to assess the possibility of predicting the yield of digestible organic matter (DOM) from the yield of green or dry matter (DM).

Changes In Digestibility With Regrowth Of Some Temperate Grasses, K Watanabe, S Furukawa, A Sato, S Saiga

IGC Proceedings (1977-2023)

Many workers have reported that the decline in digestibility of temperate grasses were steep after heading in 1st cut and lenient during the regrowth in 2nd and 3rd cuts. But in some grasses, heading is observed even in 2nd and 3rd cuts, and the late stages of regrowth were sometimes accompanied by high temperature which usually accelerate the decline in digesti­bility. So even in the regrowth, digestibility is one of the important factors to optimize cutting stage of grasses. Cutting stages in the regrowth of grasses have been discussed from the standpoint of dry matter production (Watanabe et al., 1984; …

Feeding Behavior Of Bali Cattle Fed Gliricidia Diet, K Lana, I M. Nitis, S Putra, M Suarna, W Sukanten

IGC Proceedings (1977-2023)

Even though Gliricidia sepium has been used as fodder in the tropics, the extend of its utilization by ruminant is not well documented (NFTA, 1987). When mixed with other forages, Gliricidia sepium consumption by Bali cattle can be as high as 50 % during the wet season and increases up to 66 % during the dry season (Nitis et al., 1988). The presence of inhibiting substances has been suggested to cause the low palatibility of the Gliricidia leaf (Cheeke and Raharjo, 1987; Rodriguez et al., 1987). The objective of this experiment was to study the preference of Bali steer on …

Electronic Measurement Of Grazing Time And Intake In Free Roaming Livestock, J R. Forwood, M M. Hulse

IGC Proceedings (1977-2023)

Herbage intake is one of the critical factors in understanding why livestock perform at various levels on different forages, however acceptable methods of measuring voluntary intake of free-roaming livestock are still lacking. Commonly used indirect measurement methods estimate pasture herbage loss or animal gain, fecal output and digestibility equations, grazing behavior calculations or indicators (Greenlaugh, 1982). More direct attempts of measuring intake include the Animal Weight Telemetry System (AWATS) of Horn and Miller (1979), multiple impedance plethysmography (Stuth et al., 1981) and the conductivity transducing cannula (CTC: Forwood et al., 1985). With new technology becoming avail­able in smaller, more affordable …

Pasture Species Preferences By Horses In New Zealand, W F. Hunt, R.J M. Hay, D Clark

IGC Proceedings (1977-2023)

The equine breeding industry of New Zealand makes a con­siderable contribution to the export earnings, but the pro­duction base of that industry, i.e. the equine pastures have been neglected by our researchers. Thoroughbred studs are estab­lished on ex-dairy or ex-sheep farms which are usually sown with perennial ryegrass and white clover. Ryegrass based pastures can be highly productive, but in New Zealand suffer from the Argentine stem weevil - ryegrass staggers dilemma. i.e. Low endophyte ryegrasses do not survive Argentine stem weevil, but resistant high-endophyte ryegrasses cause the ani­mal muscular disorder« ryegrass staggers». The seasonal pro­ductivity pattern of ryegrass is …

La Consommation De Matiere Sche De Fourrages Disponibles En Zone Tropicale, D Richard, H Guerin, G Roberge, D Friot

IGC Proceedings (1977-2023)

Un certain nombre de publications fournissent des donnees sur les consommations de matiere seche (MS) des fourrages dans les regions intertropicales sans qu'il soit toujours possible de differencier les variations liees a la capacite d'ingestion de !'animal ou a l'ingestibilite du fourrage, facteurs conditionnant les quantites de matiere seche volontairement ingerees (MSVI). Par ailleurs, les donnees publiees pour un meme fourrage sont souvent tres variables ; par exemple, les quantites de MSVI de Digitaria decumbens extraites de 5 publications varient de plus de 40 p. 100 pour des repousses de meme age (Richard, 1987) sans qu'il soit possible d'identifier les …

Particulate And Fluid Retention Times In Sheep As Influenced By Forage Morphological Composition And Intake, D J.R Cherney, D R. Mertens

IGC Proceedings (1977-2023)

Production by ruminants on high forage diets is often limited by intake. If fill limits intake, residue must escape the rumen through digestion or passage for further intake to occur. Resistance to escape of forage residues from the rumen is a function of physical and morphological characteristics of the forage, although the nature of the relationship is not fully understood (Moseley and Jones, 1984). Understanding of factors affecting passage of undigested residue is important to ensure maximum forage utilization in ruminant diets. It was hypothesized that differences in forage morphological composition, particle length and rates of passage of morpho­logical components …

Responses In Ingestive Behavior By Sheep Changes In Sward Structure, P D. Penning, A J. Parsons, G E. Hooper, R J. Orr

IGC Proceedings (1977-2023)

Recent work has shown how herbage growth, ingestive behaviour and herbage intake may be related to sward height under continuous stocking (Parsons et al., 1986; Penning, 1986). However, the application of these relationships to other grazing managements, where differences in herbage mass, tiller number and leaf to stem ratio at the same sward heights occur, have not been considered. The objective of this study was to determine the major factors affecting ingestive behaviour and intake of herbage by sheep grazing swards differing in structure and morphology but with similar heights.

Factor Affecting The Eating Rate Of Forage Feeds, G Moseley, A Antuna Manendez

IGC Proceedings (1977-2023)

The total amount of a forage feed eaten by an animal may be regarded as the product of rate of eating and time spent eating. Balch and Campling (1962) suggested that it is controlled largely by the rate at which the forage can be broken down phy­sically and passed through the foregut. Differences in voluntary

intake between forage feeds may, however, be due to the effects of extrinsic factors such as environment, animal condition and feed presentation, or to inherent feed characteristics which con­trol the rate and extent of breakdown and digestion. The degree to which physical plant characteristics may …

Influence Of The Nature Of Hay On Its Ingestibility And The Kinetics Of Intake During Large Meals In Sheep And Cows, R Baumont, J P. Brun, J P. Dulphy

IGC Proceedings (1977-2023)

Ingestibility is the quantity of a forage that can be eaten by a standard animal when it is fed ad libitum as the sole feed (INRA, 1978). The eating pattern of ruminants reflects the way in which intake is controlled. The animal eats a large meal when a new batch of forage is distributed ; meals thereafter are small until the next distribution (Dulphy & Faverdin, 1987). To make a closer study of forage ingestibility, it seemed interesting to record the daily pattern of intake and to analyse in detail the large meals, which are 60 to 90 % of …

Relative Palatability Of Some Little-Known Tropical Forage Legumes, R Schultze-Kraft, C Lascano, G Benavides, J M. Gomez

IGC Proceedings (1977-2023)

In preliminary agronomic evaluations some of the little­know legumes recently selected in Southeast Asia have shown good adaptation to an acid, low-fertility Ultisol (CIAT, 1984, 1985). It is recognized that early evaluation of forage species should include an assessment of relative palatability (Joblin, 1962), particularly for tropical legumes where some species have been found to be highly unpalatable to cattle (Warmke et al., 1952). This paper reports on two cafeteria grazing trials conducted to assess the relative palatability of some new Southeast Asian legume germplasm as well as some South American species and ecotypes assumed to be of low palatability.

Fiber Composition Of Successive Cuts Of Lucerne, D Kolarski, J Pavesic-Popovic,, O Krstic, K Koljajic

IGC Proceedings (1977-2023)

The plant cell walls contain lignin, cellulose, hemicellulose, fiber bound protein and fiber bound minerals. Their nutritive value is limited by their degree of lignification, while cell con­tents is not limited (Barton et al., 1977). Type and extent oflig­nin-polysaccharide bounding could affect digestion more than amount of lignin (Jung et Fahey, 1983). The purpose of these studies was to determine chemical and fiber composition of four cuts of lucerne (Medicago sativa, CV Kl).

Relationship Between The Mineral Content In Pastures And The Content Of These Elements In Blood Serum In Dairy Cows, A Lachowski, I Kuczynska, W Wojciechowski

IGC Proceedings (1977-2023)

Grass tetany, a conditioned Mg deficiency of improper K: (Ca + Mg) ratio is a nutritional problem in various parts of Poland. The aim of the investigations was to determine to what degree the mineral content of grasses in the pastures influenced the mineral content in blood serum in dairy cows. This is very important when the animals are grazing and when cattle slurry is used on grasslands. In the literature we can find opinion con­sidering hypomagnaesemia as a metabolic disorder of rumin­ants typified by low blood serum Mg and generally accompanied by hypocalcemia. It has been related to low …