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On The Scale Dependence Of Foraging In Terrestrial Herbivores, John M. Fryxell, C. B. D. Fortin, J. Wilmshurst

IGC Proceedings (1977-2023)

Meaningful modeling of the spatial and trophic dynamics of terrestrial herbivores demands understanding of the constraints and fitness objectives that presumably underlie behavior. This is complex in terrestrial herbivores, because of scale-dependent constraints on nutrient or energy gain. Mechanistic processes of forage cropping, forage mastication, movements between feeding stations, and forage digestion each have unique constraints that apply on different time, size, and spatial scales. Moreover, competing activities are rarely taken into account. Experimental testing of foraging objectives is therefore clouded by uncertainty regarding which time scale is most relevant from the animal’s perspective, leading to confusion and misrepresentation in …

Foraging Strategies On Rangeland: Effects On Intake And Animal Performance, Peter O’Reagain

IGC Proceedings (1977-2023)

Rangelands exhibit extreme spatial and temporal variability in forage quality and availability. The animals that utilise these rangelands have consequently evolved a range of foraging strategies in an attempt to cope with this variability and maintain nutrient intake. In general, animals respond to and exploit spatial variability at all scales by selecting those items or units which optimise the intake of digestible nutrients and hence animal production. Animals similarly employ a variety of strategies to cope with temporal variability on rangelands. These strategies may include adjusting foraging behaviour and/or exploiting critical resources or resource areas to buffer temporal variability in …

Influence Of Sward Height, Concentrate Supplementation And Season On Grazing Activity Of Beef Cows, O. J. Gekara, E. C. Prigge, W. B. Bryan, M. Schettini, E. L. Nestor

IGC Proceedings (1977-2023)

The influence of sward height, concentrate supplementation and season on daily pattern of forage consumption of lactating beef cows grazing cool season pastures was determined. Cows (n=24; BW=535±10.8 kg) were randomly assigned to eight plots maintained at sward heights (SH) of either 4-8 cm or 8-12 cm and fed three levels of concentrate supplement: none = 0 kg/day, low = 3.12 kg/day or high = 6.24 kg/day. Cows on lower SH had greater (P < .08) forage dry matter intake and spent an additional 1.2 hours/day (P < .01) grazing compared to the higher SH. Cows on lower SH consumed 7.7 kg/day of forage dry matter and grazed 9.4 hours/day whereas those on higher SH consumed 7.1 kg/day and grazed 8.2 hours/day. Cows on lower SH grazed 0.7 hours/day (P < .06) and 0.4 hours/day (P < .08) longer at 06:00-10:00 hour and 11:00-13:00 hour, respectively, compared to the higher SH. Grazing efficiency (kg of forage consumed/hour of grazing) decreased (P < .01) as season progressed. Season influenced duration of grazing activity (P < .01). Cows grazed 0.5 hours longer (P < .01) at 06:00-10:00 hour late in summer (August) compared to spring (May) and mid summer (June/July). Cows grazed 0.3 hours longer (P < .08) at 11:00-13:00 hour during spring compared to late summer.

Safflower (Carthamus Tintorius): A Promising Forage Crop For Semi-Arid Regions, Y. Leshem, I. Bruckental, S. Y. Landau, G. Ashbell, Z. Weinberg

IGC Proceedings (1977-2023)

The yield, quality, preservation and intake of safflower hay were determined in two successive years - 1998 and 1999. Field experiments carried out at the Bet Dagan experimental station on the coastal plain of Israel under rain-fed conditions. A spineless variety was tested under three sowing dates. Yield decreased and quality improved as the sowing date receded from November 12 to February 3. Respective yields, IVDMD and CP content were: 22 and 8 ton DM/ha, 48.9% and 65.5% , 10.0% and 14.6%. Safflower at 290, 410 and 770 g/kg DM was ensiled in 1.5-l anaerobic glass jars with or without …

Effects Of Different Levels Of Energy On Growth Of Grazing And Drylot Fed Holstein Heifers, L. P. Novaes, C. E. Polan

IGC Proceedings (1977-2023)

Growth of Holstein heifers were studied to evaluate the combination of a drylot phase followed by feeding energy for pasture supplementation during the grazing season of 1988. Heifers grazed a grass-legume mixture in six paddocks of 1.5 ha each. After drylot, animals were equally allotted to pasture and none or 2.0 kg/d of corn were fed in addition to grazing in a changeover design with repeated measurements. Heifers were fed a high (HE) or low energy (LE) diets in confinement and daily gains were 1190 (HE) and 990 g/day (LE) which were different. On pasture, corn supplementation did not enhance …

Leaf Fragment Identification Of Subtropical Native Grass Species, C. H. E. C. Poli, J. M. Rosito, A. G. Schirmer, P. R. Boggiano, P. C. De F. Carvalho

IGC Proceedings (1977-2023)

The present study was carried out to characterise leaf fragments of important plant species of a subtropical native sward in the southernmost state of Brazil. Thirteen important grass species were collected from April to May 1999. Both sides of the leaves were observed using a stereomicroscope. In addition, two approaches were tested to provide a clearer characterisation of the leaves of each species: the leaves were either dried or frozen. The kind and number of veins, the kind and number of hair, and the arrangements and number of stomates on both sides of each leaf are the most useful characteristics …

Nitrogen Fertilization In Paspalum Dilatatum, Poir: Herbage Production, Nutritive Value And Structural Characteristics, G. Acosta, V. A. Deregibus

IGC Proceedings (1977-2023)

It was studied the effect of nitrogen application on structural changes and quantity and quality characteristics of a Paspalum dilatatum Poir sward, under field conditions during two growing seasons. The nitrogen (N) rates were 0 and 440 kg ha^-1 applied during the first year in split applications. The nitrogen fertilization increased leaf, stem and cumulative total dry matter yield, plant height, tiller density, cover ground and leaf crude protein yield.

Using On-Farm Monitoring Of Ergovaline And Tall Fescue Composition For Horse Pasture Management, Krista Lea, S. Ray Smith

Plant and Soil Sciences Faculty Publications

Central Kentucky horse pastures contain significant populations of tall fescue (Schedonorus arundinacea (Schreb.) Dumort) infected with an endophyte (Epichloë coenophialum (Morgan-Jones and Gams) Bacon and Schardl) known to produce several ergot alkaloids, with ergovaline in the highest concentration. While most classes of horses are not adversely affected by average levels of ergovaline in pastures, late term pregnant mares have a low tolerance to ergovaline and the related ergot alkaloids. Endophyte-infected tall fescue has been known to cause prolonged gestation, thickened placenta, dystocia, agalactia, and foal and mare mortality. The University of Kentucky Horse Pasture Evaluation Program utilizes ergovaline …

Alfalfa Response To Phosphorus Sources Associated With The Application Of Liming And Gypsum-Shoot Numbers, P. Sarmento, M. Corsi, F. P. Campos

IGC Proceedings (1977-2023)

Alfalfa (Medicago sativa L.) was grown in a Typic Mapluolox soil with triple superphosphate (TS), Gafsa phosphate (GP) and GP with gypsum (GP + G). Three rates of phosphorus application were used 50, 100 and 200 mg P dm^-3, before and after liming. Alfalfa was harvested three times. Basal and axillary shoot numbers in alfalfa increased with increasing phosphorus rates. Shoots were produced in higher number with GP in comparison with TS. GP + G resulted in higher basal shoot number than GP. However, there was no gypsum effect on axillary shoot numbers. Liming before or after …

Soil Nitrate Level Variation Under Intensive Nitrogen Fertilized Coastcross Pasture, O. Primavesi, A. C. Primavesi, L. A. Corrêa, H. Cantarella, A. G. Silva

IGC Proceedings (1977-2023)

Nitrate levels in soil profile after the first N application on coastcross pasture, grown on a dark red latosol (Hapludox), in São Carlos, SP, Brazil, under tropical altitude climate, were measured at 7-day intervals, to monitor possible losses in depth. Soil nitrate rates varied with high rates of N-ammonium nitrate (200 kg ha^-1 per cutting) in surface layers. Danger of environmental impact was low in the studied conditions.

Saturated Field Hydraulic Conductivity Variation In Intensively Managed Tropical Pastures, O. Primavesi, A. C. Primavesi, S. R. Vieira

IGC Proceedings (1977-2023)

Saturated field hydraulic conductivity was measured, using a Guelph permeameter, at the depths of 10, 20 and 60 cm, to verify the effect of intensively managed, compared to extensively managed ones, beef cattle production systems on pastures grown on three soils (Hapludox, Eutrudox, Paleudalf), in São Carlos, SP, Brazil, under tropical altitude climate. Significant differences occurred within depths (P < 0.05). However, differences decreased with years and, therefore, differences among soils and between management systems were also reduced. Highest mean conductivity values occurred at 60-cm depth and at the extensively managed sward on the sandy Hapludox. Intensively managed Paleudalf showed high resistance to reduction of conductivity at 10-cm depth. A general year effect appeared claiming for more studies on this matter.

Against The Odds: Hybrid Zones Between Mangrove Killifish Species With Different Mating Systems, Waldir M. Berbel-Filho, Andrey Tatarenkov, George Pacheco, Helder M. V. Espírito-Santo, Mateus G. Lira, Carlos Garcia De Leaniz, John C. Avise, Sergio M. Q. Lima, Carlos M. Rodriguez Lopez, Sofia Consuegra

Horticulture Faculty Publications

Different mating systems are expected to affect the extent and direction of hybridization. Due to the different levels of sexual conflict, the weak inbreeder/strong outbreeder (WISO) hypothesis predicts that gametes from self-incompatible (SI) species should outcompete gametes from self-compatible (SC) ones. However, other factors such as timing of selfing and unilateral incompatibilities may also play a role on the direction of hybridization. In addition, differential mating opportunities provided by different mating systems are also expected to affect the direction of introgression in hybrid zones involving outcrossers and selfers. Here, we explored these hypotheses with a unique case of recent hybridization …

The Effect Of Feed Supplementation And Sward Characteristics On The Ingestive Behaviour Of Grazing Ewes, C. H. E. C. Poli, Marta G. Da Rocha, C. C. Pires, Luis H. E. Farinatti, D. Montagner, G. Bica

IGC Proceedings (1977-2023)

The objective of this study was to assess the effect of protein/energy supplementation and sward physical characteristics on grazing behaviour of lactating ewes grazing Italian ryegrass (Lolium multiflorum Lam.). The experiment was carried out in the spring of 1999 at the Universidade Federal de Santa Maria. The grazing behaviour was assessed in two periods: 2 and 3 September, and 8 and 9 October of 1999, using a group of twelve yearling ewes. Groups of four ewes were either supplemented (with 1% of the animals live weight) with soybean meal (protein source), with corn (energy source) or not supplemented. The …

The Effect Of Sward Surface Height On Sheep Grazing Activities, Paulo C. De F. Carvalho, E. O. Silveira, L. S. Pontes, C. H. E. C. Poli, A. B. Soares, H. M. M. Ribeiro Filho

IGC Proceedings (1977-2023)

The objective of this study was to assess the effect of Italian ryegrass (Lolium multiflorum Lam.) sward height on grazing activities. The experiment was carried out at the Research Station of Universidade Federal do Rio Grande do Sul, Brazil. Yearling no-castrated male lambs behavior was assessed in terms of diurnal grazing, ruminating and idling time in three periods: 27 September 11 and 25 October. Sward surface height was monitored using a sward stick and samples of 0.25 m² were cut to ground level to estimate herbage and leaf lamina mass. The experiment was carried out in a randomised …

Grazing Behavior And Activity Patterns By Free-Grazing Cattle In The Pantanal Region, S. A. Santos, C. Costa, L. V. A. S. Chalita, A. Pott, J. M. Alvarez, A. G. Ortiz

IGC Proceedings (1977-2023)

A study of habitat selection and habitat use by free-grazing cattle was conducted in the Pantanal, from October 1997 to September 1999. Observation periods lasted 13 hours per day during three days in each month. The location and activity duration of each group of animals was recorded by continuous sampling. Rumination, walking and resting times were affected (P < 0,05) by interaction between month and year and grazing time differed (P < 0,05) only between months. On average, cows spent 54.9, 29.6, 10.6 and 4.9% of their diurnal hours grazing, ruminating, walking and resting, respectively. The grazing time spent in each landscape unit was influenced (P < 0,05) by interaction between month and year. The cows exploited more intensively the temporary ponds in 97/98 (26 min ha^-1) and the edge of ponds in 98/99 (23.2 min ha^-1). Therefore, the adequate grazing management practice may not follow fixed rules for the Pantanal.

Impact Of Overseeding Cool-Season Annual Forages On Spring Regrowth Of Tifton 85 Bermudagrass, Ricardo A. Reis, Lynn E. Sollenberger, D. Urbano

IGC Proceedings (1977-2023)

Field observations have shown stand reduction and slow spring regrowth of Tifton 85 bermudagrass (Cynodon spp.) pastures overseeded with temperate forages for grazing during the cool season. This experiment compared the effect of cool-season management programs, including overseeding and use of different grazing treatments, on productivity of Tifton 85 the following warm season. There were seven treatments: four were bermudagrass overseeded with a cool-season annual forage mixture (two grasses and two legumes) and grazed differentially, and three were bermudagrass controls with differences in amount of residual stubble remaining at beginning of autumn. There was only a slight delay in …

Variation Of Herbage Intake (Hi) From Upland Pasture, As Influenced By The Grazing Initiation Date (Gid), D. Maæešiæ, M. Kneževiæ, Z. Štafa, J. Leto

IGC Proceedings (1977-2023)

Studies were conducted on an experimental pasture belonging to the Arrhenatherethum medioeur. and Lolio-Cynosureth. assoc. with D. glomerata, L. perenne and T. repens as main species, at an altitude of 680 m. Four equally sized paddocks (0.3 ha) were grazed by 10 Charolais heifers. The differences in total herbage dry matter intake (HDMI) between the four paddocks with different grazing initiation dates (GID) were significant (P < 0.05). The results of this experiment show that in order to achieve a higher HDMI and better herbage utilization an earlier initiation of grazing is recommended. That is, grazing should commence when the sward height is about 15 cm.

Two-Dimensional Monitoring Of Spatial Distribution Of Herbage Mass Under Grazing, S. Ogura, Masahiko Hirata

IGC Proceedings (1977-2023)

Spatial distribution of herbage mass (HM) was monitored two-dimensionally during the grazing season (from May to November) in a bahiagrass pasture rotationally grazed by cattle. An electronic capacitance probe was used to estimate HM in 1464 permanent positions (50 × 50 cm) whose centres formed 1.5 × 1.5 m grids in the central 90 × 34.5 m area of the pasture. The highest mean HM was in September and October, while coefficient of variation in November. The two-dimensional charting of HM showed almost stable spatial patterns throughout the grazing season, with some patches of high HM appearing and disappearing. The …

The Effect Of Herbage Mass Of A Pasture On The Spatially Heterogeneous Grazing By Cattle, S. Ogura, Masahiko Hirata

IGC Proceedings (1977-2023)

To obtain information on spatially heterogeneous grazing by large herbivores at different time scales, spatial distribution of herbage mass and rate of defoliation was investigated on a bahiagrass (Paspalum notatum Flügge) pasture grazed by cattle during 4 to 5-day grazing periods in May, August and October. Pre-grazing herbage mass (M_pre) showed decreasing mean values and increasing spatial heterogeneity with the progress of grazing in all grazing periods, while the rate of defoliation showed inconsistent changes with season. Spatial distribution of the rate of defoliation was always more heterogeneous than that of M_pre. The correlation coefficient …

Relationships Between Spatial Distributions Of Herbage Mass And Utilization In A Pasture Progressively Grazed By Cattle, Masahiko Hirata, S. Ogura

IGC Proceedings (1977-2023)

To obtain some information about the mechanisms behind the spatially heterogeneous grazing of a pasture by large herbivores, the relationships between the spatial distributions of herbage mass, herbage consumption and ingestive behavior were investigated on a bahiagrass (Paspalum notatum Flügge) pasture during a 6-day grazing period with cattle. The animals almost always consumed more herbage from locations with higher pre-grazing herbage masses, which was attributed to greater bite weights. It was suggested that the high spatial heterogeneity in the rate of defoliation was caused mainly by the spatial heterogeneity in both the bite weight and the number of visits …

Protein Prenylation In The Moss Physcomitrium Patens, Zayna Qaissi, Anam F. Ahmed, Mark P. Running, Katherine Vo. Brown

The Cardinal Edge

TITLE

Protein Prenylation in the moss Physcomitrium patens

AUTHORS

Zayna H. Qaissi*, Anam F. Ahmed*, Katherine V. Brown, Mark P. Running**

*Co-presenters

**Faculty Mentor

Protein prenylation is the addition of a 15 or 20 carbon lipid to a cysteine near carboxyl terminus of target proteins. Prentlyation increases hydrophobicity, which facilitates membrane associations and protein-protein interaction. Protein prenylation is generally conserved among eukaryotes, and mutations in genes that carry out prenylation are lethal in animals and yeast. In plants prenylation mutations are not always lethal, but they do affect development, disease resistance, biofuel production, and drought response, among other processes of …

Adapting Tropical Forages To Low-Fertility Soils, Idupulapati M. Rao

IGC Proceedings (1977-2023)

Tropical forages growing in low-fertility acid soils usually increase the amount of dry matter partitioned to roots at the expense of shoot growth, but substantially different adaptive attributes to such soils have been found, both between and within species. By possessing the C₄ pathway of photosynthesis, grasses are more efficient than legumes in using N, Ca, and P, whereas legume roots are more efficient in extracting nutrients from low-fertility soils. Phosphorus uptake efficiency (mg of P uptake in shoot biomass per unit root length) of the legume Arachis pintoi is several times higher than that of the grass Brachiaria …

Adaptation Of Forage Species To Drought, D. J. Barker, J. R. Caradus

IGC Proceedings (1977-2023)

Variability in rainfall is the single greatest cause of variation in forage production for a given site. Current climate scenarios predict future annual rainfall to decrease at some geographic regions. The intensity of future rainfall is also predicted to increase at other regions, with the expectation of greater variability in soil moisture. The adaptation of forage species to drought is an issue that is likely to remain with us into the future.

Precise definitions are critical to water relations work, and imprecise use of terms has complicated comparisons of some studies on plant response to drought. Drought is a purely …

Spittlebugs: Bioecology, Host Plant Resistance And Advances In Ipm, José R. Valério, C. Cardona, D. C. Peck, G. Sotelo

IGC Proceedings (1977-2023)

Several species and genera of spittlebugs (Homoptera: Cercopidae) are economic pests of grasses in tropical America. These insects compete with grazing animals by reducing forage availability and quality. They may cause serious losses on millions of hectares of improved pastures based on cultivars of several species of Brachiaria (signal grasses). Except for the cultivar Marandu, most of the available commercial cultivars of Brachiaria are susceptible to spittlebugs. In spite of their economic importance, much research need to be done yet. Such insect-plant system encompasses a diverse group of spittlebug species, a diverse group of forage grass species, which are under …

Grassland Plant Diseases: Management And Control, S. Chakraborty

IGC Proceedings (1977-2023)

Grasslands cover 40% of the earth’s surface and support animal-based industries; maintain soil cover, watersheds and biodiversity; sequester atmospheric carbon for storage in the soil; and provide tourism and leisure income. Diseases continue to decrease herbage and seed yield and reduce nutritive value and palatability of grasslands to impact on animal health and productivity but realistic data on loss are hard to find. Although principles of disease management remain the same, strategies used in crop protection can not be directly applied to grasslands due to differences in heterogeneity, population size, density and spatial distribution and population continuity. Low per hectare …

Soil Carbon And Nitrogen Dynamics After Pasture Installation In The Amazon Region, C. C. Cerri, M. Bernoux, C. E. P. Cerri

IGC Proceedings (1977-2023)

The objective of this paper is to present the soil carbon (C) and nitrogen (N) dynamics in a chronosequence made of a forest and pastures of different ages established in a Oxisol in the Western Brazilian Amazon Basin. The results of soil Carbon and Nitrogen stocks and gases fluxes were discussed. Stable ¹³C isotopic technique was used to calculate for a determinate age of pasture installation, the proportion of soil C remaining from the forest system and the proportion of soil C introduced by the grasses of the pasture system. The C lost from the original pool under the …

Micronutrients In Grassland Production, U. C. Gupta, F. A. Monteiro, J. C. Werner

IGC Proceedings (1977-2023)

Micronutrients, also known as trace minerals, which chiefly include boron (B), molybdenum (Mo), copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe), are required in extremely small quantities by crops and livestock. Their name, however, is not meant to imply their role is minor. Their lack, e.g., can cause serious crop production problems in forages and health disorders in livestock. This presentation includes the response of forage legumes and grasses to micronutrients, their deficiency and sufficiency levels in forages and their sufficiency levels in livestock. Forage legumes are more responsive to micronutrients, particularly B and Mo, than grasses. There are …

Pasture Seed Production Technology In Brazil, Ronaldo Pereira De Andrade

IGC Proceedings (1977-2023)

Efficient and low cost production systems, which rely on the use of cultivated pastures, are the basis of beef and milk production in Brazil. The success of these pasture-based systems would not be possible without the support of an aggressive and dynamic pasture seed production sector to supply the internal demand, which is estimated to be around 90000 tons per year. The market is dominated by grass species and among them, Brachiaria. brizantha cv. Marandu accounts for more than 80% of the total seed volume in the market. Seed production systems in Brazil vary from highly specialized to opportunistic accordingly …

Meeting The Changing Need For Herbage Seed Quality Assurance In The 21st Century, D. S. Loch, K. G. Boyce

IGC Proceedings (1977-2023)

Quality assurance is a key element in the herbage seed supply chain. The measurement and management of seed quality is discussed in terms of its four main parameters - genetic, physical, vital, and phytosanitary quality - which provide information on the expected performance of herbage seed when sown in the field. During the past century, seed quality management systems have evolved in response to national and regional differences in economic development, crop characteristics, merit testing, and the demands of international trade. The pace of change in the management of seed quality assurance has intensified in developed countries over the past …

Novel Grasses And Legumes Germplam: Advances And Perspectives For Tropical Zones, E. A. Pizarro

IGC Proceedings (1977-2023)

It has been the aim, in the present article, to bring together as much as possible scientific evidence and experience in new available germplasm for tropical zones.

The economic importance of the Brachiaria, Paspalum and Pennisetum grasses is well established. New germplasm has become available since 1980. This paper reviews evaluations of Brachiaria accessions in humid lowlands and savannas of tropical America. The selection criteria need to be revised. Also, it is necessary to expose the new material as early as possible to farmers in order to select new germplasm with high chances of adoption.

Within the genus Paspalum …