Agronomy and Crop Sciences Commons^™

Semiarid Grassland And Winter Cereals For Lamb Production In Northeast Patagonia, Argentina, D. P. Miñón, G. G. Durañona, J. C. García Vinent, H. D. Giorgetti, G. D. Rodríguez

IGC Proceedings (1977-2023)

In northeastern Patagonia where grain crops often led to harvest failure, low yields and a high drought risk, a lamb production system was established. On a 10 years old agriculture wheat cropping was interrupted in 1996, allowing re-vegetation through exclusion of grazing. Natural grassland recovered, prevailing the species Stipa tenuis, Piptochaetium napostaense, Stipa ambigua. Part of the plot was sown to wheat grass (Thinopyrum ponticum). In 1999, to improve sheep feeding, oat (Avena sativa) and barley (Hordeum vulgare) were sown for grazing during winter-spring season. In this system Corriedale sheep, Texel x australian …

Nutritive Quality Of Tropical Grasses Sown Under A Pine Plantation, D. Gutmanis, Antonio João Lourenço, V. B. G. Alcantara, Maria T. Colozza

IGC Proceedings (1977-2023)

A trial was conducted in Brazil to evaluate the nutritive quality of 6 tropical grasses: tanzania (Panicum maximum cv. Tanzania), green-panic (P. maximum var. Trichoglume), aruana (P. maximum cv. Aruana), brizanta (Brachiaria brizantha), humidicola (B. humidicola) and tifton-85 (Cynodon dactylon cv. Tifton 85), planted under two different densities of pines (Pinus elliottis): 200 and 400 stems/ha, as well as in full sunlight. The results showed a significant increase in protein content and a significant decrease in NDF and cellulose contents as tree density increased. Comparing the values obtained under shading conditions …

Production And Mineral Composition Of Tropical Grasses Sown Under A Pine Plantation, D. Gutmanis, V. B. G. Alcantara, Maria T. Colozza, Antonio João Lourenço

IGC Proceedings (1977-2023)

A trial was conducted in Brazil to evaluate the performance of 6 tropical grasses: tanzania (Panicum maximum cv. Tanzania), green-panic (P. maximum var. Trichoglume), aruana (P. maximum cv. Aruana), brizanta (Brachiaria brizantha), humidicola (B. humidicola) and tifton-85 (Cynodon dactylon cv. Tifton 85), planted under two different densities of pines (Pinus elliottis): 200 and 400 stems/ha, as well as in the full sunlight. The results showed that the dry matter yield decreased as shading increased. The grasses tanzania and brizanta were the most tolerant to shading. Although N concentration increased with …

Dry Matter Production And Nutritive Value Of Alfalfa (Medicago Sativa L.) And Orchardgrass (Dactylis Glomerata L.) Under Different Light Regimes, A. C. Varella, P. L. Peri, R. J. Lucas, D. J. Moot, D. L. Mcneil

IGC Proceedings (1977-2023)

Spring and summer alfalfa dry matter and nitrogen production rates were greater than orchardgrass in open pasture and under three shade levels. Ten years old Pinus radiata allowed 60% light transmissivity. The addition of artificial shade resulted in 45% and 25% transmissivity. Orchardgrass pastures were nitrogen deficient and water stressed. In contrast, alfalfa was not stressed and it was more light responsive than orchardgrass. Differences in nutritive value were relatively small between species and between light regimes. Sheep liveweight gain on alfalfa was greater than on orchardgrass. Orchardgrass demonstrated shade tolerance, but alfalfa was more productive even at 25% transmissivity. …

Different Methods Of Artificial Shade For Agro-Silvipastoral Research, A. C. Varella, D. J. Moot, R. J. Lucas, D. L. Mcneil, P. L. Peri, K. M. Pollock

IGC Proceedings (1977-2023)

Artificial shading sources are used to simulate silvipastoral light environments and study the effect of shade on pasture. Different sources of shade may not imitate normal forest light environment. An experiment was conducted to examine the light environment and effect on pasture yield components of two artificial shading materials. Alfalfa (Medicago sativa L.) pasture was submitted to three light regimes: full sunlight (100% transmissivity); black shade cloth (40%) and wooden slats (45%).

The pattern of light exposure for plants differed under slats and shade cloth, but light intensity and quality were similar. Alfalfa dry matter (DM) yield and leaf …

Competition For Light In A Leucaena Leucocephala / Chloris Gayana Silvopastoral System, N. F. G. Rethman, J. P. Lindeque

IGC Proceedings (1977-2023)

The spatial variation in the vigour of Leucaena (Leucaena leucocephala cv. Cunningham) trees growing together with Rhodesgrass (Chloris gayana cv. Katambora) in an alley cropping system made it possible to assess the competitive effect for light. The height and especially lateral development of trees had a strong influence on light interception by the canopy, with radiation in the intercrop area being 49% lower where the trees were more vigorous. There was a corresponding (43%) decrease in grass production. These findings indicate that future studies should also include aspects such as espacement of trees, pruning of trees in the …

Optimizing Yield And Quality Of Orchardgrass Pasture In Temperate Silvipastoral Systems, P. L. Peri, R. J. Lucas, D. J. Moot, A. C. Varella, D. L. Mcneil

IGC Proceedings (1977-2023)

The objective of this study was to provide grazing management recommendations for a silvipastoral system by determining the effects of shade and nitrogen (N) on the pattern of dry matter accumulation and nutritive value of orchardgrass (Dactylis glomerata) in a subhumid temperate environment. Orchardgrass in open pasture (100% transmittance) and under 10 year old Pinus radiata tree shade (60% transmittance) at 200 stems/ha was used as the main plot and nitrogen (0 and 300 kg N/ha as synthetic urine) was the subplot factor. Dry matter (DM) production of orchardgrass in the first 60-day spring rotation was similar in …

Herbage Characteristics As Affected By The Canopies Of Dominant Trees In A Savanna Of Southern Mozambique, James P. Muir, A. Alage, Inacio C. Maposse

IGC Proceedings (1977-2023)

This study surveyed the species composition, forage yield and forage nitrogen concentration of the herbaceous layer 50, 100 and 200% of the canopy radius from the trunks of many-stemmed false thorn, knob thorn, scented thorn and marula trees in a southern Mozambican savanna. Tree species did not affect herbaceous DM yield or species diversity. Neither direction nor distance from the tree trunk affected DM or specific diversity. Crude protein percentages were 15% higher for legumes and 9% higher for grasses at 50% canopy than at 200% canopy. Grasses under the marulas, the only non-legume tree in the study, had 18% …

Selecting New Brachiaria For Brazilian Pastures, Cacilda B. Do Valle, Valéria P. B. Euclides, Manuel C. M. Macedo, José R. Valério, S. Calixto

IGC Proceedings (1977-2023)

Brazilian beef production relies heavily on cultivated pastures, of which about 80% are planted mainly to two Brachiaria cultivars. The narrowness of diversity associated with reproduction by apomixis of most plants in this genus prompted an intense search for new cultivars amongst recently collected and introduced ecotypes from Africa. This paper reports results for a three-year evaluation of 21 pre-selected ecotypes in two typical Cerrado ecosystems. Plots, replicated four times, were seeded in rows and cut every 6 weeks during the rainy season followed by a cut in the middle and one at the end of the dry season. Significant …

Diversity And Composition Of Plant Species In The Geita Gold Mining Catchment Area, Tanzania, Mariam G. Mgendi, Mkabwa Lawrence Manoko, William J.S. Mwegoha

Journal of Humanities and Social Sciences

A study on the diversity of plant species is of vital importance for the conservation of natural ecosystems that are increasingly being threatened by various anthropogenic activities. Greater diversity makes ecosystems healthier and resilient to stress, thus providing its services on which humans depend. This study aimed to assess the health of the ecosystem around the Geita Gold Mine (GGM) based on the diversity and composition of plant species. Two transects with a total of 14 sampling sites were established where the number of plant species were systematically recorded using nested quadrats. The diversity of species was determined using species …

Supplmentary Feeding And Management Strategies To Overcome Drought Situations On Three High Producing New Zealand Seasonal Dairy Farms, S. H. Benson, P. N. P. Matthews

IGC Proceedings (1977-2023)

This paper investigates the outcomes of the management strategies to overcome dry summer conditions on three New Zealand seasonal supply dairy farms where the summer management philosophy is towards production rather than survival aimed at giving the farmer control rather than accepting the unreliable production outcomes often achieved. Actual data collected from the case farms as part of a large on-farm monitoring programme was used to model the dry 1998/99 season. This was compared with simulated models for an average season to estimate milksolids responses (g milksolids (MS)/kg DM) and net returns (cents/kg DM) to the additional feeds used. In …

A Simulation Model To Evaluate Supplementation Of Tropical Forage Diets For Dairy Cows, A. G. Assis, O. F. Campos, J. Dijkstra, J. France

IGC Proceedings (1977-2023)

A dynamic model of digestion kinetics has been built to evaluate dairy cattle diets based on tropical feeds and to estimate the potential of tropical forages for milk production associated with available supplements. Results of simulation were very consistent showing that grazed elephant grass alone can supply nutrients for cow maintenance and yield of 7.10 kg milk/day. Nevertheless, to produce 25 kg/day on grazed elephant grass, a dairy cow would need to be supplemented with 5.85 kg/day of a mixture of cottonseed meal (50%) plus ground maize (50%), while on maize silage it would be necessary 4.15 kg of the …

Performance Of Beef Heifers Of Various Genetic Groups, Supplemented Or Not, In Coastcross Pastures, Armando De A. Rodrigues, Geraldo M. Da Cruz, Rogério T. Barbosa, Maurício M. De Alencar, Luciano De A. Corrêa, Gilson P. De Oliveira

IGC Proceedings (1977-2023)

The objective of this study was to determine whether the performance of beef heifers of different genetic groups was affected by breed x nutritional environment interactions. Sixty four weaned heifers, 16 per genetic group: ½ Angus + ½ Nellore (AN), ½ Canchim + ½ Nellore (CN), ½ Simmental + ½ Nellore (SN) and pure Nellore (NE), were used with or without 3.0 kg of concentrate.animal^-1 .day^-1 in a fertilized coastcross pasture under rotational grazing system. There were effects of genetic group and supplementation (P< 0.05) on the weight and age at first estrus, but there was no interaction between them. In a rotational grazing system with 4000 kg of available dry matter per hectare with 13% of crude protein, the crossbred AN, supplemented or not, was more precocious (111 days) than Nellore heifers, showing the first estrus at 356 days of age and 324 kg of live weight.

Animal Performance On Brachiaria Brizantha Alone Or Supplemented With Concentrate Or Protein Bank Of Leucaena Leucocephala, Antonio João Lourenço, Paulo Roberto Leme, Marcelo De Queiroz Manella

IGC Proceedings (1977-2023)

The experiment was carried out at the Instituto Zootecnia, Nova Odessa, SP, Brasil, from June/1998 to March/2000 (634 days), and the liveweight gains of Nelore steers was evaluated, per animal and per area, on Brachiaria brizantha alone (T₁), B. brizantha + Leucaena leucocephala (T₂), B. brizantha + supplemental feeding during the dry season (T₃) and B. brizantha + supplemental feeding during the dry and rainy season (T₄). The experimental design was a randomized block, with four replications each one composed by three paddocks rotationally grazed by Nelore steers. Mean weight gain per …

Influence Of Surfactant-Humectant Adjuvants On Physical Properties, Droplet Size, And Efficacy Of Glufosinate Formulations, Estefania G. Polli, Guilherme S. Alves, Jesaelen Gizotti De Moraes, Greg Robert Kruger

Department of Agronomy and Horticulture: Faculty Publications

Glufosinate efficacy is inconsistent among weed species and under environmental conditions that favor rapid droplet drying. Surfactant-humectant adjuvants could maximize glufosinate efficacy by increasing wetting and penetration into the leaf surface while decreasing evaporation rate (ER). However, there is a lack of information in the literature about the interaction of surfactant-humectants adjuvants with glufosinate. The objective of this study was to investigate the influence of surfactanthumectant adjuvants on the physical properties, droplet size, and efficacy of two glufosinate formulations. Laboratory, greenhouse, and field studies were conducted at the Pesticide Application Technology Laboratory of the University of Nebraska- Lincoln. Treatment design …

Urine Calcium But Not Plasma Calcium Or Urine Hydroxyproline Is Increased By A Systemic Acidosis In The Dairy Cow, J. R. Roche, Dawn E. Dalley, F. O’Mara, E. S. Kolver

IGC Proceedings (1977-2023)

Eight non-lactating, pregnant Holstein-Friesian cows were allocated to two treatments and individually offered diets differing in dietary cation-anion difference. Decreasing the dietary cation-anion difference reduced the urine pH within hours of anionic salt supplementation. Plasma calcium concentration was unaffected by dietary cation-anion difference but urine calcium concentration was significantly increased within 10 days of including anionic salts in the diet. Faecal calcium concentration was significantly reduced, indicating increased calcium absorption. Dietary calcium concentration or dietary cationanion difference did not significantly affect urinary hydroxyproline.

Dry Matter Intake Of Periparturient Cows On A Fresh Pasture/Pasture-Hay Diet, J. R. Roche, Dawn E. Dalley, F. O’Mara, E. S. Kolver

IGC Proceedings (1977-2023)

Reports of the depression in dry matter intake in the periparturient period have been inconsistent and little dry matter intake data is available for an all-forage diet prior to calving. Data to examine intake depression prior to calving was obtained from two experiments. In experiment 1, sixteen non-lactating, periparturient cows ate 1.3% of pre-calving body weight of grass-hay and freshly cut grass for two weeks pre-calving (restricted). Experiment 2 comprised thiry-six cows that ate 1.6% of pre-calving body weight of grass-hay and freshly cut grass for the final two weeks of pregnancy (ad libitum). Individual dry matter intakes …

Effectt Of Supplements On Forage Degradability Of Brachiaria Brizantha Cv. Marandu Grazed By Steers, J. R. A. Pereira, Ricardo A. Reis, L. R. De A. Rodrigues, D. Freitas

IGC Proceedings (1977-2023)

The supplementation effect was evaluated using crossbred rumen-fistulated steers maintained in a Brachiaria brizantha cv. marandu pasture. The animals received energy supplementation (corn-COR); low degradability protein supplementation (corn gluten-GLU); and high degradability protein supplementation (soybean-SBM) at two levels N1 (± 0.5 kg/an/day) and N2 (± 1.5 kg/an/day); or no supplementation (Control). The factorial (3x2), plus the control, was studied according to complete randomized block design with three replications. The supplementation did not affect (P> 0.05) the potential degradability (POD), the effective degradability (EFD), and the degradation rates (DR) of the forage (extrusa). The GLU supplementation provided higher (P< 0.05) EFD of the NIDN fraction than the SBM, and both did not differ (P> 0.05) of …

Use Of Supplements For Increasing Performances Of Suckling Martinik Ewes When Fed Tropical Forages, E. O. Jimenez, G. Alexandre, H. Archimède, P. Despois, M. Jean-Bart, C. Jacquet

IGC Proceedings (1977-2023)

Experiments have been carried out to determine the effects of supplementation upon milk production and growing performances with hair sheep Martinik ewes weighing 48 ± 4 kg liveweight (LW). In a first trial, 6 single bearing ewes (group GS) were offered individually a daily 0.5 kg of commercial pellets. They were compared to the control group (GN; 6 ewes) with no supplement during 10 weeks of lactation. Basal diet was chopped Digitaria decumbens grass ad libitum. In a second trial, level of supplementation was adapted to the ewes’ litter size: 6 twins bearing ewes (TW) and 6 single (SI). …

Performance Of Dairy Goats To Alfalfa Silage Based Diets Supplemented With Different Sources Of Carbohydrates, J. L. Danelón, P. Allocati, M. Wawrzkiewicz, S. Bedogne, E. Ceballos, M. D’Alessio, L. Barletta, C. Colatto, D. Victoria

IGC Proceedings (1977-2023)

Lactating Saanen dairy goats fed alfalfa silage (AS) based diets in four 4x4 Latin Square designed experiment were studied for the effects of supplementation of three different type of carbohydrates (wheat grain, (W); sorghum grain, (SG) and dry citrus pulp, (DCP)) on milk yield, composition and chewing activities. Sixteen does (45± 10 DIM and 2.016 kg ± 0.48 4% FCM) housed indoors in individual pens in a four 4x4 experiment were fed four diets 1) AS (33.9%DM, 19.9%CP, 44.01%NDF); 2) ASW (52.4%DM, 19.8%CP, 33.7%NDF); 3) ASSG (50.9%DM, 17.9%CP, 37%NDF), 4) ASDCP (52.5%DM, 16.12%CP, 39.1%NDF) with forage-to-concentrate ratios of 100:0 or …