Weed Science Commons^™

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

IGC Proceedings (1977-2023)

Growth of Holstein heifers was studied for 1987 grazing season to evaluate pasture-drylot systems for raising dairy replacements. Orchardgrass (Dactylis glomerata L), tall fescue (Festuca arundinacea Schreb), bluegrass (Poa pratensis L) and white (Trifolium repens L) and red clover (Trifolium pratense, L) were the principal components of the grass-legume mixture in six paddocks of 1.5 ha each. Carrying capacity was estimated at six animals/ha (3.1 animal units) and excess forage was harvested as hay to control forage growth and quality. Grazing days were 140 days. None or 2.0 kg/d …

Intake And Growth Of Steers Offered Different Allowances Of Autumn Grass And Concentrates, Edward G. O’Riordan, P. French, Padraig O’Kiely, A. P. Moloney

IGC Proceedings (1977-2023)

The aim of this experiment was to quantify the relationship between autumn grass supply and concentrate supplementation level on grass intake and animal performance. One hundred and ten continental steers (567kg) were assigned to ten treatments in a three grass allowances: (6, 12 and 18kg dry matter (DM) per head daily) by three concentrate levels: (0, 2.5 and 5kg/head/daily) factorial design with a positive control group offered concentrates ad-libitum. Grass allowance was offered daily and concentrates were fed individually. The experiment began on August 22 and all animals were slaughtered after a mean experimental period of 95 days. Grass …

Fatty Acid Composition And Eating Quality Of Muscle From Steers Offered Grazed Grass, Grass Silage Or Concentrate-Based Diets, A. P. Moloney, P. French

IGC Proceedings (1977-2023)

The effects of grazed grass, grass silage or concentrates on the eating quality and fatty acid composition of intra-muscular fat of steers fed to achieve similar carcass growth rates were investigated. Fifty steers were assigned to one of five dietary treatments. The experimental rations offered daily for 85 days pre-slaughter were (a) grass silage plus 4 kg concentrate, (b) 8 kg concentrate plus 1 kg hay, (c) 6 kg grazed grass dry matter (DM) plus 5 kg concentrate, (d) 12 kg grazed grass DM plus 2.5 kg concentrate or (e) 22 kg grazed grass DM. Decreasing the proportion of concentrate …

Supplementation Of Lactating Cows Grazing Stargrass (Cynodon Nlenfuensis Var. Nlenfuensis) With Conjugated Linoleic Acid: Effects On Persistency And Estimated Net Energy Balance, S. R. Medeiros, D. E. Oliveira, L. J. M. Aroeira, M. Mcguire, D. P. D. Lanna

IGC Proceedings (1977-2023)

Thirty crossbread cows grazed stargrass (Cynodon nlenfuensis var. nlenfuensis) receiving 4kg/d of a supplement formulated to provide 115% of metabolizable protein requirements from the 4^th to the 11^th week of lactation. The cows received either 150g/head/day of Megalac (Control) or 150g/head/day of a Ca-protected conjugated linoleic acid (CLA, Church & Dwight). Residual effects of treatment were evaluated in weeks 12^th and 13^th. Milk production increased in CLA treated cows (P< 0.05). CLA decreased milk fat content (P< 0.0001) and yield (P< 0.01). Protected CLA increased protein content (P< 0.01) and yield (P< 0.01). The CLA residual effect on milk fat ends within one week after withdrawal but the benefits on milk yield and total solids production continued, due to the increased persistency. The estimated energy balance and intake were not greatly affected by treatment, as treated cows had higher milk volume and had higher protein productions.

Use Of Supplements For Maintenance Of Nelore Bullocks In Brachiaria Decumbens, During The Dry Season In Acre, Brazilian Amazon, J. C. Carneiro, Judson F. Valentim, L. A. R. Valle

IGC Proceedings (1977-2023)

This study had the objective of evaluating animal performance and net economic returns of Nelore bullocks receiving: 1) mineral mixture (MM), 2) mineral mixture + urea (MMU), and 3) multiple supplement (MS), during the dry season of 1999 in Acre, Brazilian Amazon. The animals were maintained in pastures of Brachiaria decumbens, and liveweight gains, forage availability and chemical composition were assessed during the experimental period. Liveweight gains of 0.58, 0.65 and 0.60 kg/day, respectively, for MM, MMU and MS, were not different (P> 0.05). The use of MMU provided additional net economic return of 10.8% in comparison with the …

Roots And Potatoes As Supplements To An Alfalfa – Grass Diet To Dairy Cows, T. Eriksson, P. Ciszuk, E. Burstedt

IGC Proceedings (1977-2023)

Fourteen multiparous dairy cows were used in 3 x 3 change-over experiment designed to study effects of replacing barley by roots and potatoes in diets based on leguminous forage on feed intake, milk production and utilisation of feed nitrogen. The cows received a mixture of alfalfa (Medicago L.) and grass silage ad libitum and an isoenergetic quantity of a supplement based on either barley and potatoes (Ba/P), fodder beets (Beta vulgaris L.) and potatoes (Be/P) or barley (Ba). The grass in grass silage was dominated by timothy (Phleum pratense L.). Total DM intake as well as yield …

Agronomic Evaluation Of Forage Grasses Under Mature Rubber Plantation, N. L. Costa, Valdinei T. Paulino, A. C. M. Igreja, C. R. Townsend, J. A. Magalhães, R. G. De A Pereira, T. S. Paulino

IGC Proceedings (1977-2023)

The agronomic performance of seven forage grasses, under a mature rubber plantation, was assessed in a cutting trial carried out at Porto Velho, Rondônia. During the rainy season, the higher dry matter yields were obtained with B. brizantha, P. atratum BRA-9610 and B. humidicola. During the dry season, the grasses more productive were B. brizantha and P. atratum BRA-9610. In both seasons, magnesium and potassium contents did not vary among grasses. During the rainy season, the higher nitrogen and phosphorus contents were obtained with P. regnelli BRA-0159 and, P. guenoarum BRA-3824 and B. humidicola, respectively, while P. atratum …

Constraints And Opportunities For Development Of Grasslands In Urban Areas Of The Niayes Zone In Senegal, S. T. Fall, I. Cissé

IGC Proceedings (1977-2023)

A survey was carried out in urban areas of the Niayes zone in Senegal to explore grasslands development in agropastoral systems around towns. Rapid rural appraisal and farms multiple visits were done to describe the forage cropping system, identify constraints and opportunities of developing grasslands in urban areas. In Niayes urban areas, forage production system is being developed based on the cropping of several grass and tree species. Only a minority of farmers is involved in that activity. Level of grass production is rather low. Weak development of grasslands is observed. Main reasons are: farmer poor willingness to crop for …

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 …

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.