Duilio Guerra Bandinelli

Comportamento ingestivo de novilhos de corte em pastagem de aveia preta e azevém com níveis distintos de folhas verdes

The objective of this trial was to evaluate how two levels of green leaves biomass, represented by 350 and 600kg ha-1 of green leaves dry matter (GLDM) affected beef steers behaviour and its bite rate. Evaluations of ingestive behaviour were performed with focal animals observed visually on two periods of 24 hours, with beginning and end at 01 pm, during pasture growth season, at 08/16-17 and 09/24-25/2002. Three trained observers were used for each turn of six hours, one for each two contiguous paddocks (where three focal animals grazed). At 10 minutes intervals, grazing time, rumination activities and rest were registered and estimated the bite rate, as the number of apprehension bites per minute. The lower dry matter percentage existing in the pasture during the first evaluation was responsible for the higher grazing time, when comparing the periods. In the first evaluation, the activity complementary to grazing was rumination and there was not differences for rest time. The lower biomass treatment induced the steers to take more bites as a way of optimizing forage consumption.

Variáveis morfogênicas de Andropogon lateralis Nees submetido a níveis de nitrogênio nas quatro estações do ano

Este trabalho foi realizado com o objetivo de avaliar a resposta morfogenica de Andropogon lateralis ao uso de diferentes niveis de nitrogenio, sob a forma de ureia. Foram utilizadas plantas em canteiros com afilhos marcados para se monitorar as variaveis em estudo. Em cada estacao do ano, afilhos foram marcados e aplicados os tratamentos: 0, 100, 200 e 400kg/ha de N. Foram avaliadas taxas de: alongamento, aparecimento, senescencia, filocrono e comprimento de folhas expandidas. O tratamento com 200kg/ha de N apresentou as maiores taxas de alongamento e aparecimento de folhas (P£0,061) nas quatro estacoes do ano. As demais doses de N apresentaram respostas diferentes no decorrer das estacoes, com diferencas entre tratamentos nas estacoes. A senescencia foliar, nos tratamentos que receberam N, foi maior no outono e inverno, nao apresentando diferenca nas demais estacoes. O filocrono nao diferiu entre tratamentos, apenas sofrendo alternância de valores com as diferentes estacoes. O comprimento medio de folhas completamente expandidas foi superior no tratamento com 200kg/ha de N.

Effect of structure of a cool season pasture on grazing behaviour of beef steers

The effect of different pasture structures imposed by treatments of green leaf lamina biomass (GLLB) levels of 350 and 600 kg/ha of dry matter (MS), over animals grazing behaviour was evaluated in this experiment. The pasture was oat (Avena strigosa Schreb.) and Italian ryegrass (Lolium multiflorum Lam.). Animals activities were recorded in August and September, in 24 consecutive hours, by trained observers. In the hours of the day in which grazing were more intense, grazing stations remaining time, distance between feed stations and the frequency of remaining in each grazing site were recorded. Preference for sites located nearest to drinking points were found, in each paddock. Distances between feeding stations and time of remaining in these were similar for both treatments. The treatment with 350 kg/ha of DM of GLLB was not a biomass level that affect remaining time in grazing stations.

Composição florística de pastagem natural afetada por fontes de fósforo, calagem e introdução de espécies forrageiras de estação fria

Natural pastures of Rio Grande do Sul State, South of Brazil, have low forage productivity in the autumn-winter. An alternative to improve systems based on these pastures is introduction of winter forage species, fertilization and liming of soil. The present work had the objective of evaluating the effect of phosphorus sources, lime and introduction of winter forage species in the pasture botanical composition dynamics. The treatments used were: T1 - simple superphosphate + lime + winter forage species introduction; T2 - triple superphosphate + lime + winter forage species introduction; T3 - triple superphosphate + winter forage species introduction; T4 - Gafsa rock phosphate + winter forage species introduction; T5 - winter forage species introduction without phosphorus and lime; T6 - reference only with natural pasture. To evaluate the botanical composition dynamics, periodic botanical evaluations were done during twenty two months, using BOTANAL method. The results showed that treatments did not modify the botanical composition of natural pasture during the evaluation period.

Sistemas de alimentação para a recria de ovinos a pasto: avaliação do desempenho animal e características da forragem

Um experimento foi conduzido na Fundacao Estadual de Pesquisa Agropecuaria (FEPAGRO), em Sao Gabriel, Rio Grande do Sul (RS), com objetivo de avaliar o desempenho de cordeiras em recria, as caracteristicas da pastagem, a composicao quimica e a cinetica de degradacao nas alternativas: pastagem cultivada de milheto (Pennisetum americanum (L.) Leeke) (PCM), pastagem natural (PN) e pastagem natural melhorada (PNM), que constituiram os tratamentos. O periodo de pastejo foi de 29 de janeiro a 14 de abril de 2005, sendo este caracterizado por uma forte estiagem. A PNM apresentou valores medios de massa de forragem superiores aos demais tratamentos, pela grande quantidade de material morto de azevem presente na forragem disponivel. A PCM apresentou maior proporcao de folhas em relacao a PN e a PNM. A carga animal media de 914kg de PV ha-1 da PCM foi superior a de 261kg de PV ha-1 e de 467kg de PV ha-1 da PN e da PNM, respectivamente. O ganho medio diario (GMD) no tratamento PCM (0,151kg dia-1) foi superior ao da PN (0,053kg dia-1) e da PNM (0,058kg dia-1), proporcionando maior peso vivo final (36kg de PV.animal-1) e escore corporal final (3,7 unidades) na PCM. Foram observados maiores valores de proteina bruta e menores de FDA e FDN na PCM em relacao a PN e a PNM. O volume final de gas, a taxa de degradacao e o tempo de colonizacao refletiram com precisao a composicao quimica e os ganhos de peso observados, sendo melhores para a PCM.

Variáveis morfogênicas de milheto (Pennisetum americanum) mantido em duas alturas de pastejo

This work evaluated the morphogenic response of pearl millet (Pennisetum americanum) to two heights of pasture management. Marked tillers were used to check the variables being studied. Proposed treatments were average heights of 20-30 and 40-50cm. The variables evaluated were: phyllochron; average numbers of elongated leaves and of green leaves per tiller; appearance, defoliation, elongation and leaf senescence rates. The treatment with average height of 20-30cm presented greater senescence rate and greater number of elongating leaves, respectively, in the first and second periods of evaluation. In the treatment with height of 40-50cm a greater number of senescent leaves, greater final leaf length and phyllochron was observed, respectively in the first and second periods. The rate of leaf defoliation differed between treatments, being higher in the lower height of plants, in both periods. The rate of leaf appearance was higher in the second period in the lower height of plants, influenced by the lower height of the tiller in this period. The morphogenic responses can be assigned to changes in pasture structure imposed by the treatments. The use of a grazing height around 20-30cm maintained a higher proportion of leaves in the pasture.

Alternativa de manejo de pastagem hibernal: níveis de biomassa de lâmina foliar verde

Objetivou-se, com este trabalho, avaliar a producao animal e as variaveis inerentes a pastagem manejada com niveis de 350 e 600 kg/ha de biomassa de lâmina foliar verde (MSFV). Os tratamentos representaram massas de forragem de 617 e 1139 kg/ha de MS, na ordem anteriormente citada, ficando abaixo da recomendacao para a maximizacao do desempenho dos animais. Entre os tratamentos, nao foram encontradas diferencas nas medias das taxas de acumulo diario de forragem e de lâminas foliares verdes, na producao total de forragem, no ganho medio diario e na carga animal, bem como no ganho de peso vivo por hectare, que se manteve em torno de 430 kg/ha para os dois tratamentos. A oferta de forragem diferiu entre os tratamentos sendo, em media, 5,47 e 7,69 kg de MS/100 kg de peso vivo para 350 e 600 kg/ha de MSFV, respectivamente.

Recria de terneiros de corte em pastagem de estação fria sob níveis de biomassa de folhas verdes: economicidade e eficiência alimentar

The animal production, its cost and animal feeding efficiency are analyzed in this work. Treatments were levels of green leaf lamina biomass (GLLB), of 350 and 600kg ha-1 of dry matter (DM), in oat and Italian ryegrass pasture. Experimental animals were beef calves, from Charolais breed and its crosses with Nelore breed, with average initial age of nine months and 175kg of live weight. Average results of 103 days of pasture season indicates that animal and forage production were not affected by treatments. Total pasture production costs and the efficiency of transformation of forage in animal liveweight were similar in both GLLB levels. Treatment with 600kg ha-1 of GLLB presented the best economical results, with higher gross income and profit per hectare and lower cost per kg of liveweight produced.

Desempenho animal e produtividade de pastagens tropicais no noroeste do Rio Grande do Sul

Productivity of dwarf elephantgrass (Pennisetum purpureum Schum. cv. Mott) and tifton 85 (Cynodon dactylon x Cynodon nlemfuensis) pastures was evaluated under continuous grazing, in the Northwest area of Rio Grande do Sul. Twelve multiparous Holstein cows, at 100 days of lactation were evaluated and the put-and-take technique was used to regulate the stocking rate to maintain 4% of leaf lamina on offer. In the first year, dwarf elephantgrass and tifton 85 were different in leaf accumulation rates (31.2 vs 22.6kg/ha/day) and animal production (17.4 vs 20kg of milk/cow/day). In the second year, tifton 85 had higher leaf accumulation rates (38.8 vs 21.9kg/ha/day), stocking rate (2,157 vs 1,084kg of live weight/ha), and production per area (70 vs 41.3kg of milk/ha/day) than dwarf elephantgrass. Comparing the second to the first years, tifton 85 maintained 88% of stocking rate and 80% of production per area, while dwarf elephantgrass only 46% and 56%, respectively. Average individual production of 17kg of milk/cow/day indicates an unexplored potential of tropical grasses in dairy production systems, especially in the South of Brazil.