Adriano Rudi Maixner

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.

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.

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.