Meiotic chromosomes and nucleolar behavior in testicular cells of the grassland spittlebugs Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana (Hemiptera, Auchenorrhyncha)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Quality of the forage apparently consumed by beef calves in natural grassland under fertilization and oversown with cool season forage species

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thermoregulatory responses of Alpine goats during thermal stress

Eight non-lactating Alpine goats, averaging 57kg, were paired according to weight and assigned randomly to 2 groups of 4 animals, control (CG) and treatment (TG) with feed and water ad libitum. An adjustment period of 7 days with all animals at thermoneutral conditions was followed by a 28-day period when TG was exposed to air temperatures averaging 35.0 degrees C, from 0800 to 1700h, including simulated solar radiation, and thermoneutral conditions from 2700 to 0800h. CG remained under thermoneutral conditions. Respiratory frequency was greater, tidal volume lower, and respiratory minute volume greater for TG than CG (176 vs 30 breaths/min, P<.001, 105 vs 293ml, P<.01; 18.4 vs 9.21, P<.05). Respiratory evaporation and sweating rate as well as rectal and skin temperatures were greater for TG than CG (14.59 vs 6.32 kcal h(-1), P<.01; 43.97 vs.00 g m(-2) h(-1), P<.001; 40.0 vs 38.9 degrees C, P<.001; 39.3 vs 35.8 degrees C, P<.01). There was no difference between groups for hematocrit and feed intake, but water consumption was greater for stressed goats than control ones (28.3 vs 29.7%; 1.44 vs 1.49 kg/day; 3.07 vs 1.26 I/day, P<.05), Final body weights of both groups were similar to initial ones. It was concluded that non-lactating goats tolerated well a 35 degrees C day temperature which is 5 degrees C above the upper critical temperature, with a black-globe temperature of 39.1 degrees C and a Botsball temperature of 28.3 degrees C, though a certain degree of hyperthermia may occur, as long as thermoneutral conditions have prevailed during the night.

Mitigation of N2O emissions from grassland by nitrification inhibitor and actilith F2 applied with fertilizer and cattle slurry

Nitrous oxide (N2O) is involved in both ozone destruction and global warming. In agricultural soils it is produced by nitrification and denitrification mainly after fertilization. Nitrification inhibitors have been proposed as one of the management tools for the reduction of the potential hazards of fertilizer-derived N2O. Addition of nitrification inhibitors to fertilizers maintains soil N in ammonium form, thereby gaseous N losses by nitrification and denitrification are less likely to occur and there is increased N utilization by the sward. We present a study aimed to evaluate the effectiveness of the nitrification inhibitor dicyandiamide (DCD) and of the slurry additive Actilith F2 on N2O emissions following application of calcium ammonium nitrate or cattle slurry to a mixed clover/ryegrass sward in the Basque Country. The results indicate that large differences in N2O emission occur depending on fertilizer type and the presence or absence of a nitrification inhibitor. There is considerable scope for immediate reduction of emissions by applying DCD with calcium ammonium nitrate or cattle slurry. DCD, applied at 25 kg ha-1, reduced the amount of N lost as N2O by 60% and 42% when applied with cattle slurry and calcium ammonium nitrate, respectively. Actilith F2 did not reduce N2O emissions and it produced a long lasting mineralization of previously immobilized added N.

Snake assemblage in a disturbed grassland environment in Rio Grande do Sul State, southern Brazil: Population fluctuations of Liophis poecilogyrus and Pseudablabes agassizii

A mark-recapture study of a snake assemblage using pitfall traps with drift fences was carried out in a disturbed grassland environment (e.g. cattle breeding and cultivations), located in the Pampa Biome, in the central region of the Rio Grande do Sul State, southern Brazil. From February 2001 to January 2004 we caught 272 snakes belonging to 20 species from the following families: Elapidae (5%), Viperidae (10%), and Colubridae (85%). The assemblage had a unimodal seasonal pattern of activity, and the highest number of captures occurred between September and May. There was a positive and significant correlation between the number of captures and monthly minimum and maximum average temperatures. Recruitment was observed from January to April. During the study, the area was affected by human activities, which altered the community structure: Pseudablabes agassizii was negatively affected by habitat devastation while Liophis poecilogyrus took advantage of this. Our results reinforced the impression that Pseudablabes agassizii is a habitat specialist species. We extend the understanding of the susceptibility of this species to environmental destruction in open natural environments of South America, and propose its use as a potential bio-indicator of the Pampa biome. We also discuss the importance of conservation strategies for snakes in grasslands of southern Brazil. © Finnish Zoological and Botanical Publishing Board 2007.

Feedbacks between vegetation and disturbance processes promote long-term persistence of forest-grassland mosaics in south Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)