Influence of nursery conditions on germination and initial development of pejibaye (Bactris gasipaes)

Pejibaye (Bactris gasipaes) seeds were genninated in trays covered with transparent pIastic. Vermiculite or composted shredded pine Ieaves were used as substrate. The trays were kept in a glasshouse under natural light (treatment GL) or 60% shade (treatment GS), or in an open-side pIastic greenhouse under natural light (treatment PL). The total emergence percentage and the emergence rate were significantIy higher for treatment GS, 45.5% and 8.62 x 10-3 day-1 respectively, than for GL (17.5% and 5.41 x 10-3 day-l) and PL (16.5% and 5.21 x 10-3 day-l). There was no difference between substrates. Higher emergence percentage in treatment GS was caused by more adequate substrate temperature (l6.5°C to 31.9°C). In trealment GL the substrate temperature varied between 17.rC and 38.5°C, achieving the highest average (28°C) and the Iargest thermal amplitude (20.8°C). Temperature of treatment PL varied between 12.6°C and 27.6°C, with the lowest average (20.l°C). Visual observation suggested that shade may favours the initial development of seedlings. Substrate temperature might be regarded as a better indicative of environmentaI conditions for gennination than the air temperature. Shade inside the glasshouse protected gennination substrate from extreme temperatures.Semillas de pejibaye (Bactris gasipaes) fueron germinadas en bandejas con cubiertas plásticas transparentes, Dos tipos de sustrato (vermiculita y hojas de pino molidas y parcialmente humificadas), y tres tipos de cobertura (en un invernadero de vidrio con luz directa (OL), o 60% de sombra (OS) y bajo cubierta plástica con luz directa (PL) fueron estudiados, El tipo de sustrato no afectó significativamente el por· centaje o la tasa de germinaci6n de las semillas de pejibaye, Los mayores porcentajes y tasas de germinación se observaron en el tratamiento OS (45,5% y 8,62 x 10-3 dia-l respectivamente), En el tratamiento OL el porcentaje y la tasa de germinaci6n fueron 17,5% y 5.41 x 10-3 dia-l , y en el tratamiento PL 16.5% Y 5.21 x 10-3 dia-l , respectivamente, El mejor comportamiento del pejibaye en el tratamiento OS fue atribuido a una más adecuada temperatura de germinación, En el tratamiento OS las temperaturas del sustrato se mantuvieron entre l6,SOC y 31.9°C mientras que en el tratamiento OL alcanzaron valores más extremos (17, 7°C y 38,5°C). En el tratamiento PL la temperatura del sustrato varió entre los 12,6°C y los 27,6°C, Observación visual sugire que el sombreo puede favorecer el desarollo inicial de las plántulas de pejibaye, Más que la temperatura del aire, la temperatura del substrato fue la principal determinante de la germinación del pejibaye, El sombreo proteji6 el sustrato de germinaci6n de alcanzar temperaturas extremas

The presence of black vultures at the calving sites and its effects on cows' and calves' behaviour immediately following parturition

Black vultures (Coragyps atratus) are often present near calving sites, and under this situation they may play a positive role by removing animal carcasses and afterbirth or a negative role by attacking neonate calves or disturbing cow-calf behaviours following parturition. Cow-calf behaviour was recorded over a 4-year study period from a total of 300 births involving 200 Nellore, 54 Guzerat, 20 Gyr and 26 Caracu cows. The calving site in relation to the location of the herd, considering cow-calf pairs within, close or distant to the herd, the presence of vultures and the behaviour of cows and calves were recorded instantaneously, at 5-min interval. On average, vultures were present at 80% of the calving sites. The frequency of vultures present at calving sites was dependent on the years for the Nellore herd, increasing from 1998 to 2003. When vultures were present, the time that the cow was in contact with its calf decreased, and the percentage of time that the cow was standing still increased. Vultures were observed pecking cows and their neonates during 34.1% of all recordings. However, in only two cases pecking injuries were actually observed on calves that were noted to be very weak. The preliminary results suggest that although black vultures cannot be characterized as a predator of neonate calves, they sometimes attack neonate calves and their presence near the calving sites alter the behaviours of cows and calves. © 2012 The Animal Consortium