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2. For the first experiment, 4 groups of 15 birds (ISA Brown) were subjected to each of the experimental treatments (using three perches with angles of 0° (horizontal control), 30°, 45° or 60° between them). The birds were required to move upward between the perches for each treatment and then to move downward between the perches, as a second part of the experiment.
3. Birds moving up between the perches took significantly longer at 60° than at any other angle. No birds failed to complete the task.
4. For birds moving downward between the perches, the median time to complete the task increased significandy with angle. Furthermore, the number of birds failing to complete the task increased with angle.
5. A second experiment was conducted to test whether the vertical or horizontal component of distance affected birds’ ability to negotiate perches separated by different angles.
6. For the second experiment 4 groups of 10 Lohmann Brown laying hens were subjected to each of the following treatments: two horizontal perches separated by 30° or 60° and either direcdy, horizontally or vertically separated by a set distance of 50 cm. Birds were required to move both up and down between perches.
7. Birds negotiated horizontally‐separated perches more successfully at 30° than at 60°. However, when the vertical distance between the perches was 50 cm there was no significant difference in the ability of birds to move downward at 30° or 60°. For birds moving upward, 60° was easier to negotiate dian 30°.
8. The vertical and horizontal separations, as well as the different angles affected the ability of birds to move between perches. There was a general decreasing trend in ability with increasing vertical separation between perches.
9. The findings are important in terms of arrangements of perches to improve bird welfare. To minimise die risk of injury, the angle between perches at different heights should be no more than 45 degrees, and die horizontal and vertical distances between these perches minimised, to allow the birds to be able to move downwards more easily. 相似文献
2. The mean residence time (MRT) of salicylate (SA) after i.v. administration of SS was 6.08 ± 0.59 and 3.32 ± 0.27 h and after oral administration was 6.95 ± 0.72 and 4.55 ± 0.71 h in chickens and turkeys, respectively. The elimination half-life (T 1/2 e) was shorter in turkeys compared with chickens. The value of body clearance (ClB) was higher in turkeys than in chickens, but the apparent volume of distribution (V ss) was similarly low in both species. The bioavailability of SS was complete and the maximal plasma concentration of SA (C max) after oral administration was 96.93 ± 8.06 and 91.76 ± 9.64 µg/ml, respectively, in chickens and turkeys.
3. The MRT of ASA after iv administration was 0.24 ± 0.08 and 0.24 ± 0.02 h and after oral administration was 0.78 ± 0.25 and 0.59 ± 0.13 h, respectively, in chickens and turkeys. In both species, T 1/2 e was very short, ClB and V ss were similar and markedly higher than those of salicylate. The bioavailability of unchanged ASA was low and C max after oral administration was 6.9 ± 3.6 µg/ml in chickens and 8.6 ± 1.3 µg/ml in turkeys. 相似文献
2. In both lines, the increase of egg storage temperature from 12°C (standard level) to 30°C increased the egg weight loss during storage, shortened the incubation period and reduced the hatching success.
3. Similar to standard egg storage temperature, LG quail hatched earlier than HG quail after egg storage at 30°C and early and late mortality of both lines increased with a prolonged period of egg storage. In contrast to the standard egg storage conditions, no line differences in hatchability were observed.
4. The results did not identify a relationship between the decrease in hatchability or embryo viability and line differences in external egg parameters as well as any important role of undesirable changes induced by a high storage temperature on albumen viscosity.
5. The pattern of embryonic death, low developmental rate of embryos and a dichotomy between the development of the extra-embryonic vascular system and the embryo itself during egg storage at high temperature implied that an insufficient nutrient supply in consequence of developmental delay could represent a key factor in increasing early and late embryo mortality. 相似文献