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2. In the first week after trimming, when trimmed birds were compared with untrimmed controls, they were less active (sat and slept more), fed less, preened less and generally engaged in less beak‐related behaviour.
3. These differences waned sharply during week 2 and had disappeared by week 5. There were very few differences between hot‐ and cold‐cut birds.
4. There were also differences in production variables: trimmed birds grew more slowly during the week after trimming, their food intake was depressed for 3 weeks and food conversion efficiency improved for 2 weeks.
5. The only significant effect on feather scores was better plumage condition in the groups trimmed at 1 d and scored at 6 weeks.
6. To examine the anatomical effects 36 ISA Brown chicks trimmed by hot or cold cut at 1 d or 10 d of age were killed at 21 and 42 d after trimming, and their beaks were processed and examined histologically. In all trimmed groups healing was very rapid and no scar tissue was seen but, unlike the controls, the regrown tips contained no afferent nerves or sensory corpuscles.
7. Beak lengths immediately after trimming were 40% to 50% shorter than controls; the anatomical consequences of both methods were identical.
8. Overall, it was judged that the effects on behaviour and beak anatomy were much less severe than previously reported for birds trimmed at older ages. If birds do have to be trimmed then the procedure should be carried out in young birds: from the birds' standpoint 1 d appears to be the most suitable. 相似文献
Significantly higher serum IgE concentrations (P<0.01) were present in horses which bled profusely than in those which bled mildly or not at all. Reductions in serum IgE concentrations were evident following exercise in most horses and, even though these reductions were not statistically significant, this suggested the possibility that circulating IgE had become bound to basophils or to bronchial mast cells as a result of the exercise. 相似文献
2. Half the hens had undergone beak trimming at 18 weeks, but in many cases regrowth had occurred.
3. Plumage damage and loss was significantly reduced in beak‐trimmed birds compared with birds with normal beaks. Tier and cage design had no effect.
4. This finding supports the idea that feather pecking is the important factor in causing plumage damage, rather than abrasion.
5. A comparison between 64 birds in which beak regrowth had occurred, and 64 in which it remained truncated, showed that both groups had similar plumage scores.
6. It appears to be the beak‐trimming procedure which is important; subsequent regrowth being irrelevant. 相似文献