Effect of regrouping on heterophil to lymphocyte ratio, tonic immobility duration, and fluctuating asymmetry in layer stocks
The aim of this study was to analyze the effect of regrouping on heterophil to lymphocyte ratio (HL), tonic immobility duration (TI), and fluctuating asymmetry (FA). In experiment 1, 192 chicks were reared in cages with or without regrouping. There was similar HL, TI, and FA of leg length, wing length, and leg width in resident, intruder, and control groups, suggesting that regrouping did not affect the stress and fear of chicks. The effect of regrouping was significant for FA of toe length (P < 0.05), being smaller in resident than intruder chicks. This result suggests that residents were less stressed than intruders, and asymmetrical toes are a good predictor of social stress between these two groups. In experiment 2, 120 resident black cockerels were housed in pens with intruders of wheaten (residents 1), blue (residents 2), or both plumage colours (residents 3), or without (controls) regrouping. There were significant differences (P < 0.01) for HL, being smaller in residents mixed with intruders than in birds from resident-only groups. This result suggests that regrouping was not a stressful event for residents and it even reduced the stress in resident cockerels. Residents 3 had longer TI and higher FA of wattle length than residents 1 and 2, suggesting that TI and asymmetrical wattles are a good predictor of social stress among resident groups, mixing with intruders from two plumage colours being more stressful than mixing with intruders from only one. In conclusion, regrouping did not result in pronounced stress or fear responses. Although there is evidence from earlier research that physical stressors result in increases of HL TI, and FA, the effect of social stress on these indicators might be different. © Verlag Eugen Ulmer, Stuttgart.
| Main Authors: | , , , , |
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| Format: | journal article biblioteca |
| Language: | English |
| Published: |
Verlag Eugen Ulmer
2014
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| Subjects: | Laying hens, Regrouping, Heterophil to lymphocyte ratio, Tonic immobility, Fluctuating asymmetry, |
| Online Access: | http://hdl.handle.net/20.500.12792/3582 http://hdl.handle.net/10261/294388 |
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| Summary: | The aim of this study was to analyze the effect of regrouping on heterophil to lymphocyte ratio (HL), tonic immobility duration (TI), and fluctuating asymmetry (FA). In experiment 1, 192 chicks were reared in cages with or without regrouping. There was similar HL, TI, and FA of leg length, wing length, and leg width in resident, intruder, and control groups, suggesting that regrouping did not affect the stress and fear of chicks. The effect of regrouping was significant for FA of toe length (P < 0.05), being smaller in resident than intruder chicks. This result suggests that residents were less stressed than intruders, and asymmetrical toes are a good predictor of social stress between these two groups. In experiment 2, 120 resident black cockerels were housed in pens with intruders of wheaten (residents 1), blue (residents 2), or both plumage colours (residents 3), or without (controls) regrouping. There were significant differences (P < 0.01) for HL, being smaller in residents mixed with intruders than in birds from resident-only groups. This result suggests that regrouping was not a stressful event for residents and it even reduced the stress in resident cockerels. Residents 3 had longer TI and higher FA of wattle length than residents 1 and 2, suggesting that TI and asymmetrical wattles are a good predictor of social stress among resident groups, mixing with intruders from two plumage colours being more stressful than mixing with intruders from only one. In conclusion, regrouping did not result in pronounced stress or fear responses. Although there is evidence from earlier research that physical stressors result in increases of HL TI, and FA, the effect of social stress on these indicators might be different. © Verlag Eugen Ulmer, Stuttgart. |
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