| 1. |
- Henriksen, Rie, et al.
(författare)
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Effect of contact incubation on stress, behavior and body composition in the precocial Red jungle fowl
- 2021
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Ingår i: Hormones and Behavior. - : Academic Press. - 0018-506X .- 1095-6867. ; 128
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Tidskriftsartikel (refereegranskat)abstract
- Birds use contact incubation to warm their eggs above ambient temperature required for embryonic development. In contrast, birds in the industry as well as many birds in breeding programs and scientific studies are incubated in conventional incubators that warm eggs via circulating warm air. This means that contact incubated eggs have different thermal properties than eggs incubated in a conventional incubator. In light of previous studies showing that small differences in incubation temperature can affect chicks post-hatching phenotype, we investigated the consequences of incubating Red jungle fowl eggs at the same temperature (37 degrees C) either via contact incubation or warm air incubation. We found that contact incubated chicks had a more robust body composition, were more explorative and had a higher temperature preference early in life, as well as a sex dependent difference in plasma Corticosterone levels pre-hatch (measured in down-feathers) and post-hatch (measured in plasma) compared to chicks incubated in a conventional warm air incubator. While previous studies have demonstrated that embryonic development and post-hatch phenotype is sensitive to small variations in temperature, our study demonstrates for the first time that the way heat is distributed to the egg has a similar magnitude of effect on post-hatch phenotype and highlights the sensitivity of the incubation period in shaping birds post-hatch phenotype.
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| 2. |
- Sauveroche, Mathilde, et al.
(författare)
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Hair cortisol in horses (Equus caballus) in relation to management regimes, personality and breed
- 2020
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Ingår i: Journal of Veterinary Behavior. - : Elsevier. - 1558-7878. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- Hair cortisol is a promising biomarker to measure long-term stress since cortisol is incorporated into the hair shaft as it grows. However, few studies have previously assessed hair cortisol concentrations (HCC) in horses. In this study, HCC was evaluated in both mane hair from the neck and body hair from the withers in 153 horses of different breeds, from seven different stables with three different management regimes (Free-roaming horses, Riding school horses, Trotter horses). In addition, 4 hours of behavioral observations were performed at each stable, and for 43 of the horses, a personality survey was completed. Mane and withers HCC correlated moderately, but significantly (rs=0.48, p<0.001). Differences between the stables were found for both mane and withers hair (both p<0.01) and the stable with lowest HCC also showed highest occurrences of positive social and resting behaviors (both p<0.01). There were no significant differences in HCC between the management regimes even though Free-roaming horses showed less negative social behavior compared to Riding school horses (p=0.041) and Trotter horses (p=0.055). The personality traits Dominance, Anxiousness, and Excitability revealed weak to moderate correlations with mane HCC (rs=-0.34, p=0.027; rs=-0.46, p=0.002; rs=-0.31, p=0.043 respectively) which might suggest that personality could also be related to long-term stress levels in horses.
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