Although much research has studied the effects of acute stress in bovines, the effects of chronic stress on cattle behaviour has been poorly studied. Attention biases have been used to evidence negative affective states by quantifying attention to a novel threatening stimulus. Here we examined if a composite chronic stress treatment impacts the behaviour of beef cattle as measured through attention bias during a Fear Response Test. This study complied with UK Home Office regulations and ISAE ethical guidelines. Limousin (n=40) or Angus (n=40) cross steers were assigned to a chronic stress (S) or control treatment (C), each treatment with four replicate groups. After a baseline of 8 weeks at a floor space allowance of 8.72 m2 per animal, S steers received a reduced space allowance (4.35 m2 per animal) and were weekly subjected to regrouping, transport for 20 minutes and isolation for 10 minutes. At the end of the chronic stress period (8 weeks), C and S animals experienced a fear test in a 4.4 x 16.3m arena subdivided into 12 quadrants and their movement tracked. Each steer was allowed to acclimate for 90s, followed by the sudden appearance of a startling stimulus (a person with a high visibility jacket opening an umbrella once). The person remained static in the arena for an additional 90s. Reaction to the startle was recorded as well as subsequent behaviour and activity (running, walking, standing). Behavioural and location data were analyzed in separate Principal Components Analyses (PCA). For the Behaviour Analysis PCA, PC1 was labelled as “Inactive - Active” correlating with behaviours such as vigilance (r=0.77; P<0.0001) and walking duration (r=-0.75; P<0.0001); PC2 was labelled as “Distance travelled pre-startle vs post-startle” and PC3 as “Attention towards novelty”. These PCs explained 29.3, 18.6 and 10.5% of the variance respectively. Animal scores on PC1 were affected by their sire identity (eta2 (analog to R2) 0.36; P<0.05), while PC2 and PC3 were affected by treatment (eta2 0.16; 0.19; P<0.01) and pen (eta2 0.38; 0.34; P<0.05). In PC2, C animals travelled further post-startle than pre-startle (proportional increase 6.92 and 18.33 for S and C animals; P<0.05) whilst in PC3, S animals showed more attention towards the novel stimulus (P<0.01). The PCA developed to describe the location of animals relative to the startling stimulus identified two dimensions that explained 34.9% and 29.6% of the variance, but the S or C treatment did not influence the location of cattle relative to the stimulus after its appearance. These results indicate differences in behavioural responses and attention to a novel stimulus by animals subjected to a composite stress treatment, suggesting that they may have experienced a more negative affective state. Faecal cortisol and response to an ACTH challenge will be presented to help interpret the response of cattle to chronic stress.
|Number of pages||1|
|Publication status||Print publication - 5 Aug 2019|
|Event||53rd Congress of the International Society for Applied Ethology (ISAE) - Bergen, Norway|
Duration: 5 Aug 2019 → 9 Aug 2019
|Conference||53rd Congress of the International Society for Applied Ethology (ISAE)|
|Period||5/08/19 → 9/08/19|