| dc.description.abstract | There is a close relationship between animal welfare and stress. A good indicator of animal
welfare can be the absence of stress. Chronic stress is associated with a long-term
condition were the animal cannot fully recover, maladaption. Lameness, as an often painful
situation can cause chronic stress. The aim of this thesis is to review the concept of stress
focusing on chronic stress and lameness as a chronic stressor. Several measures
(physiological and behavioral parameters, performance and health indices, endocrine
indicators, biochemical indicators, immune indices etc.) of chronic stress have been
proposed as chronic markers. Special attention has been paid to heart rate variability
(HRV) used in an experiment I got to be a part of were behavior and HRV of chronically
stressed (lame) cows at feed bunk during feeding were examined. 52 dairy cows divided
into two groups of lame (locomotion score:3-5) and non-lame (locomotion score: 1-2) was
compared. Heart rate (HR) and HRV were measured when the cows were standing at the
feed bunk eating and dominance score (DS) was calculated for each animal based on
aggression rate (AR). Fecal cortisol concentration was also measured. Result showed a
higher HR (beats/min) in lame cows and the HRV indicated a higher parasympathetic tone
in lame cows (increase in rMSSD(ms), HF(normalized units) and SD1(ms)). The
dominance score was lower in lame cows compared to non lame. The result suggest that
the effect of lameness can be manifested in HRV confirmed by the observed differences in
aggression levels of lame and non lame cows. | en |
