[Cortisol concentration before, during and after sham foot trimming in German Holstein cows - the suitability of different matrices].

OBJECTIVE

The objective of this study was to determine whether changes in cortisol concentration measured in blood serum (KoB) of cows exposed to an acute stressor shows a correlation to cortisol concentrations in saliva (KoS), tears (KoT) and milk (KoM) as well as the concentration of cortisol metabolites in feces (KoK).

MATERIALS AND METHODS

In 10 healthy German Holstein cows, sham foot trimming (sKB) including the movement/fixation of the cows through/in a foot trimming chute was used as a model for acute stress. KoB, KoS, KoT, KoM and KoK were measured once a day for 10 days. During sKB, performed on day 4, KoB and KoT were measured at the initiation of foot trimming (minute 0) as well as 15, 25, 30, 40, 50, 60 and 80 minutes later. Additionally, KoK was measured 480, 540, 600 and 660 minutes after the start of sKB.

RESULTS

KoB and KoT increased during sKB and reached a maximum at 60 minutes followed by a decrease. KoK increased after sKB and reached a maximum at 660 minutes. There was a significant correlation between KoB and KoT, KoK and KoB and a trend towards a significant correlation between KoK and KoT during sKB. KoB and KoT were significantly correlated (area under the curve, minute 0-10, p = 0.04). KoB decreased significantly from day 1 to day 4 (p < 0.01). On day, 5 KoB (p = 0.03) and KoK (p < 0.01) were significantly higher. KoS and KoT served as good proxies for KoB throughout the study, and KoK and KoB exhibited similar profiles. There were several differences between the profiles of KoM and KoB. During the 10-day measurement period, a significant positive correlation was detected between KoB and KoS (p = 0.002) as well as between KoB and KoT (p = 0.002).

CONCLUSIONS AND CLINICAL RELEVANCE

The collection of tear fluid and saliva for determination of cortisol concentrations are non-invasive alternatives to blood sampling. Calm handling of cows may reduce their stress reaction and thus improve animal welfare.