Mjölkkors välbefinnande i AMS och konventionell lösdrift : skillnader i beteende och hormonstatus för oxytosin och kortisol mellan kor av hög och låg social rang

Abstract: The purpose with this study was to investigate how the behaviour and physiological parameters differ between high ranked and low ranked cows, and between cows in an automatic milking system verses conventional milking parlour. The study was carried out at the Kungsängen research Centre, Department of animal nutrition an management, Swedish University of Agriculture Sciences, Uppsala. Twelve cows, the six highest and the six lowest in social rank were selected from the automatic milking system for the experiment. Ten cows, the five highest and five lowest in social rank were selected from the conventional system. Blood samples were taken during milking and resting. The blood samples were analysed on the hormones oxytocin and cortisol. Before and during milking a behavioural study was conducted. The results from the blood samples indicated that cows in the automatic milking system expired the time in the waiting area and the milking process more stressful compared to the conventional cows. Furthermore the conventional cows had higher concentrations of oxytocin 30 minutes after completed milking. Even though the low ranked cows in the automatic milking system spent more time and received more threats in the waiting area compared to the high ranked AMS-cows, non significant differences in concentration of oxytocin and cortisol during milking was found between the ranking groups. The low ranked AMS-cows seemed to have to adjust their behaviour to the high ranked cows, but this didn't seemed to be stressful for them according to the hormone study. The results of the hormone study indicated that to receive threats are not more stressful than to deliver threats. The high ranked cows tended to tramp more during milking than the low ranked cows. These results could indicate that the high ranked cows expired the milking process more trying than the low ranked cows. These results are not supported by the results from the hormone study. The behaviour tramp and kick did not always reflect how the cow expired the milking process, since cows that were tramping and kicking a lot during milking didn't had to have high concentrations of cortisol and low concentrations of oxytocin during milking. The high ranked cows had higher concentrations of oxytocin during resting compared to the low ranked cows. That could indicate that the high ranked cows felt more safe and secure during resting.