Evaluation of nose pressing behaviour in dairy cows in terms of HRV and behaviour

Abstract

Nose pressing can be described as a behavior shown in dairy cows which push the nose firmly and directly onto barn objects. Little is known about the reasons why this behavior takes place, only a previous investigation related the performing of this behavior with a decrease on parasympathetic activity. The main task of this study is to investigate whether this previous results may be confirmed in terms of heart rate variability (HRV) during resting, waiting and milking, and to get a global idea about how the barn environment influence the performing of nose pressing in terms of behavior. 7 cows identified as exhibiting nose pressing and 7 control animals were observed in the barn and during the milking procedures along fifteen days. They were monitored with heart rate recorders POLAR® RS800CX and the lying and standing bouts were evaluated using HOBO Pendant® G Data Logger UA-004-64. The behaviors observed in the barn did not differ from NP to control animals; however, there were a higher variability in the first group. During lying, there was not found any difference between groups and, during waiting and milking, NP animals showed a significant lower HR than control cows. The performance of NP behavior during milking showed lower values of RMSSD, STD RR and STD HR than when NP was not showed; i.e. higher parasympathetic activity observed while NP took place. In brief, it seems that NP animals did not trigger relaxing systemic changes by nose pressing. In addition, the great variability of the behavior observations and the intermittence of the performing of nose pressing might prove that nose pressing is a transitory behavior.