|This work investigates different non-invasive biomarkers for behaviour traits in beef and dairy cow. After a general introduction on behaviour tests, animal stress and biomarkers, the work is divided into three parts: In the first part, infrared thermography (IRT) is discussed as a method for the diagnosis of animal welfare, pain, disease, inflammation and stress in a literature review in chapter III. The second part (chapter IV) describes an experiment to compare the maternal ability in German Simmental (beef) and German Black Pied cattle. The objectives of the study were 1) to test if dairy cows have a less distinctive motherliness than beef cows and 2) to prove if oxytocin is a potential biomarker for the maternal behaviour. The third part in chapter V describes the experiment in which the docility of the breeds Charolais and German Simmental (beef) was tested with the help of two handling tests. The goal of the experiment was to proof if the hormone level of testosterone has an influence on the docility of the cattle.
Infrared thermal imaging has gained popularity in various disciplines of animal science. However, the usefulness of IRT differs for diverse diseases, infections and other purposes. Stress caused by pain, especially at disbudding, cattle branding, tail docking or surgical castration can be detected by IRT. The measurement of psychological stress, e.g. at horse jumping events or during the slaughtering of pigs, can be performed well by IRT. While a good suitability was attested for detection of virus infections, the usability of IRT for detection of diseases of the locomotor system and udder infections is often limited to a supplementary tool. Different reliabilities of IRT can be found in literature for the detection of diverse diseases, as the sensitivity and specificity are strongly dependent on the temperature cut-off value, the time of measurement (clinical or post-clinical stage) as well as the evaluation routine, assuming that all or only the maximum temperatures are included in the evaluation. In farm animal research, plenty of animal and environmental related factors show an influence on the measurements obtained by IRT, limiting the informative value of the technique. Thus, IRT cannot be considered as a panacea and should also not be used as the sole technique, but it can provide a good, non-invasive assistance for many areas of animal research and practical issues, like the detection of stress and diseases.
The second part focused on the experiment on maternal behaviour, in which 20 cow-calf dyads each of Simmental (S) and German Black Pied Cattle (BP) was examined on the 2nd and again on the 3rd day of the calf’s life during situations with and without human handling of the calf. For one hour the frequency of interactions between cow and calf were quantified. During handling the calf, the cow’s willingness to defend her calf and the overall maternal behaviour was scored. For the detection of stress, saliva samples for cortisol and oxytocin analysis, heart rate and thermal images of the eye were taken. The oxytocin concentration in saliva was used to test the hormone as a biomarker for maternal ability. The mixed model analysis revealed that the BP cattle had significantly higher oxytocin and cortisol levels, but lower heart rates than S cattle. The heart frequency and the defensive behaviour showed that during handling the calf, S cattle are more agitated and more difficult to handle than BP cattle. Although the beef cattle (S) showed more defensive behaviour, a lower number of interactions were presented to their calf compared to BP. Therefore, beef cows do not seem to be per se more maternal compared to dairy cows. As only the correlation of oxytocin to the interactions to the calf existed, it cannot be clearly stated that a higher oxytocin level in cows is correlated with greater total maternal ability.
The objective of the experiment in the third part was to ascertain if a higher testosterone level in beef cows is associated with more aggressive behaviour and lower docility during behaviour tests. Therefore, 21 German Simmental (S) and 20 Charolais heifers (C) were subjected with one repetition to a chute test as well as a separation- and restraint test. Beside the collection of behavioural parameters, the heart rate, thermal images of the eye and saliva samples for cortisol and testosterone analysis were collected during the tests. For all physiological and most of the behavioural parameters, significant breed differences were detected. Different behavioural parameters of the chute test and the separation- and restraint test indicated that breed C is easier to handle and has the better docility compared with the breed S. The physiological parameters for stress as well as behavioural parameters specified the S heifers to be more agitated and harder to handle. Due to the fact that the C heifers had considerably higher testosterone levels compared with S heifers, a higher level of the hormone testosterone can be interpreted as adjuvant for a better temperament. Contrary to our hypothesis, heifers with a higher testosterone level seem to be more calm, relaxed and easier to handle, probably due to less fearfulness.