D ISCUSSION

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While Sparrow’s heart rate was constant among the days, his muscular activity presented two peaks during day 1 and day 2 (Figure 5.18). These peaks were in correspondence of a drop of Sleep percentage, but they are not associated to an increase of Movement. Therefore, these peaks are due to different behaviors, as Self-grooming, that has a peak in day 2 or other minor behaviors (e.g., Scratch).

Figure 5.18. Mean activity muscular index and heart rate during the four days.

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In normal conditions, dogs need an environment that could be differentiated and both physically and socially stimulating [267–269]. This kind of environment is crucial to avoid development of stereotypies and/or abnormal behaviors [270–272], abnormal HPA axis activation [273], and separation-related anxiety problems after adoption [274]. Besides, enrichments promote animal natural behavior and increase welfare [281–283].

However, findings from this experiment seem to provide contrasting data. After a preliminary analysis of data, it appears that there is not a pattern shared among dogs neither in physiological nor in behavioral data. In the first approach, behavioral data are statistically different among dogs and, even if test were not performed for the second approach, descriptive statistics points out many differences inside the sample.

Physiological data have proven to be hard to interpret. If it could be possible to consider more positive a situation characterized by a lower heart rate, core temperature seems to provide only information about emotional activation [113,261] but not about emotional valence while the muscular activity index cannot be used as a welfare indicator.

Approach 1 points out that dogs reacted differently to the proposed situations. Brando showed a peak in temperature during environmental enrichment week that was not accompanied by a similar raise neither in heart rate nor in muscular activity index suggesting an interest towards the toys that was probably very moderated according to very little time spent interacting with them. On the other hand, behavioral data indicated that Brando had some kind of interest for the female, but this was not supported by physiological data that did not vary compared to the baseline, as happened for the week with the human visitor.

Buck physiological parameters varied among weeks, however their patterns were not overlapping. Between baseline and enrichments week, heart rate remained constant while temperature increased; the next week they had an opposite trend as heart rate increased while temperature decreased and finally in the fourth week heart rate decreased again (remaining higher than baseline values) while temperature remained constant. Behavioral data did not help as Buck slept for the majority of the time ignoring the stimuli during both the female and the environmental enrichments week. Reading together behavioral and heart rate data suggests that Buck was disturbed by social enrichments having a higher heart rate without a detectable change in his behavior. Overall, his welfare does not seem to be improved.

Jack reacted positively to the enrichments proposed even though at a different extent.

According to heart rate, while environmental enrichments seem to have a calming effect on him, both

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social stimuli raised this parameter. Behavioral data partially confirm these evidences. During the environmental enrichments he interacted for a very little time with the toys (even if time spent on the cot suggests that he did not like it) but he spent a lot of time with the female. Besides, during the whole experiment he performed less stereotypies but this drop did not reach any statistical threshold.

Approach 2 was focused on the male-female relationship because it was hypothesized that it could be the most impactful situation given the importance of socialization and because the female remained continuously in contact with the male and she was not limited to only daily visits. Analyzing descriptive statistics, data collected for Buck and Jack confirmed results of Approach 1.

Brad muscular activity decreased during day 1, due to a strong decrease in Locomotor stereotypies and to the increment in the percentage of time spent sleeping. It returned to baseline values during day 2 and day 5 since he increased Movement, and this pattern suggests that Brad is getting used to the presence of the female. Overall, this pattern of behavior indicates that Brad did not enjoy the presence of the female even though the constant pattern of HR suggests that the disturbance caused is not too stressful.

Scotty is another dog that spends a lot of time sleeping. Muscular activity pattern and heart rate had both a drop during day 1, in correspondence of a drop in Movement and a peak in Sleep, but they quickly recovered to baseline value during day 2 and day 5. Again, behavioral data points out an overwhelming time spent sleeping and almost no interactions between the animals and therefore they did not suggest that inserting the female improved the welfare.

Finally, Sparrow presents constant heart rate and an increased muscular activity during day 1 and day 2 but it was not correlated to either an increment in Movement or to social relationships;

instead, it was due self-directed behaviors like Self-grooming or Scratch. However, behavioral data suggested that he was positively influenced by the presence of the female that increased explorative behaviors and elicited even affiliative behaviors; but this effect seems lasting only for the first two days as during the fifth day behaviors returned to baseline value.

Dogs reacted differently to the different situations: some dogs seem to be disturbed by the enrichments and others seem to benefit from them. However, environmental enrichments have elicited mild reactions in all dogs and therefore it is difficult to say if this situation had been perceived as positive or negative. On the other hand, social enrichments elicited stronger reactions, both physiological and behavioral, but very different among dogs. However, it is important to note that background information about these dogs were unknown and the sample included only male socially isolated since a long time; therefore, even if the sample seems very homogeneous, it could be possible

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that past experiences play an important role in modulating responses to the enrichments. This lead to think that there is not a single path to improve sheltered dogs’ welfare and enrichments should be carefully thought on a case-by-case basis.

Aside from completing physiological and behavioral analysis, future developments should include extensions of this experiment, comparing similar situations with bigger samples. Since it is unlikely that would be possible to use telemeters again, different physiological measurements have to be taken, such as hair, plasmatic or fecal cortisol [177,287,288]. Besides, it will be a paramount issue an accurate as possible analysis of dogs’ background and the choice of samples including dogs of different age, sex, and socialization.