About Results
At this facility, as well as in many zoos, animals considered to be “similar”, like these three species, are often kept under the same care guidelines due to their taxonomical closeness or overlapping habitats. The results of this study show that their needs may be different enough to deserve an evaluation and re-assessment of the current guidelines in order to fine-tune them to the particular needs of each species.
Based on the behavioural data collected:
- Dorcas gazelles seem to be more nervous and easily alarmed and therefore could benefit from more visual barriers around their enclosure or relocation to less transited areas of the farm.
- Dama gazelles’ tendency to consume more concentrate feed (sometimes to possibly harmful amounts) may indicate a nutrient deficiency in their diet.
- Cuvier’s gazelles being most inactive and at the same time most likely to perform pacing behaviours may be a sign of an issue with their physical environment, such as enclosure size or furnishing, or social environment, considering they were the species with most fights recorded.
The drastic behavioural changes observed after the first diet change (Base1 to Base2) are evidence of the critical role of roughage in the daily diet of captive ruminants. The animals showed both more natural species-specific behaviours, such as foraging, as well as signs of general calmness (sitting to ruminate or rest and less alarm calls) most likely linked to lower stress levels.
It would seem like the great impact of the first diet change lessened the possible effects of the enrichment by directly approaching some of the underlying issues. However, the provision of fresh browse was still clearly beneficial, and the gazelles favoured it over the alfalfa as roughage:
- It offered an opportunity for these animals to perform naturalistic behaviours regarding their feeding habits, as it required longer manipulation times, careful picking of leaves around spikes, and also adds bark to their diet.
The animals were more active and spent more time eating, tackling some of the bigger issues of captivity: inappropriate diets and inactivity which often lead to obesity and other concerns.
However, certain behaviours we considered to be stereotypies or undesired behaviours persisted regardless of the enrichment. There may be a couple of explanations for such, which would require of more research:
- They could be learned behaviours or “habits” which animals in captivity are known to keep after having expressed stereotypies in the past
- The source of the stress may have not been addressed properly; be it the enclosure’s physical or social structure, or subtleties in their environment (noise, presence of perceived danger, etc.).
“Out of control“
It is important to note that the results obtained for what was supposed to be the control group of Dama gazelles (C14) were unexpected in that they seemed to show heightened levels of stress despite maintaining the same conditions.
We believe it could have been caused by their enclosure’s placement: this herd was situated next to one of our experimental groups (C11), at slightly different height levels, but within view of each other. The initial experimental design considered the fresh browse to be no different from the permanently-in-sight trees surrounding the enclosure, but a difference seemed evident once it became a specific resource that was given to another group. We theorise that the sight of their neighbouring herd enjoying their provided enrichment may have caused heightened frustration levels among the control group, possibly leading to coping mechanisms such as licking of the wall adjacent to the experimental group (where they were most commonly observed performed this behaviour) – fights among herd-mates for a spot on the wall were also observed – and an increase in the consumption of alfalfa, their only provided fresh diet.
The same conditions were true for our Cuvier’s gazelle control group (C24), which was place next to a Dama gazelle experimental group (C25) without visual barriers. However, their behaviour did not change in the same way, this herd seemed indifferent to the experimental treatment on their neighbours and continued to behave normally. This could have been due to the species differences between C24 and C25, being C14 and C11 both Dama gazelle groups, and possibly incentivising more social interactions between the different herds.
In general, variation between different herds seemed to hinder the data analysis rather than help it, especially so for variables directly related to outside, localized stimuli, such as alarm behaviours. This should be considered in future studies where perhaps the herds, observed under different conditions, could suffice to act as their own control.
Conclusion
In conclusion, and at large, not only is diet a critical part of captive ungulate management, but it can also be a tool, when used as enrichment, to evaluate the animals’ welfare and approach underlying issues that may otherwise go unnoticed. This study helped reduce abnormal behaviours and improved welfare, but at the same time other possible concerns came to light due to the imperfect effectivity of the enrichment. Other issues to consider are enclosure and social group structures, which may be approached, in the future, by either integral changes to the facility or offering other types of enrichment, for which effectivity can then be assessed in order to better understand the needs of the animals we keep and perfect the care we provide.