Abstract: Studies on three species of big cats at Dublin Zoo have led to firm conclusions about the effects of certain forms of enrichment, some of which will be presented here. Lions, jaguars, and snow leopards were studied over two years and their behaviours quantified using focal animal sampling during selected hours during daylight. By comparison of these activity budgets with and without the enrichments being present, it was possible to identify the exact behavioural changes caused by each enrichment method, and to quantify these changes. In this contribution we present results showing that the presence of a platform in both lion and jaguar enclosures dramatically reduced stereotypic pacing behaviour. We will demonstrate that the effects of short term enrichment devices may have a wide range of effects on behaviours which outlast the presence of the stimulus. For instance scents added to the cage, or food/play items such as horse hides, hidden fish or ice-blocks often reduce pacing and increase resting later in the day, even after the cats have ceased using the enrichment items. This reduction in pacing and increase in resting time often meant that the amount of the enclosure used per hour was actually reduced with the presence of new stimuli, as result opposite to what might have been expected. The results of these studies will be discussed in relation to effective animal management.

Abstract: Melengestrol acetate (MGA) is the most widely used contraceptive in zoo felids, but the mechanism of contraception and the pathologic effects have not been investigated. For this study, the effects of MGA on folliculogenesis were assessed, and the association of MGA with ovarian lesions was evaluated. Comparisons were made among the histopathologic findings in the ovaries from 88 captive wild felids (representing 15 species) divided into three groups: 37 currently contracepted with MGA, eight previously exposed to MGA, and 43 never contracepted. Ninety-one percent of the felids evaluated had tertiary follicles, and no differences were noted between contracepted and uncontracepted cats. Some MGA-contracepted cats also had corpora lutea indicating recent ovulation. These results indicate that folliculogenesis is not suppressed by current doses of MGA and ovulation occurred in some cats. Therefore, the contraceptive actions of MGA do not occur by suppressing folliculogenesis, and MGA-contracepted felids likely have endogenous estrogens that may confound progestin effects on the uterus. Cystic rete ovarii was the most common pathologic finding, but they were not more prevalent in MGA-contracepted cats. These findings indicate that MGA is not associated with ovarian disease, including ovarian cancer, in contrast to the uterine lesions noted in MGA-treated cats.