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Immediate Plan:

Based on the findings of minimal uterine pathology together with the observation of a large preovulatory follicle on the left ovary, we put Mas Merah and Ara together for breeding at 2 pm. We were excited to see some very convincing estrus behavior by Mas Merah and breeding activity by Ara (Figure 2). The 2 animals were watch closely for 2 hours with multiple mounting attempts made as well as at least one short period of intromission. Based on the large size of the POF, it is likely that we put the 2 animals together towards the end of the period of maximum receptivity. Based on Dr. Roth’s work with Emi in Cincinnati (Roth et. al., 2001), breeding and induced ovulation appears to occur at a follicular size of ~24 mm. This would suggest that perhaps we were 12 hours late in our introduction of Mas Merah for breeding.

Ovulation was documented within 48 hours of breeding as illustrated by the identification of an ovulation site and formation of a corpus luteum (Figures 4 and 5). This was a significant event that supported previous work by Dr. Roth and illustrated that such work in zoological setting can be applied directly to enhance breeding management in other captive environments. This finding also serves to highlight the importance of using ultrasound as a tool to assist rhino management efforts for the Sumatran rhino.

Recommendations:

• Continue breeding Mas Merah based on progesterone assay combined with ultrasound data.

• Initiate post-breeding ultrasound monitoring for early pregnancy as outlined in Appendix A.

• Consider use of oral progesterone supplement (as was done with Emi in Cincinnati) if early embryo loss is observed or if progesterone levels remain elevated beyond 21 day period in absence of documented pregnancy.

Reproductive Exam Details: MAS MERAH

Mas Merah Figure 1 (29 August). Day of breeding Mas Merah and Ara with 26 mm Preovulatory follicle on Mas Merah’s left ovary.

Mas Merah Figure 2 (29 August). First successful breeding of Mas Merah and Ara. This event was facilitated by timed introduction of the pair based on observation of 26 mm Preovulatory follicle on Mas Merah’s left ovary. more »

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