Reproductive Endocrinology as a Management Tool

Using hormone analysis as an additional tool to manage introductions can be very useful, particularly in females where behavioural signs of oestrus are weak or unreliable. Non-invasive approaches are preferable as they minimise the disturbance to the animal and can allow long-term sampling as part of the keepers’ daily routine. Faecal samples are often preferable to urine samples, as collection is often easier, and requires no additional training of the animal, instead fresh samples can be collected when the animal is let outside first thing in the morning. Samples should be frozen immediately after collection, and stored frozen until shipping to a laboratory for analysis.

Samples collected at least every other day are necessary for characterising oestrous cycles in females, and can be used to determine a females’ typical oestrous cycle length. This can then be used to predict when she will next be in oestrus, and therefore give keepers extra confidence when deciding when to introduce a pair (or trio) for breeding purposes. See below for an example of results of hormone sampling to predict cycling. Samples collected on a weekly basis are sufficient to investigate differences in testosterone between males. You can download a faecal sample collection protocol here.

Graph showing Progesterone metabolites () measured in faeces collected from a female Black rhino can be used to characterise oestrous cycles. However, the length of oestrous cycles can be highly variable, with a normal cycle lasting between 20-40 days in length (green sections). However, shorter cycles less than 20 days (not shown) and longer cycles greater than 40 days in length (orange sections) are also relatively common, and periods of acyclicity (red section) are also observed.

Progesterone metabolites measured in faeces collected from a female Black rhino can be used to characterise oestrous cycles. However, the length of oestrous cycles can be highly variable, with a normal cycle lasting between 20-40 days in length (green sections). However, shorter cycles less than 20 days (not shown) and longer cycles greater than 40 days in length (orange sections) are also relatively common, and periods of acyclicity (red section) are also observed.

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