Abstract

Training was implemented for a female pygmy hippopotamus (Choeropsis liberiensis) to voluntarily enter a corridor. The corridor was accessible for an examiner from one side through vertical bars to provide protected contact. Front and back of the corridor remained open at all times so that the animal was able to quit the session whenever desired. Small vegetable items were fed to the animal to encourage it to stand in place during the procedures. The animal was desensitized to being touched by a gel-coated ultrasound probe (4C-RS, 2.0–5.0 MHz Convex, on a Logic V2, GE Healthcare ultrasound system, Buckinghamshire, Great Britain). Aggressive or other unwanted behavior was never observed. Weekly to bi-monthly transabdominal ultrasound examination was performed during two gestation periods of the same individual with a gestation length of 205 and 207 days, respectively. Each pregnancy resulted in the birth of a healthy female with a birth weight of 4.9 kg and 5.67 kg, respectively. Evidence of pregnancy was first observed on day 87 post-mating, while during the next weeks, fetal structures like cardiac activity, liver, and gallbladder, vena cava as well as cardiac chambers were identified, and their size determined (Table 1). Vulvar swelling was present 25 and 27 days antepartum and transabdominal fetal movements were palpable at the same time by placing a hand on the abdomen. Training pygmy hippos for minor procedures can be performed using simple designs of open corridors in protected contact. Holders are encouraged to train animals for this procedure in order to gain insight in physiological data of this species.

Table 1. First recognition of gestational signs using transabdominal ultrasound of fetal structures, visual inspection or palpation in a trained pygmy hippo

*The presenting author is vet advisor of the pygmy hippo EEP