Sperm motilities were high in these rhinoceroses. These samples had very little accessory gland fluids in them and therefore were probably not representative of a normal ejaculate. Sperm abnormalities were high in these species. White and Indian rhinoceroses exhibited primarily sperm tail abnormalities while the black rhinoceros had a high percentage of more serious head abnormalities.
A video of semen collection and semen processing procedures is available from: Dr. Nan Schaffer, Milwaukee County Zoo, 10001 W. Bluemound Road, Milwaukee, Wisconsin 53226.
Chutes used for restraint in sperm collection. Equipment manipulations and personnel protection is facilitated by restraining rhinoceroses in chutes. During procedures at zoos, observations were made on the effectiveness of current chute systems in restraining rhinoceroses. Chutes should be strong enough to bear the weight plus the force of the rhinoceros. Six- to eight-inch pipes embedded in the ground have restricted these animals. Four-inch pipe has been used but it must be reenforced and firmly anchored. Some of these structures were built with dead-ends, which some rhinoceroses have been reluctant to enter. Rhinoceroses become more rapidly accustomed to chutes that they pass through every day. These chutes are more convenient for personnel. Rhinoceroses loaded in chutes have become accustomed to the close quarters. However, apprehension in some individuals has caused them to either mount the chute or lie down. These movements can cause injury to the rhinoceros or personnel. To prevent mounting, the chute should be higher than the length of the animal and lack places to leverage the front foot or head. High vertical bars have best resolved this problem. Vertical bars also prevent personnel from becoming wedged if the animal sits down. However both vertical bars and horizontal bars will trap personnel, it movement of the animal is extensive within the chute. Tight-fitting chutes have stabilized rhinoceroses and allowed more technical manipulations with the animal. Procedures are also facilitated if the lower part of the chute on either side of the rear of the animal can be opened. This allows better maneuverability of different equipment. Different equipment and a greater variety of procedures are applicable on rhinoceroses restrained in chutes.
Ejaculate volumes are high in rhinoceroses. The low volumes in white rhinoceroses have resulted from incomplete ejaculation in these animals. The highest sperm counts were from an Indian rhinoceros, but these values resulted from sperm-rich samples resulting from the ejaculation of a highly conditioned animal. Volume Concentration Motility Abnormality in ml x 10 / ml % % bicornis (3) 0.2-60 0.1 - 80 0.90 40-90 simum (6) 0.2-8 2.0-300 0.80 20-86 unicornis (2) 0.1-500 0.0-20,000 0-95 5-92 End
These are usually latex coverings filled with warm water. They provide warmth and pressure stimulation to the penis. AVs have been minimally successful in collection of semen from rhinoceroses. Lack of sustained erections in the rhinoceros has made placement of AVs difficult. Furthermore, use of AVs caused ejaculation of only sperm-free fluids. AVs may prove to be useful with further training of rhinoceroses, in high libido animals or olifactory stimulated animals.
Semen has been cryopreserved from Rhinoceros unicornis, Ceratotherium simum, Diceros bicornis. Both pellet and straw cryopreservation methods have been used in the rhinoceros. Poor recovery of rhinoceros sperm from freezing is indicated by low postthaw motilities (20-70%). Some improvement in recovery is noted in the Indian rhinoceros, however only the sperm-rich fraction of this rhino's ejaculate was frozen. In the sperm-poor fraction, sperm were not successfully cryopreserved. This sperm-poor fraction had higher concentrations of accessory gland fluids. Accessory gland fluid is indicated as one of the factors contributing to the difficulty in freezing rhinoceros semen. Due to the problems with cryopreservation, an extended life medium is being developed for use in rhinoceroses in cooperation with Dr. Barry Bavister at the University of Wisconsin in Madison. Samples retrieved from rhinoceroses are initially examined for viability and then mixed with the extended life medium. This medium holds the sperm at room temperature for overnight express shipping back to Madison. At the Madison labs, highly technical analyses of sperm are performed. Preliminary trials with transport of semen have been successful in the rhinoceros.
Rhinoceroses have been anesthetized for electroejaculation but only limited attempts can be made without risk to the animal. Multiple samples can be obtained with minimum or no risk to the animal by semen collection from unanesthetized rhinoceroses.
It has been successfully applied to the rhinoceros. Direct massage of the penis begins with slow stroking that proceeds to vigorous massaging by the operator until the rhinoceros ejaculates. Rhinoceroses are the most receptive to this procedure and therefore it has been the method most frequently used. It is also the easiest to apply. This method was immediately successful in two black rhinoceroses, however, in two white and two Indian rhinoceroses, protracted periods of training were required. For instance, ten months of training were required to obtain seminal fluids with significant sperm counts in one Indian rhinoceros. However, with further conditioning with penile massage, this animal began to ejaculate fluids that contained sperm concentrations in the billions. This method can be successful within a short period in high libido and cooperative rhinoceroses. In less receptive animals, the procedure will take more training, but the results can be highly productive.
Rectal massage in the rhinoceros involves massaging the accessory glands just inside the anus. Rectal massage alone was also ineffective in producing seminal fluids from the rhinoceroses of this report. However, when rectal massage was followed with penile massage, seminal fluids were acquired from one white and one Indian rhinoceros. In addition, with this combination of methods, ejaculates with higher sperm concentrations were obtained from one Indian rhinoceros. These concentrations were significantly higher than penile massage alone. Rectal massage may be useful in rhinoceroses before performing any semen collection procedure.
Rhinoceroses have been anesthesized for electroejaculation, but unanesthetized rhinoceroses have been successfully electroejaculated with both rectal probe and hand-held ring electrodes. As with rectal massage, this stimulation produced seminal emission into the posterior urethra. Semen was then retrieved only after penile stimulation. These fluids also had higher sperm counts than penile stimulation alone. Electroejaculation has been minimally used in the rhinoceros and with further development and improvement, it may become an effective method in the unanesthetized rhinoceros.
Both of these methods have indicated the presence of sperm, but determinations about other semen parameters are limited.
