Hand rearing should only occur if absolutely necessary.
There are successful experiences with the hand rearing of Black rhinos. Hand rearing is only recommended when there is no other possibility. The infant should always remain with the mother and (when needed) be additionally bottle fed. Hand rearing could become necessary when the young is rejected by the mother or medical problems with the mother and / or infant exist, or when the infant fails to nurse. The hand rearing of an infant has to be considered very carefully and intensive care of one or two keepers will be needed.
Record keeping: Accurate record keeping is extremely important. Maintain a daily log of formula intake, body weight, body temperatures, and faecal output and consistency. It is helpful to have this information in a format such that one month’s statistics may be viewed on one page. Note exercise times and behavioural changes each day. Rhino calves should urinate large amounts daily without the assistance of physical stimulation. Weigh the calf at the same time each day for two to four weeks, every other day until two months of age, twice a week until three months of age, and once a week until five to six months of age. Weights may be obtained by leading the calf onto a platform scale while it is nursing on a bottle (Gage, 2002). All information should be sent to the EEP coordinator.
The following items should be on hand:
Pliable, one litre polyethylene laboratory bottle with a narrow mouth
Artificial lamb’s nipple with a crosscut opening
Calf bottles and calf nipples
Large containers with screw tops for storing formula
Large cooking pot, hot plate, large refrigerator, sink, disinfectant and bottle brush
Measuring cups, gram scale, walk-on platform scale
Large stuffed animal to serve as a companion
A radiant room heater, or other safe heating system, and an electric blanket may be needed (Gage, 2002)
Housing: For a healthy calf the air temperature should be between 15-30oC. If the air temperature is expected to drop below 15oC, for example during the night, a heater will be needed. When the calf is hypothermic or debilitated a constant temperature of 26-30oC is recommended. For bedding substrates like soft hay should be used. Wood shavings should be avoided due to possible intake, when the calf lies with its lips on the ground (Gage, 2002).
For mental and physical development a large exercise yard is important. A healthy new-born should be walked for half an hour, twice a day. The first few days the calf is allowed to explore the yard on its own with a keeper nearby for emotional security. A rhino calf loves to run and will do so after three-four days of age. This daily exercise encourages normal defecation (Gage, 2002; Wagner and Edwards, 2002).
For comfort and companionship a large stuffed animal may be placed with the calf. If another large ungulate neonate is available, it may be placed with the rhino calf after it has reached one week of age, replacing the stuffed animal. When there is no neonate ungulate available a young or adult sheep or goat can be used. Developing the bond between the two animals might take a week. First when one of them is nervous, it may be necessary to separate them during the night, putting the stuffed animal back in with the rhino calf. A companion animal also discourages the rhino from becoming dependent on keepers for security and companionship (Gage, 2002; Wagner and Edwards, 2002). Before introducing any companion animals it is essential that you know the full health history of the animal and the group it came from. Also, the animal must be healthy and parasite free. It is recommended that you check with your own veterinary advisor before any introduction to ensure that disease is not transmitted from the companion animal to the young rhino.
Toys should be provided at an age of one or two weeks. The toys should provide the calf to exercise its natural behaviour of head butting. It is important that the animal does not practise this behaviour on the keepers, due to potential danger, this behaviour should be discouraged. Suitable toys are: two electric cart tires bolted together in order to keep them upright and rolling, large plastic trash cans, boomer balls, or any other object which can be pushed around without the risk of the young rhino wedging its head inside the object (Gage, 2002).
Milk composition and formula selection: Based on available data, rhinoceros milk is more dilute than milks of other ungulate species. It is low in solids, low in protein, very low in fat, and high in sugar compared with milk of equids, bovids and cervids (Dierenfeld, 1996).
Though rhinoceros’ milk is different from cow’s milk, the latter may still be appropriate for hand rearing rhinos if used in combination with other ingredients, like extra iron, vitamins and lactaid. There is also special artificial milk available, and horse milk can be used as well. Cow’s milk is low in iron; consequently, an iron source should be added to the formula at two drops per 100 g of formula. In addition, infant vitamins should also be added to the formula at two drops per 100 g of formula. Some infant vitamins may contains added iron.
The animal may also benefit from the addition of lactaid at one drop per 100 g of formula. Lactaid aids in carbohydrate digestion and helps prevent possible gastrointestinal distress (Dierenfeld, 1996). If the neonate is less than 24 hours old, colostrums diluted 50% with water or an electrolyte solution for ungulates, such as Replenish, should be administered for the first 24 hours. Though species-specific is preferred, cow colostrums may be used. To avoid gastrointestinal distress, a diluted formula may be offered beginning on day two. The formula can be gradually increased to full concentration depending on the animal’s health, including weight gain and stool condition.
Feeding regime: Hygiene is very important in order to avoid contamination of the milk. The calf should be preferably bottle fed instead of feeding with a bucket to avoid hasty drinking. Fresh water should be available at all times.
Quantity fed should range from 10% to 13% of body weight. Rhinos do not need to be fed around the clock. Animals should be fed every two hours. Because infants suckle during daylight hours, feeding should be equally spaced in a twelve hour period not to exceed 3% of body weight at any one feeding. It is recommended that feeding begin with 10% of body weight split equally into seven feeds two hours apart during daylight hours.
The quantity of formula fed should be adjusted daily based on the animal’s weight. Animals should be weighed at the same time each day. During the first weeks feeding should also be during night, with an interval of two to three hours. If diarrhoea occurs, the quantity of formula fed should be decreased or the formula diluted until stool condition returns to normal. If diarrhoea is persistent, an electrolyte solution can be used to dilute the formula, replacing some or all of the water. In addition, the number of feedings can be increased to lessen the quantity fed at any one time.
Formula can be prepared ahead of time and warmed as needed. Water should be boiled to decrease possible contamination due to pathogens, and then refrigerated before being added to the formula. The formula should be refrigerated and used within 72 hours.
Prior to feeding, the formula should be warmed to the animal’s body temperature. Calf nipples work well. Bottles should be boiled before use. Diluted bleach may be used as a disinfectant. Formula left over from each feed should be discarded (Dierenfeld, 1996; EAZA yearbook, 1995; Gage, 2002).
Weaning: Weaning may begin as early as six months and should be completed in one year. Weaning is a slow process involving carefully monitoring body weight and solid food consumption. Animals should have access to solid food at all times.
A nutritionally complete pelleted diet such as Calf Manna, horse feeds or high fibre ungulate pellets, in addition to alfalfa hay, is appropriate. Formula may be decreased by gradually elimination the number of feeds or decreasing the amount offered per feed and gradually decreasing the number of feeds (Dierenfeld, 1996; Gage, 2002).