Survivability of orphaned manatee (Trichechus manatus) calves has historically been poor.1 While some of this is due to arrival condition, the milk formula itself can cause adverse gastrointestinal effects. Many different artificial milk recipes have been tried with limited success. Development of a new formula in 2010 has produced promising results in 6 manatee calves at Sea World Orlando.
Until 2010, the formula most commonly utilized at SWO consisted of 50% Esbilac, 25% Isomil and 25% Nutramigen. As of 2008, none of the manatee calves exclusively fed that formula were successfully rehabilitated for release.
Rescued calves brought to SWF receive a full diagnostic workup including: physical exam, blood, fecal, and whole body radiographs. Dehydration and hypoglycemia are common presenting problems. These are corrected through oral ± parenteral fluids and dextrose. Once rehydrated, calves are fed a milk formula every 3 hours for a total of 8 feedings per day. Feeding is initially accomplished via orogastric or nasogastric tubing because of the animal's inability or refusal to accept a bottle.
Gastrointestinal disorders frequently seen in orphaned calves include: diarrhea, constipation, decreased appetite, WBCs on fecal cytology, and positive fecal occult blood. The most severe complication is pneumatosis intestinalis, a sequela to necrotizing enterocolitis, mechanical obstruction/ileus or vascular compromise. In human infants, artificial milk formula is one of risk factors for pneumatosis. Common practice for calves with pneumatosis was to change the formula to 100% Nutramigen, which seemed to help resolve the GI problems but led to static weight or weight loss necessitating a return to the original formula.
In July 2010, an orphaned female manatee was brought to SWF and started on the Nutramigen/Isomil/Esbilac formula. She experienced intermittent GI symptoms that culminated in severe pneumatosis intestinalis on radiographs in October 2010. Her GI disease improved with treatment and Nutramigen but her weight stagnated. In November 2010, she was started on a predigested liquid protein supplement that contained no sugar, fat, sorbitol or carbohydrates and immediately started gaining weight. The base formula was then transitioned from Nutramigen to EleCare, a common formula for human babies battling with necrotizing enterocolitis starting in December 2010. In March 2011 a combination of oils (sustainable palm nut, macadamia, and coconut) was added at a 2:2:1 ratio in combination with MCT oil already in the diet to try to better align the fatty acid composition to natural manatee milk. The calf did very well following the change in formula and was recently returned back to her natural habitat.
To date, the newer EleCare formula has been utilized for eight orphaned manatee calves, including four that presented in poor condition (emaciated, preexisting constipation or pneumatosis). The two that did not survive had disease unrelated to the gastrointestinal tract. The formula (protein 7.9%, fat 10.2%, sugar 5.9%) is closer in composition to manatee milk (protein: 8.0%, fat 8.0–16.0%, sugar 1.0%) than those previously published. It has been associated with less gastrointestinal issues and increased calf survivability.
The authors wish to thank Dr. Scott Gearhart, Dr. Michelle Davis, Dr. Stacy DiRocco, Alice Jones, Kristen Clark, Carmen Peccie, and the entire Sea World Orlando Animal Care Staff for hard work and dedication to these cases.
* Presenting author
1. Campbell TW, et al. Medical problems of orphaned manatee calves (Trichechus manatus latirostris). In: Proceedings of the IAAAM 21st Annual Conference, Vancouver, BC, Canada; 1990.