Abstract
The horned guan (Oreophasis derbianus) is currently a critically endangered species; the remaining populations are very small, severely fragmented, and presumably declining.4 It is a cracid that is endemic to Guatemala and Mexico, inhabiting the few cloud forests remaining in the area. Mature animals can weight up to 2 kg.1 The earliest records of horned guans in captivity came from the 70s, and it was not until 1994 that the first successful captive reproduction took place.1,2 The international Studbook currently reports 60 captive live animals.2 Africam Safari Zoo located in Puebla Mexico houses 26 individuals.
At Africam Safari, horned guan enclosures are spacious and contain several perches for roosting due to their arboreal nature, as well as vegetation to provide cover. Generally, breeding pairs are maintained together all year through with exception of aggressive individuals. Some degree of visual isolation of breeding pairs from each other and also from humans is desirable. Nesting boxes are placed high in the enclosure, and breeding generally occurs in the beginning of the year (January through April). The clutch size is usually 2 eggs and the incubation period is approximately 32 to 34 days. Artificial incubation and hand rearing chicks has been successful; resulting in two clutches from each pair per year.
Behavioral observations have revealed that fruit (82%) and leaves (17%) make up the majority of the diet in the wild, and invertebrates may also be eaten occasionally.3 In captivity 9 different vegetables including avocado are the base of the diet plus a commercial poultry concentrate.6
Horned guans tolerate capture with handheld nets and handling for induction of inhalation anesthesia (isoflurane). Struggling may produce hyperthermia and procedures should be planned for cooler times of day. It is common for them to lose feathers if not handled carefully. Stress produced with these procedures is variable between animals but it is common to see a decrease in food intake for several days after handling, and severe weight loss in cases where periodic handling is needed. The standard method of identifying the gender is by direct laparoscopic visualization of gonads.
In general, horned guans are hardy birds and are not prone to disease. Similar to other cracidae, it is believed, that horned guans are susceptible to most of the diseases affecting poultry.5 Viral diseases have not been diagnosed in horned guans at Africam Safari. A fatal case of tracheal granuloma (aspergillosis) was diagnosed during quarantine in one individual. Low numbers of endoparasites have been found and included ascarids, Trichomonas spp., Amidostomum spp., Capillaria spp., Strongyloides spp., Heterakis spp., and Coccidia. Bacterial species found in routine surveys in adult animals for enteric pathogens include, Serratia spp., Klebsiella pneumoniae, Enterococcus faecalis, Enterobacter spp., Escherichia coli, Micrococcus spp., Staphylococcus spp., Streptococcus spp., Proteus vulgaris, Klebsiella rhinoscleromatis, Proteus mirabilis, Edwarsiella tarda, and Proteus morganii.
Horned guans presented for medical attention for non-infectious diseases were found to have general clinical signs such as emaciation, weight loss, abnormal behavior, and lethargy. Dystocia was the most common medical problem presented so far (n=5), affecting mature hens and first-time egg layers. This condition presumably arises due to stress and low environmental humidity compared to their natural habitat. One animal was presented with uterine prolapse, and others with chronic dystocia with severe tissue pressure necrosis (n=3). In birds where treatment could be initiated early, good results were obtained although the effect on the long-term reproductive status of the affected individuals is unknown.
Stress and trauma due to cage mate aggression especially during introduction of new pairs, can lead to fractures, integument lacerations, weight loss, and death (n=1). The known tendency in cracids to pick objects off the ground, has produced one case of foreign body related problem. One case of bilateral cataract was surgically treated with partial success. No neoplasias have been diagnosed.
Abnormal hatching has been observed with artificial incubation, including malpositions (n=3) and malformations of the yolk sack with entrapment of one or both hind limbs (n=5). Variations in the frequency of rotation are possibly the etiology for these conditions. There was one case of lateral leg rotation and two neonates died of egg yolk contamination and septicemia
Literature Cited
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