Variation in Growth and Potentially Associated Health Status in Hermann's and Spur‐Thighed Tortoise (Testudo hermanni and Testudo graeca)

Abstract

Captive reptiles often show higher growth rates than in the wild, possibly due to higher feeding intensity. Although health problems are usually linked to inappropriate diets, fast growth itself, such as triggered by appropriate diets fed in high amounts, has traditionally also been considered unfavorable for tortoises. We document growth rates (based on age and mass) from private Testudo hermanni and T. graeca breeders, which are generally higher than those reported for free-ranging specimens, but show enormous variation. Tortoise patients presented to an exotics clinic also covered the whole growth rate spectrum. To test whether fast growth was associated with diseases, the age-body mass relationship of these patients was tested, in a retrospective evaluation, for additional influence factors, such as dietary history and occurrence of certain diet and growth-related diseases. No indication was found that animals particularly heavy for their age were more prone to diet/growth-related disorders. In general, tortoises fed diets with meat/grain were heavier for their age than tortoises fed more appropriate diets; dietary history was not related to a particular disease. The results suggest the age-body mass relationship may not be suitable for testing effects of fast growth; an age-body length relationship would be more appropriate. Animals presented for a diet/growth-related disorder were younger than animals presented for other reasons; there was a significant negative correlation between the severity of pyramiding and age, suggesting that growth-related disorders may well limit the life expectancy of tortoises. Controlled clinical studies are required to fully test this hypothesis.

Assessment of dual-energy x-ray absorptiometry for use in evaluating the effects of dietary and environmental management on Hermann's tortoises (Testudo hermanni)

“…More recently, growth-related disorders, especially pyramiding, have been detected more frequently in younger tortoises, possibly indicating a limitation in the life expectancy of tortoises with such pathological conditions. 74 See Table 2 for remainder of key. ertheless, the authors of that study 74 suggest that this should not be considered conclusive evidence and that controlled clinical studies are necessary to assess the health risks related to fast growth in tortoises.…”

“…74 See Table 2 for remainder of key. ertheless, the authors of that study 74 suggest that this should not be considered conclusive evidence and that controlled clinical studies are necessary to assess the health risks related to fast growth in tortoises.…”

“…The significant differences in body weight between the seminatural control group and the captive group fed vegetables intended for human consumption suggested that captive-reared chelonians should be fed a more natural diet to achieve growth similar to that of free-ranging tortoises, as has been mentioned in other studies. [70][71][72][73] In fact, distinctive differences in the growth of captive and free-ranging tortoises have been reported, 74 with the intrinsic growth rate of each captive Geochelone sulcata being 1.4 to 2.6 times as high as that of a typical free-living tortoise. Whether faster growth rates are linked to health problems 70,73 or to a shorter life expectancy has been debated.…”

Physically Effective Fiber Threshold, Apparent Digestibility, and Novel Fecal Microbiome Identification of the Leopard Tortoise (Stigmochelys pardalis)

“…Captive tortoise diets have traditionally varied in composition, containing domestic produce, hay, and commercial dog and cat foods (Davis, 1979;Donoghue and McKeown, 1999;Lickel, 2010;Ritz et al, 2012). These diets pose two concerns, 1) nutrient imbalance, which may result in nutritional disorders (Donoghue and McKeown, 1999;Fledelius et al, 2005;Ritz et al, 2012), and 2) most extant herbivorous reptiles lack teeth (Spellerberg, 1982;Norman and Weishampel, 1985;Stevens and Hume, 1998), and may be adapted to larger ingesta particles than what these diets provide.…”

“…These diets pose two concerns, 1) nutrient imbalance, which may result in nutritional disorders (Donoghue and McKeown, 1999;Fledelius et al, 2005;Ritz et al, 2012), and 2) most extant herbivorous reptiles lack teeth (Spellerberg, 1982;Norman and Weishampel, 1985;Stevens and Hume, 1998), and may be adapted to larger ingesta particles than what these diets provide.…”