Improvised explosive device detection (IDD) dogs explore up to 40 km of land daily and therefore have energetic demands that may be above the National Research Council’s requirement for working dogs. This study was designed to quantify metabolic energy intake (MEI) and total energy expenditure (TEE) in a group of IDD dogs. Two groups of dogs that had undergone different training protocols (CP1, n=8 and CP2, n=11) underwent a 5-day deployment simulation that consisted of combined road clearing, orbit and point-to-point activities and lasted approximately 9 h per day. The CP1 dogs were fed according to the IDD Marine Corps Manual, while CP2 dogs were offered additional calories based on pilot study data of energy expenditure. The MEI was calculated based on feed intake rates and chemical composition of the diets. TEE was quantified using the doubly-labelled water technique in 2 of the CP1 dogs and 7 of the CP2 dogs. During the 5-day deployment simulation the MEI ranged from 189-310 kcal/bodyweight (BW)0.75 per day, with the CP2 dogs at the higher end because they were offered more feed. The TEE ranged between 375-507 kcal/BW0.75 per day, above the MEI, suggesting the dogs were in negative energy balance and metabolic reserves within the body were combusted for energy production. These findings reveal that energy requirements of deployed military working dogs are higher than previously published metabolic energy requirements of working dogs.

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Leptin is a hormone that plays a key role in regulating energy intake, appetite, and metabolism. In some mammals, leptin has been shown to circulate at levels proportional to body fat, which could make it useful for nonlethal evaluation of body condition. Leptin's usefulness for estimating fat levels (i.e., body condition) of white-tailed deer (Odocoileus virginianus) is unknown. We quantified serum leptin concentrations in a sample of free-ranging, female deer collected in July 2008 and March 2009 from coastal North Carolina, USA. We compared leptin concentrations with kidney fat index, femur marrow fat index, and kidney fat mass. Additionally, we assessed differences in leptin concentrations between the two seasons, lactating and nonlactating females, and gestating and nongestating females. Leptin concentrations were similar between seasons but were lower in lactating and gestating females. We did not detect significant relationships between leptin and the body fat metrics, indicating that leptin may have limited value for estimating fat reserves in white-tailed deer.

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