Non-Invasive Infrared Thermographic Assessment of Regional Surface Temperature in Adult Tripureswari Ducks of Tripura, India
Sukanta Das *
Department of Veterinary Anatomy, College of Veterinary Sciences and Animal Husbandry, R. K. Nagar Tripura West, India
*Author to whom correspondence should be addressed.
Abstract
Infrared thermography (IRT) is a quick, non-contact, non-invasive, and stress-free method for assessing the thermal physiology of livestock and birds. The Tripureswari duck is an indigenous duck genetic resource of Tripura registered by ICAR-NBAGR (INDIA_DUCK_1900_TRIPURESWARI_11004) and is mostly reared under backyard and semi-intensive farming systems for egg and meat production, with an annual average egg production of 70 to 101 eggs and an adult body weight of 1.199 kg at 12 months (ICAR-National Bureau of Animal Genetic Resources. Although adapted and evolved in the hot and humid tropical climate of Tripura, its surface thermal profile has not been documented. Therefore, the present preliminary study was undertaken to assess surface temperatures at different anatomical body regions using an infrared thermal camera in six apparently healthy adult male and six adult female Tripureswari ducks. The study revealed that the uncovered and highly vascularised regions, namely the leg (39.83 ± 0.37 °C and 39.53 ± 0.17 °C), periorbital area (39.20 ± 0.12 °C and 39.00 ± 0.17 °C), and under-wing surface (39.07 ± 0.11 °C and 38.82 ± 0.19 °C), respectively, in adult male and female Tripureswari ducks had the highest recorded temperatures and were identified as primary thermal windows for radiative heat loss. Among densely insulated feathered regions, the primary feather area (rump) (29.87 ± 0.32 °C and 30.18 ± 0.18 °C), flank (29.90 ± 0.14 °C and 30.62 ± 0.35 °C), and undertail coverts showed the lowest temperatures. The sharp temperature gradient between the hottest and coolest regions supports the role of plumage in regulating core temperature while allowing selective peripheral heat dissipation. The overall surface temperature pattern recorded in the present study showed minimal influence of sex, with a significantly warmer bill temperature in females (37.57 ± 0.17 °C) than in males (37.02 ± 0.15 °C) (p < 0.05). Males had a significantly higher mantle surface temperature (35.13 ± 0.16 °C) than females (34.28 ± 0.34 °C) (p < 0.05). Chin temperature showed a non-significant trend towards a higher value in males (36.93 ± 0.10 °C) than in females, while flank temperature was slightly higher in females (30.62 ± 0.35 °C) than in males (29.90 ± 0.14 °C). Variation in mantle temperature may be due to differences in dorsal feather distribution density. Given the small sample size, imaging protocol, camera precision, and other physiological, environmental, and management-related variables, it is too early to interpret the absolute significance of sex-related patterns. These preliminary observations, recorded for the first time in the Tripureswari duck breed of Tripura, may help to validate its adaptation and hardiness to the humid wetland agro-climate of Tripura.
Keywords: Tripureswari duck, infrared thermography, surface temperature, thermal windows, thermoregulation, indigenous duck, heat dissipation, plumage insulation, avian thermal physiology