Thermographic evaluation of the lower critical temperature in weanling horses.
ABSTRACT Accommodating weanling horses in loose housing (sleeping hall with deep-litter bed and paddock) environments in winter at northern latitudes exposes the nonhuman animals to low ambient temperatures. We determined the heat loss of nine weanling horses in a cold environment by infrared thermography to assess their thermoregulatory capacity. The rate of heat loss was 73.5 to 98.7 W/m2 from the neck and 69.9 to 94.3 W/m2 from the trunk. The heat loss was higher at -16 degrees C than at 0 degrees C and -9 degrees C (p</=.01), indicating that the lower critical temperature may have been between -9 degrees C and -16 degrees C. Surprisingly, the heat loss from the trunk was less at -23 degrees C than -16 degrees C (p<.05). The frost on the surface of the hair coat at -23 degrees C probably disturbed the thermographic examination. Thus, thermography is not necessarily suitable for determining heat loss at very cold temperatures. Our results emphasize the importance of taking the housing temperature into account in planning the feeding of cold-housed weanling horses in northern latitudes.
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ABSTRACT: We examined daytime shelter-seeking behavior (SSB) in domestic horses housed outdoors and studied the relationship of temperature, precipitation, and wind speed with SSB. We studied 50-60 Arabian horses (depending upon time of year) and 3-5 draft horses. Horses were divided among 8 pastures containing sheds. There were 2 study phases. In the first, up to 676 scan samples were taken for each pasture over a 12-month period (total observations = 5,025). At each observation, we noted whether or not a shed was being used. In the second phase, randomly selected focal animals were chosen from each pasture and observed twice per week for 16 weeks. Forty-four focal animals were observed (total observations = 3930). At each sampling time, we noted weather conditions and recorded whether each subject was standing or lying inside or next to shelters. Shelter usage ranged from a low of 4.9 m/s. When wind was >2.2 m/s, there was a significant effect of rain on shelter usage, that is, more horses used shelters in rainy, breezy conditions (P 2.2 m/s, there was a significant effect of snow on shelter usage, that is, more horses used shelters in snowy, breezy conditions (P < 0.01). Though overall shelter usage was typicallyJournal of Veterinary Behavior Clinical Applications and Research 09/2010; 5(5):276-282. · 1.22 Impact Factor
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ABSTRACT: =0.63). Low ambient temperature increased ME intake by about 1.8% in November (pAgricultural and Food Science 12/2008; 17(4):338-350. · 1.00 Impact Factor
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ABSTRACT: This review of the use of thermographic technique in equines introduces the principles upon which infrared radiation and thermoregulatory physiology are based and describes the instrumentation used and its practical use. The advantage of this imaging technique is that it is a noninvasive thermographic examination, both from an operational (the animal and the operator) and health (no penetrating radiation is used) standpoint. Advantages and disadvantages of this technique, equine applications, and physiological assessments are discussed.Journal of Equine Veterinary Science 03/2014; 34(3):345–350. · 0.62 Impact Factor