Thermographic Evaluation of the Lower Critical Temperature in Weanling Horses
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.
Available from: Camie R Heleski
- "Abbreviations: Num DF, numerator degrees of freedom; Den DF, denominator degrees of freedom; F-test, F-statistic; Pr>F, the probability associated with an F-statistic. more mature horses (Autio et al., 2007), thus their motivation to seek shelter is higher. Further research that looks into the ideal number of sheds or shed space available to outdoor-housed horses should take age dynamics into consideration. "
[Show abstract] [Hide abstract]
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 typically
Available from: Laura Boyle
- "Another concern when keeping cows outdoors during winter is the possibility of cold stress. The lowest critical temperature of an animal is the temperature below which the animals' metabolic rate and the rate of non-evaporative heat loss increase linearly (Autio et al., 2007). Nutrition level, hair length, environmental conditions, subcutaneous fat depth and heat production are among factors that interact to influence the lowest critical temperature (Wagner, 1988). "
[Show abstract] [Hide abstract]
ABSTRACT: This research compared three wood-chip out-wintering pad (OWP; an unsheltered OWP; a sheltered OWP (both with a concrete feed apron); and an unsheltered OWP with silage provided directly on top of the wood-chip bedding (self-feed OWP)) designs and cubicle housing with regard to dairy cow performance during the pre-partum period, and for 8 weeks post partum. Data were compared during 2 years. In Year 1, the unsheltered (space allowance = 12 m2 per cow) and sheltered (6 m2 per cow) OWPs were compared with cubicle housing (n = 49 cows per treatment). In Year 2, all three OWP designs (12 m2 per cow) were compared with cubicle housing (n = 24 cows per treatment, split into two replicates). Animals were dried off and assigned to treatment in the autumn, and remained there until calving in spring. Subsequently, they were managed at pasture during lactation. Outcome measures for analysis during the pre-partum period were feed intake, live weight, body condition score (BCS), heat production and heat loss, and post-partum were live weight, BCS, milk yield and milk composition. In Year 1, all cows had a similar live weight, but both pre-partum and at calving cows on the unsheltered OWP had a lower BCS than cows in cubicles (P < 0.05). However, in Year 2, there were no differences in either live weight or BCS. In Year 1, cows in the unsheltered OWP produced less heat than in cubicles (P < 0.05), but in Year 2, there was no treatment effect. In both years, cows in unsheltered OWPs lost more heat than cows in the sheltered OWP (P < 0.001). Treatment had no effect on milk composition either year. However, in Year 2, cows in the self-feed OWP had higher milk yields than the other treatments (P < 0.05). The lower BCS and heat production values in unsheltered treatments during Year 1 were probably because of higher rainfall and wind-speed values of that year. However, in both years, live weight in all treatments increased pre partum, and BCS did not decrease, indicating that unsheltered cows did not need to mobilise body reserves. Thus, OWPs could be a suitable pre-partum alternative to cubicle housing for dry dairy cows with regard to some aspects of dairy cow productive performance. However, further research should be carried out to investigate longer-term effects.
[Show abstract] [Hide abstract]
ABSTRACT: The demand for information relating to the nutrition of horses in a cold environment is increasing with the popularity of loose housing of horses. This study examined the energy intake and growth of 10 weanling horses from November to March (22 weeks) in a loose housing system (paddock and insulated sleeping hall with deep-litter bed). The horses were measured weekly for body condition and body weight, and the feeding was adjusted according to a horse's body condition. Metabolizable energy (ME) intake was compared to Finnish (MTT 2006) and Swedish (SLU 2004) nutrient requirements for 6-12-month-old horses. ME intake (75.5 ± 11.8 MJ d-1, mean ± SD) was on average 24.6% above the requirements. The intake varied in a non-linear fashion in the course of the winter: y = 0.086x2 - 0.902x + 71.5, where x is weeks from November to March (p<0.001, R2=0.63). Low ambient temperature increased ME intake by about 1.8% in November (p<0.001), 0.5% in December (p<0.001) and 0.2% in January (p<0.05) per 1 °C decrease in ambient temperature when compared to nutrient requirements, but not in February and March. We conclude that the amount of extra energy needed decreases during the winter as the horses grow and acclimatize to the cold housing environment, i.e. as their body insulation increases. Horses gain weight at or above expected rates in cold conditions when the increased energy need is taken into account in the feeding.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.