Abstract

The objective of this  study was to  determine  the  climatic energy demand i.e. the  non-evaporative heat loss expressed in watts  per square metre (W/m2) of horses at low temperatures. Five horses were used; 4 Standardbred trotters and 1 Shetland pony stallion. The horses were  fed for maintenance and light work and housed   in a warm environment (15-20°C). Measurements were made in a climate chamber at 6 different temperatures;  -3,6, 15,20,30 and 37°C. Each horse was in the climate chamber for 1.5 h on each occasion. The measuring  period was 1 h. A hygrometric tent inside the  climate chamber was  used to  measure evaporative heat loss. Ambient air temperature, radiant temperature, deep body temperature, skin and coat temperatures were measured and, together with cutaneous evaporative  heat loss, used to calculate  the  non-evaporative heat loss. The lower critical temperature (LCT) was estimated  for  each  horse  in  the  study. The average LCT of horses acclimatised to an indoor temperature of 1529°C was 18.2"C. At LCT the  average  total heat loss was 127 W/m2. The corresponding  partitioned heat loss was 96 W/m2 non- evaporative and 31 W/mZ evaporative. The results show an average maximal tissue thermal resistance of 0.076 K*m2/W and an average thermal resistance of the coat of 0.087 K*m2/W. The climatic  energy demand for  these horses was 3 W/m2*"C for  temperatures below LCT in dry  and calm conditions. For a 500 kg horse this additional energy requirement could be met by an extra 0.15 kg hay/"C below LCT. Smaller and lighter weight horses need relatively more feed in cold conditions.

Keywords

horse; heat loss; thermal resistance; lower critical temperature

Published in

Equine Veterinary Journal
1995, Volume: 27, number: S18, pages: 396-399

SLU Authors

• Morgan, Karin

  • Department of Agricultural Engineering, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Zoology
Medical Bioscience


Publication identifier

DOI: https://doi.org/10.1111/j.2042-3306.1995.tb04960.x

Permanent link to this page (URI)

https://res.slu.se/id/publ/122638