Protection from the elements - part one: a comparative study of shelter use, hair density and heat loss in donkeys, horses and mules
Observational data and quantitative measurements. Modelling using Generalised Linear Mixed Models (GLMM) to compare variables.
- A study of shelter seeking behaviour
Observations made 1-2 x per week for each animal for behaviour (location, activity, insect harassment and time of day) and for weather (temperature, precipitation, wind speed, luminous flux and shelter conditions)
- A study of hair density
5cm squared Small area of neck hair is clipped four times a year, dried and weighed. Hair strand thickness and length is also assessed.
- A study of heat loss
Comparable data exists for horses. Scientific measurement of actual heat loss from different body parts. Images taken in different ambient temperatures of dry and wet animals.
- To assess the protection donkeys (and mules) require when kept in the UK (and compare this with horses).
- To provide scientific evidence that can inform government, equine charity and equine industry guidelines.
- To improve equid welfare.
- Shelter seeking study. Donkeys spend more time indoors than horses. Donkeys seek shelter more than horses when it rains. Donkeys are more affected by changes in temperature in UK than horses. Donkeys stay inside more when the temperature is below 10. Perhaps some evidence horses start to seek shelter more when temperature is above 20. Although there were no observations in high winds, donkeys may be more affected by changes in wind in the UK than horses. Donkeys may seek shelter in moderate winds. Wind effects are likely to interact with insect density. Horses may be more affected by insect density than donkeys. Other factors may influence donkey shelter use more than insects. Relative (rather than absolute) insect density will affect shelter use.
- Hair density study. In winter donkeys and mules have thinner hair than horses. In spring donkeys have thinner hair than horses. There was no significant change in hair weight in donkeys. Horses grow a winter coat. Mules grow a winter coat but don’t seem to lose it as quickly as horses. Hair weight and length only correlate in spring in horses and donkeys.
- Heat loss study. Data collection was halted, it was decided not to proceed with this part of the project.
It was found that donkeys spend comparatively more time in shelters than horses do. Donkeys were seen to seek shelter more readily when raining or cold, whereas horses sought shelter when temperatures rose above 20°C. Donkeys showed an increase in shelter use when moderate wind speeds were recorded, where-as horses were largely happy to remain outside. When insect harassment outside increased, donkeys seemed more tolerant compared to horses. Compared to horses, donkeys don’t grow significant winter coats and have thinner and shorter hair. Mules were found to be ‘in-between’ when comparing horses and donkeys hair coat properties.
These differences in results seem to reflect the donkeys’ and horses’ evolutionary background. Donkeys are more tolerant of higher temperatures than horses, but not as tolerant of cooler, wetter weather. This, coupled with the donkey’s thinner coat, suggests that the shelter requirements for the two species are different, with donkeys requiring additional protection from the elements in temperate climates.