Driving around the Yarra Valley today going from lesson to lesson and home again, I saw over 100 horses (yes, I counted them, just out of curiosity!) standing in the sun wearing winter rugs, with over 3/4 of them in 'combo' rugs (where the neck is all rugged up as well). My car's temperature readout said it was 20 degrees celsius (around 70F) outside, so I had to wonder why these poor horses had been left to sweat all day in their eskimo clothing? Plus, many of them without shade .... They stand alone or in little clusters, unmoving, heads down. Who can blame them for not moving - movement would cause even more heat, especially for those horses on hills. Last night I checked the weather website, so I knew what we were in for today (unseasonably warm weather) and so this morning my troughs were topped up in readiness for thirsty horses! I would hope that horse owners make a regular habit of checking weather forecasts too ... for extremes of weather, warnings, etc. But many, it seems, only care if the weather is suitable for riding ...
While I lean toward the No Rugs camp, I'm trying not to be judgemental when I see horses in the above scenario. A person who agists their horse in a paddock alone and who only visits on a Saturday afternoon, would be at the mercy of the weather, if they choose to rug their horse. When I talk with clients like this, they tell me they put rugs on at the first burst of cold weather (mid autumn and take them off mid-spring), worried their horses will be cold and also to avoid the criticism of their fellow agistees who accuse them of being 'cruel'. Now, I agree, if a horse is standing all alone in a treeless, shelterless paddock, in bitter wind rain and cold, I wouldn't feel good about that either. Obvious thing is to ensure the horse has a shelter (one he will use, ask me for a design) as well as plenty of hay (warms them up in winter) - and a buddy (for many reasons).
I have a student who hails from Germany, and she is constantly amazed by all the rugging of horses we do here in Australia. While we all admire the sleek coats constant rugging produces, we must admit (once we know and understand the scientific facts about how a horse regulates his/her own body temperature) that it's probably not the best thing 24/7 for a healthy, well fed horse who has shelter and friends.
It is a part of the horse owner's responsibility (challenge!) to tend to their horse daily, and where possible, to allow their horse's body to breathe, get dirty and feel free. In short, to ensure their horse feels comfortable. Some horses will try anything to get their rugs off, hence the tears and rips ... but we've fixed that, with electric fencing, special space-age fabrics that won't tear, and miracle strappings that won't budge even with 500kgs leaning on them!
So whatever your position on rugging, please do what you can to help educate someone who doesn't understand how their horse may be feeling (ie: very hot) and do your best not to fall into the trap of leaving rugs on during warmer days. And just for fun, put your heaviest full-length winter jacket on, and stand out in the sun for awhile - will give anyone a whole new perspective!