With the price of a new, professionally made horse blanket ranging from $60 to over $140, horse lovers who also own a sturdy sewing machine are choosing to make a horse blanket at home.
Yes, you can. With enough cheap pattern material, a patient horse and a little time, you can make a custom blanket pattern that's the perfect fit for your equine friend.
Start at the thrift store. Used bedsheets are the perfect material for horse blanket patterns---they're cheap (around $5 or less), easy to get, and the sheet is much wider than any material you will find at the fabric store. Depending on the size of your horse, a queen-sized top sheet, i.e. not the kind with elastic at the corners, should be big enough. Try to get a sheet that's in good shape, not threadbare with use. You want your pattern to last a long time.
Try the easy way first. If you already have a horse blanket and want a pattern in order to make an additional or replacement blanket, spread the sheet out on a flat surface, lay the old blanket on top, and trace around the edges of the old blanket. If you don't have a horse blanket, see if you can borrow a friend's, try it on your own horse to make sure it fits, then trace that one.
Either way, add 1 inch of sheet all the way around your tracing for seam allowance and cut it out. You have your pattern.
Measure your horse. If you don't have access to a blanket or your horse is particularly hard to fit, you will first need to measure him from the withers to just beyond the croup. That is the length of the blanket pattern. Don't forget to add 1 inch on each end for seam allowance.
Then measure your horse from the spine to the knee. This is the width of the blanket pattern. Again, don't forget to add 1 inch on each side for seam allowance.
Finally, measure your horse's chest from shoulder to shoulder. Rather than a straight rectangle, you will be making a rectangle with an added bit at the one end to cover the chest. Look at a friend's horse blanket to see an example of this. You will need to add a few extra inches to be able to overlap each other with fasteners so the finished blanket completely covers the animal's chest.
Draw your pattern. Lay the sheet on a flat surface, and mark or draw your horse's measurements on it. Since it's a pattern, not the actual blanket, it doesn't matter which way you orient the measurements, just so they fit on the sheet somehow. Cut around your drawing, and you have your blanket pattern.