In winter some addition to the ordinary shoe is necessary to prevent horses from slipping on ice and snow. In Great Britain the weather is so changeable that a regular provision for frost is seldom made, as it is in countries where ice and snow prevail for weeks or months at a stretch. Here our roads are covered with ice and snow with very little notice, and may be free again in a day or two. Horse-owners therefore provide temporary arrangements to meet the short, occasional spells of slippery weather. The most temporary method of affording foothold is by the use of what are called frost-nails. These appliances are very similar to the ordinary horse-shoe nail but with a larger head, and brought to a sharp point or to a chisel-edge. The smaller ones may be driven into the holes from which a nail has been removed. The larger are only used at the heels in an extra hole specially provided for them. These holes are punched through the heels of the shoe, which is fitted a little wider than usual, so that a frost - nail when driven does not enter the hoof at all, but passes through the shoe, and is fixed by being twisted over the shoe. Frost - nails are very useful for an emergency, but not for continued use.

Fig. 646. - Frost-nails.

When frosty weather looks as though it were to continue for some time, horses are "roughed" or "sharped". The shoes are taken off, heated in the fire, and the heels turned down so as to form a sharp projection that will cut into ice or frozen snow, and so give firm foothold. On hard roads this sharp projection soon becomes worn away, and the process of roughing has to be repeated. This repeated removal of shoes injures the feet, not only by the driving of nails through old holes, but by the shortening of the shoe, necessitated by the roughing. So injurious is repeated roughing, that a better but more expensive method is now adopted by all sensible men who have horses of value that must continue at work during frost and snow. From about the middle of November to the middle of March sufficient frost to render roads unsafe may at any time appear. To meet this the shoes, before being put on, are furnished with holes at the heels, or both at toe and heel. These holes are made with a thread, into which movable steel sharps can be screwed when wanted. To keep the holes clear a cork may be screwed into them, or better still, square steel plugs may be used during ordinary weather, and replaced by the sharps when frost arrives. No removal of shoes is required by this method, and no sharp projections need be left in the shoes when the horses are in the stable.

Fig. 647. - Steel Sharps to be Screwed into Shoes when required.