One clue led to another, and finally I tracked down an interesting account of how--and why--the US Army selected its horseshoes in the mid-1930s. Paved roads were everywhere by then, and they realized that, in the event of war, artillery would be transported over pavement, and the horses' feet would have to accommodate hard-surfaced roads of different types.
The November-December 1935 edition of The Field Artillery Journal tells us about it:
The First Battalion, 16th Field Artillery stationed at Fort Myer, Virginia, recently completed a march from its home station to the concentration area of the First Army Reserve at Indiantown Gap, Pennsylvania, and return to Fort Myer, Virginia.
- Total distance covered, 301.3 miles.
- Average march per day, 18.7 miles.
- Speed varied between 4 and 5 miles per hour.
Horses were changed daily within the teams and sometimes by spare animals. Also the changing of complete teams from gun to caisson helped to equalize the loads. The use of Hippo Straps was resorted to upon suspicion of a sore neck and before the actual sore was apparent.
The shoeing problem presented many difficulties. Horses that walked with a drag walk--that is that would slide their feet over the road--soon wore out their shoes. Some animals would wear out a set of shoes in one day's march, others in two days, and practically all animals had to be shod within a week's time.
It was discovered that by building up a toe calk and heel calks to the same level on each shoe that they would last much longer. Caution had to be taken that heel calks did not wear down faster than the toe calks, thereby throwing the foot out of level. In one battery, 33 horses were shod in a 24-hour period.
As evidence of the splendid work done by the horseshoers, there was no case in which an animal cast a shoe during the entire march.
Another difficulty encountered was slippery roads. These were a serious menace to both animals and men and such roads should be avoided where possible. Roads of this nature are extremely difficult to recognize by motor reconnaissance. Even after stopping your car and making a very careful examination of the road surface it's a two-to-one bet that you are wrong and your nonslippery road will turn out to be something like an ice skating rink.
By experience in selection of routes this much can be said: Slippery roads usually have a high crown, that is the sides of the road slope off rather steeply, they are always made of a mixture of stone and asphalt or stone and some tar product. The appearance of the surface is most deceptive. It may appear rough or smooth and still be slippery. The presence of asphalt or tar on this surface is a sure sign of danger.
Concrete highways were found to be excellent and no slipping occurred on this type of road except where an unusual amount of repair work with tar or asphalt had been carried out.
Certain new types of asphalt pavement--such as that now being laid in Maryland on some of its state roads and the city of Washington, D.C.--make excellent footing for horses. In fact it proved to be the best type of hard surface on which to march.
The results accomplished are attributed mainly to the following reasons:
- A thorough reconnaissance and careful selection of routes;
- The time of day selected for the march;
- The close supervision of the care of animals;
- The care taken to insure a sufficiency of water for animals;
- The superior work of the horseshoers;
- Gaits maintained throughout the march.
The article goes into great details about how often and by what system the horses were watered, and lots of other details.
Looking at these findings in hindsight, there is no discussion about any benefit or down side of raising the horse's foot off the ground with the calks, or what effect the calks may have had on the horses' foot landing patterns.
It seems the goal was to decrease the amount of time between shoeings by increasing the wear that the shoe could provide.
The author also does not comment on whether the horses had better or worse traction on different types of pavement encountered based on whether they were flat shod or shod with calks.
This video shows an artillery team in action during the National Cavalry Competition in 2011 at Fort Reno in Oklahoma; this is a unit from Fort Sill, also in Oklahoma. (Photo via U.S. Army Veterinary Corps Historical Preservation Group)
No followup to this article was published so it's difficult to know if the calked shoes were adopted for permanent use on the horses or if this experiment was just for the benefit of the prescribed long march.
While it seems insensitive to the horses to make judgments based on the longevity of a steel shoe, the Army had very practical design-making systems that would be based on what would happen during a war situation, where the loss of a horse from work because of needing re-shoeing, or the loss of shoes, or the quick wear of shoes might affect the ability of the battalion to move the guns to new positions.
Another question this brings to mind is that calked shoes weren't new, and removable calks were available commercially, but the military had been using flat shoes previously, although the reason behind that preference isn't stated--and might have been a good one. There's more than one way to calk a horse, and they chose the most labor-intensive method: having the horseshoers (the US military did not the use of the word "farrier") forge them in the fire.
No answers to these questions are to be found...at least not so far.
--written by Fran Jurga
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Thanks to the U.S. Army Veterinary Corps Historical Preservation Group for their mention of the horseshoe wear study of the Fort Myers unit.
To learn more:
Historic Hoofcare: Ice Harvesting (special shoes for winter traction)
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