Weight Bearing As It Affects Horn Growth
Of the 90 percent of lameness in dairy cattle involving the feet, the majority of these disorders affect the outside claws of the rear feet. This raises a red flag as if nutrition and feeding errors were responsible for these conditions, then we would see similar lame conditions in all the claws of all the feet. Through years of study, it was discovered the likely cause of such disorders is linked directly to weight-bearing and the effect of housing conditions. That is, confinement to concrete or other hard surfaces has an affect on the weight distribution.
Weight-Bearing in Cattle
The anatomical differences between the lateral and medial claw of rear feet have significant implications on weight-bearing hoof overgrowth. As the hind legs of cattle are connected via ball-and-socket joint, this creates a rigid structure of support. One might think the weight distribution to be equal; however, during movement the weight distribution between and within the claws change. This weight distribution is believed to be a significant reason for accelerated hoof growth and higher instances of disorders.
The front feet of cattle are more flexible as they are not connected by a ball-and-joint-socket. As they are connected by tendons and ligaments, weight distribution effects are cushioned. Variations of weight distribution are less pronounced and occurrences of lameness is less frequent.
Principles of Hoof Trimming
The art of hoof trimming is based on a unique set of scientific principles. This scientific basis follows the concept that functional weight distribution is even distribution of weight. A toe length of three inches will correlate with a sole thickness of ¼ inch creating evenly distributed weight bearing forces. However, variations in surface hardness will affect the rate of which hoof growth occurs. That is, toe length on cattle kept on hard surfaces will be shorter than those kept in a softer environment. Should a toe happen to overgrow, the thickness will increase, displacing the weight bearing axis back. This results in weight forces towards the heel, leading to pressure points that may induce sole ulcers.
Normal horn growth is about ⅕ to ¼ of an inch per month. Although you may think cattle kept on hard surfaces need less frequent trimming, just the opposite is true. Their hooves need to be trimmed frequently due to the fact the hard surface is more uncomfortable for the animals. Also, the hard surface causes more blood flow to the hoof, thus increasing growth rate.
Cattle will benefit from trimming 1 to 2 times annually. However, circumstance dictates frequency and there will be cows that need trimming more often. That is, you must take into consideration housing conditions, hoof growth and claw disease when determining the frequency of hoof trimming.