Take Control of Your Herd’s Foot Health Dr. Sarel van Amstel, BVSc, Dip Med Vet, M Med Vet, Diplomat ACVIM By Rudy Pooch Lameness is an important economic problem in all sectors of the cattle industry. One of the main problems is laminitis that leads to changes in claw Dr. Sarel van Amstel conformation and results in chronic lameness, weight loss, reproductive losses and early culling. Subacute/subclinical laminitis, mostly seen in cattle, is a systemic disease in which the foot is one of the main targets because it’s extremely vascular and has a rich nerve supply. Inflammatory mediators and endotoxins cause disruption in horn growth, alterations in blood flow and stimulation of pain receptors leading to pain and lameness. Laminitis is a multifactorial condition associated with nutrition, body weight, claw conformation and size and normal weight distribution. In general, healthy feet are highly
dependent on normal rumen fermentation.
Structure and Weight Distribution The foot consists of two digits, and at the end of each digit, is a claw. The “medial” is the inner claw, while the “lateral” is the outer claw. In a perfectly normal back foot, the outside claw is slightly bigger than the inside claw and bears more weight than the inside claw. Most often, lameness will occur in the outer claw, particularly in the back legs. More weight being placed on the outside claw makes this area susceptible or prone to concussion due to weight-bearing forces. The back legs are a rigid, boney system going through the pelvis. There’s not much flexibility between the outside and inside claws. In the back legs, the normal weight distribution ratio of a heifer is 60:40 between the outside and inside claw. The front legs are a muscular structure attached through the chest, allowing them much more flexibility between the two claws than the back
legs. The weight distribution ratio is 50:50, although the medial claw bears slightly more weight than the back under normal conditions. The third phalanx (P3) is located inside the foot. On the outside of P3 is the horn structure of the claw. It’s suspended within the claw by ligaments including the distal cushion and normally gives when the animal walks. “When it bears weight, the P3 doesn’t sink down evenly. It sinks down more to the inside and causes concussion and bruising to the corium. This is the most common site for sole ulcers,” said Dr. van Amstel, retired professor in the Large Animal Clinical Sciences Department at the University of Tennessee College of Veterinary Medicine.
Nutrition Nutritionally, many different factors can contribute to laminitis including incorrect fiber to grain ratio. For example, many producers in the Midwest run cattle on harvested cornstalks during the fall and winter months. Cattle load their rumen with whole corn, a highly fermentable
Figure 1: Diagram sourced from Manual Of Foot Care In Cattle by Jan Shearer, Sarel van Amstel and Adrian Gonzalez, published by the Hoard’s Dairyman Bookstore, www.hoards.com/bookstore 38
RED ANGUS Magazine October 2021
