The appearance of footrot is fairly typical and begins as a swelling of the skin between the claws. This swelling usually begins within 24 hours of the onset of the infection. The toes become separated due to the swelling and the skin appears reddened. The foot is very painful and the animal can be quite lame at this time. A fissure or crack develops along the swollen area for part or all of the length of the interdigital space. Yellow to grayish tissue extends from this crack and the lesion has a characteristic foul odor. The area around the coronary band can be swollen and red. Affected cattle can have a mild fever, refuse feed, lose weight, and be mildly to severely lame. Also, it is common for affected cattle to loss a considerable amount of weight during a bout with footrot. If the footrot lesion does not heal satisfactorily, very serious problems can develop. The structures just beneath the skin of the foot include the bones of the foot, the tendons, and joint of the foot. If these underlying structures are invaded by bacteria-particularly the joints, bones, or tendons, therapy is very difficult and the chances of recovery are much lower.
Footrot can usually be recognized in typical cases; however, a number of conditions can be confused with footrot. These conditions include corns, puncture wounds due to nails, needles, or other sharp objects, sole abscesses, fractures of the bones of the foot, and a newly recognized condition that primarily affects dairy cattle, "hairy footwarts". All lame feet should be carefully examined and it should not be assumed that all lame cattle have footrot. If you have any questions regarding the condition affecting your cattle, you should contact your veterinarian for diagnosis and advice.
Source: John Maas, DVM, MS, Diplomate, ACVN & ACVIM, Extension Veterinarian, School of Veterinary Medicine - University of California-Davis