This photograph is from an ox, and is an easy one. It is an excellent portrayal of an important lesions. Note its color, texture, note intramuscular septa, and imagine what this might feel like and perhaps what it might smell like. It is obvious that this animal suffered an acute disease and was perhaps without the function of this muscle. It might have been lame, depending on where this muscle is from.
You have undoubtedly assumed that this is from a calf with blackleg, and that is correct.
What is the etiologic agent of blackleg?
