3. The anatomy of the cow’s foot is fairly delicate and particularly prone to the effects of shearing forces
Due to the “ballerina” tip toeing style of a cow, the forces on a cow’s feet where they interact with their walking surface are high. The sole horn is “joined” to the wall horn by the white line; a junction only 5-10mm thick. When I deliver lameness training, I liken that joint to my joinery skills – two (thin) flat surfaces stuck with cheap wood glue and destined to fail! The reason good joiners use fancy joints is because they understand that a thin, flat surfaced joint is inherently weak. But this is exactly what we find at the white line of a cow.
The white line junction is perfectly strong enough and functional for non-domesticated ruminants in a pastoral setting. However, cows walking on concrete (a completely unyielding surface) and having to make sharp turns, often under pressure from a boss cow, dog, human or backing gate is a recipe for a lameness disaster. As you go about the farm, listen for that “scrawking” sound as the feet lose traction and slide across the surface of the concrete. What you are hearing there is shear forces literally tearing the white line. Over time, repeated insult to the white line will weaken it, damage it, cause it to bruise and eventually allow foreign material to work its way in and cause a very painful lameness.
The solution to white line disease is relatively simple – respect the teetering predicament of the ballerina cow and don’t pressure her whilst she is walking and don’t ask her to walk on uneven surfaces such as broken concrete or stony tracks that can also exert shear forces on the white line.
4. Early Detection and Prompt Effective Treatment (EDPET) of Lameness is critical
Some lame cows are an inevitability, however good your preventative measures are. The key to success is spotting these lame cows early and treating them effectively to achieve a cure. The sad reality is that most cases of lameness are detected and treated too late. Many of these cows will then enter a vicious cycle of recurring bouts of lameness and this can change the anatomy of the foot as new bone is deposited due to inappropriate inflammatory responses within the foot, best illustrated by the X ray images of the P3 bone above.
The main problem we face is that a lame cow needs treating when she is mobility score 2 and this is a pretty subtle degree of lameness which can be hard to detect. We often become “lameness blind” when we see the same cows every day so engaging a RoMS accredited independent mobility scorer can be really beneficial and a worthwhile investment.
Unfortunately left undetected, MS2 cows often deteriorate to mobility score 3 by which time the irreversible changes mentioned above have occured that will consign that cow to repeated bouts of lameness throughout her life.