The main objective of hoof trimming is to prevent lameness by shortening the dorsal wall to restore a more upright foot angle and reducing excessive thickness of the sole at the toe, thereby distributing weight more evenly over the weight-bearing surface of each claw and balancing weight bearing between the 2 claws. To achieve these objectives, several different trimming methods have been described, mainly differing in how they leave the angle of the sole relative to the metatarsals.
A majority of methods advocate a flat sole whereby the abaxial and axial walls are trimmed to be level and perpendicular to the axis of the metatarsals. The differences that exist between these flat sole methods are mainly procedural. Originally advocated by Toussait-Raven, this method focuses on using specific measurement to achieve proper dorsal wall length and toe thickness. Other methods prefer to use hoof angle or sole reading strategies to achieve appropriate length and thickness. Adaptations to the flat sole method have been advocated and have focused on increasing the amount of horn removed underneath the flexor tuberosity (modelling) to reduce pressure on the sole ulcer location.
Alternatives to the flat sole method encourage a sloped sole whereby the abaxial wall is higher than the axial wall. Proponents of this method consider this a more natural sole angle and the procedures to achieve this angle focus on reading the sole and stopping when dehydrated horn disappears.
How commonly are each of these methods used? Of 44 trimmers surveyed at the 2014 Hoof Trimmers Association conference:
- 55% used the Dutch functional trimming described by Toussait-Raven;
- 17% used the sole-reading white line method described by Roger Blowey;
- 12% used the Kansas method described by Ladd Siebert;
- 15% used a combination of methods
Unfortunately, few data exist about the relative efficacy of these various trimming methods. Gerard Cramer’s research group recently surveyed published research studies that examined the effects of hoof trimming on animal behaviour, physiologic changes and efficacy in reducing lameness. Although these studies revealed that hoof trimming may initiate a stress response, change behaviour, improve components of weight bearing, and reduce lameness in specific environmental conditions, few of the studies described the trimming method used in enough detail to determine effects of method on any of these outcomes.
Clearly, if we are to end the controversy over which trimming method is best, a well-controlled study comparing methods and their outcomes in both lame and non-lame cows is required.
source: Grant C. Stoddard & Gerard Cramer, A Review of the Relationship Between Hoof Trimming and Dairy Cattle Welfare, Vet Clin Food Anim 33 (2017) 365–375 (available here).