8 interesting facts about the anatomy of the cow’s foot

In this article, Tom introduces eight interesting anatomical facts about the amazing bovine foot and looks at how they can impact on certain aspects of lameness, its management and control.

Consider the facts here and it’s no wonder that cows need time and money invested in caring for their feet. Teetering on their tiptoes like a 600kg ballerina is no mean feat for our wonderful cows. Lameness, or poor mobility, has never had more attention from various sectors of our industry. Whilst it impacts negatively on cows’ welfare, it also costs producers money. A typical case of lameness costs in the region of £300, or put another way, £2 per day lame. In terms of pence per litre of milk, reducing your prevalence of lameness (mobility score 2 or 3) from 20% to 10% could see you 0.9ppl or more better off. To see for yourself, have a look at the very useful AHDB dairy lameness cost calculator.

How does the anatomy of a cow’s foot impact on the cow and those of us involved in cattle mobility management?

1. Cows need regular preventative work doing on their feet – routine foot trimming

Walking on the equivalent of fingernails that are growing at a rate of 5mm per month means that a regular manicure/pedicure for our cows is obligatory. Every cow should have her feet routinely inspected and if necessary, functionally trimmed by a competent foot trimmer at least once per year. Typically, this will be around the time of dry off but an additional early lactation inspection/trim (60-100 DIM), especially in high yielding cows may be advisable.

Cows that have not had a routine foot inspection/trim are more likely to have overgrown claws that tend to cause more weight to be distributed towards the heels and excess sole horn at the sole ulcer site. Trimming at dry off is also an essential part of mitigating some of the risks associated with calving and trimming at 60-100 DIM can be helpful at nipping sole bruising or sole ulcers in the bud.

X Ray, CT and ultrasound scanning has recently provided us with some compelling evidence that, for most Holstein dairy cows, we should be trimming the toe to at least 85mm rather than the industry standard 75mm dictated by the original Dutch Five Step Method. There is no doubt as time goes on we will learn even more in this area.

2. The anatomy of the foot makes the period around calving particularly high risk

The time around calving represents a particularly high risk period for the cow for several reasons:

• The hormone relaxin, released at calving to allow the calf to pass through the pelvis, inadvertently also causes the bones of the foot to drop within the hoof capsule and pinch the quick at the sole ulcer site.
• The digital cushion, that functionally dissipates forces in the foot, is made of fat and is prone to shrinkage in early lactation due to negative energy balance. This increases the risk of pinching of the quick at the sole ulcer site. A potential perfect storm when combined with the effects of relaxin described above.
  Fresh calved cows often suffer social group changes that increase the risk of them having to stand for longer at a time when the structures in the foot are at their most vulnerable. This again increases the risk of pinching of the quick at the sole ulcer site.
• Hoof horn grows at about 5mm/month so the impact of damage to the quick around calving time takes about 2-3 months to manifest itself on the sole surface as either sole bruising or an ulcer.
• Unfortunately, many fresh calved cows are not given the preferential management that they need, and this can lead them to stand for longer than necessary and exacerbate negative energy balance leading to weight loss. Improving cow comfort with fresh cow loose housed groups and taking steps to minimise negative energy balance can significantly reduce the chances of “calving related lameness” occurring.

X-ray of digital cushion
Credit: Dr Reuben Newsome/University of Nottingham/AHDB

White line disease

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.

Recent studies into the effective treatment of lameness have shown that as well as needing to treat promptly, efficacy is significantly increased if a lame cow is trimmed, blocked and given a dose of a non-steroidal anti-inflammatory drug (NSAID). In fact, it was the addition of the NSAID that really made the difference as shown in the table below – increasing the success of treatment from around 70% to 86%. Antibiotics are rarely needed for uncomplicated white line and sole ulcers, so this makes nil milk withdrawal NSAIDs particularly attractive.

“Evaluation of treatments for claw horn lesions in dairy cows in a randomized controlled trial”, Thomas Et. al., Journal of Dairy Science, 2015.

EDPET

• Regular mobility scoring – the gold standard would be fortnightly
• Lift the foot of all MS2 & MS3 cows immediately
• Perform functional trim eg Dutch Five Step Method
• Use more blocks and NSAIDs even on mild cases – there is excellent evidence to support this
• Practise routine hoof inspection/trimming at least once per year performed by a competent, professional hoof trimmer

Lameness treatment, management and control is a huge subject and an area we are learning more about all the time. Our Feet First Team can assist in all aspects of this. Simply call Emma Harding on 01948 665593 or LLM Lancs on 01772 866014 for more details about how the team can help