Research shows the welfare, comfort and production of dairy cows can benefit significantly from management practices such as deep sand beds and well-grooved concrete, but an emerging problem indicates these practices may cause havoc in the heifer sheds. Hannah Noble reports.
The occurrence of reverse corkscrew claws in heifers was a relatively unheard of foot health concern until recent years.
Veterinary consultant Sara Pedersen, of Farm Dynamics, and cattle foot trimmer Joe Kirby, of Kirby Cattle Services, say there are simple ways of preventing the lesion before it becomes a widespread problem on UK dairy farms.
Ms Pedersen says: “Normally the traditional corkscrew would affect the outside claw of the hind feet of older cows, but the ones we are seeing in heifers are predominantly affecting the inside claw of the hind feet, hence calling it reverse corkscrew.”
The reverse corkscrew claw is caused when uneven pressure is placed through the foot, forcing it to grow in an abnormal way and it usually affects the rear inside or medial claw.
Mr Kirby adds: “Effectively the outside of the foot is twisting down towards the ground. It can be so severe sometimes that the wall which is normally on the inside of the foot twists so it is on top of the foot.
“Rather than the outside claw being the claw the heifer would normally bear the most weight on, the weight distribution gradually reverses to the inside claw and, in the most severe cases, they are taking all of their weight through the inside claw.”
Among cattle foot health specialists, the general consensus is that there are a number of factors combining to create the issue in heifers.
Although the problem seems to be more widespread in the USA than in the UK, Ms Pedersen says all the farms which have encountered problems tended to rear heifers in a specific type of system, with a specific set of circumstances, many of which are commonplace on dairy farms in the UK too.
She says: “We know how to manage adult cows to ensure good foot health with good grooving and sand-bedded cubicles key to this. However, when we apply these principles to growing heifers, it can lead to problems.”
Some of the contributing factors to reverse corkscrew claws in heifers include:
Ms Pedersen says: “I think we have really improved our ability to create very grippy floor surfaces, but this actually enables heifers to push harder against the feed barrier as they feel more confident. Ultimately, this creates more forces through the feet, so this needs to be managed carefully.”
This is especially a problem in heifers with reverse corkscrew claws which have little tissue between the twisted pedal bone and the hoof sole.
Another property of sand which contributes towards the hoof lesion is the friction it provides on the concrete flooring which allows the heifer even more grip.
Ms Pedersen says: “We have really improved our ability to rear heifers and, when combined with the use of more sexed semen, perhaps this is leading to more overstocking of sheds.
“This leads to more competition for space at the feed barrier and therefore more pushing.”
Heifers also take longer to eat than an adult cow, as they have a smaller bite size, meaning they spend longer at the feed barrier and therefore longer pushing against it.
She says: “We often expect heifers to grow into the system, but it is important to try and ensure the system can be altered to accommodate growing heifers. For example, the height of headrails can be adjusted as they grow to help avoid some of the concerns around pushing and stretching.
“Head locking yokes can also be an issue because heifers have more in their way when they are feeding. They have to work a bit harder to get to the feed and push more compared to a simple rail or diagonal feed barrier.”
Abnormal forces cause anatomical changes in the skeletal makeup of the foot, resulting in twisted pedal bones and even bony spurs in the worst cases. This means forces will be exerted through the foot in the wrong way for the rest of the animal’s life and will predispose them to problems later on.
Ms Pedersen says: “These heifers are at increased risk of being over-trimmed and suffering from thin soles, because instead of the bottom of the pedal bone being flat in the foot, it is twisted so the outside of the pedal bone is closer to the sole along the outer wall of the hoof.”
Mr Kirby says despite being able to manage the problem to some extent, heifers and cows with these lesions require a lot more maintenance than the average cow and, unfortunately, there is no way of reversing the effects.
He says: “As foot trimmers, 90% of the problems we see in cattle are in the outside claw, but we are actually starting to see the problems becoming more prominent on the inside claw on heifers.
“In terms of the way you tackle these lesions when you are trimming, it would not be your traditional way you would trim a foot. It should only be done by experienced trimmers.
“Traditionally, when we trim a cow’s foot we are trying to shift the weight from the outside claw to the inside claw, but with these heifers you actually have the reverse problem.
“More of the weight is on the inside claw and what you are trying to do is balance it up with the outside claw while ensuring you do not compromise sole thickness.”