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Hock injuries: What causes them and what to do about it

Michelle Reeves for Progressive Dairyman Published on 29 March 2019

With the first round of proAction’s animal care assessments concluded, the areas that assessors examine on-farm have gained added attention in the industry: injuries on hocks, knees and necks, as well as lameness and body condition score. Although Canadian dairy farmers are scoring well in these categories and generally raising the bar when it comes to animal comfort, we have gathered information in this article to help you monitor your herd’s success with respect to hock injuries.

How do hock injuries develop?

The hock is a large, bony joint with little padding around it for protection (see Figure 1). There are different types of injuries that can afflict hocks (see Figure 2). If the bony area is often rubbing against a hard surface, hair loss can occur. If the rubbing breaks the skin and the animal is still lying on a rough surface, the pressure put on the skin between the bone and the hard lying surface can cut off its blood supply. The skin can become so damaged that an open sore develops.

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Hock area

Any open lesion lets bacteria in, which can then cause infection. Hock swelling is the most severe kind of hock injury, and it occurs when the tissue under the skin or the joint itself gets inflamed. This inflammation can happen in two ways. It can be an acute injury, where the hock suddenly bangs against a hard surface – for example, when a cow slips and falls in an alleyway. Or the swelling can be the result of prolonged pressure on the joint, like when a cow spends long amounts of time lying on a hard surface.

Hock injuries

Are hock injuries linked to other health problems?

Hock lesions have been shown to be associated with lameness. They have a circular relationship with each other, meaning that hock lesions can lead to lameness, just as lameness can lead to hock lesions. In the first case, a swollen hock will make it difficult and painful for a cow to walk normally. On the other hand, if a cow has a painful lameness-causing lesion such as sole ulcers or digital dermatitis, she will lie down for longer periods, increasing the risk of a hock injury by creating more friction between the ground and the sensitive hock skin. For these reasons, lameness and hock lesions regularly occur at the same time.

Hock lesions can also be associated with mastitis. Researchers have studied the bacteria that causes mastitis and found that hock skin could contribute to its life cycle. They state that milk containing the bacteria falls onto the cow's bedding, which then colonizes the hock skin when the cow lies down. This is especially likely if the hock skin is irritated or already damaged. The hock area then becomes a reservoir for the bacteria, which multiply and make their way back onto the teat skin, spreading and causing new mastitis cases.

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What can farmers do to prevent hock injuries?

According to research from the University of British Columbia, increasing the amount of bedding under the cows can be very effective at reducing the number and severity of hock lesions. A few different studies have found that bedding depth is more important than bedding type. In the day-to-day life of a producer, it can be challenging to ensure bedding stays deep and actually stays under the cows at all times. Solutions are usually farm specific and come as a result of a careful evaluation of a farm’s needs. To find the optimal way to provide a softer lying surface for their animals, farmers need to assess the common risk factors: stall surface, bedding type, bedding depth, bedding routines, stall design and stall dimensions.

In one study, switching to deep-bedded stalls reduced the odds of hock lesions by 95 percent. A few other management practices were linked to lower levels of hock injuries, including clean bedding, access to pasture during the dry period and avoiding the use of automatic scrapers for manure removal. Farms where the stalls were well maintained and had a smooth, level concrete base also had fewer hock injuries.  end mark

References omitted but are available upon request. Click here to email an editor.

Michelle Reeves
  • Michelle Reeves

  • Bilingual Extension & Education Specialist
  • Holstein Canada

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