Effective control of lameness in dairy cows
Awareness
of the impact of lameness on dairy cow welfare and economics has grown
massively in the last 30 years. Our understanding of the causes and risk
factors have also improved. This article covers the major advances in
our understanding of how to control lameness.
The
majority of lameness is down to a small number of conditions. For the
grazing herds white line separation leading to abscesses and infections
under the wall is usually most common, followed by stone penetrations,
with or without thin soles. For housed herds the problems tend to be
sole bruising, sole ulcers, white line separation and digital
dermatitis. Young stock will be sporadically affected by inter-digital
necrobacillosis (otherwise known as foul, footrot or phlegmon), an acute
infection between the claws, which can affect cattle of any age or
type, including beef animals. Understanding the lesions that cause
lameness will aid in identifying the major risk factors to focus on for
control.
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| lame cow |
Digital dermatitis: a relatively new and changing disease
Digital
dermatitis (DD) was first reported in Italy in 1974 and since then has
undergone a global epidemic. Acute infections on the skin around the
hooves progress, without treatment, to chronic wart-like lesions. With
the moist anaerobic conditions created by slurry and mud on the feet,
infections are hard to ascertain, so the mainstays of control include
improving yard hygiene and regular foot disinfection using foot baths.
Latest concepts in foot baths includes finding ways to maximize the
number of foot plunges in disinfectants and ways to reduce particulate
contamination.
However, the greatest impact is made when combinations
of, consistent yard hygiene, foot disinfection and proactive lesion
detection with effective treatment are implemented. Treatment must
include the newer group of severe necrotic claw lesions, such as toe
necrosis and wall ulcers. There is some evidence to suggested there are
many different bacteria involved in making infections more or less
severe, and so bio-security and bio-containment (to prevent spread between
herds and management groups) remains a priority, even for herds with
digital dermatitis.
Resting is important
Sole
ulcer is the term for when a full thickness defect in the horn develops
in the mid-sole region of the outer hind claw or inner foreclaw. Mostly
hind feet are affected. Historically a lot of emphasis was placed on
control of acidosis and nutrition for preventing sole ulcers, but that
failed to explain why mostly outer hind claws were affected and the link
is still unproven and nutritional interventions have remained largely
ineffective for control. More recently, a biomechanical hypothesis has
stood up well to scientific scrutiny.
Most
sole ulcers occur 2-4 months following calving. One research group
demonstrated there are massive changes in the connective tissue within
the hooves around calving which lead to failure of the ligament or
attachments between bone and hoof, similar to laminitis in the horse.
Compression of the soft tissues under the sole leads to inflammation and
damage to horn producing cells. This may be compounded by a poorly
developed digital cushion in heifers and thin cows. However, given the
opportunity to rest, cows will recover from this initial bruising. If
resting times become compromised because of poor cubicle comfort, heat
stress or long penning times then a chronic inflammatory focus persists.
Applying blocks to the opposite claw to rest the injured claw and
giving anti-inflammatory drugs has been shown to successfully treat
these cows but chronic scarring to the digital cushion means recurrence
of lameness and bruising is highly likely.
Cow friendly underfoot surfaces
Cows
are naturally pasture based herbivores, and housing on concrete or
walking on tracks presents great risks to foot health through trauma.
Concrete will bruise soles and white lines, predisposing to sole ulcers
and white line separation. Long distances walked on tracks or concrete
can wear soles and heels so they are thin and prone to further bruising.
Lameness reduces wear on a painful claw, increasing the overloading and
predisposing to further lameness. There are many innovative ways in
which dairy farmers have tried to reduce the impact of walking on hard
surfaces, including the use of rubber matting and Astroturf. These
materials are challenging to manage and in the case of rubber, expensive
to lay.
The
risks of hard walking surfaces are compounded when cows are penned or
herded for milking, as dominant cows will bully and push heifers or low
dominance cows. Slips and scrabbling behaviour is particularly
problematic. Therefore, stocking rates, proper design of facilities,
maintenance of grip and gentle stock handling all play a major part in
reducing bruising and subsequent white line lesions.
Skill and training are pivotal
Thankfully
long-gone are the days when we would see cows with Aladdin slipper
feet. The economics do not permit the neglect of foot health to that
degree. If anything, we now see the effects of over-trimming more
commonly. The published hoof trimming method has not changed much in 30
years, while the modern Holstein is 25% larger than the traditional
Friesian. Given that the Dutch Five Step Method hoof trimming was first
developed using Friesians it’s perhaps no surprise that changes are
required. Various modifications to the trimming approach have been
proposed but these remain scientifically un-tested. Precautionary
principles should apply to sound animals undergoing routine foot checks
1-3 times per year, with heel, walls and sole thickness preserved in
animals with good foot angle.
Monitoring progress is key to managing risks
The
growing herd size has resulted in a growing sophistication and
professionalism within the dairy industry. Innovation in housing design
has demonstrated the significance of the environment to foot health. The
proactive attitude of managers has shown lameness is not an
inevitability of dairy farming. Many of the larger dairy units have
applied routine foot checks by professionally trained trimmers, regular
foot disinfection following strict protocols and regular screening for
lameness using lameness scoring approaches.
When using lameness and
lesion data generated from large herds it is possible to identify risks
and management factors leading to better foot health. The results have
been revolutionary and have unlocked productivity in many herds hampered
by lameness and consequential losses of fertility, premature culling
and loss of milk yield due to lameness. The pace of changes within the
industry means the next five years will be an exciting period for the
advancement of precision livestock farming, with the introduction of new
technology for quantifying and optimising foot health and herd
management.
Tags:
Dairy Farming