Dr Tom Barragry PhD, MSc.MVB, MRCVS Dip ECVPT
Lameness is a major problem in UK dairy herds and is the third largest cause of income loss after infertility and mas-titis.
In addition, it is widely recognised as a major animal welfare problem. In the UK, it is estimated that the prevalence of dairy cow lameness ranges from 22-30 per cent in herds.
An alarmingly high proportion of dairy cattle and many beef operations are affected specifically by Digital Dermatitis (DD).
Many other complicated foot issues like necrotic toe and wall lesions, severe heel erosion, severe sole ulcers, and severe cases of foul-in-the-foot can be associated with digital dermatitis.
The pain and stress of foot problems coupled with limitations on mobility and feeding can weaken the immune system and lower disease resistance.
Numerous papers demonstrate that clinical lameness will significantly reduce milk yield as well as elevating the SCC and mastitis problems.
In addition, foot lameness impacts negatively on fertility, with lame cows showing increased mean calving to first service intervals and calving to conception intervals.
Culling of cows because of lameness is another expected detrimental outcome. (See fig 1)
Digital Dermatitis (DD) caused by infectious agents such as spirochaetes/treponema is a stubborn hoof disorder at the back of the heel that occurs on almost all cattle farms. It thrives in moist conditions.
Characteristically it shows as a wound on the hoof claw skin, usually where the skin between the claw merges into hoof horn. The condition is red and strawberry-like, is very painful and highly contagious.
The incidence of this type of lameness in cows is now far higher than it was 25 years ago, and this undoubtedly is due to changes in the dairy industry such as herd size, housing, wetter conditions, nutrition, and management.
With more and more dairy cows living in confinement and on concrete for longer periods of time, more and more cows are suffering from lameness.
Proper claw trimming and a clean dry environment and daily foot bathing at milking is an essential component of any footcare pro-gramme.
Once again, prevention of lameness by routine prophylactic foot bathing of “healthy cows” is economically far better than the very costly “cure”.
Appearance of clinical signs and lesions of DD may well indicate that a proper prophylactic footbathing programme has probably not been in place.
The main sources of infection are other animals with lesions, and the aim must be to prevent the disease and hence reduce the reservoir of infection.
Thus, individual treatments and
herd prophylaxis by regular foot-baths is a cornerstone of lameness control.
Copper sulphate, zinc and formalin have been the mainstays in footbathing solutions for many years.
However, they are not ideal and have a number of undesirable properties.
When spillages or residual footbath solutions of copper are deposited on soil, high levels of copper in the soil can accumulate, which can have toxic and negative effects on plant growth.
Copper is poisonous to plants, animals and the ecosystem and has residual activity.
It also impacts negatively on bacterial flora and resistance. For-
malin is known to harden the hoof; it is also carcinogenic, and its toxic fumes are potentially very hazardous.
Both can be adversely affected by the presence of organic matter in high concentrations. In addition, they are not very effective against active lesions and require a concentration considerably larger than the min-imum inhibitory concentration (MIC) for their disinfectant action in many cases.
In recent years, as the search for useful, safe, and effective holistic products has intensified, a number of plant-based flavonoids, polyphenols, terpines, terpinols, and essential oils have been used successfully as routine footbaths for prevention of foot problems.
Many of them possess antibacterial and anti-inflammatory action in addition to enhancing hoof horn quality. A particularly interesting novel and natural compound in this category is Tea Tree Oil (TTO).
Tea Tree oil (TTO) in combination with organic acids (Hoofsure Endurance) is an environmentally friendly option available as an effect-ive footbath alternative to copper and formalin.
Its positive effects have been widely documented in the scientific literature. Tea Tree Oil is antibacterial and anti-inflammatory.
Crucially, it is also effective against bacterial biofilm formation, the protective shield below which bacteria can replicate and invade further, and which is also a major mechanism of clinical resistance to antimicrobials.
TTO with organic acids has high penetrative properties and is highly active in the presence of organic matter.
Comparative trials have shown Tea Tree Oil to be more potent and more rapidly acting than either copper sulphate or formalin, as well as maintaining higher efficacy in the presence of organic matter.
Published Trials of TTO Footbath Efficacy:
n In a published trial in University of Kentucky (Smith et al. ref 2), TTO was found to be non-inferior to copper sulphate in a comparative clinical evaluation of cattle footbaths. Over a nine-week trial period, both TTO and copper sulphate were effective in reducing digital dermatitis by 32 per cent.
At 18 weeks TTO had reduced digital dermatitis levels by 49 per cent while copper sulphate had reduced it by 46 per cent. (Ref 2)
n A Royal Veterinary College trial (2014) in London (Bell & Dyson, ref 3), compared the efficacy of cattle footbaths of TTO and formalin for management and prevention of DD.
An evaluation was performed on 90 lame cows in a 24-week split footbath study.
Preliminary results showed TTO reduced digital dermatitis by 51 per cent whereas with formalin the reduction was lower at 43 per cent.
(3). A peer reviewed published study from Iran in 2013 (Nourouzian et al, ref 4) described a farm study with 182 dairy cows with DD which were treated twice daily with TTO/organic acid footbath over a two-week period with subsequent follow up over three months.
At the end of the trial period, using a scoring system, the decrease in lameness, pain, lesion colour and size in the animals treated with Hoofsure Endurance was seen to be significantly reduced (at the statistical level of P<0.05) when compared to the lesion incidence at the beginning of the trial period.
(4) In vitro published studies (Mason et al ref 5) comparing microbiological efficacy of TTO/organic acids, formalin, and copper sulphate, showed that TTO/Organic acids (Hoofsure Endurance) were more potent than either copper or formalin against bacteria, had a quicker onset of action, and was more effective in the presence of organic matter.
(Mason et al ref 5)
In addition, the study confirmed that copper sulphate and formalin had a bacteriostatic (prevents growth) effect whereas TTO had a bactericidal (kills) effect.
The use of holistic environmentally friendly, but proven, effective phytochemical compounds offer a modern and more enlightened way forward in the management of foot problems, especially for DD in cattle.
Their high efficacy and safety permit the avoidance of use of blunter instruments and more toxic traditional chemicals such as formalin and copper sulphate.
Additionally, when used con-sistently and prophylactically, daily (at milking), they are hugely cost effective in reducing the clinical development, appearance and spread-
ing of foot lesions, and all of the associated negative financial im-pacts.
Lameness is one of the costliest “gateway” diseases on farm.
TTO will also reduce reliance on antibiotics for treatment of clinical lesions, hence lowering antimicrobial usage (AMU) and contributing to the minimisation of antimicrobial resistance (AMR) development.
n Dr T Barragry acts as independent veterinary consultant to Provita Ltd.