Footrot control and eradication (elimination) strategies

doi:10.1016/j.smallrumres.2009.09.026

Small Ruminant Research

Volume 86, Issues 1–3, October 2009, Pages 90-93

https://doi.org/10.1016/j.smallrumres.2009.09.026 Get rights and content

Abstract

Footrot is a major welfare problem and cause of economic losses in most sheep-keeping countries. The main reasons why this is the case are reviewed, particularly the effects of weather, environment and husbandry methods on the spread of the disease. The main methods for control and elimination (eradication) are briefly described. Attention is drawn to the fact that control is particularly difficult in temperate countries without predictable non-transmission periods.

Introduction

Footrot is a disease with a long history. The statements “The dreadful and too frequent disease termed footrot” (Youatt in Sheep: their Breeds, Management and Diseases, 1837) and “No disease occasions more acute suffering to the sheep, and annoyance to the farmer, than footrot” (Blacklock's Treatise on Sheep, 1838) show that sheep keepers have been struggling with this disease for approaching 200 years at least and still the struggle goes on today in most major sheep-keeping countries. By the 1830s, it had been established that the disease was infectious, that it was made worse by wet underfoot conditions and by running large groups of sheep together, risk factors that we recognise today. So why does the disease remain so difficult to control and why has eradication not been successful on a much wider scale than is currently the case? The answers involve the complex nature of the disease with different clinical presentations from benign to virulent, difficulties in differential diagnosis, the complex effects of environment and temperature on transmission, the financial and other resources needed to tackle the disease, the biosecurity status of individual flocks, the attitude of sheep keepers to the welfare implications of the disease and the will to do something about it.

Control implies keeping the disease to a low level, such that the costs of the disease in lowered production and costs of labour and materials needed are acceptable (ignoring the welfare implications of any lame sheep being present). This is the position taken (or claimed to be taken) by many sheep keepers in the United Kingdom. Eradication means the total removal of the disease (but not necessarily an end to lame sheep since there are many other causes of lameness). Eradication (strictly speaking elimination, if eradication is defined as global elimination [Dowdie and Hopkins, 1998, quoted in Green and George, 2008]) has been successfully carried out in parts of Australia, where the climate facilitates this, as well as in a few flocks in the United Kingdom, where the weather and widespread practice of winter housing are much more conducive to year-round spread of disease.

Section snippets

Maintenance and spread of the infection within a flock

Footrot is caused by the invasion and separation of the horny structures of the foot by the bacterium Dichelobacter nodosus. This requires prior devitalisation of the interdigital skin and infection with Fusobacterium necrophorum, since D. nodosus is unable to invade healthy interdigital skin (Egerton, 2007). F. necrophorum is a ubiquitous environmental organism, but D. nodosus is only found in infected feet and can live in the environment (particularly if warm and damp) for only 7 days,

Treatment and control methods

Management of footrot has been reviewed by Abbott and Lewis (2005); recently Green and George (2008) have reviewed knowledge of footrot with particular emphasis on control or elimination strategies for Great Britain.

Successful control usually involves a combination of measures to minimise lameness due to footrot and these need to be determined according to the circumstances of each individual flock. They include various forms of treatment, vaccination to increase immunity, identifying and

Eradication (elimination) of footrot

Programmes have been carried out in parts of Australia with considerable success. In Western Australia, it is estimated that only 0.7% of premises have virulent footrot (Mitchell, 2001). In New South Wales, a similar programme reduced the number of affected flocks to less than 4% (Egerton et al., 2004). Both programmes relied upon predictability of non-transmission periods during dry, hot weather together with treatment of infected animals and strict culling of non-responders. Replacements

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There are more references available in the full text version of this article.

Cited by (27)

Gamithromycin in sheep: Pharmacokinetics and clinical evaluation against ovine footrot
2022, Research in Veterinary Science
Citation Excerpt :
Ovine footrot is a multifactorial contagious disease associated with the anaerobic bacteria Dichelobacter nodosus and Fusobacterium necrophorum (Abbott and Lewis, 2005; Bennett et al., 2009; Winter, 2009; Zanolari et al., 2021).
In the context of a development program to obtain the market authorization of injectable gamithromycin 15% w/v solution (Zactran®, Boehringer Ingelheim) for use in sheep against footrot, the pharmacokinetic profile of gamithromycin was established and the safety and efficacy of the treatment were confirmed in a multicenter field study in Europe.
The basic pharmacokinetic parameters established in healthy young Merino sheep administered gamithromycin at 6 mg/kg body weight based on the analysis of plasma samples which were collected in intervals up to 12 days after subcutaneous injection were: area under the curve until last quantifiable concentration, 8.88 ± 2.33 μg*h/mL; maximum plasma concentration, 448 ± 180 ng/mL; terminal half-life, 42.5 ± 5.25 h.
The safety and clinical efficacy against footrot of gamithromycin 15% w/v solution were evaluated in comparison to tilmicosin 30% w/v solution (Micotil®, Elanco) treatment in 364 sheep of various breeds, sex and age from commercial farms in the United Kingdom (2 sites), Germany (3 sites) and France (1 site). Animals were enrolled based on lesions characteristic of footrot and lameness associated with the presence of footrot-related bacterial pathogens and were randomly allocated and treated in a 1:1 ratio with a single subcutaneous dose of gamithromycin or tilmicosin at label dosage (6 or 10 mg/kg body weight, respectively). Lameness and footrot lesions were evaluated at five and 21 days after treatment; the injection site in all animals was examined the day after treatment and followed up daily in the animals with injection site reaction until complete injection site reaction resolution.
Samples of 310 and 120 animals tested positive for Dichelobacter nodosus and Fusobacterium necrophorum, respectively, at inclusion, and data of 359 animals were included into the combined analyses (5 animals excluded for unintentional overdosing [1], lack of follow-up [1], concurrent antibiotic medication for non-footrot conditions [3]). Lameness scores at 21 days after treatment demonstrated a significantly (p = 0.0396) better success for the gamithromycin treatment compared to the tilmicosin treatment (97.8% vs. 93.3%). Post-dosing footrot lesion scores followed similar trends of rapid and marked decrease (improvement) for both treatments with similar (p = 0.127) treatment success for the gamithromycin and tilmicosin treatments (97.8% and 96.0%, respectively). Both treatments were safe; injection site reactions noted in 19 gamithromycin- and 25 tilmicosin-treated animals resolved within five days or six days of treatment, respectively.
Gamithromycin 15% w/v solution administered once to sheep by subcutaneous injection at 6 mg/kg body weight demonstrated a pharmacokinetic profile similar to that reported previously in sheep and cattle and was confirmed to be a safe and efficacious treatment for naturally occurring ovine footrot in a multicenter clinical field study conducted in Europe.
Contagious ovine digital dermatitis: An emerging disease
2014, Veterinary Journal
Citation Excerpt :
Footrot, inter-digital dermatitis and CODD are the three principal infectious causes of lameness in sheep in the UK (Grogono-Thomas and Johnston, 1997; Kaler and Green, 2008; Conington et al., 2010). Given that footrot and inter-digital dermatitis have been reported in sheep in both the UK and elsewhere for considerably longer than CODD (Beveridge, 1941; Winter, 2009), there is a comparatively better understanding of their epidemiology (Green and George, 2008). CODD was first reported in the UK in 1997 (Harwood et al., 1997), and a recent survey of UK farmers found that 88.4% of respondents indicated that they had not seen CODD prior to this time (Angell et al., 2014).
The novel sheep disease, contagious ovine digital dermatitis (CODD) was first described in the UK in 1997. The disease is characterised by severe lameness associated with initial inflammation at the coronary band, followed by progressive separation of the hoof capsule from the underlying tissue. On microbiological examination, treponeme bacteria have been frequently isolated from cases of CODD, including treponemes phylogenetically identical to those associated with bovine digital dermatitis (BDD). Dichelobacter nodosus and Fusobacterium necrophorum have also been isolated from CODD lesions although their role in the pathogenesis remains uncertain. While epidemiological data indicate that the prevalence of CODD is increasing in the UK, the routes of transmission and associated risk factors have not been clearly elucidated.
Evidenced-based treatment trials indicate that parenteral administration of long-acting amoxicillin is an efficacious treatment for CODD, while anecdotal evidence suggests other antibiotics, given locally and/or parenterally, may also be beneficial. Further microbiological and epidemiological research is urgently required to develop sustainable control strategies, including the development of vaccines and appropriate biosecurity and farm management protocols. In this review current knowledge of the clinical, aetiological, and epidemiological aspects of CODD is assessed as well as approaches to its control.
A review of footrot in sheep: Aetiology, risk factors and control methods
2013, Livestock Science
Citation Excerpt :
None of these measures offers a long-term easy-care approach to disease management. The full range of control methods of footrot in sheep, goats and deer have been extensively reviewed by Abbott and Lewis (2005), Egerton (2008b), Egerton et al. (1989), Stewart (1989a, b), Winter (2009, 2011). More recently Wassink et al. (2003) have described the recurring use of parenteral antibiotics to treat lameness in sheep and concluded that this was an effective means of control of footrot.
Footrot is one of the major causes of lameness in sheep, goats and other ruminants. It is at times a highly contagious disease resulting from mixed bacterial infection with Dichelobacter nodosus as a necessary component. Disease manifestation can range from low to high prevalence depending on host, bacterial, environmental and climatic conditions, resulting in benign, intermediate and virulent forms of footrot. Accepted control methods include eradication of non-benign disease from affected flocks, control largely through vaccination, topical and systemic treatment and preventative measures through strategic vaccination. Not all forms of footrot warrant control or eradication since the cost of such preventative measures may outweigh the impact and cost of diseases as in the case of benign footrot.
Treatment and Control of Hoof Disorders in Sheep and Goats
2011, Veterinary Clinics of North America - Food Animal Practice
Breeding objectives for sheep in Ireland: A bio-economic approach
2010, Livestock Science
Breeding objectives for meat sheep in Ireland have been defined and used in the development of selection sub-indices to provide commercial producers with an economic comparison of animals for specific performance trait groups. Using trait-by-trait bio-economic models and a range of methodologies, economic weights (in € per lamb born per genetic standard deviation in the trait) have been calculated for maternal and terminal sire performance traits as follows: production traits; −€1.41 for days to slaughter, €0.35 for carcase conformation class, −€0.52 for carcase fat class, lambing traits; −€0.69 for lambing difficulty for single-bearing ewes, −€0.37 for lambing difficulty for multiple-bearing ewes, €1.15 for lamb survival, maternal traits; €0.83 for number of lambs born, −€1.49 for ewe mature weight, health traits; −€0.09 for lamb foot rot, and −€0.82 for ewe foot rot. Results indicate the significant value of improving the ability of lambs to survive to weaning, without increasing number of lambs born. The highly negative economic weight for both days to slaughter and mature size represents a powerful unfavourable relationship between the two traits.
Economic values for lambing difficulty and foot rot represent the significant costs these traits have in the Irish sheep production system.
In the early stages of the development of the genetic improvement program for sheep in Ireland the breeding objective defined in this paper provides directed emphasis for trait recording, selection strategies, and mating systems. In addition the economic weights provide indications as to how much genetic improvement in a specific trait would be worth paying for. The proposed formulation of the total economic index as sub-indices provides the ability for commercial farmers to adjust breeding emphasis towards specific market outcomes or address key production aspects in their particular farming system.
The importance of feet examination in sheep health management
2010, Small Ruminant Research
Citation Excerpt :
This number represents a welfare problem and an economic loss to the farmer. Most lameness is confined to the foot and can be easily treated assuming it is caught in the early stages (Winter, 2004b,c, 2008, 2009). If left untreated, simple conditions can become far more complicated.
Lameness is still the biggest welfare issue present on sheep farms. In order to prevent and control lameness outbreaks on sheep farms, a good set-up is required, as well as a systematic approach to examining the foot and limb. The cause of lameness cannot be assumed to be foot-rot, but instead there are a whole host of conditions. These may be of a microbial aetiology, such as scald or contagious ovine digital dermatitis, or of non-microbial aetiology, such as white-line lesions or toe granulomas. The consequences of lameness can be far reaching, not only affecting the number of lambs born, but also the size of the lamb and whether they manage to get in lamb the following year. It can result in the difference between making a profit or a loss in the financial year.

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^☆: This paper is part of the special issue entitled: Keynote lectures of the 7th International Sheep Veterinary Congress 2009, Guest Edited by Snorre Stuen, Martha J. Ulvund and George C. Fthenakis.

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Small Ruminant Research

Abstract

Introduction

Section snippets

Maintenance and spread of the infection within a flock

Treatment and control methods

Eradication (elimination) of footrot

References (18)

Current approaches to the management of ovine footrot

Vet. J.

Vaccination against ovine footrot

J. Comp. Pathol.

Association between alleles of the ovine major histocompatability complex and resistance to footrot

Res. Vet. Sci.

Assessment of current knowledge of footrot in sheep with particular reference to Dichelobacter nodosus and implications for elimination or control strategies for sheep in Great Britain

Vet. J.

Lameness in sheep

Small Rumin. Res.

Footrot in sheep

Vet. Rec.

Diseases of the feet

Parenteral antibiotic treatment of ovine footrot

Aus. Vet. J.

Eradication of footrot from New South Wales

Cited by (27)

Gamithromycin in sheep: Pharmacokinetics and clinical evaluation against ovine footrot

Contagious ovine digital dermatitis: An emerging disease

A review of footrot in sheep: Aetiology, risk factors and control methods

Treatment and Control of Hoof Disorders in Sheep and Goats

Breeding objectives for sheep in Ireland: A bio-economic approach

The importance of feet examination in sheep health management

Footrot control and eradication (elimination) strategies☆

Abstract

Introduction

Section snippets

Maintenance and spread of the infection within a flock

Treatment and control methods

Eradication (elimination) of footrot

Vet. J.

J. Comp. Pathol.

Res. Vet. Sci.

Vet. J.

Small Rumin. Res.

Footrot in sheep

Vet. Rec.

Diseases of the feet

Parenteral antibiotic treatment of ovine footrot

Aus. Vet. J.

Eradication of footrot from New South Wales