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Research
Research EDITORIAL
Predict and prevent versus test and treat Peter Orpin, Dick Sibley THERE is no shortage of health challenges to livestock populations that play an essential part in modern agriculture. Despite the best endeavours of the veterinary profession, many of our livestock species still suffer from diseases that affect their health, welfare and productivity. This is hardly due to a failure of effort, or a lack of understanding or knowledge of the diseases that still occur commonly. The economic impacts associated with the production inefficiencies brought about by disease and poor productivity are also well understood (Erb 1984). In addition, there is developing evidence that the significant environmental impacts of agricultural livestock are closely correlated with production efficiency, which in itself is closely correlated to health and productivity (Capper and
Peter Orpin, BVSc, MRCVS, Park Vet Group, 82-84 High Street, Whetstone, Leicester LE8 6LQ, UK e-mail: [email protected] Dick Sibley, BVSc, HonFRCVS, West Ridge Veterinary Practice, 5 Chapple Road, Witheridge, Devon EX16 8AS, UK e-mail: [email protected]
others 2009). ‘Where you have livestock you have deadstock’ is a common saying among livestock farmers, but this is not necessarily true: while many dairy farmers sustain significant wastage and inefficiency through cows being prematurely culled due to sickness, death or injury, many others successfully minimise their losses (Orpin and Esselmont 2010). Many of these forced culls are animals that succumb to disease or injuries that can be prevented. The great variability between the best and the worst culling performance in our dairy herds suggests that these losses are not inevitable, but preventable. What is lacking in our quest to truly predict and prevent disease and injury is a thorough understanding of the risks that predispose our livestock to health threats and a structured system to identify these risks on individual farms and in livestock populations. Once we have this understanding, along with a coherent structure for delivering preventive veterinary care, it would be possible to construct a programme of risk management to prevent trouble before it arises, rather than waiting for a problem to appear and then trying to fix it. The concept of risk
April 19, 2014 | Veterinary Record | 403
Downloaded from http://veterinaryrecord.bmj.com/ on June 18, 2015 - Published by group.bmj.com
Research
Research
farmers and their veterinarians management to predict and of the benefits of preventive prevent disease is not new: healthcare, and for them to many of us recall the somewhat accept that their herds might be rudimentary and intermittent at risk of diseases that they did lectures on preventive medicine not consider to be significant or of our college days gone by, potential problems. Each and which concentrated on looking every herd had different risks for risks of disease and dealing and challenges; a circumstance with them appropriately; for that has been recognised in example, ventilating youngstock the TB strategy, which clearly buildings to prevent pneumonia stipulates that a single inflexible (Gibbs 2001), adhering to the five policy will not fit all farms. point plan to control and prevent Once engaged, farmers involved mastitis (Jones and Ohnstad in the programme were offered 2002) and adopting grazing options that allowed them to strategies to minimise parasite prevent, control or eradicate burdens (White and Fisher 1994). disease according to their However, the risks that affect aspirations, resources and risk diseases that threaten cattle The proximity of cows in housed systems can facilitate profile. The number of farmers today are less well understood, disease spread that selected each management and may be more complex and option are shown in Table 2. more difficult to manage. Indeed, This demonstrates the need for a variety infectious diseases and production it seems that modern farming systems of control strategy options. This had the diseases such as bovine viral diarrhoea, may have inadvertently increased the risks effect of ensuring both engagement and Johne’s disease, dairy cow lameness of many infectious diseases entering and ownership, such that many farmers are and mastitis have been well accepted by spreading within a herd, as herds expand, now spending thousands of pounds of veterinarians and farmers in regional health coalesce and become concentrated in their own money on testing, managing schemes, such as the Southwest Healthy densely stocked areas of the country. Data and controlling diseases such as Johne’s, Livestock Initiative (an animal health and collected into our health management which they did not even realise was welfare programme funded by the Rural programme database (myhealthyherd.com) endemic in their herds before the start of the Development Programme for England (Table 1) show that most modern dairy programme. in the southwest of the UK). Thousands herds are at a high risk of Johne’s disease The success of the Southwest Healthy of farmers and hundreds of veterinary entering their populations, not least due Livestock Initiative was largely due to the practitioners engaged in a programme to the economic pressures that they have structured programme of engagement, that involved identifying risks as well as had to endure and the management and education and delivery to individual determining the status of herds of those husbandry changes driven by economic farmers by trained and committed vets who wished to participate. The success survival and other external pressures. who were properly rewarded for their of the initial engagement programme The draft Bovine TB Strategy published endeavours. Those vets provided flexible, highlighted the need to enlighten both by Defra last year (Defra 2013), which has just been finalised (see VR, April 12, 2014, p 367) represents a paradigm shift in the management of this particular endemic TABLE 1: Risk data from dairy farms engaged in Johne’s disease management generated disease; the document reveals that most using myhealthyherd.com cattle herds are not affected by TB. About 25 Frequently Occasionally Never per cent of herds in the endemically infected General biosecurity risks relevant to Johne’s disease (2993 dairy herds) (per cent) (per cent) (per cent) TB areas have been under TB restrictions in the past year and over 40 per cent of herds Introduction of cattle on to the farm 13.7 62.1 24.2 in the high risk TB areas have not had a Cattle share grazing or buildings with cattle of unknown disease status 2.9 8.2 88.9 reactor in the last 10 years. However, many are at risk of the disease and there is at last Slurry or farmyard manure from another farm is spread on land 0.6 4.9 94.5 a recognition that effort and resources must Cattle have access to waterways that pass through another livestock farm 14.5 38.7 46.8 be directed towards preventing infection in these herds as well as identifying infection in Cattle are fed with feeds that could have had contact with other animals 1.8 16.1 82.2 those that are already infected. However, the risks that predispose herds and individuals Frequently Occasionally Never Johne’s disease-specific biosecurity risks (2296 dairy herds) (per cent) (per cent) (per cent) to TB infection are not well understood. Research resources have been directed to Groups of animals of unknown Johne’s disease status have been introduced to the 13.4 39.6 47.0 two main pillars of TB management – herd within last ten years surveillance and vaccination – while the Individual animals of unknown Johne’s disease status have been introduced to the 11.0 57.8 31.2 other two essential components of health herd within last 10 years status, biosecurity and bio-containment of Slurry of farmyard manure from another farm is spread onto youngstock pastures 0.4 4.2 95.4 risks, have not had the same research effort. Calves have access to waterways that pass through another livestock farm 6.6 28.2 65.2 These latter two essential pillars of disease Youngstock graze on pastures that are heavily infested with rabbits 13.8 48.9 37.3 control need to become integral to animal health programmes (Sibley 2010, Sibley Youngstock co-graze pastures with sheep of unknown disease status 8.0 21.9 72.1 2014). Calves are fed on colostrum from other herds that may be at high risk of 2.0 4.0 94 The concepts of risk management in Mycobacterium avium subspecies paratuberculosis infection the prevention and control of endemic 404 | Veterinary Record | April 19, 2014
Downloaded from http://veterinaryrecord.bmj.com/ on June 18, 2015 - Published by group.bmj.com
Research slaughtered, while in 2013 there were none. Yet there has never been Number (per cent) a surveillance test for of dairy farms diagnosis in live animals 221 (26.3) other than clinical signs, and no treatment of 163 (19.4) affected animals; the 93 (11.1) traditional approach of testing for disease and 8 (1) treating the affected 49 (8.5) animals was never going 274 (32.7) to work. The disease was controlled by the 7 (0.8) management of risk, 24 (2.9) the main one of which was identified early in the epidemic by an epic piece of work by a group of epidemiologists (Wilesmith and others 1988). The regulated management of these risks led to the decline and eventual eradication of this disease by predicting and preventing its spread. The same could be done for many other endemic diseases if only we more fully understood the risks and engaged farmers in their management. Many of the diseases that threaten the efficiency of our modern livestock populations are similar ‘slow-burning’ problems, with long incubation periods, multiple risk factors, and inherent difficulties in diagnosis due to latency or anergy, vaccination and treatment. Local, regional and national programmes to deal with such diseases will require engagement, commitment and ambition from all those involved, along with structured and wellmanaged packages from which farmers can choose. Gaps in our knowledge will
TABLE 2: Number of farms that selected each management option in the Southwest Healthy Livestock Initiative Management option Improved farm management of whole herd to limit spread Single annual test of all adults, targeted risk management and improved farm management Test and cull with improved farm management Firebreak vaccination with improved farm management Biosecurity, protection and monitoring Quarterly testing and targeted risk-based control Purchase all replacements and breed to terminal sire Vet-specified custom strategy
aspirational, affordable and beneficial health management plans for bovine viral diarrhoea, Johne’s disease, lameness and mastitis to thousands of cattle farmers, as well as sheep parasite management plans to sheep farmers in the southwest of England, such that over 40 per cent of all dairy farmers in the region became involved in at least one of the work strands. Data on both known and putative risks now exist on a central database, which can be linked to disease prevalence, allowing further analysis of the significance of particular risks and can be used to predict future trends. The same could be done for TB, if only the risks were more properly understood and quantified. The importance of risk management is illustrated by one of the most successful national disease control and eradication campaigns of recent years. At its height in 1992, over 36,000 cows with BSE were
need to be filled so that coherent and effective programmes of prevention and control can be implemented on any farm in any situation. The role of the motivated, local vet engaging, guiding and enthusing farmers to higher levels of technical performance cannot be underestimated if we are to tackle the more demanding diseases within a more challenging marketplace.
References
CAPPER, J. L., CADY, R. A. & BAUMAN, D. E. (2009) The environmental impact of dairy production: 1944 compared with 2007. Journal of Animal Science 87, 2160-2167 DEFRA (2013) Proposals for new bovine TB control measures: tackling transmission between cattle herds. https://consult.defra.gov.uk/animal-health-and-welfare/proposals-for-new-bovine-tb-control-measures/ supporting_documents/Consultation%20document%20new%20cattle%20measures%20final.pdf. Accessed April 11, 2014 ERB, H. (1984) Economics for veterinary farm practice. In Practice doi:10.1136/inpract.6.2.33 GIBBS, A. (2001) Practical approach to the control of pneumonia in housed calves. In Practice doi:10.1136/ inpract.23.1.32 JONES, T. & OHNSTAD, I. (2002) Milking procedures recommended for the control of bovine mastitis. In Practice doi:10.1136/inpract.24.9.502 ORPIN, P. G. & ESSLEMONT, R. J. (2010) Culling and wastage in dairy herds: an update on incidence and economic impact in dairy herds in the UK. Cattle Practice 18, 163-172 SIBLEY, R. (2010) Biosecurity in the dairy herd. In Practice doi:10.1136/inp.c3913 SIBLEY, R. (2014) Biosecurity in the beef herd. In Practice (In press) WHITE, D. & FISHER, M. (1994) Strategies for the control of parasitic gastroenteritis. In Practice doi:10.1136/ inpract.16.2.73 WILESMITH, J. W., WELLS, G. A., CRANWELL, M. P. & RYAN, J. B. (1988) Bovine spongiform encephalopathy: epidemiological studies. Veterinary Record doi:10.1136/vr.123.25.638
doi:10.1136/vr.g2749
April 19, 2014 | Veterinary Record | 405
Downloaded from http://veterinaryrecord.bmj.com/ on June 18, 2015 - Published by group.bmj.com
Predict and prevent versus test and treat Peter Orpin and Dick Sibley Veterinary Record 2014 174: 403-405
doi: 10.1136/vr.g2749 Updated information and services can be found at: http://veterinaryrecord.bmj.com/content/174/16/403
These include:
References Email alerting service
This article cites 2 articles, 0 of which you can access for free at: http://veterinaryrecord.bmj.com/content/174/16/403#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
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Research
Research EDITORIAL
Predict and prevent versus test and treat Peter Orpin, Dick Sibley THERE is no shortage of health challenges to livestock populations that play an essential part in modern agriculture. Despite the best endeavours of the veterinary profession, many of our livestock species still suffer from diseases that affect their health, welfare and productivity. This is hardly due to a failure of effort, or a lack of understanding or knowledge of the diseases that still occur commonly. The economic impacts associated with the production inefficiencies brought about by disease and poor productivity are also well understood (Erb 1984). In addition, there is developing evidence that the significant environmental impacts of agricultural livestock are closely correlated with production efficiency, which in itself is closely correlated to health and productivity (Capper and
Peter Orpin, BVSc, MRCVS, Park Vet Group, 82-84 High Street, Whetstone, Leicester LE8 6LQ, UK e-mail: [email protected] Dick Sibley, BVSc, HonFRCVS, West Ridge Veterinary Practice, 5 Chapple Road, Witheridge, Devon EX16 8AS, UK e-mail: [email protected]
others 2009). ‘Where you have livestock you have deadstock’ is a common saying among livestock farmers, but this is not necessarily true: while many dairy farmers sustain significant wastage and inefficiency through cows being prematurely culled due to sickness, death or injury, many others successfully minimise their losses (Orpin and Esselmont 2010). Many of these forced culls are animals that succumb to disease or injuries that can be prevented. The great variability between the best and the worst culling performance in our dairy herds suggests that these losses are not inevitable, but preventable. What is lacking in our quest to truly predict and prevent disease and injury is a thorough understanding of the risks that predispose our livestock to health threats and a structured system to identify these risks on individual farms and in livestock populations. Once we have this understanding, along with a coherent structure for delivering preventive veterinary care, it would be possible to construct a programme of risk management to prevent trouble before it arises, rather than waiting for a problem to appear and then trying to fix it. The concept of risk
April 19, 2014 | Veterinary Record | 403
Downloaded from http://veterinaryrecord.bmj.com/ on June 18, 2015 - Published by group.bmj.com
Research
Research
farmers and their veterinarians management to predict and of the benefits of preventive prevent disease is not new: healthcare, and for them to many of us recall the somewhat accept that their herds might be rudimentary and intermittent at risk of diseases that they did lectures on preventive medicine not consider to be significant or of our college days gone by, potential problems. Each and which concentrated on looking every herd had different risks for risks of disease and dealing and challenges; a circumstance with them appropriately; for that has been recognised in example, ventilating youngstock the TB strategy, which clearly buildings to prevent pneumonia stipulates that a single inflexible (Gibbs 2001), adhering to the five policy will not fit all farms. point plan to control and prevent Once engaged, farmers involved mastitis (Jones and Ohnstad in the programme were offered 2002) and adopting grazing options that allowed them to strategies to minimise parasite prevent, control or eradicate burdens (White and Fisher 1994). disease according to their However, the risks that affect aspirations, resources and risk diseases that threaten cattle The proximity of cows in housed systems can facilitate profile. The number of farmers today are less well understood, disease spread that selected each management and may be more complex and option are shown in Table 2. more difficult to manage. Indeed, This demonstrates the need for a variety infectious diseases and production it seems that modern farming systems of control strategy options. This had the diseases such as bovine viral diarrhoea, may have inadvertently increased the risks effect of ensuring both engagement and Johne’s disease, dairy cow lameness of many infectious diseases entering and ownership, such that many farmers are and mastitis have been well accepted by spreading within a herd, as herds expand, now spending thousands of pounds of veterinarians and farmers in regional health coalesce and become concentrated in their own money on testing, managing schemes, such as the Southwest Healthy densely stocked areas of the country. Data and controlling diseases such as Johne’s, Livestock Initiative (an animal health and collected into our health management which they did not even realise was welfare programme funded by the Rural programme database (myhealthyherd.com) endemic in their herds before the start of the Development Programme for England (Table 1) show that most modern dairy programme. in the southwest of the UK). Thousands herds are at a high risk of Johne’s disease The success of the Southwest Healthy of farmers and hundreds of veterinary entering their populations, not least due Livestock Initiative was largely due to the practitioners engaged in a programme to the economic pressures that they have structured programme of engagement, that involved identifying risks as well as had to endure and the management and education and delivery to individual determining the status of herds of those husbandry changes driven by economic farmers by trained and committed vets who wished to participate. The success survival and other external pressures. who were properly rewarded for their of the initial engagement programme The draft Bovine TB Strategy published endeavours. Those vets provided flexible, highlighted the need to enlighten both by Defra last year (Defra 2013), which has just been finalised (see VR, April 12, 2014, p 367) represents a paradigm shift in the management of this particular endemic TABLE 1: Risk data from dairy farms engaged in Johne’s disease management generated disease; the document reveals that most using myhealthyherd.com cattle herds are not affected by TB. About 25 Frequently Occasionally Never per cent of herds in the endemically infected General biosecurity risks relevant to Johne’s disease (2993 dairy herds) (per cent) (per cent) (per cent) TB areas have been under TB restrictions in the past year and over 40 per cent of herds Introduction of cattle on to the farm 13.7 62.1 24.2 in the high risk TB areas have not had a Cattle share grazing or buildings with cattle of unknown disease status 2.9 8.2 88.9 reactor in the last 10 years. However, many are at risk of the disease and there is at last Slurry or farmyard manure from another farm is spread on land 0.6 4.9 94.5 a recognition that effort and resources must Cattle have access to waterways that pass through another livestock farm 14.5 38.7 46.8 be directed towards preventing infection in these herds as well as identifying infection in Cattle are fed with feeds that could have had contact with other animals 1.8 16.1 82.2 those that are already infected. However, the risks that predispose herds and individuals Frequently Occasionally Never Johne’s disease-specific biosecurity risks (2296 dairy herds) (per cent) (per cent) (per cent) to TB infection are not well understood. Research resources have been directed to Groups of animals of unknown Johne’s disease status have been introduced to the 13.4 39.6 47.0 two main pillars of TB management – herd within last ten years surveillance and vaccination – while the Individual animals of unknown Johne’s disease status have been introduced to the 11.0 57.8 31.2 other two essential components of health herd within last 10 years status, biosecurity and bio-containment of Slurry of farmyard manure from another farm is spread onto youngstock pastures 0.4 4.2 95.4 risks, have not had the same research effort. Calves have access to waterways that pass through another livestock farm 6.6 28.2 65.2 These latter two essential pillars of disease Youngstock graze on pastures that are heavily infested with rabbits 13.8 48.9 37.3 control need to become integral to animal health programmes (Sibley 2010, Sibley Youngstock co-graze pastures with sheep of unknown disease status 8.0 21.9 72.1 2014). Calves are fed on colostrum from other herds that may be at high risk of 2.0 4.0 94 The concepts of risk management in Mycobacterium avium subspecies paratuberculosis infection the prevention and control of endemic 404 | Veterinary Record | April 19, 2014
Downloaded from http://veterinaryrecord.bmj.com/ on June 18, 2015 - Published by group.bmj.com
Research slaughtered, while in 2013 there were none. Yet there has never been Number (per cent) a surveillance test for of dairy farms diagnosis in live animals 221 (26.3) other than clinical signs, and no treatment of 163 (19.4) affected animals; the 93 (11.1) traditional approach of testing for disease and 8 (1) treating the affected 49 (8.5) animals was never going 274 (32.7) to work. The disease was controlled by the 7 (0.8) management of risk, 24 (2.9) the main one of which was identified early in the epidemic by an epic piece of work by a group of epidemiologists (Wilesmith and others 1988). The regulated management of these risks led to the decline and eventual eradication of this disease by predicting and preventing its spread. The same could be done for many other endemic diseases if only we more fully understood the risks and engaged farmers in their management. Many of the diseases that threaten the efficiency of our modern livestock populations are similar ‘slow-burning’ problems, with long incubation periods, multiple risk factors, and inherent difficulties in diagnosis due to latency or anergy, vaccination and treatment. Local, regional and national programmes to deal with such diseases will require engagement, commitment and ambition from all those involved, along with structured and wellmanaged packages from which farmers can choose. Gaps in our knowledge will
TABLE 2: Number of farms that selected each management option in the Southwest Healthy Livestock Initiative Management option Improved farm management of whole herd to limit spread Single annual test of all adults, targeted risk management and improved farm management Test and cull with improved farm management Firebreak vaccination with improved farm management Biosecurity, protection and monitoring Quarterly testing and targeted risk-based control Purchase all replacements and breed to terminal sire Vet-specified custom strategy
aspirational, affordable and beneficial health management plans for bovine viral diarrhoea, Johne’s disease, lameness and mastitis to thousands of cattle farmers, as well as sheep parasite management plans to sheep farmers in the southwest of England, such that over 40 per cent of all dairy farmers in the region became involved in at least one of the work strands. Data on both known and putative risks now exist on a central database, which can be linked to disease prevalence, allowing further analysis of the significance of particular risks and can be used to predict future trends. The same could be done for TB, if only the risks were more properly understood and quantified. The importance of risk management is illustrated by one of the most successful national disease control and eradication campaigns of recent years. At its height in 1992, over 36,000 cows with BSE were
need to be filled so that coherent and effective programmes of prevention and control can be implemented on any farm in any situation. The role of the motivated, local vet engaging, guiding and enthusing farmers to higher levels of technical performance cannot be underestimated if we are to tackle the more demanding diseases within a more challenging marketplace.
References
CAPPER, J. L., CADY, R. A. & BAUMAN, D. E. (2009) The environmental impact of dairy production: 1944 compared with 2007. Journal of Animal Science 87, 2160-2167 DEFRA (2013) Proposals for new bovine TB control measures: tackling transmission between cattle herds. https://consult.defra.gov.uk/animal-health-and-welfare/proposals-for-new-bovine-tb-control-measures/ supporting_documents/Consultation%20document%20new%20cattle%20measures%20final.pdf. Accessed April 11, 2014 ERB, H. (1984) Economics for veterinary farm practice. In Practice doi:10.1136/inpract.6.2.33 GIBBS, A. (2001) Practical approach to the control of pneumonia in housed calves. In Practice doi:10.1136/ inpract.23.1.32 JONES, T. & OHNSTAD, I. (2002) Milking procedures recommended for the control of bovine mastitis. In Practice doi:10.1136/inpract.24.9.502 ORPIN, P. G. & ESSLEMONT, R. J. (2010) Culling and wastage in dairy herds: an update on incidence and economic impact in dairy herds in the UK. Cattle Practice 18, 163-172 SIBLEY, R. (2010) Biosecurity in the dairy herd. In Practice doi:10.1136/inp.c3913 SIBLEY, R. (2014) Biosecurity in the beef herd. In Practice (In press) WHITE, D. & FISHER, M. (1994) Strategies for the control of parasitic gastroenteritis. In Practice doi:10.1136/ inpract.16.2.73 WILESMITH, J. W., WELLS, G. A., CRANWELL, M. P. & RYAN, J. B. (1988) Bovine spongiform encephalopathy: epidemiological studies. Veterinary Record doi:10.1136/vr.123.25.638
doi:10.1136/vr.g2749
April 19, 2014 | Veterinary Record | 405
Downloaded from http://veterinaryrecord.bmj.com/ on June 18, 2015 - Published by group.bmj.com
Predict and prevent versus test and treat Peter Orpin and Dick Sibley Veterinary Record 2014 174: 403-405
doi: 10.1136/vr.g2749 Updated information and services can be found at: http://veterinaryrecord.bmj.com/content/174/16/403
These include:
References Email alerting service
This article cites 2 articles, 0 of which you can access for free at: http://veterinaryrecord.bmj.com/content/174/16/403#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
