SHEEP LIVER FLUKE
- Top of page
- Climatological regions of the UK
- WEATHER SUMMARY
- January 2013 parasite update and forecast
- SHEEP LIVER FLUKE
- CATTLE LIVER FLUKE
- SHEEP NEMATODES
- CATTLE NEMATODES
As forecast earlier in the year, this season's forecast indicates that there is a risk of very high levels of liver fluke disease in all of Scotland, Wales and western England. Although figures are not available to produce a Northern Ireland forecast, climate data also suggest a very high risk there. Fluke disease is forecast to be a significant risk across most of the rest of the UK, although the figures for East Anglia are at a level usually associated with a low risk of disease. Localised areas that have remained wet for long periods over the summer and autumn may present a threat to livestock in any part of the country, and the fencing-off of such areas provides some control of infection without increasing selection for flukicide resistance.
[ A fluke problem in a flock might only be recognised in January when poor scanning results are obtained. ]
[ Sub-acute fascioliasis – this liver shows signs of adult and immature fluke infection ]
The first sign of a fluke problem on a farm might be seen in January when poor scanning results are obtained. At this time of year, there is often a mixture of adult and immature fluke in the liver causing condition loss, dullness, anaemia, abdominal pain and sometimes death. This is termed sub-acute fascioliasis.
Deaths due to acute and sub-acute disease may continue in many regions into the winter. Mean daily maximum temperatures for November were just 10°C in southern England, and lower across the rest of the UK, indicating that little fresh fluke infection will have been passing from snails onto the pasture.
[ High-risk fluke pastures that have been wet through the summer may still be dangerous to grazing stock through the winter. ]
However, the infectious stages (metacercariae) already on the pasture are highly resistant, so cases of acute fluke may therefore occur through January or even later, particularly in the high-risk regions. If there is severe penetrating frost, this will reduce their numbers and therefore reduce the risk of fresh infection of livestock.
Ill thrift and poor production due to chronic disease, caused by fluke picked up 10–12 weeks or more earlier, will be a major risk in inadequately treated animals this winter/spring.
Wet autumn conditions in many areas are likely to have resulted in many snails becoming infected by fluke before they become dormant for the winter. This increases the risk of early disease in livestock next year when infection is released from these snails. A disease forecast will be produced at the end of June next year, which will also take into account the climatic conditions in the spring/early summer as infection emerges from the snails.
Farms with a history of fluke should consider a winter (December/January) dose to remove adult and immature fluke. Sheep in high-risk areas may remain exposed to potentially risky pastures through the winter and consideration should be given to administering a repeat dose to these animals 4–6 weeks later.
[ Grazing cattle at considered at risk could be dosed now with a product effective against immature and adult fluke. ]
Farms that have not had fluke in the past should consult their vet and put in place the monitoring/treatment regime that their individual farm circumstances require.
The need for activity against immature fluke at this time means that triclabendazole (TBZ) may be the drug of choice as it kills fluke down to a few days old; however, there are concerns about resistant fluke, particularly after repeated use. Depending on the level of likely challenge, one of the other drugs with activity against immature fluke (closantel, nitroxynil) may be used in order to reduce selection for TBZ-resistant fluke. The effectiveness of treatments should be monitored by faecal egg counts, post mortem examinations etc.
The treatment of any outbreaks of fluke disease at this time should involve a move to fluke-free ground if possible. If closantel or nitroxynil rather than TBZ are used to treat clinical disease then follow up treatments are usually needed to remove those fluke too young to be treated by the first dose. If a move is not possible, then 3-weekly treatment may be needed throughout the risk period.
- Top of page
- Climatological regions of the UK
- WEATHER SUMMARY
- January 2013 parasite update and forecast
- SHEEP LIVER FLUKE
- CATTLE LIVER FLUKE
- SHEEP NEMATODES
- CATTLE NEMATODES
Scour, straining and weight loss caused by coccidia usually affects calves under 6 months old, and is associated with high stocking rates, poor levels of hygiene and other disease or nutritional problems. It is seen in all months of the year, although most disease is seen in calves at grass over the summer (VIDA 2011). This year, factors such as shortage of bedding and potential nutritional problems could lead to an increased risk of coccidiosis. In out-wintered stock, highly poached fields and large amounts of standing water will also increase the risk.
Sotirios Karvountzis MRCVS
I qualified from Thessalonika in 1994 and started in a predominately large animal practice in Holsworthy, Devon. I then moved to Shepton Mallet, where I became a partner. My main clinical interests include cattle fertility, reproductive and abdominal surgery, semen and bull testing, foot trimming and pathology. At the practice, I organise the foot trimming course and have been the speaker on animal health seminars for a variety of milk buyers. I am also a .NET, SQL and VBA computer programmer, with a main interest in SQL databases. With input from my practice colleagues, I have developed the monthly analysis program Milk Alert ©/ Benchmarking, which allows reporting on large amounts of cattle data.
I also work as a helicopter pilot, being a holder of a Commercial Pilot's Licence CPL(H) with Instrument Rating IR(H).
I am told it is very British when striking up a conversation to start with the weather. This area is still recovering from this year's unprecedented rainy weather. The grazing season was shortened, crops failed and some farmers are concerned about feed supplies for this winter. The biggest casualty has been maize with some of our producers just completing their maize harvest. On a positive note, most people have reported good quality grass silage harvested, albeit of lesser quantity.
It comes as no surprise to see that between July and August this year, median bulk milk somatic cell counts as reported by NML for our clients were elevated (Fig. 1). The reduction came from September onwards and this coincided with the beginning of the housing season. Equally, the amount of milking cow tubes which the practice sold during that period was also elevated, indicating increased levels of mastitis. The main causes of this were environmental, with Strep. uberis and E. coli or other coliforms regularly recovered.
My colleague Peter Edmondson who deals with most herd problems relating to mastitis and cell counts in our practice has certainly been busy this summer. Our proactive approach has been put to the test. Thankfully we are collecting data for all our producers' milk quality bulk milk NML results and each month we have hit lists of those whose cell counts or mastitis have been over the target. Nearly all of them are grateful when we contact them.
Apart from bulk milk quality results, we collate all their milk recordings into one file allowing us to see the wider practice trend. Milk Proteins for animals calved between 14 and 60 days were below 3% through summer indicating some levels of energy deficiency (Fig. 2).
We had seen a lot of ketotic cows, although the number of displaced abomasa was not high for this time of the year. Milk proteins for freshly calved animals have recovered since September, which coincides with a number of herds being housed.
For the past 10 years, we have been losing an average of 2–3 dairy farms. The main reasons are retirement, diversification, or lack of successors to take on the farm. The numbers of farms that are changing vets are very, very small, I am relieved to say, however this drift accumulated over a period of 10 years becomes a sizeable number. Equally there are limited ways that a practice can increase the number of farms it has on its books.
In our attempt to beat that trend, we have purchased the large animal section of a neighbouring mixed practice. This has now increased our total number of units significantly, but in real terms has brought us back to where we were 10 years ago. This exercise has been quite a challenge and has been led by Paddy who did a sterling job. The long term challenge for us is to bring these new clients into the Shepton ‘fold’ and the Shepton way of thinking, i.e. progressive, proactive and with a deep understanding of what makes farmers ‘tick’. Nobody likes change, even if it is for the better, so this is perhaps about us working even more closely with them.
For the past three years we have been auditing our surgical cases, with the main focus on LDA corrective surgery, caesarean section, RDAs and caecal displacements. We have now been carrying out laparoscopic corrections of our DAs for over 15 months and the results so far are indeed interesting. Cases corrected laparoscopically have produced 7.7 litres of milk daily for the 120 days following the operation, more than the ones corrected by the Guymer-Sterner method (Toggle). Also, the laparoscopic cases have been showing higher peaks by 6.6 litres compared to the Guymer-Sterner ones. The significance testing for both results was P> 0.05. The laparoscopically corrected cases showed a higher calving to conception interval by 23 days compared to the Guymer-Sterner ones, possibly due to their higher yields. The latter is also statistically significant.
The most popular laparoscopic approach is the standing method (Fig. 3), where the treated animal can join the herd at the following milking and requires a minimum of one helper plus the surgeon. The two step method (Fig. 4), allows not only LDA correction but non-volvular RDA corrections as well as abdominal exploratory laparoscopy. Finally, having carried out thoracoscopies, these should not be discounted (although I must say the very first one was unintentional).
The possibility of combining sector ultrasonography to diagnose ailments, and using laparoscopy to correct them when applicable, would increase the range of diseases that a clinician is be able to treat successfully (beyond the non-specific combination of penicillin- streptomycin and flunixin).
On a lesser note, as part of XL Vets, we have carried out Schmallenberg bulk milk testing. The results were surprising and can be correlated to a number of milk drop outbreaks. Most of these cases were with or without pyrexia or abortions.
Unsurprisingly, there is huge disappointment amongst our farmers at the government's cancellation of the badger cull. There is hope that it will go ahead next year, once all the logistical details have be taken into account.
Finally, we all wonder why the milk price dropped in late spring this year, only to go up again later on. Perhaps the dairies have realised the obvious: if they don't look after their farmers and don't secure their supplies, one day they will have no milk produced domestically.
I need to end this now, as my other half is complaining that I don't spend enough time with her…
Until next time, all the best!
Neil Sargison BA VetMB PhD DSHP DipECSRHM FRCVS
I spent most of my formative years on my grandparents' dairy farm, and have worked as a farm animal veterinary practitioner in Scotland and New Zealand since graduating from Cambridge in 1984. I have been employed by the University of Edinburgh for 14 years working in the Royal (Dick) School of Veterinary Studies' first opinion Farm Animal Practice, predominantly with beef cattle, but also with dairy cattle and sheep. I have an interest in the subject of sheep health and production, originating from a period when I kept a flock of about 200 ewes while working in my native north-east of Scotland. I have written a textbook that outlines my approach to the diagnosis and management of sheep diseases.
Writing this report in December from the Madhya Pradesh district of central India where the day and night time temperatures are about 25°C and 12°C, respectively and the seasonal absence of winter rainfall is amply, albeit perhaps unsustainably, balanced by irrigation, it is easy to forget for a moment the impact of atrocious weather in eastern Scotland. In fact, despite the agreeable climate, Indian farmers and smallholders face similar animal health challenges to their counterparts in eastern Scotland, principally: meeting the nutritional requirements of their animals; identifying and addressing trace element deficiencies; helminth, protozoa and ectoparasite control; infectious disease plagues; and vector borne diseases. Furthermore, the challenge of identifying primarily management solutions to these problems in the face of inefficacy of pharmaceutical control and unavailability of drugs is the same as that in eastern Scotland. The warm and dry conditions in India result in particular animal health issues, such as tick infestations and tick-borne diseases due to the favourable conditions for ticks off their hosts, and trematode infections, in particular paramphistomes and schistosomes, where animals are drawn to the margins of ponds to drink.
[ The calf mortality rate on this Indian dairy farm, hand milking 700 Murrah buffalo is 90%. The principal causes are the same as those affecting cattle in the UK, namely poor hygiene and colostrum management. ]
- (2 and 3)
[ Ticks, tick borne diseases and tick control are major problems throughout India. ]
[ Ticks under the chin of a nondescript cow. ]
- (4 and 5)
[ Animals queuing up for examination at a village treatment camp. Most will be given a fenbendazole tablet and a trace element supplement (Fig. 5), but this cannot address the primary management problems. ]
Autumn 2012 was persistently much wetter than average in eastern Scotland, compounding the effects of what were amongst the wettest spring and summer seasons on record. As a direct consequence pasture growth was poor, and availability was compromised by poaching and soil contamination. Lambs have been slow to finish, calf growth has been poor and ewes and lambs generally entered the winter in poor body condition. Many farmers housed their lambs in order to finish them on grain-based rations, and housed their cattle early due to the state of their fields. The situation is not helped by a general shortage of good straw for bedding, variable grain yields and quality, and the value of conserved forage ranging from satisfactory in a few cases to awful in the majority. To make matters even worse, lambs that have been slow to finish are a drain on resources that should be prioritised to other classes of animals, while their additional time spent on the farm leaves them vulnerable to the compounding effects of other diseases, such as lameness, respiratory disease, fasciolosis, nematode parasitism, and trace element deficiencies, which might not have arisen had the animals been moved off the farm earlier.
[ Poor, mouldy whole crop silage, made late in the season in impossibly wet conditions. ]
Cobalt and selenium deficiencies have been diagnosed in ill thrifty lambs. The incidence of trace element deficiencies is often associated with the height of the water table, leading to higher herbage concentrations of molybdenum which interferes with copper uptake, and high levels of iron and sulphur intake along with soil contaminated herbage, interfering with the absorption of copper and probably also selenium and cobalt. Copper deficiency has been identified during routine monitoring of lambs, raising concerns about the specific need to supplement ewes to prevent swayback occurring in their lambs next spring.
Ewes are generally in poor body condition, which will inevitably reduce their ovulation and conception rates, giving rise to poor lambing percentages. Also, ewes that are in poor body condition now will require carefully planned nutritional management to avoid metabolic diseases such as pregnancy toxaemia occurring next spring, and to avoid high mortality rates in their underweight and undernourished newborn lambs. The incidence of lameness and respiratory disease in ewes has been higher than usual, again due to the wet weather conditions.
Fasciolosis has been a widespread and serious concern throughout eastern Scotland for the past few years. This year, however, the severity of subacute fasciolosis has been greater than ever, made worse on several farms by the confirmed presence of triclabendazole resistance. Slaughterhouse feedback on the incidence of fasciolosis has proved to be a useful, albeit hitherto undervalued, resource for many of our farmer clients. Increasingly fasciolosis is diagnosed despite adherence to a flock or herd health plan involving whole flock or herd metaphylactic triclabendazole treatments during the early winter predicted high risk period for subacute disease. This approach was never likely to be sustainable, and the confirmation or suspicion of triclabendazole resistance in Fasciola hepatica in many sheep flocks and beef herds in our region rightly changes our approach to disease control. Our farmer clients have been forced to instigate preventive management strategies, involving host evasion of high levels of metacercarial challenge, grazing management to control snail and free living fluke-stage habitats, and the strategic use of flukicidal drugs, with the aim of interrupting the parasite life cycle through reduced host egg shedding. In fact, these strategies, involving strategic flukicide treatments during the late spring as mean daily temperatures exceed 10°C and fluke egg development starts, have proved to be successful in preventing production loss due to fasciolosis.
Paramphistomes have been identified in both sheep and in cattle in eastern Scotland as incidental findings while monitoring the control of fasciolosis. We have used molecular methods to confirm the identity of these parasites as being Calicophoron daubneyi. The parasite is present throughout mainland Europe, sometimes causing scour and even deaths during migration of immature stages from the duodenum to the forestomach, and was probably introduced to the UK with imported cattle or buffalo. Wet weather conditions will have subsequently favoured what are presumed to be water snail intermediate hosts.
Most of the beef cattle herds in eastern Scotland are predominantly spring calving, following a rigid nine-week mating period during the summer. The results of pregnancy diagnosis in spring calving beef herds have been varied, with a few achieving excellent results while others have been disappointing. Most herds manage their heifers to calve at two years old, monitor the body condition score of their animals, have compact 3-cycle mating periods following previous compact calving periods; and use of sound bulls. The target barren rate in these herds is less than 6%.
Most spring-calving cows in well-managed herds in eastern Scotland usually enter the winter in good body condition of 3.5 (on a range of 1 to 5), however, this year the body condition of many is between 1.5 and 2.5, which means that they will need planned and expensive feeding management in order to ensure that they calve in condition score 2.5. Given the quality of the forage that is available and the cost of grain, this may prove to be impractical, in which case post partum anoestrous periods will be extended, leading to high barren rates after a compact mating period next summer. Furthermore, if improved feeding is delayed until late pregnancy, there could be a risk of dystocia due to oversized calves, although this is difficult to quantify. It will be more important than ever to manage production limiting diseases, in particular fasciolosis and trace element deficiencies, which could otherwise compound the problems faced by animals already in poor body condition.
[ The body condition score of these spring calving suckler cows after weaning is on average one unit less than it ought to be. ]
The number of autumn calving beef cows requiring Caesarian section was much lower than in previous years, probably reflecting generally poorer body condition scores of the cows and poor nutrition during the period of maximum foetal development during the final third of pregnancy, rather than being due to improved dam and bull selection. Nutritional management with regards to feeding during late pregnancy is harder in autumn calving cows on pasture than in spring calving cows, which are usually housed and forage-fed during late winter.
On a more positive note, the incidences of gastrointestinal nematode and lungworm parasitism have been lower than during recent years, presumably as a consequence of climate and grazing management. There have been very few outbreaks of respiratory disease in housed calves, possibly reflecting the widespread and appropriate use of vaccines, combined with creep feeding before housing and weaning by removing the cows from the calves a few weeks after housing to minimise stressful management over the housing and weaning period.
At the time of writing, Schmallenberg virus has not been identified in eastern Scotland, although based on serological testing, the virus is present in neighbouring Northumberland. Our farmer clients ought to be concerned about the consequences of wind-blown spread of virus-infected midges and infection of autumn calving cows and spring lambing ewes during the first third of pregnancy. However, for the time being in the absence of an available vaccine, there is little that they can practically do to reduce the risk, especially in animals that must be kept outdoors. Most are focussed on the consequences of the awful weather, some of which are at least manageable.
John Watkinson BVSc CertCHP MRCVS
On graduating from Liverpool in 1984 I spent four years in mixed practice working in Shropshire and Hertfordshire together with undertaking locums for six months. In 1988 I returned to my ‘home’ practice in Wensleydale where the workload is still mixed but predominantly livestock orientated. In recent years we have operated a shared out of hours rota with my neighbouring practice which has a similar spectrum of clientele. It has worked well. My spare time is often spent as a Rugby allickadoo.
It has certainly been a weird year for weather across the UK not least in the Yorkshire Dales. We had no hay time, no Yorkshire Show, no maize worth harvesting and no weather to harvest and re-sow crops in the autumn. I have also had my first bucket of water and ice cubes brought forth in the first week of November!
A handful of dairy herds in the locality have now responded to these factors by housing cattle all year round as the only means of controlling the variables. As we all know there are pros and cons to this but it is nevertheless easy to understand the farmers' perspectives. At least these cattle didn't have to contend with the two days of record rainfall in August and September (Figs. 1 and 2).
I always feel a warm philanthropic glow when I see my taxes being spent in Scotland and Wales to support their livestock sectors; what with ‘headage’ payments maintaining livestock numbers and the £48,000 tuition grant to a Scottish trainee Vet student, together with their livestock health initiatives subsidised from England. There seems no political will or progress on English rural issues. Thank goodness we are not plagued by TB as in the West Country, but the ever increasing drain on the DEFRA budget of repetitive vain attempts to control TB will surely mean that Whitehall is not likely to support other similar English initiatives to improve the lot of our livestock sector and the practices that serve it.
My experience of how the Regional Development Agency allocated funds for the last round of farmer training initiatives was not good. Blatantly obvious conflicts of interests were ignored by poor quality administration of the funds via LANTRA. I fear this is likely to continue without change of personnel. In the latest debacle of training fund allocation direct from DEFRA, the lion's share of the Animal Health and Welfare ‘pot’ was awarded to EBLEX and Dairy Co who already are recipients of largesse from the livestock farming community via the compulsory levies. You couldn't make it up, as they say!
Despite not being Scottish or Welsh, we have tested the water (without grant or subsidies) on a local BVD control initiative. One of my neighbouring practices has instigated this project and has recruited a fair number of contiguous farms with decent geographical boundaries, with the aim over the near future of extending or coalescing other similar patches together in the surrounding district. We shall see.
With the help of Pfizer, following a farmer meeting (again) on SCOPS we have tested a much higher number of pre and post drench FECs than normal. Some resistance has been found, but the main feature for me has been how many scouring lambs do not need drenching at all. The past 30 years in the UK have created the perfect scenario for worm resistance; allow the trade outlets unrestricted access to sell anthelmintics, make it cheaper by the year and farmers respond by pouring white drench down anything either scoured or penned up for management tasks. Pfizer's initiative is to be applauded – but how long before their novel drench is available to salesmen rather than professionals? Who else is going to advise a farmer not to drench?
A couple of clinical oddities to note over the summer:
A call to a cow with suspect ‘staggers’ in a large field proved interesting. As we approached slowly to attempt restraint, we could see she appeared tetanic but as we carefully tried to catch her she dropped dead on the spot, as though she had been shot. The farmer had checked the group two hours previously with normal findings. What's the word for faster than peracute?
At a routine dairy visit, a client commented that “you can't get the staff nowadays, someone (himself) served this cow at 20 days calved – just check her anyway”. Yes, you've guessed, PD positive. It must have been the weather what done it.