Sheep / Cattle / equine NovemBER 2014 nzerf scholarship tape worms Theileria Photos by Richard Hilson www.vshb.co.nz
NEW ZEALAND EQUINE RESEARCH FOUNDATION VET FARRIER SCHOLARSHIP 2014 DAVE KRUGER Jordaan Aplin and I were fortunate enough to be awarded the New Zealand Equine Research Foundation (NZERF) Vet Farrier Scholarship for 2014. This is an initiative by the NZERF that provides funding towards continuing education for a vet and farrier from the same area in New Zealand. We spent two weeks during August at the Podiatry Department of Rood and Riddle Equine Hospital in Lexington, Kentucky, USA. Kentucky is the horse capital of America with around 12000 thoroughbred foals born in the district annually (one third of the total USA foal crop). Rood and Riddle Equine Hospital is the leading provider of equine veterinary services in Lexington with a staff of over sixty vets and caters for everything from reproduction, surgery, imaging, stem cell therapy, equine pharmacology, podiatry dentistry and a host of other disciplines. The podiatry unit has four specialist podiatry veterinarians who are highly qualified in both equine veterinary medicine and farriery. There are also five full time farriers and two fabricating engineers employed in the department. We were made extremely welcome and spent each day working alongside one of the podiatrists, both in the hospital and out on farm. The thoroughbred properties we visited and worked at are stunning, with miles and miles of post and rail fencing encompassing immaculately groomed Kentucky Bluegrass pastures. With the annual yearling sales due to commence a few weeks after our visit a huge focus was on yearling preparation and correct, regular trimming of feet to maintain perfect limb comformation. Laminitis was very prevalent particularly in brood mares. This appeared to be related to the high sugar content of the Bluegrass pasture, similar to the problem we have with perennial ryegrass pastures in New Zealand. Some of these were extremely serious and were hospitalised. The principles of treatment were the same as we were accustomed to elevation of the heel in the acute phase of laminitis with gradual remodelling of the foot around the displaced pedal bone over time. We saw a number of venograms performed (contrast radiographs to evaluate blood supply) as well as a deep flexor tenotomy on one horse. The venogram technique used at Rood and Riddle was very simple and effective and I am sure I will be performing many more of these extremely valuable radiographic studies than I have to date. Glue on shoes were used extensively, especially in remedial cases for quarter cracks, hoof wall injuries, laminitis and where treatment plates were indicated such as solar penetrating wounds. I was extremely impressed with the Sigafoos glue on cuff shoes, as they can be adapted to such a large variety of applications. Although quite complex, the Rood and Riddle team made working with this technology look very simple. I believe we should be investigating the use of these shoes in New Zealand. I picked up many practical tips that I am sure I will find very useful back in the Bay. These included the use of chloride dioxide foot soaks for infections such as seedy toe and white line disease as well as some really practical ways to apply foot casts and use regional antibiotics in cases of deep foot infections. The use of medical maggots for treatment of necrotic deep wounds was fascinating and I believe under utilised in New Zealand. These maggots are from a fly species that only feed on dead tissue. They do a remarkable job of cleaning up necrotic wounds, essentially performing microsurgery in deeper tissues that could not otherwise be reached by conventional flushing techniques. Overall I found this trip to be one of the most valuable continuing education experiences I have had and would like to thank the NZERF for making it possible. I would also like to acknowledge Drs Raul Bras and Vern Dryden, two of the most capable veterinarians and farriers I have had the pleasure of working with. Their hospitality was amazing and they really went out of their way to involve and educate us.
What flystrike product should I use this year? Flystrike is the second most costly parasitic disease of sheep in New Zealand, ranking only behind gastro-intestinal roundworms in economic importance. Estimates are that flystrike costs the New Zealand sheep industry approximately $37 million per year through losses from deaths, cost of treatments, and lost meat and wool production. Research has shown that even relatively small strikes can cause a marked appetite loss in the struck animal with a resulting loss in weight- recovering this lost weight can take significant time. Ewes and ewe hoggets struck in late summer/autumn are far less likely to get in lamb and we note this at scanning time. There are four species of blowfly that initiate strikes on sheep in New Zealand, with the Australian green blowfly (Lucilia cuprina) and the European green blowfly (Lucilia sericata) recognised as the most important primary strike flies. Prevention of flystrike caused by the larvae of these species is largely reliant on application of a range of insecticides by a variety of means (saturation dipping, jetting, low volume pour ons or spray ons) to the fleece of at-risk animals, along with good animal husbandry such as effective worm control to prevent faecal soiling and crutching and shearing at appropriate times. The flystrike preventative compounds most commonly used in New Zealand belong to the broad insect growth regulator (IGR) group of chemicals. These fall into two distinct chemical classes by having different, unrelated modes of action. These are: The triazine/pyrimidine derivatives cyromazine (Cyrazin) and dicyclanil (CLiK, CLiKZiN) and The benzoyl phenyl urea (BPU) compounds diflubenzuron (Fleecemaster, Zenith) and triflumuron (Zapp, Exit) The triazine and pyrimidine products appear to prevent first instar maggots from completing their moult and development through to second stage larvae. Note that these compounds have no effect against lice. The triazine derivative, cyromazine, was first registered for use in New Zealand in the mid 1980s as Vetrazin, while dicyclanil has been available as CLiK since 1998. BPU compounds are thought to affect the deposition of chitin (a key component of the cuticle of all insects) so these also have activity and label claims for louse control. Diflubenzuron was first available as Zenith in the early 1990s, followed by triflumuron as Zapp since 1998. The Lucilia spp blowflies have demonstrated a remarkable ability to develop resistance to various chemicals. Strains of L. cuprina and L. sericata resistant to diazinon, an organophosphate, have been recorded throughout New Zealand. Resistance by the Aussie fly to diflubenzuron was confirmed in Australia in 2002 with cross resistance to diazinon identified as a factor. A large recent NZ survey found five of fifteen strains of the European green blowfly had a high level of tolerance to triflumuron. However there was little sign of resistance to dicyclanil and this backed up field observations where good levels of flystrike protection are still afforded by this active. Conversely nineteen strains of L cuprina, the Australian green blowfly, were tested, with little resistance to either active ingredient. This is perhaps a little surprising as it is usually L. cuprina that appears as being resistant to chemicals, rather than L. sericata. When we combine this information with reports of treatment failures in the field it is probably safe to assume that resistance is now well established, particularly in North Western regions of the North Island, in this species. We all need to be aware of the possibility and its implications. Minimising the losses caused by flystrike requires a planned preventative treatment approach using effective products. A preventative approach means that treatments are applied before expected fly activity rather than waiting until animals are getting struck before treating these are referred to as reactive treatments and production losses will have already occurred. Resistance management now needs to be factored in when planning flystrike prevention programs alongside other key factors such as rainfall, class of sheep, shearing, docking and weaning dates, product application method and previous fly challenge. A key recommendation is to manage flystrike and lice as separate issues. This includes treating each parasite with effective products at the appropriate time (e.g. application of louse pour ons off shears), which depending on application method used will be different for flystrike prevention and louse control. Other strategies include using a different chemical, with a different mode of action, to treat active flystrike compared to any preventative treatment applied, and to use different chemicals for flystrike prevention and louse control. Farmers cannot afford any level of flystrike from an economic point of view with the effects on meat and wool production and ewe fertility well demonstrated. Increasingly they cannot afford flystrike from a welfare perspective either. Getting this right is part of an individual farm animal health plan. (Adapted, with permission, from an article by Colin McKay) nait transition ends for cattle on 1 july, 2015 1 July 2015 is the end of the NAIT programme s transition phase for cattle! All cattle need to be tagged and registered in the NAIT database by this date. This includes pre-nait stock (cattle born before 1 July 2012). Find out more at www.nait.co.nz/end-of-transition or call into the clinic to discuss your requirements
theileria Theileria has been diagnosed in Hawke s Bay in the last few months, mostly in dairying areas. Theileria orientalis Ikeda strain has been in NZ since 2012. This is a disease of all cattle that is transmitted through cattle ticks but so far the greatest impact has been with the dairy industry in high tick population areas such as Northland, Auckland, Waikato, Bay of Plenty, Gisborne and Taranaki. Ticks do occur in Hawke s Bay especially near the coast but reports of occurrence are often limited by how closely observations are made as juvenile ticks are very small and hard to see. The ticks become infected by sucking blood from infected cattle and pass theileria on to other uninfected cows with each subsequent feeding. The tick life cycle involves a number of feedings followed by moults throughout which the infected stage stays infected. However, the adult female does not pass the theileria onto the eggs, so eggs and nymphs (before feeding) are not infected. Nymphs and adults go through a hibernation phase from mid April till late July when they don t move or feed. Therefore an infected tick may have a lifecycle of up to a year. Ticks require adequate cover such as long rank pasture for survival. Ticks can also feed on all other livestock (and even hares, rabbits, birds, dogs etc) and therefore can be carried between properties. Once an infected tick bites a cow, the incubation period is 2-6 weeks and the disease caused is anaemia. The symptoms include pale udder, nose and vulva, lethargy, increased heart rate and respiration rate, weight loss, drop in milk production, non responsive downer cow and death. Once a cow is infected she has the clinical disease and can take about three weeks to recover before developing immunity. She remains infected for life (a source of infection for the ticks to Clare Ryan pass on to other uninfected cows) but does not seem to get a reoccurrence of the clinical disease again. Treatment options include once a day milking or drying off, increased feeding and decreased activity especially for those not severely affected. Blood transfusions may also be necessary for severely affected cows. There is a treatment called Buparvaquone which kills the protozoa in the cow but with massively long withholdings of 49 days for milk and 430 days for meat (as well as controls about identification); very little of the drug has been used yet. Tickicides such as Bayticol in areas with big tick numbers can help slow the transmission of the disease but will not stop it due to the lifecycle of ticks being mostly off the cow. Control Plan: Tickicide on all cattle coming from north (before getting on the truck) limit spread of infected ticks Blood test your herd to see whether your herd already has infection. If you have theileria already, monitor. If you don t have it be careful when buying in cattle. Blood test all brought in cattle (before arrival) especially important if your herd doesn t have it. Decrease stress on cattle feed well, monitor and treat illnesses quickly and effectively. Early detection of cases leads to better outcomes OBSERVATION!!! We have come up with this five point control plan and recommend all cattle farmers discuss this with their vet to work out the best plan for their farm. We can t eradicate ticks, can t stop cattle movement around New Zealand, and there is no vaccine available- so we can t stop Theileria. Tapeworm in lambs simon Marshall Lambs are susceptible to infection with a tapeworm called Monezia expansa. Lambs become infected after eating pasture contaminated with cysts produced by a free living soil mite. Lambs that become infected in the spring spontaneously lose their infection over the next 4-5 months and generally become resistant to infection. Tapeworm segments in the faeces are very obvious after drenching. We often hear about how many tapeworms the lambs were carrying as farmers see large volumes of segments expelled after drenching. Over the years there has been a lot of debate about whether tapeworm infection causes reduced production through growth rate depression. There have been many trials showing no growth rate response and a couple of trials showing a growth rate response when a tapeworm drench (Praziquantel) was included in the treatment group. So we can say that on some occasions in some seasons a tape worm drench for lambs will give a production response and sometimes it won t. It is hard to predict when this will or won t occur. One of the trials that did show a production response was completed in 1996 by Southworth et. al. They showed a 3kg increase in bodyweight over a 2 month period between October and December between the control group and the tapeworm & roundworm treated group and a 2 kg difference between the roundworm only treated group vs the roundworm & tapeworm treated group. These results were statistically significant. Another trial that showed a production response was carried out in 2010-2011. The trial was carried out over 3 farms. This trial showed an increase in live-weight gain and a reduction in dag score over all farms. There was a difference in the magnitude of the differences on each individual farm. They concluded that using a roundworm drench containing a tapeworm drench in lambs pre-weaning improved; dag score, faecal consistency and live-weight gain. They did note that the year the trial was carried out the feed covers were low and the ewes were in medium to light condition. So this may have made it more likely that a response was seen. A common approach to tapeworm drenching is to give lambs a drench containing Praziquantel for their first 1-2 drenches. This may start one month pre-weaning or at weaning. There is reasonable evidence to support this practice but it must be realised that the response will differ between years and between farms. An interesting point to note is that one trial found that the tapeworms were resistant to Praziquantel. This may explain the differences in production response that is seen between farms. The most important principle to remember is that roundworms will have the biggest impact on production in lambs so they need to be well controlled by using a parasite management plan. Part of this plan will be the use of an effective drench. You need to know what drenches are effective so make sure you have completed a faecal egg count reduction test and do regular drench checks.
Seasonal Update Hastings/Napier October has been a tricky month for most as its still isn t that warm in the mornings and it got really dry, really quickly after those high winds. Fortunately the rain did come and finally the grass is starting to bolt. The majority of farms are only on top of the grass though and there isn t much excess in most places because of those extra lambs that we have around. Watch out for bloat though, as there is lots of clover. The maize is only just starting to pop up around town which seems a little late and farmers are finally getting crops in now the wind has settled down to allow spraying. Waipukurau What a busy period it s been of late; at the time of writing we have had all hands to the pump disbudding and vaccinating calves, metrichecking dairy cows, setting up A.I programmes, testing for trace elements in cattle and sheep (blood sampling and liver biopsying) whilst just beginning to make in roads into the de-velvetting of stags. On top of this we have had a couple of globetrotting vets involved in overseas ventures in countries as exotic as Saudi Arabia, China and Khazakstan! Several woolshed Dannevirke The spring that has stuttered on and on finally kicked into gear mid-october with some consistent sunshine and warm rain, this has relieved feed pressure on many dairy and sheep farms alike. Hopefully we get some more of the same in the next few weeks to keep things going as we head into mating for the dairy farmers and early beef cows. Feed quality has generally been good as short pasture covers come away with high clover content. Predictably, this has resulted a high bloat challenge early in the season on some Helen Taylor Theileria has well and truly established itself in most of our regions so if you need to find out what your herd status is then get up to 20 cows in for a pooled blood test the test is relatively cheap and the information you gain is very good value for money. If you are still trying to get your head around the whole disease then give us a ring at the clinic as we have all been busy upskilling ourselves on this new disease. Its been great to see some boats heading down the road for a service so hopefully you have all had a relaxing labour weekend - early reports are that the fish are biting and the crays are plentiful. Harry Whiteside meetings were held across the region emphasising the value of various faecal egg count tests and sheep scanning; thanks to all who attended these informative sessions. With the warmer temperatures grass has really taken off and lambs/calves are blooming. Winter coats are being shed and animals are really starting to gloss up. Clover is thriving so watch out for bloat and be wary of clostridial diseases on the lush tucker greening up the district. Tim Hogan places. Lamb survival appears to be very good although this will become clearer as more docking results filter through. Some stormy weather at the start of hogget lambing is bound to affect their results. The outlook from here is positive, as least as far as production goes, with pasture growth starting to outstrip demand and most stock, particularly cattle, in good condition. With the shield safely locked up for the summer what else can you ask for?! stihl chainsaw WINNERS SEPTEMBER HASTINGS: W A X Couper Greenlees Farm WAIPUKURAU: Paul & Catherine Robottom, Pendle Hill Station DANNEVIRKE: Brent & Jenny Stewart Ram runs No excuses! The ram run planning is underway again for 2014/15 Please contact us at the clinic to get your rams checked this year so you get the best results next year!
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