livestock Professor Sang continues: “Vaccines are available for PRRS but are not fully effective, resulting in PRRS being an endemic disease of pigs in the UK, with the consequent economic losses and animal welfare challenges. “A genetic approach that would give pigs protection against this disease would be good for the welfare of the pig and good for the farmer. The PRRS virus binds to a particular protein on the surface
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of cells of the pig, which enabled the use of genetic engineering by Professor Sang and her colleagues at the Roslin Institute to edit that protein in order to prevent infection by the virus. “Colleagues used CRISPRCas9 to chop out part of the protein from the pig’s gene – they showed that the pig is still perfectly healthy and happy, but if you try and infect the pig with PRRS, it just won’t become infected. That shows really strong genetic resistance.”
Bold plans to eradicate BVD and sheep scab by 2031 The livestock industry has set out bold ambitions to eradicate sheep scab and Bovine Viral Diarrhoea (BVD) by 2031, among other goals, following a Ruminant Health and Welfare (RH&W) workshop held on 29 June. The workshop included over 70 leading farmers, vets, researchers and industry stakeholders from across the four nations of the UK. Attendees set the agenda in advance by singling out ‘actionable’ sheep and cattle diseases from a list of priorities identified in the RH&W grassroot survey results released in May. RH&W chair Nigel Miller explained that by setting management, control and/or eradication targets for the year 2031, the workshop participants were aiming to create a new high-health environment across farms of the four nations before the next decade. “We need this health platform to elevate animal welfare and play a part in securing export markets,” he explained. “We are going into a period of extraordinary change; we have got to be willing to push back on the accepted boundaries of health and production. World
class economic efficiency and the building pressures of low carbon production demand a higher national flock and herd health status; mapping out clear change targets is a vital step to secure that goal.” Sheep scab, now endemic in the national flock and affecting 10-15% of farms with about 8,000 outbreaks each year costing up to £202 million, was one of the most popular topics selected for debate. The group set out coordinated control, mandatory annual screening, flock traceability, and vaccination for sheep scab as key objectives on the way to eradication. Dr Stewart Burgess at Moredun Research Institute said a new vaccine would help in the long term, but interim goals like notifiable or reportable status would create a traceable, sustainable framework. “The reality is that there are imminent threats and the status quo is not working,” said Dr Burgess. “Modelling studies have shown that focussing control on disease hotspots not only makes gains in those targeted areas, but can also have a significant impact on sheep nationwide.”
VET Wasting Away It’s funny how on certain days there seems to be a theme to my clinical calls. Last week I had thin bull, a young cow loosing weight, an older cow loosing weight and a group of second calvers in poor condition all on the same day. All beef, all at grass and all seemingly well enough in themselves - just not doing. Where’s there’s nothing obvious to hang your hat on its a case of ruling out possibilities. Top of the list is parasites. Most adult cattle have developed a resistance to worms, but liver fluke can cause disease at all ages and adult cattle don’t appear to develop resistance to fluke in the same way. So with thin animals I’ll always want to rule this out as a cause. Fluke egg counts on dung samples is what we do routinely as its quick. It does of course rely on adult fluke being present to lay the eggs. There are alternatives: an ELISA blood test that looks for antibodies against the fluke which reflects infection in the past 8wks or so, and a copro antigen test that is now used in sheep quite a bit to get a diagnosis before disease has reached the egg laying stage so you can treat quickly. The traditional assumption that cattle need to have been grazing wet , marshy, “flukey” pasture no longer holds true in my opinion. We seem to see fluke on all types of pasture now probably a reflection of wetter weather over a period of years, or a wider distribution of the small snail that completes the lifecycle. When treating for fluke be aware of three things. 1. The fluke lifecycle. Immature fluke take 12wks to become adults
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By Andy Cant Northvet Veterinary Group 2. The products. Different products kill different stages of the fluke. Eg some kill only adults, some kills adults plus immature down to different ages. 3. Timing of treatment. After housing its unlikely cattle will pick up fluke infection, so if a product claims to kill fluke down to 6wk immature, leave it 6wks after housing and you should kill out everything and have fluke free cattle at turnout So back to my clinical calls. The bull had no fluke but a significant worm egg count and liver tests showed it to be damaged. The young cow had rumen fluke which can be significant but probably a red herring in this case as the cow developed respiratory problems later in the week. The old cow had no fluke but was Johne’s positive. The second calvers had no fluke and at the end of the day probably were needing their calves weaned off them and a bit of respite care. The best strategy for fluke is of course to look for it routinely and have a treatment plan in place so you know its controlled then it wont be top of your list. But as you can see from the above cases other causes are available!
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