Graeme Kirk reports from the 2014 Irish Pig Health Society Symposium held at Mullingar in early April
Dr Laura Batista
Opening the 2014 IPHS Symposium, this year titled, Progessing Pig Production, was Dr Laura Batista. A consultant vet working mainly in North America, she gave an in-depth presentation on porcine reproductive and respiratory syndrome (PRRS), which has become a major issue in Irish pig production in recent years.
Dr Batista explained PRRS was caused by a virus that resulted in two main symptoms: reproductive faulure and respiratory disease. There were two strains of the virus – European (Type 1) and North American (Type II). A third strain had also recently been described in China, although this was still classified Type II.
The most important factor in trying to control PRRS spread was biosecurity, although this remained a difficult issue as so much was still unknown about methods of transmission.
Airborne spread of the virus had been proven at more than five miles, and animals including cats, dogs, bird and rodents – and even flys and mosquitoes – had been found to be vectors of the virus. Vehicles could also carry PRRS between farms.
Because of the uncertainties about transmission, there was no single control strategy for PRRS, but Dr Batista said that in smaller herds affected by the infection, developing immunity to the virus was probably the best way to ensure that it didn’t lead to significant economic losses. Where a control programme of this type was needed, however, it would need to be tailored to the individual farm to ensure it was effective.
The goal of many infected units was to stabilise the infection in the sow herd by assuring immunity in all breeding stock. Herd immunity prevented reproductive failure and could also decrease the likelihood of transmisson of PRRS from sows to foetuses and offspring. Breeding herd stabilisation could sometimes be accomplished by vaccination, intentional whole-herd infection, aggressive acclimatisation of replacement gilts, or a combination of these methods.
As PRRS was one of the most costly pig diseases on a global scale, and the virus, its control strategies and the effects on individual farms were so variable, Dr Batista said it was imperative that experienced practioners, diagnosticians and researchers continued to objectively expand their knowledge to better control, and eventually eliminate, the disease.
Dr Mari Speijers
Environmental enrichment for fully slatted systems was the topic tackled by Dr Mari Speijers, a researcher with Northern Ireland’s Agri-Food and Biosciences Institute (AFBI). She noted that in a natural environment, pigs would spend up to 75% of daylight hours rooting and foraging, and the inability to express these bahaviours in barren environments like slatted sheds could result in reduced welfare and expression of adverse behaviours including ear- and tail-biting.
Since 2003 EU legislation has required that housed pigs must have permanent access to materials that allow investigation and manipulation activities, and Dr Speijers pointed to the more recent definition of enrichment material from the European Food Safety Authority as: “a material which stimulates exploratory behaviour for an extended length of time, preferably comparable to the level of occupation provided by straw”.
Dr Speijers said this suggested that indestructible objects such as chains or tyres were not sufficient to meet the manipulatory needs of pigs, and couldn’t legally be used as the only enrichment.
The AFBI had undertaken an investigation of environmental enrichment methods that included visits to Switzerland, The Netherlands and Denmark.
The Swiss visit found producers using solid blocks made from compressed straw or feed by-products that were held in metal holders. Depending on the density of the blocks, these could last from 10 to 60 days.
In The Netherlands, wooden posts suspended by chains or in metal holders proved popular, with similar systems seen in Denmark too. Danish units also used ropes hanging from the ceiling to occupy pigs, although this tended to be used only as a response to tail-biting episodes.
Concluding, Dr Speijers said that most commercially available toys didn’t currently meet the legislative requirements, and there was considerable room for more research into suitable methods of enrichment.
Unfortunately, Dutch farmer Eric van den Heuvel couldn’t make it to the symposium, but his paper – A novel method to reduce undesired bacterial load through increasing the desired becterial load – was presented by Dan Kirschner of UK-based probiotic supplier Pro-B.
Mr Kirschner described the process by which Mr Van den Heuvel had reduced the level of MRSA on his pig unit by spraying everything on the farm – including washing the sows – with probiotic cleaning products.
The concept, Mr Kirschner said, was simple: bacteria, good or bad, rely on the same nutrients and the same space, but they can’t live on top of each other. Therefore, if an area is full of good bacteria, there’s no room for bad bacteria to occupy.
Probiotic cleaners are commonly used in poultry production, but are rare in pig units. Mr Van den Heuvel used an animal housing cleaner to wash his buildings and sows periodically, then every three days all surfaces were sprayed with an animal housing stabiliser. The water lines in the pig houses were treated with another probiotic product.
After six months of this routine, MRSA counts on the farm were very low, but there were added benefits in terms of reduced antibiotic use in the herd too. Mr Van den Heuvel’s figures revealed that the cost of antibiotics used had reduced from 1.42 euro/pig sold in 2008 to just 12c/pig sold in 2011.
Professor John O’Doherty
In a paper titled Nutritional strategies to reduce antibiotic usage, University College Dublin’s Prof John O’Doherty discussed some commonly used alternatives to antibiotics. These, he said, had become more commonly used since the ban on antimicrobial growth promoters in 2006, which had become a popular feature of the intensive livestock sector as a way of increasing production.
The most common approach was to use prebiotics, which Prof O’Doherty defined as non-digestible feed ingredients that beneficially affected the host by selectively stimulating the growth and/or activity of one or a number of bacteria in the colon that have the potential to promote health. The key factor with prebiotics was that they weren’t degraded by enzymes in the small intestine, but reached the large intestine where they could be utilised by beneficial bacteria.
Typical prebiotics included inulin (found in foods like onions, chicory, garlic, artichoke and asparagus) and oligofructose (produced by the partial hydrolysis of inulin), which had produced mixed results in studies. And organic acids had also produced mixed results, although the idea that they would lower the pH in the gut to promote digestion was sound.
Prof O’Doherty also considered feeding lactose as a fermentable carbohydrate and the interaction of dietary proteins and fermentable carbohydrate, as well as looking at feeding marine polysaccharides. Trials with laminarin extract from brown seaweed had shown a beneficial antibacterial effect.
In conclusion, Prof O’Doherty said that feeding an appropriate fibre was important in pig production and would result in an improvement in the well-being of animals.
A healthy diet needed to contain certain compounds that were not digestible by the host, but could be metabolised by at last some representatives of the gastrointestinal tract bacteria, and preferably the lactic acid bacteria.
Ireland needs an Island Pig Health Plan. That was the assertion of Colin Marry of the Irish Farmers Association (IFA), speaking at the IPHS Symposium.
Mr Marry said that the primary reason was to keep out disease, with three big threats in particular: the North American strain of PRRS; ASF; and PED.
But there were good commercial reasons for the move too; better herd health on the island of Ireland would allow the pig industry to become more competitive, as at the moment it couldn’t compete with the big exporters like Denmark.
Mr Marry pointed to the fact that breeding and health costs were 0.11c/kg in Ireland compared to the 2012 Interpig average of 0.08c/kg, so there was real opportunity to benefit from better herd health.
The seed for the Ireland Pig Health Plan had been sown at the 2013 IPHS symposium, where IFA began discussions with Pig Re-gen, the voluntary-levy body promoting pig health in Northern Ireland. The aims of the initiative were the prevention (or at least delay for as long as possible), identification, control and eradication of pig disease.
The plan proposes that prevention should be concentrated on the responsible importation of livestock and that all AI semen should be tested in the country of origin before being sent to Ireland. Mr Marry said this could be tied into quality assurance schemes, with penalties for producers that didn’t comply.
There were several pillars to disease identification, starting with national screening, similar to the programme already operated by Pig Re-gen. Separate PRRS testing and carcase inspections would also play a role.
The control of disease was also a multi-prong approach, but the most important thing was that it took an all-Ireland approach. Education workshops on specific disease threats, better factory wash facilities, and the introduction of pig-free visitor declarations were among the steps proposed, with the appointment of a vet/field officer also a possibility in the future.
Finally, a list of diseases would be drawn up for eradication, based on their economic significance and the chance of success. This list could also include secondary diseases, which could be just as important.
Of course, implementing such a plan will come at a cost, and Mr Marry said the funding proposal included a 3.5c/kg contribution from producers and processors, as well as matching funding from the Irish government.
But there were also substantial benefits to be gained. These included: reduced medication costs; improved performance (along with lower labour and feed costs); a more competitive industry at retail level; the ability to better target the UK market; and a more stable livelihood for Irish producers.