» Go back (Press Articles)

June 3, 2013

Strategic summer deworming for pigs helps protect profit

Sadly parasites don’t take a summer holiday and vets at Elanco Animal Health are warning pig producers that they could face an even greater challenge from the roundworm, Ascaris suum, during the warmer months. “With almost three quarters of British farms being affected and infections with the parasite costing just over nine pounds per pig, it is clear that this is a problem the industry could do without,” says Elanco vet Alvaro Hidalgo PhD DVM MBA MRCVS1, 2 This summer, a strategic rather than sporadic deworming programme is being advised to help pig producers to enhance the performance of their herd.

Once Ascaris suum worms its way into a pig unit, producers are at risk of significant costs and losses at many levels of production. Feed conversion ratios can increase by up to 10%along with average daily gain reductions.3 Add to this the rejection of livers at slaughter and a decrease in carcass and meat quality, and producers are left with substantial profit shortfalls.3Dealing with an established roundworm problem,  can be very costly and time consuming, with attempts to re-establish control, often taking years. Prevention is certainly better than cure where roundworm is concerned.

When large numbers of roundworm larvae migrate through the liver, they leave their mark in the form of white specks called ‘milk spot’ lesions. Seen at post mortem, these are the major clue that a pig has been challenged with significant numbers of the parasite. However, this only indicates a problem around four weeks before slaughter and earlier infections may not be apparent upon abattoir inspection due to the ability of the liver to regenerate. 4 Therefore, a seemingly healthy liver doesn’t necessarily equate to a healthy pig.

There is evidence that the prevalence of milk spots peaks towards the end of summer so producers need to remain particularly vigilant and maintain a targeted deworming strategy throughout the warmer months.6 Richard Pearson of the George Vet Group in Wiltshire says, “Warmer weather can escalate the problem, as the parasite life cycle is completed in a shorter time, so we know that we have to be on top of the situation in the summer months particularly. The key is to hit the parasite hard before it can complete its life cycle. Control of Ascaris suum requires long term planning and long term commitment.””

It is important to ensure that the chosen anthelmintic has demonstrated efficacy against mature and immature stages for effective control. In contrast to ivermectins, flubendazole acts against early larval stages, which are responsible for milk spot liver damage.

A strategic deworming programme, using Flubenol® 5 % w/w Premix for Medicated Feeding Stuff for five days every five weeks for all grower/finisher pigs has been shown to be effective at controlling roundworm and reducing milk spots.7-9

The treatment of other parasitic worms may also need to be considered when choosing an appropriate anthelmintic and flubendazole, again unlike ivermectins, is also active against the harmful whipworm Trichuris suis.

Spring and autumn treatments have become the established norm in the industry but it’s clear that there’s still more to be done, especially during the warmer months. A more regular and strategic programme of treatment could improve pig health and welfare and ultimately profitability for pig farmers. Alvaro Hidalgo believes that it’s easy for producers to lose focus in the summer months when juggling holiday rotas but using an in-feed product like Flubenol® that has a flexible dosing regime is much simpler to tie in with feed deliveries, “The main thing is not to allow that critical summer dose to slip. The key is to keep focused and as a result, stay profitable throughout summer.”

For further information please visit http://largeherds.com/ or contact Elanco Animal Health, Lilly House, Priestley Road, Basingstoke, Hampshire, RG24 9NL, Tel 01256 353131, Fax 01256 779510 Email elancouk@lilly.com


  1. Sanchez-Vazquez MJ, Smith RP, Kang S, Lewis F, Nielen M, Gunn GJ, Edwards SA. 2010. Identification of factors influencing the occurrence of milk spot livers in slaughtered pigs: A novel approach to understanding Ascaris suum epidemiology in British farmed pigs. Vet Parasitol, 173, p 271-279.
  2. Based on 10% increase in FCR during the finishing period after Ascaris suum infestation  (as reported by Hale et al 1985) and £0.25/kg of finishing feed. Hale O, Stewart TB and Marti OG. 1985 Influence of an Experimental Infection of Ascaris suum on performance of pigs. J Animal Science 60 220-225
  3. Knecht D, Popiołek M, Zales´ny G. 2011. Does meatiness of pigs depend on the level of gastro-intestinal parasites infection?  Prev Vet Med, 99, p 234-239. t Med, 99, p 234-239.
  4. Steenhard NR, Jungersen G, Kokotovic B, Beshah E, Dawson HD, Urban JF Jr, Roepstorff A, Thamsborg SM. 2009. Ascaris suum infection negatively affects the response to a Mycoplasma hyopneumoniae vaccination and subsequent challenge infection in pigs. Vaccine, 27, p 5161-5169.
  5. Exploring BPHS lesions time trends:(July 2005-September 2012), 26th October 2012
  6. BPHS July 2011 – June 2012: Exploring the distributions of the lesions across the regions by quarters
  7. Kanora A. 2009. Effect on productivity of treating fattening pigs every 5 weeks with flubendazole in feed. Vlaams Diergeneeskundig Tijdschrift, 78, p 170-175.
  8.  Kanora A,  Rochette F, Vlaeminck K, Goossens L. 2004. Economic appraisal of the treatment regime with Flubenol® 5% medicated feed every 5 weeks on fattening pigs. IPVS 2004, Proceedings, Vol. II, p 582.
  9. Kirwan P, MacDonald P, Kanora A. 2004. In field results in the use of a strategic de-worming