Pigs & Poultry
Diagnostics and disease complexes Surveillance and vaccinations present zero-zinc scour solutions, Jane Jordan reports. The VMD decision to allow zinc oxide products already licenced and in the supply chain to continue to be used after the withdrawal date on the 26th June 2022 will give pig producers extra time to establish alternative therapies for postweaning scours. However, many pig businesses have already removed zinc from their medicine shelves. Some are choosing to vaccinate pigs to protect them against key enteric pathogens, and routine diagnostic testing is becoming a key feature within herd health management. The combination of clinical surveillance, strategic vaccination programmes and more stringent hygiene is producing some positive outcomes. Paul Thompson, Pig Veterinary Society senior vice-president and vet at the Garth Pig Practice, says tackling post weaning scours requires clear understanding of a herd’s disease complex and a defined management plan aimed at reducing infection risk and improving piglets’ immunity. “Culture and sensitivity investigations will be imperative, going forward,” he explains. A multitude of microbial strains can be implicated in post-weaning scours, so regular screening, using diagnostic techniques such as ELISA tests, quantitative PCR tests and frequent serology, will provide valuable clinical evidence.
Quality outcomes for health and performance Ileitis is a widespread problem in
UK rearing and finishing herds. Caused by Lawsonia intracellularis, the bacterial infection tends to exist at sub-clinical levels and is often misdiagnosed. “Unless an outbreak is severe, usually presenting as a spike in mortality rates in late-stage finishers, a high incidence of watery/bloody diarrhoea, inappetence, depressed growth and general morbidity – ileitis is rarely considered significant. But it can and does compromise growth rate and FCR, even at subclinical levels and that affects production economics,” says Dr Rubén Del Pozo Sacristán, MSD Animal Health UK technical manager for pigs. A field trial on a 240-sow farrow-to-finish farm in East Anglia has shown how vaccinating pigs against Lawsonia can improve production outcomes and benefit returns. This commercial herd had a longstanding ileitis problem, which had been controlled using antibiotic medication with mixed results. Both diarrhoea and sporadic PHE-related deaths were common in growers and finishing pigs and a low-grade scour was evident from weaning. Associated mortality was around 3% and pig growth/performance was variable. The trial observed four batches of pigs that were vaccinated with Porcilis Lawsonia at 21 days of age. Each piglet received a single, 2ml dose of the vaccine (intramuscular injection) and were weaned a week
later. No medication was used during the rearing/finishing period and performance was monitored. Changes to dung consistency and pig uniformity were noticed early on, and in the nursery fewer weaners ‘went behind’. At grower stage, marked improvements to health and performance were noted and diarrhoea outbreaks decreased. Growth rates increased by 30g/ day during the weaner/grower period and performance was more consistent across all four batches. Pig quality was also better. In the finishing house PHE deaths stopped, ADG improved by between 40–45g/day and pigs reached market weight six days earlier. Growth was more uniform, which enabled pens to be cleared over a 2/3-week period, rather than the usual 4–5 weeks. The farm was able to clear 20% of its finishers in the first draw, with 70% sent for slaughter the following week. The rest followed in week three leaving pens empty, ready for cleansing/disinfection. This shorter ‘clearance time’ improved pig-flow in the finishing unit and allowed more efficient use of accommodation. Another beneficial outcome was improvements in carcase quality. Pigs were reported to be more evenly sized with better conformation and a higher proportion also achieved optimum back fat and leanness grades.
Danish experience values vaccines E. coli diarrhoea is another common cause of post-weaning scours. Many routinely vaccinate sows before farrowing to protect suckling piglets from infection, but this maternally derived protection begins to wane at around four weeks of age, so vaccinating piglets before weaning can help boost their immunity. Again, diagnostics are usually required to determine which strains of E. coli are prevalent. 87341
Elanco Animal Health swine vet and technical adviser, Kirsten Jensen, has been working with Danish vets and pig farmers to find antibioticfree alternatives to zinc-based medication. Vaccination with Elanco’s Coliprotec has been shown to effectively control E. coli-related scours. Reports suggest those using this in-water vaccine have seen a 2% reduction in mortality, with good growth and performance achieved across the early rearing period. A veterinary survey (SEGES, 2020) concluded that Coliprotec was effective at protecting young weaners from E. coli infection, although the vaccine should not be used in isolation. Vets said using Coliprotec alongside stringent hygiene/disinfection protocols and the right nutrition would optimise piglet health and reduce the threat of other enteric problems occurring. It would also benefit vaccine efficacy, performance outcomes and the need for antibiotic treatments.
Covid jab research benefits scour vaccine development SEGES Danish Pig Research Centre and Copenhagen University are currently running trials on a new combination vaccine to combat post-weaning diarrhoea. Development has been underway since 2019, and recent research during the development of a human Covid-19 vaccine is benefitting the pig vaccine programme. “If successful, the new vaccine will have a significant impact on the use of antibiotics in piglet production and make in-feed zinc treatments unnecessary,” said Poul Bækbo, senior veterinary adviser, Nutrition & Health at SEGES. Beginning in May 2022, 60 pigs will be vaccinated with the prototype vaccine and their immune responses monitored. FG CURTAIN VENTILATION TO GIVE YOU TOTAL CONTROL OF YOUR BUILDING
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