Increased mortality, poor health and a marked reduction in growth and efficiency are common; factors that can seriously damage profit margins and business viability.

PRRS activity can open the door to all sorts of health problems, says Simon Guise, Production Manager for David Black and Son at Bacton in Suffolk. He has seen the disease affect several of the units that make up Black's 3600-sow breed to finish business. In the past, its persistence has created huge fluctuations in productivity; making practical and financial management very difficult on some units.

The 750-sow Scholes Farm herd is a good example. The unit produces 74kg deadweight pigs and is profitable. Although Simon feels that performance and profit margins could benefit from some refurbishment. Built in 1982, the continuous-flow suffers from respiratory infections, that are mainly due to poor ventilation and temperature control. Enzootic Pneumonia (EP) is endemic and pigs are routinely vaccinated before or at weaning. Pleuropneumonia (APP) is another persistent offender, which was previously controlled by two doses of an autogenous vaccine, in-feed medication and injectable antibiotics. PRRS has also been identified and Simon believes it does exacerbate health problems.

Proactive

Simon Guise

Taking a proactive approach against disease, including the introduction of a comprehensive PRRS vaccination programme, has helped to improve health and growth rates. "Before we started PRRS vaccinating there were sporadic outbreaks. Problems with our rearing pigs mirrored what was happening in the breeding herd and there was no stability in our production cycle," Simon explains. Periods of good performance were often followed by poor health.

Pre-weaning mortality escalated, litters were poor followed by high losses in the rearing herd. "PRRS is an antagonist. I'm sure it allows other infections, particularly APP, to get in. Previously, when we had a PRRS outbreak, things really did deteriorate in the finishers - when both infections were rattling around it could be disastrous. But APP hasn't been nearly as bad since we started PRRS vaccinating the weaners," he adds.

Under veterinary guidance, sows have also been routinely vaccinated with Intervet's Porcilis PRRS vaccine since 2002, and to good effect. The control programme was extended to the rearing herd in 2003 when vet Jake Waddilove recommended vaccinating pigs at weaning. "We needed to stabilise health status and gain some control of PRRS in the growing herd and cut back our losses, so we took a proactive stance with the weaners and it paid off," Simon explains.

The decision to PRRS-vaccinate was taken because of the difficulty in controlling respiratory disease and PMWS in the growing herd. "I felt that the driver here was PRRS, which was confirmed by a serological survey. Results showed that the pigs were heavily challenged with PRRS virus shortly before the onset of the respiratory problem and indicated that if PRRS was controlled, then things should improve," explains Jake Waddilove. Based on this, vaccination was introduced at weaning to ensure that pigs developed adequate immunity prior to this challenge.

There was an immediate and progressive improvement in health as the vaccinated pigs came through. The difference was so profound that the APP vaccination could then be removed without any increase in disease. "This highlighted the role that PRRS had in triggering APP on this unit. Following the reduction in PRRS, less disease stress and a reduction in the stress associated with the APP vaccination, we have seen PMWS levels drop significantly," adds Jake. Problems still exist, because of the buildings, but the decision to vaccinate against PRRS, based on scientific diagnosis, has proved highly successful. It has also helped to lower the disease challenge to the breeding herd, and bring significant performance benefits in terms of numbers weaned.

Insurance

Three year's on and herd health is stable. PRRS, PMWS, EP and APP persist, with occasional flare-ups, but any outbreaks are manageable and the farm's financial position can tolerate them. This proactive approach requires considerable investment, using PRRS vaccine alone costs the company around £88,000 a year; that's about £1 a pig, but the return is between £5 and £8. It's an insurance policy the company cannot do without.

"It's always difficult to quantify the real monetary value of vaccinating. It's a considerable expense, and with PRRS I can only compare it with what happened before we vaccinated and the situation was unacceptable," says Simon. The staff are keen advocates too, and say they could not cope without a vaccination policy. "These guys don't want poor health, it makes their job more difficult. And apart from the financial cost of disease, high mortality rates are very demoralising, and you need to keep people motivated in this business."

By controlling background disease Scholes Farm has improved health and efficiency. In less than three years the team have taken 20 days off the weaning to slaughter interval. Now that PRRS is under control breeding herd performance is consistent, too. Sows produce 2.36 litters on average and more than 10.4 pigs are reared per litter, which is a marked improvement on pre-PRRS vaccination figures (see table). The rearing herd is also doing well. Mortality is around 10 per cent and average growth rates now top 590 grams a day. Days to slaughter have fallen from 195 in 2003 to 173 last year, which has helped sustain profit. FCR has hovered around 2.75 for the past three years, but Simon believes this is probably due to the buildings.

Veterinary costs are falling, as the herd is healthier. In-feed medication totals £1.20 per pig, three times less than it was in 2001, although vaccination costs per pig have increased by 75p to £2.50. More money is now spent on proactive procedures (vaccinations) rather than therapeutic treatments and overall drug costs are coming down.

Management changes, including the use of more AI, tighter health and hygiene protocols and the development of Black's own in-house multiplication programme, have also contributed to Scholes Farm's success. However, controlling key pathogens by vaccination has played an integral role in reducing disease challenge, improving productivity and maintaining profits.

Further Information

To read more about PRRS, click here