With the start of a New Year that pig producers hope to present fewer unexpected challenges than 2007, reports from NADIS Veterinary Surgeons attending pig farms are littered with observations of herds deciding to depopulate and exit the industry. The availability and possible financial assistance to control disease associated with Porcine Circovirus has come too late for some.

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Sows
The most concerning observation during the month concerned the apparent upsurge in disease associated with PRRS both in breeding and feeding herds. In the former, suspected disease accounted for episodes of poor quality pigs being born, abortions and premature farrowings (although in one case mycotoxins may also have been implicated). It is 17 years since this disease first appeared in the UK and as is typical of new diseases, the clinical picture has changed over time to become less specific and fortunately less devastating. However, it is still capable of imposing severe constraints on health and production and it may be significant that the proportion of all herds recorded under NADIS that are using PRRS vaccines has dropped from 31% in 2006 to 23% in 2007. Could it be that cost saving measures in the form of reduced vaccinations are allowing disease levels to rise?

Other specific issues noted in the breeding herd in January included:

1. Problems with sow condition believed to be the result of deterioration of insulation material in dry sow accommodation and a shift from using barley straw to wheat. The former can contribute significant levels of energy and is quite palatable. Wheat straw, particularly some of the poorer quality material available this year, has neither benefit.
2. Service problems due to poor heat detection particularly in gilts, associated with staff problems.
3. A 24% drop in farrowing rate in a herd that changed from weekly to 3 weekly batch farrowing in the first cycle. Semen quality was also questioned.

Piglets
Specific piglet issues were not widely reported in January although comments regarding piglet quality both at birth and weaning were received. These were thought to be associated with disease (PRRS), nutrition and stockmanship.

Meningitis appeared as a major problem in one herd at 2-3 weeks where not previously experienced. No explanation of why was offered.

Weaners
Overstocking continues to be a regular observation and if successful Circovirus vaccination is to be widely applied this problem will only get worse. The reasons identified included excess farrowings, slowed growth, and continued problems with marketing finishing pigs which has a backing up effect throughout the farm. Fortunately this problem seems to now be easing.

Overstocking, and pressure on accommodation generally, will certainly not help reduce the impact of many of the specific problems identified in the month, which included PMWS, (exacerbated by PRRS) tail biting, ear tip necrosis, Salmonella associated post weaning scour and ileitis. In addition, greasy pig disease, atrophic rhinitis (now something of a rarity in the UK) and Swine Dysentery were all reported.

Inadequate ventilation control and insulation, and lack of heating was highlighted as causing chilling which will equally tend to exacerbate disease.

Grower/Finishers
Many familiar problems were highlighted in the older feeding herd in January, with overstocking still a serious issue on some farms, specifically associated with vice and widespread enteric disease. There appears to be something of an increase in reports of Swine Dysentery, especially in East Anglia, and producers will need to be wary of any increase in grower scours if early detection is to be achieved.

PMWS was reported in its late onset form, in one case contributing to losses of 40%, acting as a reminder of the essential basic husbandry needs of avoidance of chilling and overcrowding (the latter often used in winter in an attempt to reduce the former).
Straw based pigs in naturally ventilated buildings are prone to chilling in winter when inadequate bedding is made available but producers should also be aware of the potential problem, highlighted in one report, of Erysipelas in growing pigs on straw, even in cold weather. (Erysipelas is erroneously often viewed as a warm weather disease.) This infection was also possibly implicated in an acute lameness problem in growers although Haemophilus parasuis was also thought to be involved.

The continued mixing of sources of weaners into finishing accommodation perpetuates respiratory disease reports and until such practices cease, disease will limit production.

Finally, two parasitic problems were highlighted:

1. Lice – rarely seen in commercial production, these skin parasites were seen in a ‘hobby farm’ and can be implicated in disease spread.
2. Milk spot livers – the result of migration of Ascaris Suum worm larvae – cannot be detected in the live animal. Membership of BHPS will assist monitoring this condition, which can have a serious impact on growth.

Through what are expected to be the coldest months of February and March, problems should be anticipated with:

1. Chilling triggering scour etc
2. Poor air flows exacerbating respiratory disease
3. Water supply problems
4. Difficulties with frozen ground outdoors, limiting feed and water uptake and mating behaviour.

Mark White BVSc DPM MRCVS

Copyright © NADIS 2008 www.nadis.org.uk

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