The National Animal Disease Information Service (NADIS) is a veterinary based clinical reporting and surveillance system based upon veterinary surgeons’ on farm visits. As well as recording anecdotal remarks on health issues (summarised in the monthly NADIS report), production and health data is also collected.

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This report covers surveillance on farm from mid June to mid July during which time the mild rather than expected hot weather was deemed by some reporters to be favourable to pigs. Some problems were however still attributed to the weather.

Sows
The usual mixture of production, fertility and health issues were described but probably the most common comments related to discussion with clients on the introduction of PCV2 vaccines. The general theme – not rigidly applied – seems to be that where farms experience problems in weaners with PMWS, sow vaccination is generally favoured. However, where the disease is occurring in older pigs there is a tendency to favour vaccination of piglets. Occasional reports suggest some farms are applying both vaccine regimes.
On the production front problems were highlighted with:-

1. Failure to cull older sows leading to loss of herd age structure and poor productivity
2. Uneven condition in sows. Whilst condition loss tends to be more common, one report highlighted excess sow condition associated with the almost incredible estimate of four tonnes of sow feed per sow per year.
3. Excessive outputs and strain on farrowing accommodation either due to unevenness of serving patterns (themselves arising from uneven fertility) or simply results being too good and no downward adjustments made to service targets. It was observed that outdoor herds could cope better with surges of production but would presuppose excess arks are available. One report in a small herd highlighted extremely low output (10 pigs reared per sow per year) – not sustainable in the current economic climate.
4. Concern over sow feed intake in farrowing room with poor temperature control as a result of fan control problems; difficulties getting an electrician to attend were blamed.

Fertility problems were highlighted in some farms, with irregular returns commonly identified. These suggest post service failure and whilst disease (e.g. PRRS) was suspected in some cases, management fault and unidentified causes were reported. Separate cases of outbreaks of premature farrowing (occurring simultaneously with increase in return to service within the herd) and stillbirths/very late mummification are strongly suggestive of infectious disease and there has been some speculations over the role of PCV2 here. This virus has the capacity to produce such problems, but its actual role is unclear.

Pressure on staff tends to feature frequently in fertility related problems; difficulties with coping with demands of batch serving was blamed for high return rates on two farms whilst staff shortages in one case were blamed for increase in returns using AI where improperly trained staff had been involved.

Mange was sporadically reported in sows although this long recognised disease is believed to be absent from a high proportion of commercial farms particularly as most breeding stock nowadays is derived from mange free farms.

MMA affecting milk output and subsequent piglet growth caused concerns but with the appropriate veterinary attention and treatment, was rapidly resolved.

Piglets
In addition to problems associated with small pigs born either as a result of disease challenge and associated infertility in early pregnancy or simply variations within litters due to old sows or very large litters –the issue of the effects of “piglet processing” were reported. Errors in the timing of Baycox (Bayer) treatment and Enzootic Pneumonia vaccine timing particularly highlighted. In one case, these interventions along with tail docking and iron injections were all done at three days of age for speed/ease with a consequent loss of efficacy.

Furthermore, in separate situations, navel and joint infection were considered to have arisen:

• In association with interference with colostrum intake as a result of teeth clipping and cross fostering being done too early (before six hours after birth).
• In large litters simply as a result of competition for colostrum intake. Hygiene and use of Naxcel (Pfizer) at birth were both identified as ways of mitigating piglet disease problems.

Injuries to piglets were highlighted:

• Facial necrosis in pigs without teeth clipping was reported.
• Savaging of newborn piglets by gilts and sows was reported on one farm as a significant source of loss.

Weaners
Discussion regarding PMWS/PCV2 vaccination dominated reports on weaner disease control with an apparent high interest in the BPEX research programme and assisted funding. Many vets comment that whilst vaccination had commenced, it was still too early to judge results.

Post weaning fading and respiratory disease was reported sporadically, although not necessarily always associated with PCV2 challenge. Feed and water availability and variations in size of pig at weaning were contributory factors.

Strep suis infection causing meningitis, acute fatal septicaemia or as part of the post weaning respiratory complex – including the frequently seen “Glässers Disease” type syndrome - was a common feature. However, an unusual syndrome of flaccid paralysis and death in weaners was considered to be due to an encephalomyelitis of unknown origin affecting 1% or more of weaners on one large commercial breeder-weaner farm.

Overstocking continues to be frequently noted for a wide range of reasons including excess farrowing, better than target performance and shortage of follow on accommodation delaying moves. The slowing of growth associated with overstocking, creates a vicious circle of problems within the continual production farm.

Various skin problems featured in reports with Greasy Pig Disease prominent but problems also with flies and straw mites causing irritation that must be carefully differentiated from mange.

Sudden deaths associated with antioxidant deficiency (Vitamin E, Vitamin C and Selenium) were seen in one complex problem herd with investigation ongoing as to why these particular pigs should have a higher than normal requirement. Post mortem examinations revealed both Mulberry Heart Disease and Hepatitis Dietetica (ruptured liver) typical of this syndrome.

Scour and looseness were infrequently seen with the general picture suggesting a lower prevalence of this syndrome than previously seen. Whilst maize in diets was implicated in one problem herd, the introduction of PCV2 vaccination is being linked by some reporters with non-specific health improvements.

Growers and Finishers
Mixed respiratory disease in growers remains common, with many veterinary surgeons commenting that herds were awaiting the benefits of PCV2 vaccination that was yet to come through into the finishing herd. PMWS/PDNS was variably reported in association with fading, sudden deaths or respiratory disease, or just associated with unevenness.
Pure enzootic pneumonia infection was also observed, either in unvaccinated pigs, or where vaccine had been given at the wrong time or where air quality was poor.

Stocking rates continue to be a cause of concern. Overstocking was seen as a result of excess production from the breeding herd as well as in a herd pushing up slaughter weight without the necessary space provision. Whilst PCV2 vaccination is expected to improve growth in finishers, care will be needed not to compromise this by overstocking if mortality rates decline significantly. A reduction of 5% in mortality will leave an extra week’s worth of pigs on farm in a breeder-feeder. Until the long term benefits of PCV2 vaccination are recognised and realised, the balance between numbers on farm increasing due to reduced mortality and reducing due to faster growth, a careful watch must be kept on stocking rates.

Injuries and skin lesions featured predominantly in reports. Tail biting was widespread, with overstocking again implicated, as well as particularly aggressive individuals starting a problem. A major outbreak in a straw yard was observed although its cause was not stated. Conversely, flank and ear damage was a serious problem in two sites – where tails are docked very short – and interestingly was not evident in the younger pigs that were the first PCV2 vaccinates to come through.

Occasional reports of fly bite lesions were received, although this problem may not be as prevalent this year as in 2006 and 2007. Mange was also reported.
Other sporadic disease problems noted during this time were:

• Erysipelas in growers, including one report, unusually, of pigs affected in fully slatted accommodation.
• Colitis in association with Maize inclusion.
• Rectal strictures contributing to overall mortality with uncertainty of the primary cause.

As summer drifts into autumn, producers should consider:

• Service target manipulation to offset anticipated autumn infertility.
• Vaccination procedures, ensuring both correct timing and technique.
• Temperature variation as cold nights alternate with warm days. Respiratory disease and vice are highly likely
• Poor digestion/scour associated with new crop grain.

Mark White BVSc DPM MRCVS

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