Control losses from MMA and locomotor disorders

By Frank Düring and Gabriele Friton, Boehringer Ingelheim Animal Health GmbH, Ingelheim, Germany. This article looks at the effects mastitis, metritis and agalactia (MMA) and locomotor disorders have in pig productivity.
calendar icon 11 November 2003
clock icon 8 minute read

Within pig production, MMA and locomotor disorders are among the leading causes of disease and loss, and constitute major threats to the success and profitability in piglet production and fattening. Up to one third of total mortality in fattening and piglet production can be caused by locomotor problems, contributing the largest share of loss; 10 to 20% of cullings in sows have their origin in locomotor problems. In fatteners, weight development was found to be slowed down by 8% in piglets suffering from lameness (birth to nine weeks of age).

On average, between 15-25% of all sows, and thus their litters, are affected by MMA. Piglet mortality was reported to be 4-5% higher in litters from sows suffering from MMA as compared to non infected sows. Considering all direct costs associated with MMA, lost income of about €15,000 in a 1,000 sow unit does not appear to be an unreasonably high figure (Table 1).

Table 1: Model calculation of losses associated with MMA.
No MMA situation, sow basis, per year
2.2 litters/year x 10 piglets weaned x 7kg/piglet 154.5kg
(11.4 piglets born alive, 12% mortality, 3 weeks at weaning)
MMA situation, sow basis, per year
2.09 litters/year x 9.49 piglets weaned x 6.76kg/piglet 134.1kg -20.4kg
per 7kg weight per piglet -2.9 piglets
x €25 value per piglet of 7kg -€72.8
(-5 litters/year and sow, -0.2 piglets born in subsequent litter, 16% mortality, 3.5% lower weaning weights)
MMA situation, herd basis, per year Total loss due to MMA
1000 sows x 20% incidence of MMA x €72.8 loss per sow €14.560

MMA and locomotor disorders are characterised by severe inflammation of the affected tissue. Inflammatory reactions are essential to initiate the pig’s immunological response at the very beginning of an infectious or traumatic event such as MMA and locomotor disorders.

When inflammatory processes, however, continue beyond the phase of initiation, their impact on affected tissues and the general condition of the pig will become increasingly deteriorating. Eventually they result in irreversible damage to organs, their physiological functions and thus the performance of pigs. The pathogenesis of inflammation is caused by infection or trauma and leads to cell destruction with subsequent release and activation of an enzyme which triggers the formation of arachidonic acid.

In a further cascade of biochemical processes, arachidonic acid is transformed through the key enzyme cyclo-oxygenase into compounds such as prostaglandins and thromboxanes. These operate as most potent mediators of local and general inflammatory reactions. Inflammations based on infectious processes have traditionally been treated with antibiotics. The symptoms of inflammations, however, are only indirectly influenced at best by removing the cause of inflammation with processes continuing until even after the elimination of pathogens. As tools to control the damaging effects of inflammatory processes, NSAIDs (Non-Steroidal-Anti-Inflammatory Drugs) have made a stunning appearance in beef and dairy production.

Fig. 1: Key effects and loss factors associated with MMA and locomotor disorders

Today, they are considered essential in the control of inflammatory conditions associated with respiratory disease, diarrhoea and mastitis. NSAIDs exert their anti-inflammatory potency by inhibiting the cyclo-oxygenase triggered formation of prostaglandins and thromboxanes.

Thus, the NSAID therapy aims at reducing local and general signs of inflammation, accelerating the improvement of the animal condition and reconstituting the well being, and consequently the performance, of the animal.

Early NSAIDs such as acetyl salicylic acid have been much appreciated in veterinary medicine for over 30 years. They have been beneficial in controlling individual prominent indicators of inflammation such as fever. Newer generation NSAIDs, such as flunixines, ketoprofens and meloxicam, are generally accepted to exhibit a considerably higher potency and to control inflammation at a broader scope, while exerting a more favourable safety profile.

Table 2: NSAIDs support piglet development in litters of MMA sows

This can be ascribed to their mode of action which is more specifically directed towards target substrates involved predominantly in the mediation of inflammatory responses as compared to related substrates which are continuously expressed to maintain regular and general body and organ functions.

But even among ‘modern’ NSAIDs, distinguishable differences can be notified: they can either be found in practical aspects such as dose-volume to be used, the local tissue tolerance and the withdrawal period; or in their potency to control certain pathogenic conditions during inflammation such as effects from high endotoxin levels.

Some NSAIDs act very quickly in relieving symptoms of inflammation, while there is a likelihood of re-occurrence unless re-treatment is conducted. Others may show a more gradual and consistent reduction of symptoms until terminal disappearance.

Different from cattle production, the acceptance of NSAIDs in pig production is yet lagging. Benefits have either not sufficiently been demonstrated or they have been discounted in favour of a primary consideration of the input/costs side rather than the cost:benefit effects.

Impact of MMA

The economical impact of MMA is determined by the time between the onset of clinical symptoms and their effective disappearance as the most critical period. Whereas antibiotic therapy eliminates the pathogens, clinical symptoms of inflammation will continue until the bacteriological cure is achieved. Thus, clinical symptoms continue to be seen for another 2-3 days after initiation of antibiotic therapy.

While the impact of MMA on sow fertility has also been reported showing more days empty and lower conception rates, the disease’s detriment is ultimately seen in and measured as the litter performance, where impaired growth and higher mortality will seriously jeopardise the success of piglet production.

Infection with pathogens and their toxins lead to a reduction up to final termination of milk production in affected glands; inflammation and pain will increasingly cause sows to deny piglets access to the glands. Milk composition may change resulting in inappropriate levels of essentially required immunoglobulins as the piglet’s first line of defence.

Table 3: Pigs suffering from locomotor disorders recover quicker after treatment with a NSAID (Friton et al., 2003)

A number of studies gave evidence that NSAIDs limit and control the symptoms of inflammation. Fever was found to be rapidly reduced in NSAID treated animals and NSAIDs helped pigs to return to feed quicker. The effect of NSAIDS, however, is not only seen in diseased animals but also in their litters: NSAIDs were shown to support the weight development of piglets from MMA sows. Additionally, mortality was reduced in general and particularly in diseased litters of MMA sows (Table 2), with higher disease and loss rates described to be frequently associated with the occurrence of MMA in sows.

One of the major reasons for the effect of modern NSAIDs is their particular ability to reduce the negative impact of both exotoxins from Gram positive cocci and endoxins released from ruptured Gram negative pathogens such as E. coli. The effect of endotoxins can be measured as an increase in the plasma level of Thromboxane B2, one of the key mediators of inflammation (Fig. 2).

Locomotor disorders

Genetic predisposition and inadequate nutrition can result in locomotor disorders. Unfavourable housing conditions, however, by far constitute the major cause of leg and claw problems. Type and condition of bedding and floor materials exert a major influence on the occurrence of locomoter problems, whereas infectious processes very often will only follow. Pigs suffering from locomoter disorders show impaired general behaviour. They will be challenged by pen mates in their social ranking, and access to feed may become more difficult. Pain will further limit the motivation to move to a minimum. As a result, the pig will evidently suffer, feed intake will be reduced and performance will be impaired while continuation of inflammatory processes will lead to irreversible damage.

Due to both their analgesic effect and their anti-inflammatory efficacy, NSAIDs can help to restore normal general behaviour in diseased pigs including patterns which reflect the pig’s well being and ability to perform. It needs to be stated though that underlying systemic reasons for lameness such as inadequate housing conditions have to be removed with first priority.

With the growing understanding of inflammatory processes and, in the worst of cases, their irreversible impact on performance, the value of a symptomatic treatment with an NSAID either as an adjunct to antibiotic therapy in case of infections, or as a stand alone therapy, becomes increasingly obvious.

Today’s NSAIDs demonstrate an exceptional safety profile, while their mode of action is targeted more specifically to inflammation related processes. Thus they provide a significant contribution and value to the protection of performance and well being in animals suffering from disease.

Fig. 2: NSAIDs substantially reduce the level of the inflammatory mediator Thromboxane B2 after administration of E. coli endotoxin (Friton et al. 2003).

Fig. 3: NSAIDs help pigs suffering from lameness to recover quicker (measured as clinical efficacy; Friton et al. 2003).

Source: Boehringer Ingelheim Animal Health - November 2003
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