Pigs: Lameness (PB1148)

Management for the Prevention of Pig Lameness

HOUSING

Solid Floors - Construction and Maintenance

All floors must provide adequate grip to prevent slippage whilst not causing physical injury or excessive abrasion to the feet or legs.

All floor surfaces become increasingly slippery when they are wet or covered in manure. Surfaces should be kept dry either by good drainage or by the use of bedding to soak up the liquid. They should also be capable of being thoroughly cleaned and disinfected to prevent the build-up of disease organisms. The appropriate grade of mortar needs to be used in the surface screed to resist the corrosive effect of urine and certain liquid by-product feeds as well as the frequent use of the power washer. In lying areas where frequent heavy scraping is not a problem, a wood float finish is generally adequate. However, dunging passages are often wet and the effect of regular scraping causes smoothing resulting in a very slippery surface. In these areas, floors should be laid using a rounded tamped finish which provides adequate grip without being severe enough to cause physical foot damage.

Solid floored farrowing accommodation can be a particular problem where good grip is required by the sow, whilst a smooth surface is required by the piglets to prevent leg damage while sucking. The cement screed mix must include a minimum of water with natural non-abrasive sand. The surface should be laid and finished with a wood float but must not be over worked. Rubber mats may be placed in farrowing accommodation to prevent damage caused by rough or worn floors. Thorough cleaning and disinfection of floors between farrowing helps to reduce levels of joint infections in piglets. Rescreeding of floors should be undertaken when surfaces deteriorate. Where scraped dunging passages have become smooth, the surface of the floor should be treated using a concrete cutting tool or with chemical abrasives.

Slatted Floors

Slats are not recommended because they cause more injuries than bedded pens and therefore are less acceptable from a welfare point of view. The main objective of using slatted floors is to support the pig whilst providing gaps of sufficient size between the slats to maintain cleanliness. When used, slats should provide adequate grip to avoid slippage whilst minimising the abrasive effect on the pig's feet. If slats are used then bedding should also be provided wherever possible since its cushioning effect helps to prevent lameness.

An important aspect of slatted floor design is the width of the solid area and the width of the gap in relation to the size of the pig it is designed for. For piglets, the solid part of the slat should be wide enough to prevent claws falling either side of the slat. For sows on concrete slats, the solid area should support the whole of the foot, although on metal slatted floors where the gaps are smaller, several narrow bars will be adequate.

The following table can be used as a guide to the width of slat and gap in relation to the size and type of pig:

 

Width of slat (mm)

Gap size (mm)

Farrowing sows and piglets
(up to 30 kg)

18 - 25

8 - 11

Finishers
(up to 100 kg)

60 - 100

10 - 20

Sows, Boars and Finishers
(over 100 kg)

80 - 100

10 - 25


Slat edges should be rounded, not sharp or chipped. Where slats of any material become damaged or uneven, the slat must be replaced. New slats should match the original to avoid gaps.

Concrete slatted floors suffer many of the problems of solid floors. In particular, surfaces have to withstand the combined effects of urine, power washing and pig movement, which increases the problem of slipperiness when wet. Furthermore, the slat edges wear and crack resulting in sharp, rough areas which significantly increase the risk of foot damage. Single slats must be well fixed down as they can be lifted by pigs.

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Metal slatted or mesh flooring is available in a wide variety of forms, which vary considerably in the degree of grip and comfort they provide. A major problem with metal floors occurs when excessive wear or rusting causes the surface to break leaving sharp edges which inflict direct damage to the pig's foot. This is often first seen beneath drinkers or wash bowls. The use of cast iron or galvanised slats prevents the problem and provides a longer life.

Plastic slatted or plastic coated metal flooring is also available in a wide variety of forms. The surfaces tend to be kinder to feet so they are particularly suitable for younger pigs. However, they can be very slippery, especially when wet. Using those types that incorporate profiling will reduce this problem.

Steps

Steps between floors can be a cause of injury either from sharp edges or from pigs losing their grip. They should be avoided where possible particularly:

  • in the service area where good grip and freedom from obstruction is essential;
  • where a sow has to back out of a stall or farrowing crate;
  • Where a step cannot be avoided the height should be as small as possible. As a guide, 100mm might be used for breeding stock or finishing pigs whilst 50mm would be more suitable for weaners.

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In some deep bedded pens, large steps are common in the feeding area. These steps should be deep enough for the pig to be able to stand on them completely when feeding. These large steps should be replaced by slopes or, where possible, intermediate steps of sufficient depth added.

In all cases, the edges should be rounded and repaired swiftly when damage occurs.

Equipment

Equipment in pig pens such as gates, pen divisions, farrowing crates and feeders can be important causes of injury if poorly designed or maintained. Damaged metal-sheeted gates are a very common cause of injury. All broken or worn equipment must be replaced or repaired immediately. Nuts and bolts must not protrude into the pen and any sharp edges should be rounded off.

All gaps either beneath or between pen divisions and gates should be large enough to avoid legs being damaged whilst being small enough to prevent heads being trapped. Gaps between sharp metal edges and the floor will damage hooves and dew claws and must be avoided. These faults are seen commonly in feeding and weighing crates, and at the edges of metal mesh floors.

Bedding

Bedding has a positive benefit in terms of lameness due to its physical cushioning effect and should be used wherever possible. Bedded areas should always be kept as dry as possible as continuous contact with wet bedding can lead to a softening of foot tissues predisposing the foot to damage and bruising which can in turn allow infection to enter the foot.

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In deep bedded systems, problems can arise with the overgrowth of claws of sows and boars due to a lack of abrasion. When kept in these circumstances, it is recommended that pigs have some access to sound concrete areas to provide abrasion for the hooves.

OUTDOOR HERDS

Lameness in outdoor sow herds will be minimised by an appropriate choice of site. When selecting the site the most important factors are:

  • a free draining light soil;
  • freedom from excessive stone levels;
  • in a low rainfall area.


Those you should avoid include:

  • stony soils and thin soils over rock, especially those containing flints as they can cause direct damage to legs and feet allowing infection to enter and;
  • heavy soils as continuous wet muddy conditions can lead to a softening of the foot tissues predisposing the animal to injury and infection.
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