FAIR Project Improving Hide and Skin Quality a project funded by the European Commission The content of this publication is the sole responsibility of its publishers and it in no way represents the views of the Commission or its services.

Newsletter No 2 (1999): Raw Material Problems & Statistics

Raw Material Problems

The European tanning industry concentrates on producing top quality leather, and this requires a consistent supply of good quality raw hides and skins.

Supply:

The raw materials, hides and skins, used by European tanners are by-products from the European and World meat, milk and fibres industries. The quantity available depends on the demand for these products, which in turn, is related to consumer preferences and density / growth of human populations in different regions of the world.

Quality:

Leather quality is primarily defined by the absence of damage to the hide or skin’s surfaces (right). The tanner also has other requirements, such as shape, area:weight yields and thickness, that define a ‘good quality’ hide or skin.

The quality and suitability of hides or skins for conversion into leather depends on the environment in which the animals live, the type of husbandry practices involved in their rearing, transportation and slaughter process.

Points & Types of Damage

Damage to the surface, or grain layer, of hides and skins can, therefore, occur during different stages in the animals life cycle, when the skin is being removed from the animal’s carcass as well as during post slaughter handling and storage:

The defects which are caused at these various stages can be categorised as physical or mechanical damage, damage resulting from diseases, infestations of the live animals by ectoparasites or husbandry practices (table 1)

Table 1 Summary of the point & type of damage occurring on hides & skins

Physical Damage

Damage to hides can be caused through mechanical means before or after the animal is slaughtered.

Injuries to livestock, resulting in scratches and cuts to the skin, can be caused by fencing (mainly barbed wire), use of goads, transporting animals, stock pens, thorns, barbs and other animals’ horns.

After slaughter the skin can still easily be damaged, for example during offtake (removal from the carcass), handling, transport or storage. This type of damage results in patches of ‘strained’, ‘broken’ or ‘abraded’ grain, open scratches and holes.

Rawstock related grain damage can also be due to bacterial putrefaction. Putrefaction in hides and skins can occur due to:

• A delay between flaying and curing/processing the raw material.

• Insufficient salting/brining of the raw hide.

• Poor penetration of the salt/brine due to heavy fat/flesh deposits.

• Insufficient draining of the salted hide allowing liquors to pool and reduce salt concentrations.

• Poor storage conditions of the raw salted hide e.g. exposure of rawstock to the elements allowing salt to be washed off or excessively warm conditions.

• Prolonged storage, particularly under warm conditions.

• When hides are iced, pockets of warm hide can remain where bacterial activity can occur.

• Soaking the raw hides without sufficient biocide protection.

Poorly cured or dried hides and skins can be damaged by maggots, moths and hide beetles during prolonged storage.

Ectoparasites & diseases

Ectoparasites are found on or just within the skin of the host animal and can be broken down into two groups: Arachnids: ticks and mites and Insects: flies, lice and keds. Fungal and bacterial infections, such as ringworm and mycotic dermatitis, are also commonly found on farm animals.

Infestations and diseases can affect animal production yields as well as the quality of the hide produced from the host animal:

• Annoyance and irritation can stress animals and disrupt grazing patterns reducing weight gains.
• Ectoparasites can transmit diseases to other animals and man. (e.g. Ticks and Lyme disease)
• Bites, skin reactions and secretions can cause physical damage to the hide.
• Irritation can lead to scratching, rubbing and biting by the host leading to increased hide damage.
• Secondary infections of affected areas, by bacteria or fungi, can also occur causing losses in production and further hide damage.

Husbandry Practices

Consumer preferences, and thus farming practices, vary across Europe. The Italian beef market, for example, is looking for pale meat, sometimes called baby beef, from intensively fed young animals. The animals are slaughtered at about 12-14 months compared to the average 18-22 months in the UK. The Spanish prefer barley feed animals (240-260 kg carcass weight), while the French market requires heavier 380-400 kg carcasses.

Variations in animal production systems will have an affect on the nature of hides and skins produced. In general hides from intensively fed animals are smaller in area for a given weight compared to non-intensively reared animals, they also tended to swell more during liming and have a higher grease content. Intensively reared animals grow more rapidly and as a consequence attain the required slaughter weight earlier and are killed at a younger age. Certain breeds of animals are also considered to be either early or late maturing, and will vary in size and shape.

Maturity of hide collagen in terms of inter- and intra-molecular bond stability is generally regarded to occur in cattle hides at about two years of age. Before these bonds stabilise the immature collagen will swell more in acid and alkali, will be more readily degraded by heat and will be more vulnerable to enzymes than mature collagen. The immature state of a hide is indicated by the greater amounts of extractable acid and alkali soluble collagen.

Farming practices, such as branding, injections, shearing, clipping, and not keep animals clean can all result, to varying degrees, in damage to the skin of the animal.

Country Summaries & Damage Statistics

A brief summary of the major raw material damage problems in each of the partner countries is given below. The types and damage incidence, where it is known, are summarised in table 2.

France

Cattle hides:

There are three main husbandry problems affecting French cattle hides: warble fly, dung and goad marks:

In 1995 25% of French hides were affected by warble damage. A government scheme to eradicate warble fly ended in July 1998. There has been a significant reduction in the number of hides affected by warble since the start of the campaign. However, the problem has not yet been totally eradicated. About 20% of hides are also affected by damage caused from other parasites (mange mites, lice and ticks).

Dung contamination, particularly on large cow hides, is a problem, with as much as 15 kg of dung occurring on some hides during the winter.

Sheep Skins:

The main areas of concern on sheep skins are from farming practices, such as shearing, injections and paint branding; parasites & diseases (sheep scab, ticks, keds, mange and flies); abattoir practices (butchers strain and poor skin shape) and putrefaction.

Finland

A significant improvement in the quality of hides over the last ten years has been attributed to reduced numbers of ‘dirty’ animals being slaughtered. Between 1993 and 1990 the proportion of excessively dungy animals decreased by 85%. Damage to hides caused by excessive dung contamination is now secondary in degree to that caused by parasites (lice and mites).

Parasite damage is seen on about 25-30% of hides and is thought to be primarily due to demodex (hair follicle) mites.

Problems have arisen recently from increased journey times during the transportation of animals to slaughter. Extra attention is now being paid to welfare of animals during transport to stop damage from horns and hooves.

Recently Finland returned to the U-trim or ‘old Scandinavian trim’, after having used the Middle-European, straight cut method for seven years.

Germany

A recent comprehensive survey of German cattle hides (1997) has shown that the majority of damage occurring on the hides originates from on the farm: manure/urine contamination (29% of hides affected), farming practices (52%) and parasites & disease (55%)

Transport damage, in the form of scratches or goad marks, affects 22% of hides. While abattoir based damage (poor shape, grain cracks and flay) is seen on 16% of the hides.

The majority of hides (69%) are affected by only one or two types of defect (figure 3). 14% of hides were seen to be defect free.

Figure 3 Number of defects affecting German hides

Greece

Bovine hides:

Farm based damage (scratches, diseases etc.) causes only minor problems on hides compared to that related to removing the hide form the animal’s carcass. 60-70% of raw hides and skins are downgraded because of poor flaying techniques. There are abattoirs with machine flaying systems, but these only produce a small percentage of the total hide production. Putrefaction damage is minor as the storage time for hides is very short.

Sheep and goat skins:

The major problem seen on sheep and goat skins is related to poor curing. High levels of bacterial damage are a particular problem on dry salted material.

Italy

The main problem associated with Italian cow hides is dung contamination. Poor animal hygiene associated with the housing of cattle for long periods has lead to the defect called ‘belly grain’. This defect is where the grain’s surface becomes distorted and roughened through prolonged contact with mature and urine. The decline in the milk market has had a significant impact on Italian livestock resources with poor investment in new technologies to keep animals clean and cut backs in labour and bedding materials such as straw.

Warble fly has been eliminated from the main infestation sites in Italy and is no longer a major problem on cattle hides. Goads and barbed wire are not in general use so damage from their use on the farm is negligible.

With the closure of many small abattoirs meat production is largely concentrated in larger slaughterhouses adapted for mechanical flaying, so the defects derived form the offtake process (flay, grain crack etc.) are minimal.

The Netherlands

Calf fattening systems are prone to lice infestations with resultant light spot damage appearing on the subsequent leather. Nearly 90% of farms have been found to be infested with lice, with 18% of the calves being affected. However, due to the fact that the calves are permanently housed, the skins are free of other types of mechanical damage

Other problems encountered are associated with the long housing periods of cattle such as keeping the animals clean and the production of greasy hides.

Spain

Farm based damages:

Mainly related to ectoparasites (including warble fly) scratches and dung. Problems can also arise from the hides being excessively greasy, which is related to the extended housing periods and feeding regimes.

Damage related to slaughtering:

Butchers strain can be a particular problem on sheep skins with damage occurring predominately in the bellies. Flay damage on hides and scratches also cause problems to the tanner.

Sweden

Farm based damages:

The main reasons for downgrading Swedish cattle hides are scratches (open and healed, mainly due to the use of barbed wire), ringworm, insects/parasites (principally lice) and manure. Each of these problem areas are addressed under the ‘Golden Hide’ improvement programme which has resulted in significant reductions in the incidence of defects on the scheme’s hides. A 40% increase in quality in the Golden Hides has been reported over the period of the scheme’s operation, and 10% more ‘high’ quality hides are being produced.

Damage related to slaughtering:

The majority of Swedish hides are produced in slaughterhouses which are using machine takeoff processes so there is very little flay damage resulting from the use of knives. The shape and trimming of the hides are also good.

Damage relating to hide trading:

Recently, within the last 2 years, salting of hides by the slaughterhouses has stopped. The hides are now chilled with ice, transported to a central hide trading organisation, where they are salted and graded. During the transition period some putrefactive damage has occurred.

United Kingdom

Farm based damage:

During the mid 1980’s the UK government lead a Warble fly eradication programme, with widespread compulsory treatment of cattle. Warble fly has now been eradicated in the UK and hides are no longer affected by warble. The treatment programme also controlled other cattle ectoparasites such as lice, tick and demodex (hair follicle) mites. Since the stopping of the compulsory treatments the levels of these parasites and the corresponding damage on hides has increased.

Results from a recent survey of hides from beef animals indicated that 81% of hides were infested with lice during the peak winter months. The incidence of light spot damage on leather is currently between 70-90%.

Scratches resulting from the widespread use of barbed wire fencing, as well as from transportation, is also a major problem..

A significant reduction in the proportion of cattle hides affected by dung has taken place since the inception of new Meat Hygiene regulations. The percentage of UK hides affected by dung fell from 73% in 1995/96 to 30% in 1998/99, the estimated amounts of dung per hide being reduced from 4 kg to 0.5 kg over the same period.

In a recent survey of UK hides nearly 90% were found to be affected by one or two major defects (figure 4). Only 7% of the hides were damage free.

Since the end of compulsory sheep dipping (for sheep scab) in 1992, there has been a dramatic increase in the levels of damage caused by ectoparasites on sheep skins - a 60% increase has been measured by the industry - and the proportion of skins meeting the 1st and 2nd grades required has reduced from about 60% of supplies to 40%. Currently it is estimated that 25 to 30% of skin production is downgraded due to sheep scab damage. Lice infestations have increased significantly and cockle damage, although small, is also on the increase.

Figure 4 Number of defects affecting UK hides

Texel sheep breeds were introduced into the UK in the early 1980s. The high proportion of skins affected by pinhole damage (50-60%) is linked to their introduction as the breed has a finer wool fibre than most traditional UK breeds.

Abattoir related damage:

Flay damage is a major concern in the UK. The quality of flay varies significantly from abattoir to abattoir. Cow hides from animals slaughtered under the BSE cull have been particularly poor in terms of flay quality. Less care is taken with these carcasses as the meat is not being used for human consumption.

Butchers strain affects a significant proportion of UK sheep skins. This has been attributed to increased killing line speeds and poor ‘setting up’ of stripping equipment.

Summary Statistics

Table 2 Summary of raw material damage and incidence in partner countries

Damage Occurring on Imported Material

European fellmongers and tanners import a significant amount of raw material form outside the Community. Although much of the damage found on these hides and skins is basically similar to that on European rawstock there are a variety of other defects encountered by processors:

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UNITED KINGDOM

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