Grain Damage in Gotland Skins

Gotland sheep breeders and skin dressers have sometimes experienced problems of varying degrees due to grain damage. Tanners across the globe (e g New Zealand, Australia, Spain and Portugal) have also had similar problems with skins from other breeds of sheep.

Grain damage, sometimes called ‘double skin’, can be a minor problem for many years, and suddenly it becomes more common. The first time Tranås Skinnberedning experienced a big outbreak of grain damage was after the very hot and dry summer of 1997.

Investigation

Having decided to investigate, we contacted people with experience in breeding, slaughtering and dressing, as well as experts at institutes in Germany and England. Throughout the years we have kept in touch with these research companies who have also carried out analyses of our skins.

They made us aware of the importance of the skinning process at the abattoirs and the importance of the initial conservation/salting procedure. For example: at mechanical skinning, skins are stretched, with serious consequences for any grain-damaged skins.

Extreme heat – what impact does it have on skins?

The research institutes supported our theory that an extremely hot and dry summer may disturb the fluid balance. So what impact does it have on the skin during such a period, if the animal doesn’t get enough water? Grass, for example, contains less water than usual. A skin should normally contain 65% water, whereas the remaining 35% consists of protein, minerals and natural fats.

What impact may the diet have?

The documentation also shows that certain aspects of the lamb’s diet may have an impact on the growth of the animal’s different skin layers and the connection between them, directly through lack of vitamins and minerals, and then affecting the speed of growth.

If the balance between nutritional supplements and other conditions for growth and strength is lost, breeding problems may occur. The fact that certain side effects emerge, is a common problem for anyone involved in the improvement business.

Rapid growth

It is possible that the Swedish Gotland sheep breed is a result of breeding which for many years has been focused on growth and lightweight but large skins.

Some years ago, Ylwa Eriksson wrote about grain damage:

“The thin, big-curl, silky skins seem to be more prone to damage. Have we reached a point where skin lightness has reached its limit?”

We can establish that certain stocks have considerable grain damage, while others have little or none. Grain damage is often stock-related. Our English laboratory claims, as mentioned, that there are also genetic reasons for weaknesses in the leather.

“We haven’t changed anything”

You often hear that “we farmers haven’t made any changes in breeding – the same quantity of fodder, grazing, the same time scale etc. Why then is there more damage?” But, having aimed high, only the tiniest disruptions can cause devastating effects.

… And there are no changes in the dressing process

We have not changed anything in our dispensary or in our mechanical treatment of the skins. Our methods for achieving good skins are based on experience acquired throughout the years. Our members of staff are selected for their respective tasks, which they treat with great respect. Our plant has a good reputation internationally. Therefore we have reason to be pleased with the quality of our skin-dressing. It is, however, unavoidable that damaged skins risk further damage in the mechanical handling that is a must in all skin-dressing plants.

We can sometimes spot grain damage already in the raw skin, i e before we have started the dressing process.

It has been shown that later slaughter results in skins with more normal strength, causing less grain damage. We often talk about maturity in connection with the slaughter of a lamb and the quality of the fur. Perhaps maturity should also be used when referring to the skin?

What now remains is the whole earlier-mentioned chain, i e breeding, handling the living animal, slaughtering and skinning, then the cooling and salting processes and finally the whole logistics chain.

A Theory

When the largest dressing company in Norway experienced problems with grain damage, it was thought that rapid skinning at abattoirs was causing or was a contributing factor to skin damage.

Since the damage is more frequent in skins from lambs slaughtered early, we therefore assume that damage can sometimes be caused by a combination of rapid growth, skinning method used and the speed of the skinning procedure.