Raw hides normally used for the production of upholstery leathers are of bovine origin. We must remember, though, that many other animal species supply hides and skins with specific characteristics suitable for shoes, leather goods or garment production. In fact we have hides and skins from horses, goats, lambs and sheep, pigs, pekari, snakes, toads, lizards etc.
Going back to the hides of our interest, the bovine ones, we must underline that it is very important for the tannery to know the origin of the hides they are going to process, because there are several elements which will influence the final result: the breed, the area of breeding, the sex, the weight range and the conservation process. Let's analyse these elements in detail:
Breed - In Europe alone there are about 50 different bovine breeds, which differ for structure, colour, thickness and tightness. If we consider, for example, two different breeds, like the Dutch Friesian and the white Marchigiana, we can easily understand that they will give two different hides. The deep diversity of the two animals affects the type of process needed to tan the hides, the characteristics of the finished leather and the type of articles which can be made
We can appreciate how the Friesian breed has a more squared shape and a straight neck, while the Marchigiana has a longer body, with a visible hump on the wrinkled neck. The Friesian has a black and white pigment, and seeing that where the hair is black, it tends to collect more heat in the sunshine, the hide in correspondence with the black pigment becomes more cornea and therefore the leather will remain more shiny if hides have only a light finish. The Marchigiana, having a lighter and uniform colour has a softer hide which also allows the production of more natural and “naked” leathers.
Area of breeding - The different areas where the animals are bred and therefore the different climates and living environments have a great influence on the quality of the hides.
Warm climates, where parasites have the right conditions to proliferate, will in fact give drier hides, with a more irregular grain structure and with more scratches.
Also the different breeding systems influence the quality of the hides: animals grown in stables and fed with fodder will have a much cleaner grain of the hide compared to those of animals bred in fields, more subject to scratches or horn marks. Furthermore, animals which are grain fed can more easily have pimples on the hides.
Sex - The sex has an influence on the size, the shape and the fibre of the hide.
Males are normally bigger, rounder and more compact than females. Among females there is a further difference between cows (which have been pregnant) and heifers (which have not). Of course cows have wider and looser bellies, while heifers will have a smaller but firmer belly.
Weight-Range - It gives the category in which one hide can fit by weight. The weight range varies from market to market.
To give an example, at the Milan hide market the following categories and weight ranges exist:
Vealskins: 8/12 kg, 12/16 kg, 16/20 kg, 20/26 kg.
Ox hides: 26/32 kg, 32/40 kg, 40/+ kg.
Bull hides: 40/45 kg, 45/+ kg.
Cowhides: 27 /- kg, 27/+ kg.
In the vealskin and ox categories, the lighter weight ranges are more appreciated due to the finer grain and the fact that, coming from younger animals, they normally carry fewer natural defects.
In the bull and cow categories, the heavier weights are more appreciated because they can give bigger hides with better cutting yields.
Conservation - Hides can be used fresh or preserved.
Fresh hides are normally preferred for higher quality articles because the problems often related to the conservation process (bacteria action, blood and salt stains, etc) can be avoided. The only difficulty is that hides must start the tanning process within maximum 24/48 hours in order to avoid putrefaction.
Preserved hides, on the contrary, can be stocked even for months if properly chilled, but the salt used in the process causes micro-wounds on their surfaces. Furthermore, if the hides are dried instead of being chilled, they also need to be re-hydrated to regain the original smoothness, but in this way they can loose tightness.