The growing internal and external demand of Iberian hams at a competitive price is favoring the production of crossed Iberian pigs, whose product with the highest added value is ham. The Duroc genetics provides many productive improvements, but has a strong impact on the quality of the products. In the last 30 years an important effort has been made in the Iberian pig sector in different areas, such as genetics, management, and especially food, mainly assessing the improvement of the lipid fraction of finished products. However, there has been a tendency towards greater pasture in hams, due to a genetic advance towards more proteolytic animals seeking greater lean growth and conformation, and a decrease in the saline content and in the curing time of the same by demand From the market. Consequently, the entry of fresh hams with high rates of proteolysis as raw material in the cured products industry, involves the transformation of meat pieces that will be rejected by the final consumer, which diminish the uniformity in the healing processes and make it difficult for the transformers the design of products adapted to the new patterns of consumption.

Analysis
Faced with this situation, in which the production of crossed Iberian pigs is fully extended in other regions of our country, the exploitations of Extremadura can not compete adequately considering production systems with higher production costs.
On the other hand, the existence, although in a minority way, of more traditional Duroc genetic lines in Extremadura (animals reared in Extremadura during the last decade without significant genetic improvements in lean growth) and that are hardly used by farmers, raise the hypothesis of the possible reduction of the current proteolytic indexes through the use of these lines in crosses with pure Iberian sows without this entailing a significant detriment of the productive performance of the animals.
The image outlines the problem to be solved in this project, which focuses on the high proteolytic index in crossed Iberian hams.
Considering all the above, it is necessary to know the value of the traditional Duroc varieties not improved by their lean growth, considering the increasing problem that represents the high proteolytic index of the animals, and that is observed in the crosses made with the new lines Lean high performance genetics. The comparative study of these varieties, could allow to design genetic crosses between traditional Duroc lines and the Iberian breed to increase the added value of the crossed Iberian pig reared in semi-extensive systems. Thus, it is concluded that there is a real possibility of promoting greater use of minority genetic resources among livestock farmers, improving their competitiveness and designing future genetic selection schemes aimed at the real needs of the industry.