When it comes to unusual feeding regimes, its hard to beat the Iberian pig, which is
fattened on acorns in the vast oak woods of southern Spain. Michael Raffael went
to see a breed thats enjoying something of a revival
THE Iberian pigs depicted in Murillos 17th century painting of the prodigal son tending swine havent changed much in the last 400 years. In the 1970s, a combination of African swine fever and modern farming practices threatened this dun-coloured, long-legged breed with extinction. But today it is flourishing, the raw material for the most expensive and sought-after ham in the world.
Iberian pigs are the product of their environment. A descendent of the wild Mediterranean boar, they thrive in a semi-arid climate of searing hot summers and winter cold snaps. Reared in small herds across the south-west Iberian Peninsula, they have all-but escaped genetic improvement.
In the past, few farmers ever considered exchanging breeding stock. What selective breeding took place (and the larger farms have records going back to the 1880s) happened on a farm-by-farm basis.
In 1955 there were over half a million breeding sows, but numbers had slumped to 60,000 by the early 1980s. The decline was due partly to disease and partly to the fashion for lean meat. Spanish breeders experimented by crossing indigenous stock with Tamworths, Durocs, Large Blacks and Berkshires. But their attempts at developing a modern commercial animal failed, not least because of the native pigs eating habits.
From this low point the breed has recovered sharply. Approximately one million Iberian pigs, known locally as pata negras on account of their black feet, are now slaughtered annually.
The breed has always been extensively reared, fattened and finished on dehesas, cultivated woodlands of umbrella-shaped evergreen cork and holm oaks. Traditionally, pata negras that have spent the early autumn grazing stubble are driven up to the highest dehesa on a farm in early November. They are accompanied by a swineherd who knocks the acorns from the tree with a long stick and keeps the herd moving from one stream to the next.
Each pig typically eats 6-10kg of acorns/day and during their 10-week acorn feast they will grow from 90kg to180kg. They gradually move downhill, becoming more lumbering and less mobile as they gain weight.
Eating the chestnut-flavoured acorns requires a special skill. The pigs vacuum them up, crush them between their molars and spit out the indigestible husks in a continuous cycle. Apparently, cross-bred pigs never got the hang of the technique.
5.5m acres of oak wood
The regions of West Andaluzia, Extremadura and parts of Castille where this grazing takes place have over 2.25m ha (5.5m acres) of oak woods. But because it takes at least 20 years for trees to reach harvestable size, the dahesa area cant in practical terms be increased.
In the past, rearing lasted two summers and one winter. Although better husbandry has speeded up the process, Iberian pigs remain a seasonal product. Slaughtering doesnt begin until mid-December and continues into early spring, when they are between 14 and 18 months old.
Breeding is done naturally – one boar being placed with 10 sows. Farrowing is in closed stalls with between seven and eight piglets/litter typical. Lactation continues for two months though small amounts of concentrates may be added. From weaning until fattening on acorns, pigs move from spring grazing to stubble or any other available crops. Farmers castrate the young animals at about six months.
Like wine grapes, pig quality varies from season-to-season and farm-to-farm. Those fattened exclusively on acorns are known as Iberico de Bellotas (acorns). Those that receive feed supplements to bring them to the required weight are designated as recebo. A third category, cebo, will have eaten conventional rations.
While the breeds dark years coincided with the move to leaner pork, its renaissance owes much to the demand for top quality gourmet products. Iberian Bellota ham has its own Declaration of Origin. Air-dried hams, shoulders and loins are cured from 18 to 20 months and account for 80% of the carcass value.
One lyrical Spanish dietician described the Iberian pig as an "olive with hooves". The intramuscular fat that gives an almost oily texture to the flesh, once seen as a major disadvantage, has become very desirable. Unlike fat in red meat, its low in saturated and very high in mono-unsaturated fatty acids. This gives it the same good-guy status as the olive oil and oily fish that are central to the Mediterranean diet.
Claims that it lowers cholesterol, however helpful to any marketing strategy, come second to the hams eating quality. Sliced wafer thin like Parma ham, it has a unique, soft, melting texture and lingering taste. By the time its dished up in a restaurant it can cost well over £100/kg to eat. It also fetches about 40% more than its rival Serrano ham produced from conventionally-fed white pigs.
The structure of the industry has changed much since its virtual demise in the 1970s and 20 companies now control the Iberian pig chain. One of the largest and oldest, Sanchez Romero Carvajal, breeds and rears its own stock, processes the meat and operates a string of shop-restaurants in Madrid, Barcelona and Seville.
Since 1996 a marketing consortium, Real Iberico, has brought together the different sectors with the aim of exporting, in particular, the hams.
Successful in Europe – France, Italy and Germany especially – its excluded from North America by US trade laws. Japan might be an attractive export market but insists on a two year swine fever-free buffer before accepting imports. An outbreak in Lerida last summer effectively shut the door.
But this is no more than an inconvenience to farmers, since the demand for Iberian ham inside Spain can barely keep pace with supply. If the hams from their acorn-fed pigs are retailing for up to k450 (£280) each, they can probably put up with the odd hiccup.