Basque Pig

Local pig breeds are adapted to the specific local environment and fed with various locally available feedstuffs. Besides their genetic merit for agro-biodi-versity, they represent the basis for sustainable local pork chains. The present chapter aims to present history and current status of the Basque pig breed, its exterior phenotypic characteristics, geographical location, production system and main products. This French autochthonous breed of pigs, which almost disappeared few decades ago, seems now consolidated, thanks to a chain organi-zation and recognised high-quality products (Protected Designation of Origin). Reproductive performance data reviewed from the literature and estimated from the LIGERAL database (herdbook) are presented. Available data on production traits including growth (early, middle, late and overall growth), feed intake, body composition and carcass traits are also summarized. Meat quality traits (pH, colour, intramuscular fat content and fatty acid composition) and back fat tissue characteristics (fatty acid profile) are also described. Studies on the Basque pig breed are scarce. Different production systems, feeding regimes and feed composition used among studies can explain differences observed between studies, especially for productive traits. However, the current review gives insight into the reproduction, production and carcass and meat quality traits of this local pig breed.


History and the current status of the breed (census)
The Basque pig (French, Pie Noir du Pays Basque) is a breed of pig native of the Basque Country (South-West of France). What is today called the Basque pig comes from the two historical breeds kept by Basque people. It was consolidated under the name only in the 1920s. With livestock sector modernisation, production of Basque pigs sharply declined in the 1960s. The breed was considered in the way of extinction in 1981 further to an inventory requested by the French Ministry of Agriculture. By this time, ITP (former IFIP name) and INRA counted only 50 sows and 5 boars left. Then, few pig breeders gathered by a dry-cured ham artisan producer, Pierre Oteiza, decided to revive the Basque breed and developed a local chain organisation. Their objective was to maintain peasant and butcher-processor artisan activities in Les Aldudes valley in the Basque Country. Afterwards, a specific farm for the preservation of Basque breed and genetic resources was developed, assisted by ITP. In 2001, the Basque chain association was created, and the instruction for further registration as protected designation of origin (PDO) was initiated. The Basque pork sector has progressively developed, based on the production of traditional and high-quality pork products. In 2016 the "Kintoa" fresh pork and Kintoa dry-cured ham (Jambon du Kintoa), produced from Basque pigs, obtained the French AOC (Appellation d'Origine Contrôlée) label. In October 2017, this national recognition was further translated at European level into the "Kintoa" PDO registration.
Presently the Basque pork chain gathers 80 members including 57 breeders or fatteners, 16 of them being also processors, 1 slaughterhouse, 4 butcherprocessor artisans, and 2 processing plants for dry-cured products. The census of Basque pig breed is presented in Figure 1. Currently, there are 28 farms of Basque breeders registered in the LIGERAL herd book, with 580 breeding sows (01/01/2017).

Exterior phenotypic characteristics
The Basque pig breed morphology information is summarised in Table 1. As suggested by its name in French, pigs are piebald, black and white (Figures 2 and 3): black head and rump. The breed standard describes animals with a slightly convex back, some of them with large black areas and a sloping croup. Limbs are large and strong well suited for outdoor rearing in extensive hilly zones. The chest is large, ribs are round, and hams have an elongated shape. Pigs have large horizontal ears, tilted over the eyes, representing two thirds of the head length. Bristles are rare and fine with a circular aspect above the rump.

Geographical location and production system
The Basque pig is originated from the Basque Country, a region located in the South-West of France and across Spain border. Nowadays farms producing Basque pigs are still located in this historical region of production. The geographical area and rearing conditions for Basque pigs dedicated to PDO Kintoa pork and dry-cured hams are detailed in specifications for AOC, the national label required before PDO registration [1]. Briefly, this region has a mild and humid climate under the influence of the Atlantic Ocean and warm winds from the South that are essential for the ripening process of the dry-cured hams. Located close to the Pyrénées mountains, this area exhibits a hilly landscape and includes grasslands and forests. To benefit from AOC/PDO registration, the pigs must be born, reared and slaughtered in the specified geographical area. Pigs (either castrated males or females before any lactation) are generally born and kept indoors with possible access to an outdoor area, up to a maximum of 5 months of age. They are then placed until slaughter in an extensive plot land that provides natural feeding resources (grass or herbaceous vegetation, roots, chestnuts or acorns) with a maximal animal density of 35 pigs/ha grassland  European Local Pig Breeds -Diversity and Performance. A Study of Project TREASURE and 25 pigs/ha forest. Plot lands must be approved by the authorities responsible for quality sign management and control. Plots include a shed, water access and a feeding area. In addition to natural feeding resources that correspond to around 50% volume of feed intake, pigs are fed with complementary (without GMO) food up to a maximum of 3.2 kg per pig and per day between 3 and 8 months of age and 2.7 kg afterwards. From weaning, the allowed foodstuffs include wheat, corn, barley, rye, triticale, sorghum, oats, peas, faba beans, lupine, vetch, flax (as seeds or derived products), soybean, sunflower and rapeseed (as seeds, meal or oil), cane or beet molasses, alfalfa, beet pulp and whey only up to 2 months before slaughter.
Pigs are slaughtered at minimum 12 and maximum 24 months of age. Specifications for carcasses are minimum 100 kg hot weight and 25 mm back fat thickness (fourth/ fifth lumbar vertebra level). Whole traceability is a guarantee for pigs and carcasses. A minimum green ham weight of 10 kg and minimum ripening duration of 16 months including 10 months in natural conditions are required for Kintoa hams (Figure 4).

Organisations for breeding, monitoring and conservation
All animals, boars, sows and piglets are individually identified and recorded in the LIGERAL herd book. A committee, composed of an expert and the technician in charge of following up the breed, validates each potential breeder considering the breed standard, the teats' number (minimum 10 functioning teats) and the inbreeding coefficient. Only pure breed reproduction is performed: natural mating usually. Also, for few years, few artificial insemination boars are available but just for slaughter pig production purposes. Usually, farms self-renew their sows and buy boars. Replacement breeding policy is based on relationship coefficients estimated by IFIP and the number of live animals per family (sows) or line (boars). One farm, dedicated to sow and boar rearing, has recently been created for the production of  replacement animals and to facilitate the establishment of new farms. The number of breeders per family and line, reproductive performances and inbreeding are reviewed at least once a year. More complete analyses of the genetic variability based on probabilities of gene origin studies are occasionally performed [2]. In addition, Basque semen doses are preserved in the French National Cryobank which contains semen collected explicitly in the 1990s and the beginning of the 2000s. This heritage material is only dedicated to breed preservation ( Table 2).

Reproductive traits
Basic data obtained on reproductive traits in this review are presented in Table 3. Averages are calculated from data recorded in the LIGERAL database. For the last available 5-year period (2012-2016), the average age of sows at the first parturition is 16.6 months. On average, sows of Basque pig breed have 1.6 litters per year with 7.5 piglets born alive [9]. The death rate of piglets until weaning in the considered study (last 5 years available period) of Basque pig breed averages 18.9%. Published data are also synthesised in Table 3. Without selection on reproductive performances, a progressive decline in litter size (born alive and weaned piglets) had been seen until 2003. Then, a slight improvement was observed [3]. Most recent  TREASURE data confirm this tendency with +0.5 born alive and +0.6 weaned piglets in the last 10 years. Technical improvement of farming can explain this. Duration of lactation is prolonged in comparison to modern intensive systems to 38.5 days, which is also reflected in the prolonged farrowing interval (228 days on average). Thus, it can be concluded that Basque pig breed has moderate fertility compared to the most prevalent breeds.

Growth performance
Basic data on growth performance obtained in this review are presented in Tables 4 and 5. Due to big differences between studies with regard to the live weight range covered, we defined the stages for growth performance as lactation (regardless of how long it was), growing stage (from weaning to approximately 30 kg live body weight) and early, middle and late fattening stages estimated between approximately 30 and 60 kg, 60 and 100 kg and above 100 kg live body weight, respectively. Sometimes the source provided only the overall growth rate for the whole fattening stage (defined as overall). It should also be noted that a big part of the collected studies tries to simulate to some extent practical conditions of the production systems used and that only a smaller part of the studies actually aimed at evaluating the breed potential for growth. In the considered studies, the weight gain in the growing stage (around 320 g/day in the three studies) is lower than observed for modern breeds denoting lesser intensity of rearing and lower growth potential. It also reflects the fact that no selection is undertaken on growth in the Basque breed, unlike modern breeds. Also the early, middle, late and overall fattening stages are characterised by much slower growth than in "modern" selected breeds and big heterogeneity (358-640, 452-560, 236-499 and 335-544 g/day in early, middle, late and overall growing stage, respectively), related to the fact that this review comprises studies where different systems and feeding levels were practised. In the context of the evaluation of growth performance, it is also of interest to observe the extreme values,  because it can be assumed that the maximum figures exhibit the growth potential of Basque pigs in ad libitum conditions of feeding (≈544 g/day in overall fattening stage).
In considered studies, the information on feed intake and feed nutritional value were scarce (max five available values), which limits the evaluation of growth potential. Average daily feed intake increased from 2.3 kg/day in the early growing stage up to max 2.9 kg/day in the late fattening stage when ad libitum feeding regime was applied.

Body composition and carcass traits
Basic data obtained in this review with some of the most commonly encountered carcass traits that could be compared are presented in Table 6.  No. = number, BW = body weight, CW = carcass weight. 1 Backfat thickness was either measured at the level of the last rib, reported as the average of measurements taken along the carcass, or between the fourth and fifth lumbar vertebra level (in agreement with specifications for AOC Kintoa studies [14][15][16]).   In considered studies, pigs of Basque breed were slaughtered between 202 and 458 days of age (n = 5 studies) and between 86 and 154 kg live weight (over 130 kg in 6 out the 8 references). In the six listed references, dressing yield was in the 72.9-81.8% interval. The back fat thickness value measured at the level of the last rib, reported as the average of measurements taken along the carcass or between the fourth and fifth lumbar vertebra level (according to AOC specifications), spanned from 26 to 51 mm (n = 8 studies), whereas muscularity measured as loin eye area was 18.1 cm 2 [13]. These values indicate lower muscular development and greater carcass fatness compared to modern breeds which can be explained by the absence of selection on fatness and muscle in the Basque breed. This variation in back fat and muscle thickness is also a consequence of the wide range of final live weight of pigs and different feeding regimes applied in considered studies.

Meat and fat quality
Basic data obtained in this review with some of the most commonly encountered meat and fat quality traits measured in longissimus muscle and subcutaneous back fat tissue that could be compared are presented in Table 7. In the studies reporting meat quality of Basque pigs, pH measured in longissimus muscle at 45 minutes and 24 h post-mortem was between 6.27 and 6.63 and between 5.54 and 5.76, respectively (n = 4 studies). Loin meat from Basque pigs also exhibited high intramuscular fat content (over 3.3% and with a maximum of 5.7%; n = 6) and a dark colour (high Minolta a* value over 9.3 in four out of five studies and moderate lightness with L* value within the 43-52 interval). Big differences in the SFA, MUFA and PUFA content of intramuscular fat in longissimus muscle were observed between the considered studies (n = 5 studies). These are due to differences concerning the feeding regime, feed composition, final body weight/age and fatness, which are all important factors influencing the fatty acid composition of meat.

Use of breed and main products
The Basque pig breed is intended for the production of traditional high-quality pork and processed products that have been now protected at national (AOC) and European (PDO) levels. The main products are listed in Table 8. The low growth rate of animals, low lean growth potential and high fatness, associated with the extensive production system including natural feeding resources, strongly interact and lead to muscle and meat phenotypic traits that are favourable for the high sensory and technological quality of pork and pork products [20]. Notably, the meat of Basque pigs exhibits a red colour, very low drip loss, low rate and moderate amplitude of post-mortem pH decline and high intramuscular fat content, all these traits playing an important and positive role on the appearance, tenderness and juiciness of pork products [18]. The high intramuscular fat associated with the high content of monounsaturated fatty acids of ham muscles is also of great interest for sensory (tenderness, flavour) and nutritional quality of dry-cured hams [15]. The very high sensory quality of pork and products from Basque pigs is recognised at both national and international levels, with the export of dry-cured hams to Japan and Hong Kong. The recent AOC/PDO official label certification will be helpful to improve consumer awareness and knowledge about these specific products and production systems and thereby should enhance the sustainability of the local Basque pork chain (Figure 5).