Turopolje Pig (Turopoljska svinja)

Turopolje pig is a fatty-type pig breed created during the Middle Ages in Turopolje region in Central Croatia. Due to its modest demands, resilience and good adaptation to outdoor rearing, the Turopolje pig has been an important food source for the local population for centuries. However, with the transition from extensive to intensive pig production in the middle of the twentieth century, this autochthonous pig breed almost disappeared. Currently, despite the state support, Turopolje pig is still endangered, with a population of only 116 sows and 14 boars. Hence, to preserve Turopolje pig breed in a more sustainable way, the breed needs to be more economically exploited and scientifically explored. Thus, the aim of this chapter is to present history and current status of Turopolje pig breed, its exterior phenotypic characteristics, geographical location, production system and main products. Moreover, a collection and review of available literature data (available until August 2017) on reproductive and productive traits, including growth performance, carcass traits and meat and fat qualities of Turopolje pig breed, were carried out. Although studies on Turopolje pig are scarce, the present review gives the first comprehensive insight into this still untapped local breed of pigs investigated in the project TREASURE.


History and current status of the breed (census)
Turopolje pig is a native Croatian breed, created during the early Middle Ages in Turopolje region near Zagreb in Central Croatia. It is a medium-sized, primitive, fatty-type pig breed. As it developed over a long period of time, the breed perfectly adapts to its natural environment, primarily continental climate conditions and lowland forest ecosystems. Due to the modest demands, resistance and good adaptation to local marsh pastures and oak and beech forests, the Turopolje pig breed for centuries has been an important food source for the local population. However, the rapid penetration of imported lean pigs in the second half of the twentieth century, as well as the ban of forest grazing, significantly reduced the interest in this breed. The result was an emerging decrease of the population size, and since 1996, the Turopolje pig breed is under the state protection. Unfortunately, despite the support the Turopolje pig breed is still endangered, and the renewal of the population has been very slow. Census of Turopolje pig breed is presented in Figure 1. Presently, there are only 12 registered farms of Turopolje pigs with about 116 breeding sows and 14 boars in the latest available status (August 2016 [1]). In the past, the meat of Turopolje pig was considered better than meat of other pig breeds [2], but today its use is sporadic and almost completely replaced with the meat of modern pig breeds and hybrids. However, as a part of the current trends in the protection of local breeds and their sustainable farming systems, it becomes justified to review the breeding of Turopolje pig breed for production of meat and local meat products. Renovation of traditional link between breed and its products and their technological and marketing development may, by itself, represent the best way for recovery and long-term preservation of Turopolje pig breed on economically sustainable base.

Exterior phenotypic characteristics
The Turopolje pig breed morphology information is summarized in Table 1. It is a medium-size breed with distinctive sporadic black spots on a white or gray coat, mostly curly hair and drooping, half-folded ears (Figures 2 and 3). Head is medium long with slightly concave profile and sturdy snout, which ensures a good

Geographical distribution and production system
Turopolje refers to a plain extending over a 45-km-long and 23-km-wide alluvial plateau, occupying an area of about 600 km 2 , with an average altitude of 110 m above sea level. It is located between Posavina (wetland plains along the Sava River) in the north and the Vukomeričke gorice (low altitude hills) in the south. The Odra River flows through it with the Lomnica tributary. Characterized by lowland oak forests, periodically flooded pastures and continental climate, Turopolje has always been suitable for outdoor livestock production, especially pig breeding. In the past Turopolje pig breed spread from Turopolje to Sisak and Draganić, later to the parts of Slavonija and Podravina and all the way to the south-western parts of Hungary. However, with the transition from extensive to intensive pig production in the mid of twentieth century, its farming drastically reduced and the breed almost disappeared. Today, Turopolje pig is reared only in a few localities, mainly in Turopolje forest and Nature Park Lonjsko Polje (Figure 4), where traditional way of pig farming has been maintained. Basically, it comprises a low-input technology of animal housing and feeding in a fully outdoor system on pasture at local forests and marsh meadows. Pigs are provided with only a simple shelter, water and some supplemented feed (e.g., 0.5-2 kg  of corn per animal daily), while the majority of animal's diet is supplied from natural resources (e.g., acorn, grass, worms, snails, shellfish, etc.). Finishing at high-grain diet, prior to slaughter is usual. Indoor housing and intensive production systems are rarely practiced.

Organizations for breeding, monitoring and conservation
The Association "Plemenita Opčina Turopoljska" (Universitatis nobilium Campi Turopolya) is the responsible breeding organization for Turopolje pig breed, assisted by Croatian Agricultural Agency, which monitors the population and keeps herd books ( Table 2). Conservation of Turopolje pig breed started once Croatia signed Convention on Biological Diversity (CBD) in 1997, and breed was added to the FAO list of endangered breeds in category of regional breeds [3]. After CBD ratification a national biodiversity strategy was established, including an action plan for the conservation of endangered breeds. Since then Turopolje pig breed is under the state of renewal and in situ protection. Funds for conservation are provided by the state. Ilica 101, 10,000 Zagreb, Croatia http://www.hpa.hr/sektori/ sektor-za-razvoj-stocarskeproizvodnje/odjel-za-svinjogojstvo/ izvorne-pasmine/

Growth performance
Basic data on growth performance obtained in this review are presented in Tables 4 and 5. In Turopolje pig breed, studies provided only growth rate in period of lactation and the overall growth rate for the whole fattening stage (defined as overall). It should also be noted that majority of collected studies simulated 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. The average daily gain in Turopolje pigs during lactation is 101 g/day [7], which is less than expected in modern pig breeds. Also, an average value obtained for the overall fattening stage is characterized by a considerably slower growth rate (429 g/day [10][11][12]) than modern pig breeds. 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 potentials of Turopolje pigs in ad libitum conditions of feeding (≈ 556 g/day in the overall fattening stage [12]).
In considered studies, the information on feed intake and feed nutritional value were scarce, which limits the evaluation of growth potential. Average daily feed intake reported was around 2.0 kg/day in the overall fattening period [11,12].

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. In considered studies, pigs of Turopolje breed were slaughtered at approximately 437 days of age (140-679 days [5,[10][11][12][13]) and average 96 kg live weight [5,10,12,13]. Dressing yield was around 80% [5,10,12,13] 1 ADG in a period of lactation regardless of how long it was. 2 ADG in a period of fattening is reported as the overall growth rate for the whole studied period ( from approximately 30 kg body weight until slaughter).     [5,[10][11][12][13]). The backfat thickness values were measured at the position of withers averaged 57 mm [10,12], at the level of the last rib 37 mm [5,10,12] and at the level of gluteus medius muscle 34 mm [11,12]. Muscularity was measured as loin eye area averaged 23 cm 2 [11] and as muscle thickness above gluteus medius 48 mm [11,12].

Meat quality
Basic data obtained in this review with some of the most commonly encountered meat and fat quality traits measured in longissimus muscle that could be found are presented in Table 7. In the studies reporting meat quality of Turopolje pigs, pH measured in longissimus muscle at 45 min and 24 h post-mortem were around 6.1 and 5.68, respectively [11,12]. The intramuscular fat content ranged from 2.2 to 5.8 (3.7% in average [5,[11][12][13], and color measured in CIE L*, a* and b* color space was 44.6, 19.3 and 5.7 for L, a* and b* [12]. SFA, MUFA and PUFA content of intramuscular fat in longissimus muscle in the considered studies were around 38, 51 and 11%, whereas SFA, MUFA and PUFA content of back fat tissue were approximately 38, 49 and 13%, respectively [5,12].

Use of breed and main products
Resilient and capable of foraging, Turopolje pig breed has always been able to survive in free range, which makes it particularly suitable for low-input, extensive production systems. Its use today represents a potential alternative to intensive farming, and it should be intended primarily for production of pork meat and products of premium quality. Meat is darker and redder in color than in standard pork, with fine muscular texture, which seems to be characteristic for this breed [4,9]. There is a higher level of accumulation of fat tissue, especially in the subcutaneous area, and between the muscles. Meat of Turopolje pigs in today's gastronomy is mainly used in special occasions for the preparation of various local food specialties (e.g., "turopoljska kotlovina", goulash, various pork roasts- Figure 5). It is also suitable for processing in typical meat products (e.g., dry-cured ham- Figure 6, bacon, dry-fermented sausages, etc.), which are highly appreciated by local consumers but for now rarely available in the market. In 2017, the breeding association "Plemenita Opčina Turopoljska" applied for the registration of fresh meat from Turopolje pig with the protected designation of origin (PDO) label, and the procedure is underway at national level.