Black Slavonian (Crna slavonska) Pig

Black Slavonian (Crna slavonska) pig was created during the second part of the nineteenth century using planned crossing between four pig breeds. It is an autochthonous pig breed in the Republic of Croatia and one of the local pig breeds investigated in the project TREASURE. The present chapter aims to present history and current status of Black Slavonian pig breed, its exterior phenotypic characteristics, reproductive traits, geographical location, production system and main products from this breed of pigs. Also, a collection and review of available literature data, available until August 2017, on productive traits of Black Slavonian pig breed were carried out. Growth performance was estimated utilising average daily gain and average daily feed intake in the overall fattening stage as this was the information mostly provided in considered studies. Carcass traits were evaluated by means of age and weight at slaughter, hot carcass weight, carcass yield, muscularity and back fat thickness. Meat quality traits of the longissimus muscle evaluated were objective colour and intramuscular fat content. Although a considerable number of studies on Black Slavonian pig were included in the current review, data on growth performance and some parameters of carcass, meat and fat quality are scarce.


History and current status of the breed (census)
Black Slavonian (Crna slavonska) pig is an autochthonous pig breed in the Republic of Croatia. It was created during the second part of the nineteenth century on the estate of Count Pfeifer, Orlovnjak, near Osijek. It is also known by the name "Fajferica". It is a result of planned crossing between four pig breeds: Mangalitsa, Berkshire, Poland China and Large Black pig. This crossing aimed to create a pig with better meat and fertility traits. The first phase of crossing includes ten gilts of Mangalitsa and Berkshire boars. Additionally, Poland China boars were included in crossing schemes every 10 years. These systematic crossings were carried out from 1870 to 1910 [1]. The final phase of creation of Black Slavonian breed was during 1920 when crossing with English black breed-large black occurred. The success of crossing and breeding was confirmed in 1873 by winning gold medals at the Vienna Agricultural Fair [2]. At the end of the nineteenth and early twentieth centuries, Black Slavonian pig was the most common and, from an economic standpoint, the most important pig in what is now eastern Croatia. Thus, it is nowadays rightly considered an indigenous breed. Census of Black Slavonian pig breed is presented in Figure 1. Presently there about 209 registered farms with 1930 breeding sows and 242 boars of Black Slavonian pig breed in the latest available status ( [3], December 2017).

Exterior phenotypic characteristics
The Black Slavonian pig breed morphology information is summarised in Table 1. By morphological characteristics, Black Slavonian pig breed is similar to Mangalitsa, although regarding physiological characteristics it is more similar to the Berkshire and Poland China pig breed. The most important characteristic of Black Slavonian pig breed is its black coat colour. The peas and snout are also dark. Black Slavonian pig is a medium-sized pig. The height of the ridge is 65 to 70 cm. The head is medium long with a dense profile and with medium-sized and semi-circular drooping ears. The muscular neck is medium wide and medium in length. The chest is deep and wide. The body and legs are relatively short, whereas the hips are wide and fallen [3] (Figures 2 and 3).

Geographical location and production system
Black Slavonian pig is bred in the area of Slavonian counties: Brodsko-Posavska, Požeško-Slavonska, Osječko-Baranjske and Vukovarsko-Srijemska. Today the Black Slavonian pig is bred, also, in the area of Sisak-Moslavačka County. Black Slavonian pig breed is suitable for keeping under extensive, intensive and semi-intensive conditions. Breeding under semi-intensive conditions is the traditional production system for Black Slavonian pig [4,5]. In this system, pigs are kept in pastures and woods where they exploit the food they find. On 1 ha of pasture area, 15 to 20 sows can be reared, depending on available nutrition and amount of the soil. To emphasise the traditional meaning of Black Slavonian pig, it is advisable to build facilities in a traditional style typical for the breeding area. Facilities for gilts and sows should be semi-open object (30 m 2 ). Size of farrowing pen should be at least 6 Â 1.5 m.
After the farrowing, piglets should be placed together. Fattening period is a final stage of production system. This period must last at least 18 months and during this period pigs can reach from 130 to 150 kg [6]. Under extensive rearing conditions, pigs are kept on pastures where all the food is available to the pigs. The basis of nutrition in the system is acorn with additional feeding during the winter period [7]. Exceptionally before farrowing, sows are placed in semi-open facilities whose floors are filled up with straw. Sows and piglets in such facilities remain until weaning [2].

Organisations for breeding, monitoring and conservation
The conservation and breeding programme began in 1994 and is carried out by the Croatian Agricultural Agency (Hrvatska poljoprivredna agencija, HPA). The agency is in charge of keeping the register, marking the pigs and assessing the breeding value of breeding male and female animals. Monetary funds support the breeding of Black Slavonian pigs (150 EUR per year per breeding animal). The pedigree issuance is carried out in cooperation with the association of breeders of Black Slavonian pig "Fajferica", which is also responsible for the implementation of the breeding programme ( Table 2).

Reproductive traits
Basic data obtained on reproductive traits in this review are presented in    [13,15,19,20]. Stillborn percentage of piglets is very variable and ranges from 1.0 to 15.9% [3,10,13,[17][18][19][20][21]; similarly piglet mortality rate until weaning spans from 5.4 to 15.9% [3, 8-10, 13, 17-21]. Duration of lactation is prolonged in comparison with modern intensive systems up to 57 days [21], which leads to a longer farrowing interval (165 to 326 days [9,13,17,18]) and also higher weaning weight (9.5 to 11.3 [13,15,19,20]). According to Uremović et al. [8], the number of live-born piglets in litter is determined by the number of farrowings, breeding system and characteristics of the boar, while the number of weaned piglets depends on seasonality, breeding system and boar characteristics. Sows have good motherly characteristics. It can be concluded that the reproduction traits of Black Slavonian pig breed are modest, but sows have good motherly characteristics. Uremović et al. [9] suggest that increasing of fertility can be achieved by crossbreeding with Duroc.

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. However, in the case of Black Slavonian pig breed, studies mostly provided 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 simulated practical conditions of the production systems used and that only a smaller part of the studies aimed at evaluating the breed potential for growth. A considerably slower growth rate characterises the overall fattening stage of Black Slavonian pigs compared to modern pig breeds (approximately 335 g/day) but also by high heterogeneity among studies (189 to 567 g/day [8,13,15,19,20,[24][25][26][27][28][29][30][31][32]). In extensive keeping conditions, average daily gain was lower when it is compared with intensive system where pigs are fed with corn, because production system affects the average daily intake, food utilisation and pig growth rate. 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 Black Slavonian pigs in ad libitum conditions of feeding (≈ 567 g/day in the overall fattening stage). Generally, the Black Slavonian pig can achieve the final weight of 100 kg in the period of 8 months, while the weight of 170 to 200 kg can be achieved in 18 to 24 months. The food conversion in these conditions ranges from 4.5 to 5 kg.
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 ranges from 1.3 to 2.3 kg/day in the overall fattening stage [13].

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 Black Slavonian breed were slaughtered when reaching the final age of 359 to 550 days [27,28,32] No. = number; ADG = average daily gain in g; Rest = restrictive feeding regime. 1 ADG in a period of lactation and growing period estimated from birth to approximately 30 kg live body weight. 2 ADG in a period of fattening is reported for early and middle fattening stage estimated between approximately 30 and 100 kg and late fattening stage estimated above 100 kg live body weight. Sometimes the source provided only the overall growth rate for the whole studied period (in that case defined as overall). No. = number, ADFI = average daily feed intake in kg/day. 1 ADFI in a period of lactation and growing estimated from birth to approximately 30 kg live body weight. 2 ADFI in a period of fattening is reported for early and middle fattening stage estimated between approximately 30 and 100 kg and late fattening stage estimated above 100 kg live body weight. Sometimes the source provided only the overall growth rate for the whole studied period (in that case defined as overall).   [13]. Also dressing yield ranges from 66.2 to 85.1% [8,13,15,24,27,28,[34][35][36][37][38] and lean meat content from 27.9 to 47.2% (SEUROP classification or dissection [8,13,15,19,20,24,27,28,33,34]). However, when taking into consideration studies with only final body weight higher than 100 kg, dressing yield is around 81% and lean meat content around 38%. The backfat thickness values measured at the level of the last rib ranges from 32 to 71 mm [13,15,19,20,24,27,28,38] and at the level of the gluteus medius muscle from 22 to 49 mm [15,31,32,[35][36][37]. Muscularity measured as loin eye area is between 27 and 38 cm 2 [13,15,24,27,28] and as muscle thickness at the cranial edge of the gluteus medius between 57 and 72 mm [13,19,20,31,32].
Comparing the proportions of fat and muscle tissue in Black Slavonian pig and modern pig breeds, it can be concluded that Black Slavonian pigs have a significantly higher proportion of fatty tissue. Karolyi et al. [26] reported that the ratio of muscle parts and fat tissue was 32% versus 27%.

Use of breed and main products
Black Slavonian pigs are today used for the production of piglets for sale, production of fattening pigs for fresh meat consumption and especially for the M muscle thickness measured according to ZP method (at the cranial edge of the gluteus medius muscle (mm)). 2 S backfat thickness measured according to ZP method (above the gluteus medius muscle (mm)). production of traditional pork products such as ham, kulen, bacon, sausage, dry cured neck and fat. More recently, the production of dry-cured ham from the Black Slavonian pigs has also begun. At present, the procedure for protection of the product "Meso crne slavonske svinje" with PDI mark is being carried out. The quality of meat and products from Black Slavonian pig has also been investigated. Results show correlations between production system and quality of smoked ham from Black Slavonian pigs; the quality was significantly better when hams were produced from pigs kept outdoors and fed with green alfalfa as the feed basis [37]. Also, the research from Karoly et al. [26] shows that Black Slavonian pigs have poorer production characteristics, but significantly improved qualitative and technological properties of meat, and that the kulen produced from Black Slavonian pigs has better quality. In the future, the production systems of Black Slavonian pigs No. = number, pH 45 = pH measured approximately 45 minutes post-mortem; pH 24 = pH measured approximately 24 hours post-mortem.
1 CIE = objective colour defined by the Commission Internationale de l'Eclairage; L* greater value indicates a lighter colour; a* greater value indicates a redder colour; b* greater value indicates a more yellow colour. must be improved and harmonised. An increase in production of quality traditional value-added products is expected