At the start of the 1970s, meat pigs were produced in accordance with a hybridisation programme, which was based on using the hybridisation effect through targeted crossbreeding. Three or four breeds were crossbred, where the basis was a dam that was cross-bred of the F1 generation, with which a sire from breeds with higher meat levels was mated. And because the sires are used as the fathers of piglets for fattening, these breeds are referred to as sire breeds. The foundations of sire breeds here were laid fifty years ago by imported livestock from the Duroc, Hampshire and Belgian Landrace.
The Duroc (D) breed was imported from the USA. They are pigs with a medium to large body frame, very solid constitution, compact body, reasonably hefty and with a solid skeleton. Its breed characteristic is rusty-red colouring in a wide range of shades. Their ears are quite long and droop. In the case of livestock for slaughter, all the most important parts display the animal’s meatiness. The meat quality is very good. In addition to meat utility, a Duroc has very good growth intensity and nutrient conversion.
The Hampshire (H) breed was also first imported from the United States of America. It has a medium to large body frame, a solid constitution, a solid body structure and a reasonably strong skeleton. Its head is lighter, its ears straight. This breed is characterised by its dark-black colour with a white saddle, which covers the shoulder and both upper limbs. All the most important parts are nice and meaty and the meat quality is good. It excels in terms of the intensity of growth and has acceptable conversion of nutrients.
Belgian Landrace (BL) pigs were imported from Belgium and the former Federal Republic of Germany. It is a breed with a medium-to-large body frame with a solid, sufficiently strong skeleton. The head is light, the ears drooping. The most important meat parts have an excellent type of meat with a medial dorsal line going to the back. The breed is also valued for achieving very good parameters in fattening. The skin and bristle colour is white.
When the central management of breeding was relaxed after November 1989, additional sire breeds were imported, specifically White Sire and Piétrain.
The White Sire (WS) breed imported from England was the sire line of the Large White. The difference is in the utility type, where dry expression of the meat utility type with the medial line on the back and the ham is required. The skin and bristles are white, the body frame is medium to large with a solid skeleton (a little larger than in the case of the dam line). The parameter monitored is very good growth ability and excellent nutrient conversion.
The Piétrain (Pn) breed was imported from the former Federal Republic of Germany, where they created a modern breed with a larger body frame that tended not to be stressed. It is a typical sire breed with the highest meat utility. It stands out thanks to its larger body frame with a solid and sufficiently massive skeleton. Its head is lighter, its ears straight. The black-and-white or spotted colouring is characteristic for the breed. Animals for breeding have a meaty utility type with excellent muscle mass in all the important parts and a medial dorsal line ending at the tail.
The solid constitution of the Duroc, excellent fattening properties of the White Sire and high meat utility of the Piétrain were the reason for creating synthetic sire lines. The breeding public therefore started to work with sire lines SL 34 (WS x D, D x WS), SL 38 (D x Pn, Pn x D), SL 48 (WS x Pn, Pn x WS), as well as SL 68 (H x Pn, Pn x H), which have the ability to satisfy the requirements of both producers and processors.