At the beginning of 2002, within the frames of the programme ”Marble Pork“ for producing high-quality pork, a new quality estimation system of young boar carcasses was started in the Estonian Pig Breeding Association. Based on the above system, the culled young boars of the tested sows of the nucleous breeding farms are being estimated at the meat industry. Thus, the meat performance data regarding the A.I. station boars as well as the siblings of the boars sold to farms are being obtained. The collected data will be recorded in the database of the Animal Recording Centre in order to be used for further breeding value estimation.

The young boars were slaughtered at the slaughter department of the Valga Meat Factory. At least 45 minutes post mortem the hot carcasses were weighed and lean content was determined by lean meat meter Ultra FOM 100. Distribution of carcasses into sale classes on the basis of lean content was carried out according to SEUROP system (Tapasigade..., 1994).
The cooled carcasses were estimated in the cold storage 24 hours after slaughter. Carcass length was measured at two points, and the backfat thickness at the thinnest point of withers (at 6^th...7^th rib) and loin (m. glutaeus medius). The right half of the hanging carcass was dissected between the 13^th and 14^th ribs, and the area of musculus longissimus dorsi was photographed using a Kodak digital camera set on a tripod. Digital photos were downloaded in the computer and using a special Scan Star program for measuring the area of musculus longissimus dorsi, the loin eye area, fat area and sidefat thickness on and in front of loin muscle (m. glutaeus medius) were determined. The Estonian Pig Breeding Association obtained the Scan Star system from Rudolf Matthäus Engineering Bureau, Germany.
pH-value of lean meat was estimated in musculus longissimus dorsi within 24 hours after slaughter.
Proceeding from the pH-value of the muscular tissue, PSE-meat pH<5.59, normal meat pH was 5.6...6.29 and DFD- meat pH > 6.3 (Talonen, 1977).
In 2002...2003, the meat performance traits of 850 young boars were estimated; 175 of the Estonian Landrace, 592 of the Estonian Large White, and 81 of the Pietrain breed. A total of 76 young boars were tested; 16 of the Estonian Landrace, 47 of the Estonian Large White, 13 of the Pietrain breed.
A majority of the estimated young boars were the offspring of the boars Fram 4398 (32 pigs), Motor 756 (26), and Asse 7398 (23) of the Estonian Landrace breed; Jommi 2864 (83), Rino 392 (71), Hudson 2958 (67), and Curry 2651 (66) of the Estonian Large White breed, and those of the boars Valor 598 (23), Julius 2343 (16) and Caesar 2345 (13) of the Pietrain breed. The boars of the Estonian Landrace breed originated from the Kehtna Mõisa OÜ, the boars of the Estonian Large White breed from Saimre Farmstead and Pihlaka Farm OÜ, and the boars of the Pietrain breed originated from Pihlaka Farm OÜ.
The data was statistically processed.

Abbreviations: CL, cm – carcass length; BFT, mm - backfat thickness at 6^th -7^th rib; LEA, cm² - loin eye area; FI - fleshing index; pH₂₄- pH- value; FOM, % - lean meat content, fixed using Ultra FOM 100; n - number; std - standard deviation.

The data presented in Table 1 demonstrate high carcass quality traits of all the estimated young boars. It is a positive result of using the semen imported from Finland, Norway and Austria.
The carcasses of the Estonian Landrace young boars were heavier (73.8 kg), and those of the Pietrain boars were lighter (70.7 kg). As expected, the carcass length of the boars of the Estonian Landrace and the Estonian Large White breed was 101.6 and 99.4 cm, respectively, whereas the carcasses of the Pietrain boars were shorter (92.6 cm).
The backfat of the white breeds (Estonian Landrace, Estonian Large White) was thinner (from 18.1 to 19.2 mm), and that of the Pietrain breed boars slightly thicker (20.4 mm). The offspring of the Pietrain breed boars, however, were remarkable for a high-quality flesh (loin eye area – 49.9 cm², lean meat content – 59.6%). Moreover, the meat characteristics of the offspring of the Estonian Landrace and the Estonian Large White boars was also good: large loin eye area (45.6 and 46.7 cm^2, respectively), and high lean meat content in a carcass (58.7%). Flesh index, i.e. backfat area : loin eye area was better in the carcasses of the Pietrain and the Estonian Large White boars (0.28 and 0.30, respectively). According to the SEUROP classification, the carcasses of young boars are distributed to S, E and U sale classes. To S-class belonged 34% of the carcasses of the offspring of the Estonian Landrace breed boars. The respective data for the Pietrain and the Estonian Large White breed were 32% and 28%. A majority of the carcasses of the evaluated boars belonged to E-class: 68% of the Estonian Large White and the Pietrain boars, and 56% of the Estonian Landrace boars.
As an average of all breeds, the offspring of the boars of the Tartu A.I. Station and nucleous breeding stations are characterized by their thin backfat (18.6 mm), a large loin eye area (46.8 cm²) and a high lean meat content of carcass (58.8%).

Table 1. Carcass quality traits of young boars by breeds

* - mean of four measurements; ** - backfat area : loin eye area; ***- Distribution of carcasses by lean meat content according to SEUROP-classification: S (lean content 60% and more), E (55...60%), U (50...55%), R (45...50%), O (40...45%), P (less than 40%).

According to SEUROP-classification, out of 850 carcasses of the evaluated young boars 29% were distributed into S-class, 65% into E-class, and 7% into U-class.
The results of the evaluation indicate that the carcass flesh of all the boars has improved (Table 2). A majority of the offspring of the evaluated boars had a thin backfat and a large loin eye area, as expected. The largest loin eye area (70.3 cm²) had the offspring of the parental pair of the Pietrain breed (Ego 5074 (boar) x 212 (sow) from the Pihlaka Farm OÜ. As regards the Estonian Landrace breed, the largest loin eye area (58.2 cm² ) had the carcasses of the descendants of the parent pair Motor 756 x 1158, and regarding the Estonian Large White breed, those of the parent pair Hudson 2958 x Rinkka 3093 (66.1 cm²).
The best meat tissue quality was observed in the offspring of the Estonian Landrace breed boars Orden 916 (lean content of carcass 62.4%), Ofir 965 (61.0%), Akab 112 (59.5%), Novo 113 (59.4%); the offspring of the Estonian Large White boars Jospel 2242 (60.2%), Hudson 2958 (59.7%), Jallis 3348 (59.6%), Opel 3374 (59.2%); and those of the Pietrain boars Cro 218 (63.5%), Umag 1512 (60.3%), Valor 598 (59.5%) and Julius 2343 (59.4%).
Based on the published experimental information (Glodek, 1985; Rei, Kirikall et al., 1994) and the earlier results obtained by the author of the present article (Põldvere et al., 1990, 1997), the improvement in pig carcasses (increase in loin eye area and share of lean meat) may result in lower meat quality, as a negative correlation was observed between the above data.
To test the meat quality of young boars, the pH value of the musculus longissimus dorsi of all the carcasses was determined. The meat tissue of most of the boars appeared to be of normal quality (pH value from 5.6 to 6.3). In smaller number of the carcasses of the Estonian Landrace and the Estonian Large White boars (0.2 and 3%, respectively) a pale, soft and exudative PSE meat (pH < 5.6) was found. In the carcasses of the more stress-susceptible boars of the Pietrain breed a higher incidence (7%) of PSE meat was observed. The DFD meat was not detected in the evaluated carcasses.

As a result of using the semen of the Estonian Landrace and the Estonian Large White breed boars for insemination of sows, the offspring with thin fat, large loin eye area and high lean percentage of a carcass can be obtained.
The Pietrain breed has particular fat build-up areas, since more fat can be found on the back, less on sides. The carcasses of the offspring of the Pietrain breed boars predominate among others for their good flesh quality parameters (large loin eye area, high lean percentage, low flesh index, large hams). The semen of the Pietrain boars should be used in crossbreeding of white breeds to get the crossbred piglets with high lean meat content.

Table 2 Carcass quality traits of the offspring of young boars

On the whole, the meat of young boars was of normal quality (low PSE meat percentage).
Selection of young boars by means of both carcass evaluation (length and thickness, Scan Star system) and the quality traits of meat (pH-value) enable the breeders to improve the carcass and pork quality of offspring.
The meat performance data of young boars provide the pig breeders with additional information necessary for decision-making.
In 2003…2008, the objective of the crossbreeding programme “Marble Pork” is to suggest ways to improve the flesh and meat quality of the Estonian breeds of swine. Based on this, the lean share in the carcasses of the breeding pigs of the white breeds should increase 63% in boars and 62% in sows, whereas the loin eye area should increase up to 48 cm².

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