BONE STRENGTH (ossis tibiae) OF NATIVE PIGS ZŁOTNICKA SPOTTED BREED AND CROSSBREDS OF POLISH LARGE WHITE AND PoLISH LANDRACE PIGS

The purpose of this study was to compare the bone strength traits in two groups of pigs different in terms of genetic value, fast growth capability and meat deposition in the body. The study covered 33 fatteners of the Złotnicka Spotted breed (ZŁP) and 20 crossbreds F1 (Polish Large White x Polish Landrace). Tibial bones were obtained following slaughter and evaluated in terms of properties and geometry, as well as bending and compressive strength. Mineral composition of the bone tissue was also established, i.e.: ash, Ca, P, Na, K, Zn and Mg. The significance of differences between the traits demonstrated by pigs in both groups subject to the study was estimated, with calculated overall correlations between the primary bone properties. The results confirmed significant differences in terms of geometry of the bones in both animal groups. In the ZŁP breed pigs, compared to the F1 crossbred group (PLW x PL), the outside and inside diameters of the tibial shaft were smaller (P ≤ 0.01), yet the average thickness of the wall of the bone was slightly larger. The bending force required to fracture the bone turned out to be lower in Złotnicka Spotted pigs, the opposite of the results obtained with regard to the compressive strength. Furthermore, calcium content, calcium-phosphorus ratio (Ca : P) and sodium content were highly statistically or significantly larger in the bone tissue of the Złotnicka Spotted pigs. Consequently, the final results show that the bone strength demonstrated by modern pig breeds subject to intensive selection focused on high growth rate and increased meat deposition is in no way lower than the same trait recognized in the Złotnicka Spotted breed kept in preservative breeding conditions