This is because with live weight efficiency, pigs which are eating an excessive amount of feed above that required for maximum lean gain and depositing the excess energy as fat, are given credit for the fat gain as it is part of the live weight growth. Pigs depositing excessive fat are somewhat less efficient in converting feed to live weight growth, because fat growth requires four times more energy than lean growth. However, pigs with high fat growth rates must have consumed excess energy via high feed intakes. For this reason, pigs with high fat accretion rates are substantially less efficient in converting feed to lean growth than genotypes with lower fat deposition rates. The means for the carcass measurements and pork quality scores are presented in Tables 2 and 4.
Large differences exist in backfat thickness, percent lean and pork quality scores.
This indicates that the majority of the variability in pork quality scores was within uniform genotype-sex groups of pigs. Uniform genetics will only partially reduce variation in pork quality. In both trials, the European pigs grew slower, consumed less feed, and had lower daily carcass fat growth rates. As a result, the European genotypes had higher ratios of lean gain to fat gain, and better lean feed conversion. However, the U.S. genotypes had higher muscle quality scores.