Carcass traits and microsatellite distributions in offspring of sires from three geographical regions of Japan.

We proposed that cattle sired by bulls from distinct geographical regions of Japan would differ in their ability to accumulate marbling and that they could be distinguished by differences in microsatellite genotypes. Semen was obtained from six, three, and one sire from the Hyogo, Shimane, and Tottori regions, respectively. Cows and heifers (n = 92) were bred by artificial insemination and raised at the Kyoto University Livestock Research Farm over several generations. The calves (n = 145) were 252 +/- 0.2 d of age (mean +/-SEM) and weighed 164 to 307 kg at the beginning of the finishing phase. Cattle produced from sires from the three regions differed significantly in days on feed (all significant differences P < 0.05). Carcass data were collected from 48, 36, and 19 offspring from the Hyogo, Shimane, and Tottori sires, respectively. There was no difference in slaughter weight (550 +/- 15 kg). Carcasses from Shimane progeny had more muscle than Hyogo cattle. Hyogo and Shimane cattle contained more kidney and 12th-rib fat than Tottori cattle, whereas Hyogo offspring had more 6th-rib fat than Shimane or Tottori offspring. There were no differences across regions in the monounsaturated:saturated fatty acid ratio. The rate of gain of 6th-rib fat for Hyogo progeny (0.033%/d) was significantly greater than that for Shimane or Tattori progeny (both 0.023%/d). Hyogo 12th-rib fat gain was 0.026%/d, which was significantly greater than that for Tottori progeny (0.010%/d). Shimane 12th-rib fat gain was intermediate (0.016%/d) between the other groups. Blood and muscle samples were used for the collection of DNA from 58, 30, and 18 offspring from the Hyogo, Shimane, and Tottori sires, respectively. Samples of the DNA were analyzed for 11 microsatellites. The BM1824 microsatellites for the Tottori progeny were not in Hardy-Weinberg equilibrium because of successive use of Hyogo sires on previous generations. The TGLA227 microsatellites for the Shimane cattle were not in Hardy-Weinberg equilibrium because of selective removal of progeny for slaughter. There were significant differences in allelic frequencies for the BM1824, ETH10, INRA23, and SPS115 and TGLA53 alleles across regions. These data are consistent with the geographical isolation of the different lines of Japanese Black cattle during their development and indicate the superiority of certain groups of sires in the accumulation of intramuscular lipid.