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.

Effect of suckling on growth and quantitative and qualitative carcass traits of once-calved heifers.

Heifers (n=72) from four breed-types were used to evaluate the effect of breed-type and parity/weaning age on growth performance and carcass characteristics of the heifers. Breed-types studied were Japanese Black (B), B×Holstein (BHo), B×BHo (BBHo), and Japanese Shorthorn (S)×B (SB); whereas parity/weaning age treatments included maiden heifers and two once-calved heifer groups in which calves weaned at either 7 or 105 days. Growth performance of the once-calved heifers was inversely proportional to the milking ability of the heifers. Differences of carcass quality were significant (P<0.05) among breed-types, but not significant (P>0.05) among parity/weaning age groups by finishing for 180 days after weaning the calves.

Effectiveness of morphometric measurements for improvement of the prediction accuracy of beef carcass composition.

Investigations were conducted into the effectiveness of morphometric measurements (MM) of beef carcass for the prediction of weights and percentages of muscle and fat using 237 carcasses of two pure and five cross-bred breed types. In addition to the MM, side weight (CW) and cross-sectional (SM) measurements were used for prediction by multiple regression analysis, singly or in combinations of these measurements. The cross-sectional measurements were made on three sections of a rib joint named R6, R9 and R12 which were cut at the anterior position of the 6th, 9th and 12th thoracic vertebrae. For the prediction of weights and percentages of muscle and fat, the MM group was the best predictor. The CW was effective only for the improvement of tissue weight prediction. The CW+MM+ SM(R12) and the MM+SM(R12) combinations were best for the tissue weight and the percentage prediction, respectively. A synergistic effect was observed between MM and SM for the improvement of tissue percentage prediction accuracy. Regrouping the data to three breed types by morphological differences and analyzing it by a principal component analysis improved the prediction accuracy. Carcass weight range which caused differences in carcass fat content did not affect the prediction accuracy of muscle and fat percentages in the carcass when MM were used.

Dietary tea reduces the iron content of beef.

We hypothesized that the lightness of Japanese beef was related to the concentration of heme iron. In Experiment 1, six Japanese Black heifers were allotted randomly to one of three treatment groups: a basal concentrate ration (40% flaked corn) or the same diet and either 2 kg/d wheat bran or 0.5 kg/d green tea. After feeding the diets for 174 d, the cattle were slaughtered and the M. longissimus thoracis, M. semimembranosus, and M. gluteus medius were sampled for meat color, iron, and lipid content. The iron content of the M. semimembranosus from the tea-fed cattle was lower than in M. semimembranosus from the control cattle, and a∗ (redness) and √(a(∗2)+b(∗2)) (saturation) values were lower in M. semimembranosus from bran- and tea-fed cattle than in control cattle. Treatment main effects (across muscles) indicated that inclusion of tea in the diet increased intramuscular lipid and reduced the muscle iron content. There was a significant negative correlation (r(2)=0.79) between muscle iron content and L(∗) value (lightness). For Experiment 2, the effect of beef breed type on meat color and iron content of M. longissimus thoracis was investigated using stored meat samples from six breeds from a previous fattening experiment done under a high nutritional plane. Muscle iron content was significantly lower in Japanese Black cattle than in Japanese Black × Holstein or Japanese Black × Japanese Black/Holstein. There was no relationship between muscle iron content and intramuscular lipid content (r(2)=0.001). In Experiment 3, samples of M. longissimus dorsi were obtained from 17 Wagyu crossbred and 3 Angus crossbred cattle fed a corn concentrate diet in the USA for 148 d. Iron content of the M. longissimus thoracis from Japanese Black and Japanese Brown × Holstein cattle fattened in Japan was significantly less than the iron content of M. longissimus dorsi from cattle raised in the USA. Overall, the data indicate that it is possible to lower muscle iron, and lighten muscle color, by feeding green tea to Japanese cattle; also, there may be a genetic basis for the lower iron, and lighter color, of beef produced in Japan.

Genetic and nutritional effects on the fatty acid composition of subcutaneous and intramuscular lipids of steers.

Genetic and nutritional influences on fatty acid composition of subcutaneous (SNL) and intramuscular neutral lipids (IMNL) and intramuscular phospholipids (IMPL) of steer carcasses were investigated by removing the effect of carcass fat percentage (CFP) or slaughter age (SA) on the fatty acid composition. To investigate the genetic influences, steer progenies from two dam breed-types (Japanese Black (JB) and f(1) between JB bull and Holstein cows) and three different maturing types of JB sires were used. Dam breed-type did not affect any of the fatty acids except 17:0 in SNL and none of those in IMNL. Percentages of 16:0, 16:1, 18:2, SFA, MUFA and PUFA in SNL differed among sires of JB dam breed-type group (p < 0.05) even after removing the effect of CFP. Studies on the effects of two nutritional planes [high(H) and medium-high(MH)] on the fatty acid composition of SNL, IMNL and IMPL were done using JB steers. The SNL and IMNL of the H plane steers contained greater percentages of saturated fatty acids at the same CFP but less at the same SA than the MH plane animals. The reverse was true for the unsaturated fatty acid contents.

Effect of breed type and sex on the fatty acid composition of subcutaneous and intramuscular lipids of finishing steers and heifers.

Effects of breed type and sex on the fatty acid composition of subcutaneous neutral lipid and intramuscular neutral and phospholipids of longissimus lumborum muscle were investigated using 145 steers and 82 heifers that consisted of pure Japanese Black and Holstein and crossbreds among Japanese Black, Holstein, Japanese Brown, and Charolais. Steers and heifers were reared on a high plane of nutrition and were fed the same concentrate diet and rice straw. All animals were slaughtered serially and carcass composition was determined by dissection of the left side of the carcass. Breed type and sex differences of fatty acid percentages of carcass lipids were compared by adjusting the percentages to mean carcass fat percentages. Heifers had higher contents of 18:1 and total monounsaturated fatty acids in subcutaneous and intramuscular neutral lipids than steers (P < .05). The fatty acid composition of intramuscular phospholipids differed between sexes for 16:0, 20:1, and 20:5, but the differences were small. Breed differences were significant (P < .05) in steers for 16:0, 16:1, 18:1, and total saturated and monounsaturated fatty acids in both subcutaneous and intramuscular neutral lipids, and iso-16:0, 16:0, and total saturated fatty acids in phospholipids, respectively. However, in heifers, fewer fatty acids differed (P < .05) among breed types in the neutral lipids. It is suggested that the Japanese Black has a genetic predisposition for producing carcass lipids containing higher concentrations of monounsaturated fatty acids than Holstein, Japanese Brown, or Charolais.

Distribution of intramuscular lipid throughout M. longissimus thoracis et lumborum in Japanese Black, Japanese Shorthorn, Holstein and Japanese Black crossbreds.

Intramuscular lipid content of M. longissimus thoracis et lumborum was determined at five locations within the ribeye muscle from 267 Japanese Black, Japanese Shorthorn, Holstein and Japanese Black crossbred steers and heifers or cows in order to investigate the distribution of marbling. Breed was a highly significant (P < 0·001) source of variation for amount of marbling at each of the locations measured. Percentage of lipid was higher at the extremities of the muscle than in the middle part and was not affected by sex at any location except for opposite the 6th rib (P > 0·05). Regression equations were derived which relate the percentage of lipid at various locations within M. longissimus thoracis et lumborum to that opposite the 6th rib. A substantial portion of the variation in marbling observed at the other locations could be accounted for by marbling at the 6th rib (R(2) = 0·73-0·90). These data confirm that marbling varies within the ribeye muscle but suggest that it is rather consistent in the distribution pattern exhibited by Japanese Black cattle and their crosses.

Relationship between Japanese beef marbling standard and intramuscular lipid in the M. longissimus thoracis of Japanese Black and American Wagyu Cattle.

Japanese Black and American Wagyu steers (n = 155) were slaughtered and graded under typical Japanese production conditions, and then analyzed for percentage ether-extractable fat at the 6th thoracic vertebra. The percentage of intramuscular lipid was used to develop a prediction equation for the Japanese beef marbling standard (BMS) with R(2) = 0·7619.

Effects of nutritional planes and brees on intramuscular-lipid deposition in M. longissimus dorsi of steers.

The influences of nutritional planes and breeds on intramuscular-lipid (IML) deposition in M. longissimus dorsi were investigated by comparing the relationships between intramuscular lipid percentages (IMLP) in the muscle and side-carcass weight (SCW), carcass-fat percentage (CFP), and slaughter age (SA). Japanese Black (JB) and Japanese Shorthorn (JS) steers were fattened under two (medium-high and high) nutritional planes, which were different only in JB and when the adjusted IMLPs were compared on the basis of SCW or CFP. Breed effects on IML deposition were investigated by using three pure breeds and four crossbred-steer groups. The means of IMLPs in the muscle adjusted to three criteria were significantly different among breeds, the IMLPs of JB and their backcrosses being higher than those of JS and Charolais crosses. IML deposition in steers was highly dependent on the genetic potential of the breeds or bulls used.