Epididymal mouse spermatozoa were separated by discontinuous Percoll density gradient centrifugation with density ranging from 1.055 to 1.107. The applied centrifugation patterns were 150×g for 5min and 250×g for 20min. Superovulated (BALB/c×C57BL/6) F₁ mouse eggs were fertilized in vitro with the separated spermatozoa, and their chromosomal preparations at the first-cleavage division were made by the air-drying method followed by C-banding. The sex ratios of diploid embryos ranged from 44.8 to 49.1%, but their deviations from the theoretical ratio of 50% were statistically insignificant. The observed ratios of sex-chromo-some combinations of XXX:XXY:XYY in the triploid eggs of the experimental groups showed no significant difference from the theoretical ratio of 1:2:1 in dispermic triploidy. These results indicate that Percoll density gradient centrifugation can not separate mouse spermatozoa into X-and Y-bearing spermatozoa under the conditions used in the present study. There was no effect on the fertility of spermatozoa separated by Percoll, although the incidence of hyperdiploids and structural aberrations increased significantly.

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Sixteen finishing barrows, weighing initially 85kg, were divided into 4 experimental treatments in a 2×2 factorial arrangement to determine the effects of a high ambient temperature (30°C vs.18°C) and dietary fat supplementation (10% of encapsulated-tallow supplementation vs 0%) on fatty acid composition of body fat. After 4 weeks of the feeding trial, pigs were slaughtered. Outer and inner layers of the backfat and the leaf fat were obtained as samples from the left half of carcass, and fatty acid composition of the fat samples was determined. Principal component analysis on fatty acid composition of the fat samples indicated that ratios of the total percentage of monounsaturated fatty acids to that of saturated fatty acids (M/S ratio) and precentages of oleic and linoleic acid represented difference in fatty acid composition in this study. M/S ratios of the outer layer of the backfat and that of the leaf fat were significantly lower at a high ambient temperature (P<0.05). Percentages of oleic acid were significantly lower at a high ambient temperature (P<0.05). Percentage of linoleic acid of the leaf fat was significantly higher (P<0.05) and that of the outer layer of the backfat tended to be higher (P<0.10) at a high ambient temperature. Melting points of the backfat samples were significantly lower in pigs fed the fat supplemented diet (P<0.01), while those of the leaf fat were not affected by dietary far supplementation. The possible mechanisms by which a high ambient temperature affected fatty acid composition of depot fats of pigs were discussed.

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Two experiments involving comparative slaughter procedures were conducted to see if the decrease in total energy retention (ER) resulted from the decreased food intake in growing chicks fed on a diet containing threonine less than its requirement. Ad libitum feeding a diet containing 50% of threonine of a control diet (6.5g/kg) decreased body weight gain, apparent metabolizable energy (AME) intake, ER, and ER/AME intake ratio. When both the control diet and the 3.25g/kg threonine diet were tube-fed at the two levels of food intake, body weight gain was significantly lower in chicks on the low-threonine diet than in the control chicks at each level of intake. Energy retained as protein was significantly decreased by the low threonine level and reduction of food intake. Energy retained as fat was affected by food intake. ER and ER/AME intake ratio were unaffected by dietary threonine level and were proportional to AME intake. Heat increment of feeding was unaffected by dietary threonine. These results indicate that the decreased ER in chicks fed on the low-threonine diet was due mainly to the decreased food intake and not to the decreased efficiency of AME utilization.

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To investigate the effect of trivalent cations on the gelation properties of meat protein, the heat-induced gel strength (rigidity) of chicken breast actomyosin with FeCl₃ was measured and the microstructures of the heat-set gels were observed by scanning electron microscopy (SEM). The maximum and minimum rigidity of thermally treated actomyosin occurred at about 0.2mM and 0.5mM FeCl₃ at pH6.0 in 0.6M KCl. The results obtained from SEM showed a thinner and smoother microstructure but the thickest and largest pore distribution in morphology when FeCl₃ was added at 0.2 and 0.5mM, resperctively. The microstructures of the heat-set gels of actomyosin with or without FeCl₃ corresponded to the results of their rigidity

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The susceptibilities to diarrhea of calves of 4 breeds, Japanese Black, Japanese Red (Kumamoto), Aberdeen Angus and Hereford, were observed in a beef herd in Hokkaido. The incidence rates of diarrhea in those breeds were 79.2, 31.6, 63.3 and 38.3% respectively and there were significantly different (p=0.001) among 4 breeds. Japanese Black and Aberdeen Angus calves tended to be more sensitive against diarrhea than Japanese Red or Hereford. There was no significantly different among 4 breeds in the age in days at the first diarrhea and the period of treatment.
Beef cattle calves are mainly reproduced in small farms which keep small numbers of cows in Japan. Though the cost for production should be expected to be decreased, effective methods such as grazing or mass production are not established yet, especially for Japanese Black calves. Calf diarrhea is one of big problems for mass production of beef cattle²⁾. However, there have been few studies of the susceptibility to diarrhea in the grazing environment for Japanese Black calves.
In the present study, we observed the susceptibilities to diarrhea of calves of 4 breeds, Japanese Black, Japanese Red (Kumanoto), Aberdeen Angus and Hereford, in a grazing herd.

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The selection of beef cows has been carried out by strain and registry examinations in Japan. Recently embryo transfer technology is applied in sire production station. However, it is very difficult to get the informations on performance of beef cows.
The objective of this study was to evaluate the carcass traits of live cows using ultrasonic method. The records of ultrasonic measurements of carcass traits were obtained from eighteen cows for producing sire (super donor cows), twenty-nine cows of ET-experiment donor (test donor cows), fourty-five cows of commercial donor and fifty-six cows of common herd in Japanese Black Cattle. The traits of M. longissimus thoracic area (MLTA), beef marbling score (BMS), subcutaneous fat thickness (SFT), intermuscular fat thickness (IMFT) and rib thickness (RT) at 7th rib section, were estimated and live body weight of the cows was also measured at that time of ultrasonic measurements. The effect of age, herd, calving season, sire, interaction of herd ×calving season and linear and quadratic regressions for weight on ultrasonic estimates of the carcass traits were analyzed by least squares methods.
Significant differences on age were found for all estimates of carcass traits except for RT. It was found that highest least squares means of MLTA and BMS were obtained at 50 and 40 to 50 months, respectively. Significant differences between the herds were found for all estimates of carcass traits. The effects of herd on MLTA, BMS and RT were detected to be highly significant (P<0.001). The common cow group was significantly larger (P<0.05) than the other herds in terms of MLTA. Super donor cow group showed the largest MLTA followed by test donor cow group and commercial donor cow group within donor cow groups, and there were significant differences this trait with each other. The BMS of donor cow groups were detected to be higher than common cow group. Significant differences on calving seasons were found for all estimates of carcass traits except for BMS. Calving on spring and summer seasons tended to be higher than the other seasons in terms of MLTA and BMS. Calving on winter had the lowest value for all estimates of carcass traits. Significant differences (P<0.001) on sires were detected for all estimates of carcass traits. Similarly, calving season×herd interaction was found to be significant (P<0.001) for all estimates of carcass traits. Linear and quadratic regressions on weight were detected significantly for all estimates of carcass traits except for quadratic regression of BMS.

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In BLUP, it is necessary to choose the most appropriate model for the data structure concerned. However, it is difficult to determine the best fitted model by using field data. In this research, we generated simulated populations of which finite loci were assumed. The structure of the population, and the accuracy of predicted breeding value by means of BLUP were investigated. A trait was assumed to be controlled by 30 loci only with additive gene effects. Farms and birth years were considered as environmental effects. Populations were simulated 50 times under 6 conditions including 3 different numbers of farms (2, 10 and 20) and 2 different selection methods for female. The generations overlapped during selection. In the polpulations obtained, increase of average inbreeding coefficient and decrease of additive genetic variance with years were observed. Additive genetic variance of the populations decreased more than the expected amount of decrease supposed to accompany the increase of average inbreeding coefficient. Therefore, this clearly shows that gametic disequilibrium or a change of gene frequency occurred in the populations. The positive genetic trends existed with years under every condition. The trends were estimated unbiasedly using breeding values predicted by animal model with all records and relationships. Consequently, this suggests that the breeding values obtained by the BLUP are unbiased even in simulated data of which finite loci were assumed.

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The most appropriate model for sire evaluation by BLUP was investigated, assuming field progeny testing system for carcass traits. Using a simulation data generated under the assumption, sire evaluation was carried out by BLUP with sire model, maternal grandsire (MGS) model and animal model. In the construction of the simulation data, 3-way numbers of fattening farms and 2-way selection methods were considered, and totally 6 conditions were set up by their combination. Concerning accuracy, sire model showed quite lower accuracy than the other two models under all conditions. On the other hand, the difference between MGS model and animal model was small, and especially in the case which the number of farms increased, the difference became negligible. The value of mean squared error was the smallest in the animal model. However, compared with the case that all animals were assumed to have records, the value of mean squared error of animal model in this research seems to be even large. The number of animals evaluated were fewer than 44 in sire model and MGS model under all conditions, while in the case of animal model, approximately 1, 000 animals were evaluated. Consequently, it is suggested that the MGS model is preferred rather than the animal model in sire evaluation for carcass traits.

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An experiment was carried out with 3 pregnant Corriedale ewes from 5 weeks before parturition to 4 weeks postpartum in order to determine the effect of lactation on serum and urinary concenrations of Ca, P and Mg. Although serum Ca and Mg concentrations declined and the serum inorganic phosphorus (Pi) concentration rose transiently during the perinatal period, each mineral value returned to its level of the 5th week before parturition in the 4th week after parturition. Of the relationships among serum Ca, Pi and Mg concentrations there was a significant positive correlation between Ca (X) and Mg (Y) (y=0.44x-0.16, r=0.70, P<0.01) and a significantly negative correlation between Pi (X) and Mg (Y) (y=-0.23x+1.27, r=-0.79, P<0.001). According to the onset of lactation, the urinary concentration (mM/mM Creatinine) changed, with Ca declining significantly (P<0.001) and Mg rising transiently (P<0.05). Milk Ca (X) and Mg (Y) concentrations declined gradually by having a significantly positive correlation between them (y=0.21x-1.69, r=0.86, P<0.05). Although the milk P concentration declined markedly, there was no correlation between P and Ca or Mg. As there was a negative correlation between serum (X) and urinary (Y) concentrations of Mg (y=-6.6x+8.3, r=0.78, P<0.05), hypomagnesemia in sheep during the perinatal period might be induced not only by milk secretion of Mg but also by increased urinary excretion of Mg.

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From the viewpoint of physicochemical assays, some factors related to the pleasant flavor and taste of beef were investigated using 5 Japanese Black Cattle branded beef; namely, Kobe, Yonezawa, Matsuzaka, Maesawa ans Hida beef.
The results obtained were as follows:
(1) No difference in the content of histidine-related dipeptides or ATP related compounds in loin lean meat and the HPLC patterns of crossed fat in the loin were observed among the 5 samples. Free amino acid content was significantly high in Hida beef and low in Matsuzaka beef.
(2) GC/MS analysis of the cooked beef flavor demonstrated that the collected yield of the aromatic part and the contents of Carbon-and Nitrogen-compounds in the flavor fraction were significantly higher in Maesawa beef than in the other samples. Acids, alcohol, aldehyde and ketone content differed between samples, and these differences appeared due to the differences in the components derived from fat.

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The effect of the solution temperature and sulfuric acid dose on the pH of hexamine (1, 3, 5, 7-tetraazatricyclo (3.3.1.1³, ⁷) decane) aqueous solution and the denaturation temperature (TD) of hide powder were studied in order to examine the tanning properties of hexamine. Moreover, the effects of hexamine on the pH of hexamine-chrome tanning liquor and the precipitation forming properties of chrome were studied.
Although hexamine began to decompose easily, a long period was required for the completion of decomposition reaction. The addition of hide powder to the hexamine solution shortened this period. The TD increase rate in hide powder caused by the decomposed materials from hexamine was slow. When the solution temperature rose and the dose of sulfuric acid increased, the decomposition of hexamine was promoted and the rate of TD increase in the hide powder accelerated.
The chrome agent accelerated the decomposition reaction of hexamine under acidic conditions in the presence of sulfuric acid. Thus, the decomposition reaction of hexamine was completed in less than half the time it took for the chrome agent free solution. Higher temperature and or the higher quantity of sulfuric acid reduced this period.
In the presence of hexamine, it is difficult for chrome to precipitate even at considerably higher pH in the chrome tanning liquox in comparison with an ordinary chrome sulfate aqueous solution. This is because decomposed materials from hexamine have a masking effect on chrome complex salts.

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The partial substitution of hexamine (1, 3, 5, 7 tetraazatricyclo [3.3.1.1³.⁷] decane) for chrome tanning agents was examined in order to reduce the amount of discharged chrome from tanneries. For this purpose, hexamine was applied in the pickling process pre-tanning. Then, the behavior of pH values in pickling and tanning liquor, chrome concentration, and the chrome content and shrinkage temperature (T_S) of pickled pelts and chrome leathers were examined. Leather qualities were evaluated and the quantity of removed chrome from chrome leather was also assayed..
Hexamine raised the T_S of pickled pelts and the pH of tanning liquor. The amount of chrome in the remaining tanning liquor was diminished drastically, however, the T_S of this leather was high. Moreover, on the whole, the quality of this leather was also approximately equal to that of the control.
The quantity of removed chrome from chrome leathers produced using hexamine was much lower than that of the control.

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A simple method for the determination of furosine as an indicator of the glycation of lysine residue in protein in samples of milk and milk products was developed. Furosine formed from the samples by heating with 12N HCl at 110°C for 12 hours was analysed by reversed phase HPLC using 0.1M phosphate-sodium buffer/acetonitrile=3:1(v/v) containing 15mM SDS (pH=6.0) as a solvent. Furosine was determined within 15 minutes with good reproducibility. Furosine content in each sample of milk (raw milk, UHT-milk and long life milk) and milk products (skim milk, infant formula milk, cheese, yogurt, condensed milk and fermented milk) were determined. As a result, advanced glycation was found in the samples of skim milk, infant formula milk and fermented milk.

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