The objectives of this study were to examine the effects of genetic selection differential (GSD) and generation interval (GI) that affect actual genetic gain per year and to predict genetic changes in the future for milk production of Hokkaido Holstein cows and progeny test bulls in Japan. The data for estimation of breeding values consisted of 305-d (240-d) records of Holstein cows that produced milk with 2 times milking from 1976 through 2001. The data included 5,012,423 records of 1,687,142 cows for milk and fat yields, and 3,574,169 records of 1,306,174 cows for protein yield. A single trait animal model with repeated records for prediction of breeding values included herd-year-parity subclass as fixed management group effects, age and month of calving within each birth year group as fixed effects, linear regression on inbreeding, random permanent environment effects of cows, random additive genetic effects of animals, and random residual effects. The GI was calculated as an interval of the birth dates between progeny and its parent and was expressed in years. The GSD was estimated as the difference between estimated breeding value (EBV) of a parent and mean EBV of cows which were contemporary with the parent. Then, GI and GSD were averaged on each birth year of progeny for four paths of selection : sires of bulls (SB), dams of bulls (DB), sires of cows (SC), and dams of cows (DC). Genetic standard deviations (σ_Gm, σ_Gf and σ_Gp) for milk, fat and protein yields were estimated based on the assumption that the accuracy of selection (square root of reliability) is equal to the correlation of predicted and true breeding values. The GI for SB and DB paths decreased steadily over the years and had dropped to 7.78 and 4.95yr in the last four years (1993 through 1996), respectively. The GI for SC and DC paths were 7.98 and 4.49yr in the last four years (1995 through 1998), respectively. The GSD for SB and DB paths were 2.19σ_Gm and 1.69σ_Gm for milk yield, 2.28σ_Gf and 1.85σ_Gf for fat yield, and 2.95σ_Gp and 2.14σ_Gp for protein yield in the last four years (1993 through 1996), respectively. The GSD of protein yield for SB and DB paths increased dramatically from 1985. The GSD of SB and DB paths for imported bulls taken into progeny test was higher than domestic produced bulls in the 1980’s, the difference of GSD between both bulls decreased in the 1990’s. The GSD for the SC path in the last four years (1995 through 1998) were 1.57σ_Gm for milk yield, 2.40σ_Gf for fat yield, and 2.18σ_Gp for protein yield. The GSD in DC path had no large changes and were below 0.10 σ_G for all traits. The annual genetic gain expected in the future for protein yield (0.30σ_Gp/yr) was greater than for fat and milk yields by +0.03σ_Gf/yr and +0.08σ_Gm/yr, respectively. Those expected annual genetic gains correspond to 157% for milk, 193% for fat, and 167% for protein with higher genetic progress than the actual genetic changes per year in the last four years. However, because indications of the possibility that selection on traits other than milk production have been intensified in the cow population of Hokkaido region, it was predicted that the actual genetic changes for milk production is smaller than the expected genetic changes.

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Marbling scores assigned by graders are comprehensively evaluated with consideration of the ratio of marbling area to ribeye area (FATPER), coarseness of marbling, etc. The purposes of this study were to calculate FATPER, overall coarseness of marbling (O_COARSE), coarseness of the largest marbling particle in rib eye (M_COARSE), ratio of minor and major axis of rib eye (MM_RATIO), and the complexity of rib eye shape (COMP) numerically by image analysis and to estimate genetic parameters for meat quality traits, including these image analysis traits. Digital images around the ribeye area at the 6th and 7th rib of 2,998 Japanese Black cattle were taken by the photographing equipment for beef cross sections during April, 2000 to March, 2002 at a meat processing plant in Hokkaido. Genetic parameters and breeding values for carcass traits and image analysis traits were estimated with an animal model using AIREMLF90 and BLUPF90 programs, respectively. The fixed effects of season by year, slaughter age and sex, and the random effects of fattening farm and additive genetic animal were included in the model. Heritability estimates of image analysis traits were 0.57 (FATPER), 0.34 (O_COARSE), 0.09 (M_COARSE), 0.32 (MM_RATIO) and 0.18 (COMP). Genetic correlations between BMS and FATPER, O_COARSE and M_COARSE were 0.97, 0.68 and 0.14, respectively. Sires with high breeding values of BMS and O_COARSE were recognized. This result indicates that the utilization of these sires lead to undesirably rough marbling.

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The effects of fresh tofu cake and tofu cake silage added with 4% ethanol feeding on carcass characteristics, fatty acid composition of carcass tissues and ruminal fermentation of growing Suffolk wethers were determined. All animals received a basal diet consisting of the second cut orchardgrass hay and beet pulp (4 : 1) for 98d. Diets were as follows : 1) formula feed for fattening beef (Control), 2) fresh tofu cake (Tofu cake), and 3) tofu cake silage added with 4% ethanol (Silage). Fatty acid composition of the intramuscular (M. longissimus thoracis), subcutaneous and perinephric fat was determined by gas-lipid chromatography (GLC). Rumen fluid was taken from each animal 2h after the morning feeding. Neither tofu cake nor silage affected the average daily gain (ADG), carcass weight and dressing percentage of lambs. However, lambs fed silage tended to gain faster than other diets. All three tissues from lambs fed tofu cake and silage had lower C16 : 0 and C17 : 0 and higher C18 : 2 contents than lambs fed control. Perinephric fat from lambs fed tofu cake and silage had lower C14 : 0 than that from control lambs. On the rumen fermentation, the animals fed tofu cake and silage had significantly higher acetic acid and lower butyric acid than the control. Silage fed lambs had the highest capronic acid and ratio of propionic acid to acetic acid in the rumen fluid. These results demonstrate that fresh tofu cake and tofu cake silage added with 4% ethanol altered the fatty acid composition of carcass tissue without affecting the carcass characteristics, and there were no problems on ruminal fermentation. These diets have an equivalent nutritional value with formula feed on the market.

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In order to find genetic markers to improve meat quality in Japanese Black cattle, we studied the effect of the Ala18Val hetero variants of the PPARγ2 (Ala/Val) on carcass traits using 139 progeny from Sire-S (Ala/Val). The progeny were composed of 70 wild type (Ala/Ala) and 69 Ala/Val type. We investigated the relationship between the Ala18Val substitution of the PPARγ2 and carcass traits, such as carcass weight (CW), rib eye area (RA), rib thickness (RT), subcutaneous fat thickness (SFT), yield estimated percentage (YE), and beef marbling standard (BMS). Data were analyzed as a randomized blocked design in which sex and slaughter houses were treated as block factors. RT in the Ala/Val type was significantly higher than that in the Ala/Ala type (P<0.01), and CW (P=0.070) and BMS (P=0.078) tended to increase in the Ala/Val type, but no significant difference was observed in RA, SFT, and YE. Moreover, the effects of the Ala18Val substitution of the PPAR2 on carcass traits were different according to the progeny’s maternal grand sire line.

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Thirty two metabolic trials were conducted to clarify the metabolic energy requirement for maintenance of dry cows fed 16 forages. Orchardgrass silage, timothy hay, alfalfa silage, corn silage, orchardgrass plus alfalfa silage, orchardgrass plus corn silage and alfalfa plus corn silage were offered to meet the TDN requirements of the cows. The metabolic energy requirements for maintenance of cows were estimated at energy equilibrium from the regression equation of ME intake on energy retention. The ME contents of corn silage was higher than that of grass or alfalfa silage. There were negative correlations between ME contents and ADL or ADF contents in forage. The estimates of metabolic energy requirements for maintenance of cows fed all forage and alfalfa were 596 and 567KJ/kg^0.75, respectively.

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To determine the usefulness of immune profile for evaluation of the immune conditions in a dairy herd, the results of the immune profile test were compared in two herd groups, one herd group with many cases of disease (diseased herd), and the other group was healthy (healthy herd). There was a 40% occurrence of peripartum disease, milk fever, displacement of abomasum and mastitis in the diseased herd. Both herds were evaluated for five milking terms. Serum total cholesterol level in the diseased herd was lower than that in the healthy herd, while on the other hand blood urea nitrogen was higher compared to the healthy herd. The number of white blood cells, neutrophils and MHC class⁺ II low (low fluorescence intensity ; monocyte) cells in the diseased herd increased compared to the healthy herd. The serum activity of interleukin-1 and tumor necrosis factor was higher in the diseased herd than in the healthy herd. These results suggest that there might be a disorder of immune condition in herds with sporadically occurring peripartum disease, thus immune profile is useful for evaluation of immune condition in herds.

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In order to reduce methane production in the rumen, possibility to augment nitrate and nitrite reduction by stimulating the growth of Wolinella succinogenes was examined. W. succinogenes that was added to in vitro cultures of mixed ruminal microbes disappeared within 4h, but addition of nitrate prolonged the time to disappear. This result could be explained by the fact that W. succinogenes acquires energy by electron transport phosphorylation (ETP) coupled with nitrate and nitrite reduction. Addition of W. succinogenes to cultures of mixed ruminal microbes stimulated nitrate and nitrite reduction. Stimulation of nitrite reduction was greater, which decreased nitrite accumulation. As a result, the adverse effect of nitrite on overall fermentation was alleviated. Addition of nitrate and W. succinogenes greatly decreased methane production without suppressing overall fermentation. Addition of fumarate, in addition to nitrate, magnified the effects of W. succinogenes on nitrate and nitrite reduction and on methane production. This could be explained by the increased growth of W. succinogenes, because this bacterium acquires additional energy by ETP coupled with fumarate reduction. Stimulation of nitrate and nitrite reduction when W. succinogenes was added was greater than when other nitrate-reducing bacteria, such as Selenomonas ruminantium and Veillonella parvula, were added. In in vivo experiments with goats, addition of nitrate to a diet increased the number of W. succinogenes in the rumen. Addition of fumarate, in addition to nitrate, further increased the number of W. succinogenes. Activities of nitrate reductase and nitrite reductase per cell mass of total bacteria in the rumen were elevated by the addition of nitrate and fumarate, suggesting that the ability of the rumen ecosystem to reduce nitrate and nitrite was enhanced. Thus, feeding a diet containing nitrate and fumarate may be effective to stimulate the growth of W. succinogenes in the rumen.

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Grading of the Beef Marbling Standard (BMS) number would be influenced not only by the ratio of marbling area to M. longissimus thoracis (rib eye) area but also by the coarseness of marbling particles and the shape of the rib eye. The aim of this study was to predict the BMS number with consideration to the coarseness of marbling particles and the shape of rib eye by using the obtained images. The coarseness of marbling particles and the shape of rib eye by computer imaging analysis, which were considered as the possible causes of a decrease in the BMS number, were investigated, and “Coarseness of single particle” was suggested. Pictures of the rib eye area of 446 Japanese Black steers with BMS number assigned by examiners of Wagyu Registry Association were used. The coarseness of a single particle was calculated by dividing the coarseness of the maximum particle by the overall coarseness and was used to distinguish a single particle on the rib eye from other marbling particles. The effect of the coarseness of marbling particles or the shape of rib eye on the grading of the BMS number was investigated to account for the decrease in the BMS number of rib eye with the same level of marbling percentage. For each BMS number, 193 samples that had a larger ratio of fat area than the average ratio were used. The BMS numbers were classified into four levels to examine the cause of the decrease in the BMS number in each level. Next, the BMS number was predicted for 446 carcasses using multiple regressions that considered the coarseness of marbling particles and the shape of rib eye. By using the coarseness of a single particle as index, a single particle on the rib eye that could have caused the decrease in the BMS number could be distinguished. There was a positive and significant correlation between the difference of fat area ratio (the difference between the fat area ratio and the average of the fat area ratio for each BMS number) and the overall coarseness, implying that the overall coarseness would cause a decrease in the BMS number. Also, the effect of the coarseness of marbling particles or the shape of rib eye on the difference of fat area ratio varied in each BMS level. Percentages of the difference between the assigned BMS number and the predicted BMS number being ±0 and ±1 were 51.4% and 92.4%, respectively.

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A simple method to estimate the decomposition rates of dry matter or organic matter during composting of cattle excrement was developed using crude ash as an indicator. This method measures only the crude ash contents before and after composting, rather than the total masses. The expressions are as follows : dry matter decomposition (%)=(1-X₀/X_i)×100 and organic matter decomposition (%)=(1-X₀/X_i×(1-X_i/100)/(1-X₀/100))×100 (X₀ : crude ash content before composting (%DM), X_i : crude ash content (%DM) after composting). The crude ash content could be measured simply at the dairy farm by a simple method, incinerating samples using an electric heater for 15 min, instead of the conventional method using an electric muffle furnaces at 600°C for 2h.

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Basic Electrolyzed Water (BEW) is termed as functional water and expected to have some rumen defaunation properties and higher absorption rate in the gastrointestinal tract of ruminants. This study was conducted to examine the effects of BEW on water absorption, ruminal environment parameters, microbial yield and nitrogen balance in sheep. Three ruminally cannulated sheep were fed a diet to supply 1.1 and 1.5 fold of the maintenance requirement for metabolizable energy and metabolizable protein, respectively. Ground water (GW) was used as a control. GW and BEW were provided to the animals ad libitum with additionally infused intra-ruminal for 25d in a randomized block design. Total intake of the tested water was 5.4, 5.1l/d for GW and BEW, respectively. Digestion coefficients did not differ (P>0.05) between the treatments. BEW intake had little effect on rumen fluid volume and the amount of ruminal outflow (P>0.05). The water absorption rate was greater (P<0.05) for BEW treatment than for GW (2.8 vs. 4.7l/d). There were neither significant difference in water excretion post absorption nor rumen fermentation parameters (pH, VFA and NH₃-N concentrations) between the treatments. This suggests that the net absorption of fermentation end-products (VFA and NH₃-N) across the rumen wall was greater for BEW treatment than for GW in conjunction with the results of the rumen fluid measurements and concentration of blood metabolites. The microbial yield and its efficiency were significantly higher (P<0.05) for BEW treatment than for GW (9.7 vs. 12.2g N/d ; 43.0 vs. 53.4g N/kg RDOM). In contrast, microbial protein supply was greater for BEW treatment, and absorbed-N retention was significantly lower than for GW treatment (19.3 vs. 5.0%, P<0.05). The obtained results indicate the potential for rumen manipulation by feeding BEW as a drinking water for the ruminants.

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