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The objective of this article is to compare feed cost, palatability and environmental impacts among feeding systems of high concentrate (HC), high hay (HH) and grass-only-fed (Gof) groups. Feed cost was the sum of costs paid for feed intake times the price of feed per kilogram. Palatability was measured by a panel taste test using HH and Gof beef and analyzed for differences. Environmental impacts were calculated based on 1 kg of Japanese beef yield of CO2 equivalents (eq) and animal end weights at each feeding stage. Results showed that the HH and Gof feeding systems could significantly reduce feed costs by approximately 60% and 78%, respectively, from the HC. In the panel taste test, 50% and 47.50% of panelists indicated that HH beef was 'extremely delicious' and 'acceptable,' respectively, while 15% indicated that Gof beef was 'extremely delicious'; 62.50% indicated that Gof beef was 'acceptable.' Environmental impacts of each feeding system in terms of CO2 equivalents (eq) were 9.32, 6.10 and 2.04 tonnes of eq for the HC, HH and Gof, respectively. The HH was an economical system that produced moderate impacts on the environment and had impressive taste.Key words: environmental impacts, feed cost, grass fattening, palatability, Wagyu. INTRODUCTIONCompared to European cattle, Japanese Black cattle have good potential to accumulate intramuscular fat called 'Shimohuri' (Gotoh et al. 2009). In the Japanese beef market, marbled beef from Japanese Black is quite popular and expensive. However, in Japan, recent attention has focused on oil prices, food mileage and environmental issues (e.g. greenhouse gases, global warming). Japan annually imports a large amount of food and animal feed equal to approximately 58.9 million tonnes throughout the world. This is equivalent to 914 billion tonnes-kilometers (t-km), or 1.6 times the yearly shipment, in terms of food mileage (Nakata 2003). In 2007, more than 24 911 960 million tonnes of grain feed were imported to Japan, and 4 564 228 million tonnes were specifically for beef cattle (USDA 2009). The Japanese beef cattle industry is highly dependent on imported feed to produce domestic marbled beef. According to these figures, beef production in general has high production costs, especially due to feed and labor costs. As a result, domestic beef can be more expensive than imported beef, making it unaffordable for consumers. Nakata (2003) also reported that feed materials have been transported from many countries with an average of 15 000 km based on the distance between Tokyo (Japan) and Cape Town (South Africa). Feedstuff production and grain transportation consume fuel energy and emit harmful gases into the environment. Feedstuff is considered a source of environmental pollution associated with beef production systems. Moreover, cattle and their waste also create environmentally harmful gases that are distributed into their French et al. (2001French et al. ( , 2003 reported that the beef carcass weight could increase even when animals are fattened by silage grass d...

The objective was to investigate the impact of nutrient intake during the early growth period on the expression of glucose metabolism-related genes in skeletal muscle of cross-bred cattle. From 1.5 to 5 months of age, group H (n=7) animals were intensively fed a high-protein and low-fat milk replacer [crude protein (CP) 28%; ether extracts (EE) 18%; max: 2.0 kg, 12 l/day], and group R (n=7) animals were fed a restricted amount of normal milk replacer (CP 25%; EE 23%; max 0.5 kg, 4 l/day). From 6 to 10 months of age, group H cattle were fed a high-nutrition total mixed ration mainly prepared from grain feed, and group R cattle were fed only roughage. Blood samples were taken from each animal at three biopsy times (1.5, 5 and 10 months of age), and the blood plasma concentration of glucose and insulin was analysed. In glucose concentration, there were no significant differences; however, the concentrations of insulin were higher in group H than in group R at 5 and 10 months of age. Muscle samples were taken by biopsy from longissimus thoracis muscle (LT) at 1.5, 5 and 10 months of age. We analysed mRNA expression levels using the quantitative real-time polymerase chain reaction (PCR) assay for glucose transporters (GLUT1 and GLUT4), insulin receptor, phosphatidylinositol 3-kinase (PI-3K), protein kinase B (PKB, also known as Akt), hexokinase 1 (HK1) and tumour necrosis factor alpha (TNFα). Although no differences were detected at 1.5 and 5 months of age, at 10 months of age, GLUT1, HK1 and TNFα mRNA expression levels were significantly higher in group H than in group R. These results suggested Glut1 that affects insulin-independently mediated glucose uptake was more responsive to improved nutrition during early growth stage than GLUT4 that insulin-dependently mediated glucose uptake in LT of cattle.

Skeletal muscle is a very heterogeneous tissue consisting of diverse cell types with specific transcription profiles. Therefore, the measured mRNA abundance of a certain cell type marker is influenced by the transcriptional activity as well as by the usually unknown number of contributing cells in the sample. In studies on the transcriptional activity of adipogenic genes, as indicators for the development of intramuscular adipocytes, an altered number of adipocytes or respective progenitor cells can mask changes in transcriptional activity. To overcome this problem, we started to use laser microdissection to isolate RNA of adipocytes and muscle fibers separately for downstream analysis. Even muscle fiber types can be collected and analyzed separately. Laser microdissection in combination with biopsy techniques enables gene expression studies of particular cell types during the life cycle of an animal. First experiences using laser microdissection for adipogenic gene expression studies in bovine skeletal muscle are described, and the influence of sample preparation and future challenges are discussed.

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