The Japanese Wagyu beef industry: current situation and future prospects - A review

Abstract

In Japan, Wagyu cattle include four Japanese breeds; Black, Brown, Shorthorn, and Polled. Today, the renowned brand name Wagyu includes not only cattle produced in Japan, but also cattle produced in countries such as Australia and the United States. In recent years, the intramuscular fat percentage in beef (longissimus muscle) from Japanese Black cattle has increased to be greater than 30%. The Japanese Black breed is genetically predisposed to producing carcass lipids containing higher concentrations of monounsaturated fatty acids than other breeds. However, there are numerous problems with the management of this breed including high production costs, disposal of untreated excrement, the requirement for imported feed, and food security risks resulting from various viral diseases introduced by imported feed. The feeding system needs to shift to one that is more efficient, and improves management for farmers, food security for consumers, and the health environment for residents of Japan. Currently, we are developing a metabolic programming and an information and communications technology (ICT, or Interne of Things) management system for Wagyu beef production as future systems. If successful, we will produce safe, high-quality Wagyu beef using domestic pasture resources while solving the problems of how to utilize increasing areas of abandoned agricultural land and to make use of the plant-based feed resources in Japan's mountainous areas.

Keywords: Fatty Acid Composition; Japanese Black; Marbling; Quality; Wagyu; Beef.

Figure 1

A Japanese Black bull (Itofuku, Oita prefecture) [16].

Figure 2

Overview of current Wagyu feeding system.

Figure 3

Official Beef Marbling Standard, including Beef Color Standard and Beef Fat Standard, from the Japan Meat Grading Association [21].

Figure 4

Body location used for carcass grading in Japan [21].

Figure 5

Correlation between Japanese Beef Marbling Standard numbers and crude fat content in the longissimus thoracis muscle from Japanese Black steers from 1996 to 2004. This figure has been modified based on the figure from the previous paper [4].

Figure 6

Meat produced by Japanese Black steers. (A) Marbled beef at the 12th thoracic vertebrae level of the longissimus thoracis muscle (BMS No. 7). (B) Macro appearance of marbled fat deposits. (C) Azan staining of transverse section (thickness: 10 μm) in the longissimus thoracis muscle of the highest-grade Japanese Black marbled beef. Myofiber bundles (white arrow) look like islands in a sea of adipose tissue (black arrow) [30]. (D) Magnified macro appearance of marbled beef. (E) Magnified appearance of Azan staining of intramuscular adipocytes [16].

Figure 7

Effect of intramuscular fat deposition on the structure of intramuscular connective tissue (IMCT). With animal growth, collagen crosslinks become more stable, and the structural integrity of IMCT increases. These changes increase the mechanical properties of IMCT, contributing to the toughening of meat. The intramuscular fat deposits, mainly in the perimysium (between muscle fiber bundles), result in marbling. This causes the remodeling of the extracellular matrix and reduces the mechanical strength of the IMCT, contributing to the tenderization of beef [35].

Figure 8

Cattle grazing on abandoned agricultural land: (A) when grazing commenced and (B) after three months [81].

Figure 9

Application of metabolic programming to beef production.

Figure 10

Comparison of body sizes between the Roughage (R) and Imprinting (HE) groups of Wagyu and Holstein steers at 26 months of age. Wagyu steers were either fed only roughage from weaning until 26 months of age (left) or fed concentrate (with access to roughage ad libitum) from three to ten months of age and only roughage from 11 to 26 months of age (right). IMF, intramuscular fat content. * Significant difference between groups (p<0.05) [79].

Figure 11

Comparison of body sizes between the Roughage (R) and Imprinting (HE) groups of Wagyu steers at ten and 30 months of age. Wagyu steers were either fed only roughage from weaning until 26 months of age (left) or were nursed with high-fat milk replacement and fed concentrate (with access to roughage ad libitum) from four to ten months of age and then fed only roughage from 11 to 30 months of age (right). IMF, intramuscular fat content. * Significant difference between groups (p<0.05). Comparison of marbling appearance and intramuscular fat content between HE and R groups at slaughter age. HE group: n = 12. R group: n = 11. * Significant difference between groups (p<0.05) [79].

Figure 12

Overview of ICT control system via a smartphone for cattle in remote areas and actuator control screen on a smartphone and the system [81]. (A) Overview of ICT control system via a smartphone for cattle in remote areas. (B) Actuator control screen on a smartphone. (C) Auto stanchon system. (D) Picture of grazing cattle caught by auto stanchon.