Image analysis traits of multiple muscles and intermuscular/subcutaneous fat influence on Japanese Black beef carcass price and genetic parameters

Tamagawa, Yuta; Takahashi, Mikiya; Hagiya, Koichi; Kuchida, Keigo

doi:.0.0.0

Article

https://doi.org/10.5713/ab.23.0330 [Accepted] Published online January 20, 2024.

Image analysis traits of multiple muscles and intermuscular/subcutaneous fat influence on Japanese Black beef carcass price and genetic parameters

Yuta Tamagawa^1,*

, Mikiya Takahashi¹

, Koichi Hagiya¹

, Keigo Kuchida¹

Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan

Correspondence: Yuta Tamagawa, Tel: +81-0155-49-5412, Fax: +81-0155-49-5462, Email: s22170026@st.obihiro.ac.jp

Received: 30 August 2023 • Revised: 26 September 2023 • Accepted: 10 November 2023

Abstract

Objective
The purposes of this study were to investigate the relationship between carcass unit price per 1 kg (UP) and multiple muscles and intermuscular fat (IF)/subcutaneous fat (SF) of beef carcasses using image analysis of cross-section images for Wagyu beef cattle in Japan, and to estimate their genetic parameters.
Methods
The carcasses used in this study were 1,807 Japanese Black (Wagyu) cattle (1,216 steers and 591 heifers). An analysis of variance (ANOVA) was conducted with UP as the dependent variable and market date, age in months, sex, and image analysis traits (IAT) as fixed effects, and standard partial regression coefficients were calculated for each IAT on UP. Also, the heritability of each IAT that affected UP and genetic correlation among IAT vs. carcass grading traits were estimated.
Results
Not only IAT related to carcass grading traits, M. trapezius dorsi, M. latissimus dorsi, and IF traits were significant differences in UP (p < 0.05). The heritability of IAT associated with UP was estimated at 0.38~0.85. The genetic correlations between the area and thickness of M. trapezius dorsi and M. latissimus dorsi vs. rib eye area (REA) were estimated to be moderately positive (0.53~0.66), while the genetic correlations between the IF area percentage vs. carcass weight (CWT), REA and yield score (YS) were estimated to be negative (-0.40, -0.56 and -0.34).
Conclusion
UP was influenced by various traits, including M. trapezius dorsi, M. latissimus dorsi, and IF traits, as well as image analysis associated with carcass grading traits. Since these IAT associated with UP had hereditary and desirable genetic correlations with carcass grading traits, these traits were also important for genetic improvement.

Keywords: Carcass Unit Price; Fats; Heritability; Image Analysis; Muscles