Genetic parameters for image analysis traits on M. longissimus thoracis and M. trapezius of carcass cross section in Japanese Black steers1

Abstract

In Japan, the degree of marbling in ribeye (M. longissimus thoracis) is evaluated in the beef meat grading process. However, other muscles (e.g., M. trapezius) are also important in determining the meat quality and carcass market prices. The purpose of this study was to estimate genetic parameters for M. longissimus thoracis (M-LONG) and M. trapezius (M-TRAP) of carcass cross section of Japanese Black steers by computer image analysis. The number of records of Japanese Black steers and the number of pedigree records were 2,925 and 10,889, respectively. Digital images of the carcass cross section were taken between the sixth and seventh ribs by photographing equipment. Muscle area (MA), fat area ratio (FAR), overall coarseness of marbling particles (OCM), and coarseness of maximum marbling particle (MMC) in M-LONG and M-TRAP were calculated by image analysis. Genetic parameters for these traits were estimated using the AIREMLF90 program with an animal model. Fixed effects that were included in the model were dates of arrival at the carcass market and slaughter age (mo), and random effects of fattening farms, additive genetic effects and residuals were included in the model. For M-LONG, heritability estimates (+/-SE) were 0.46 +/- 0.06, 0.59 +/- 0.06, 0.47 +/- 0.06, and 0.20 +/- 0.05 for MA, FAR, OCM, and MMC, respectively. Heritability estimates (+/-SE) in M-TRAP were 0.47 +/- 0.06, 0.57 +/- 0.07, 0.49 +/- 0.07, and 0.13 +/- 0.04 for the same traits. Genetic correlations between subcutaneous fat thickness and FAR for M-LONG and M-TRAP were negative (-0.21 and -0.19, respectively). Those correlations between M-LONG and M-TRAP were moderate to high for MA, FAR, OCM, and MMC (0.38, 0.52, 0.39, and 0.60, respectively). These results indicate that other muscles including M-LONG should be evaluated for more efficient genetic improvement.

Genetic Analysis of Ultrasound and Carcass Measurement Traits in a Regional Hanwoo Steer Population

“…Compared to this study, Osawa et al (2008) estimated a lower heritability (0.22) for BF in Japanese Black steers. Crews and Kemp (2001) and Nogi et al (2011) estimated a higher heritability, 0.55 in beef steers slaughtered at around 15 months of age and 0.51 in Japanese Black steers and heifers slaughtered at around 29 months of age.…”

“…For CW, the estimate in this study was higher than the estimates of Yoon et al (2002), Hwang et al (2008), or Roh et al (2010) that ranged from 0.28 to 0.41 in Hanwoo steers slaughtered at 24 months of age after the end of progeny testing or in Japanese Black steers (Osawa et al, 2008) that were slaughtered at 25 to 37 months of age. However, the heritability estimate of CW (0.61) in Japanese Black steers and heifers slaughtered at 27 to 31 months of ages was much higher (Nogi et al, 2011) than our estimate.…”

“…However this estimate was lower than that of Hwang et al (2008), the estimate of which was on Hanwoo steers raised in a test station and slaughtered at 24 months of age, earlier in life compared to steers observed in this study. Crew and Kemp (2001), Devitt and Wilton (2001), Kemp et al (2002), Osawa et al (2008), and Nogi et al (2011) reported that the heritability estimates for LMA in their study populations were 0.54, 0.45, 0.44, 0.43, and 0.49, respectively.…”

“…The averages calculated in our study population were similar to those in the report of Cheong et al (2012). The averages of carcass traits reported by Koo et al (2011) were 415.23 kg for CW, 88.29 cm 2 for LMA, 12.71 mm for BF and 5.42 for MS. Osawa et al (2008) reported that the averages of CW was 445.0 kg and LMA, BF and MS (12 score scales) estimated at the section between the 6th and 7th thoracic vertebra were 56.8 cm 2 , 2.3 mm and 5.5 at 29.6 months in Japanese Black steers. These differences might reflect regional differences in feeding steers in Korea or different methods of carcass evaluation between Korea and Japan (Japanese carcass evaluation is made between the 6th and 7th thoracic vertebra).…”

Influences of Phytoncide Supplementation on Growth Performance, Nutrient Digestibility, Blood Profiles, Diarrhea Scores and Fecal Microflora Shedding in Weaning Pigs

“…Freitag et al (1998) considered that this may reflect the higher consumption capacity of larger animals compared with untreated controls. Of course, the majority of experimental results indicate reduced feed intake at largely unchanged BW gain or final BW, leading to an improved G/F when feeding phytogenic compounds (Windisch et al, 2007). Similarly, our results confirmed this situation from 3–5 weeks.…”