Prediction of retail cuts yield using measurements obtained by image analysis

Author(s)

José Luiz Fonseca Souza

• Document type: Master's Dissertation
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT)
• Defense date: 2012-05-16

Examining board members

Saulo da Luz e Silva; Paulo Roberto Leme; Jaime Urdapiletta Tarouco

• Advisor: Saulo da Luz e Silva

Abstract

The objective of this work was to evaluate the use of carcass traits evaluated by image analysis, at 5th and 12th rib levels to estimate weight (PESPC) and percentage (PERPC) of retail cuts of castrated and non castrated Nellore cattle. During three consecutive years carcass traits of 206 animals of Nellore breed, 103 castrated and 103 non castrated males, fed for 56, 84, 112 or 140 days, were evaluated. After slaughter and carcass cooling, digital images were obtained between 5th and 6th ribs to evaluate the Longissimus muscle area (AOL5), backfat thickness (EGS5), intermuscular fat thickness (EGI5) and rib thickness (ESPCOST). A digital image between 12th and 13th ribs was also obtained to determine the Longissimus muscle area (AOL12) and backfat thickness (EGS12).Additionally cold carcass (PCF) and kidney, renal and inguinal fat (GRPI) weighs were obtained. The PESPC and PERPC were determined by completely deboning of all half carcass of every animal. The PCF plus carcass traits evaluatedat 5th rib level explained 96 to 97% of PESPC and from 24 a 50% of PERPC. Carcass traits evaluated at 12th rib level plus PCF and GRPI percentage explained 93 a 95% of PERPC and among 6 to 25% of PERPC, with a smaller determination coefficient observed in castrated males (R2=0.06). In the validation dataset equations using data obtained at 5th rib level where observed smaller R2 when compared to calibration dataset. Carcass traits evaluated by image analysis at 5th rib level can estimate retail cuts yield with similar accuracy than those obtained at 12th rib level. (AU)

• FAPESP's process: 10/02759-6 - Predicting edible portion by image analysis at fifth rib level in Nellore cattle.
• Grantee: José Luiz Fonseca Souza
• Support Opportunities: Scholarships in Brazil - Master