Effects of nutritional protocols for marbling on meat traits and beef quality of Nellore cattle finished in feedlot

Author(s)

Luana Doretto Felizari

• Document type: Master's Dissertation
• Press: Botucatu. 2022-10-07.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu
• Defense date: 2022-07-11
• Advisor: Danilo Domingues Millen; Sérgio Bertelli Pflanzer Junior

Abstract

The objective of this study was to evaluate different nutritional protocols including high-moisture corn, rumen-protected fat, zinc and organic chromium in the diets of feedlot Nellore cattle, ranked by estimated progeny difference (EPD) as high and low marbling on meat quality. In this project, were used 150 19-mo-old Nellore bulls (404,28±23,14kg), which were blocked by EPD and by initial body weight. Thirty bulls (five per bock) were slaughtered at day 0 of the study for carcass baseline measurements. Therefore, this study was carried out with 120 Nellore bulls, which were randomly allocated into 30 pens (n=4 per pen) according to the blocking criteria just described in a 2 × 2 + 1 factorial arrangement of treatments: T1) Finely-ground corn; T2) High-moisture corn; T3) Finely-ground corn + rumen-protected fat; T4) High-moisture corn + rumen-protected fat; T5) High-moisture corn + rumen-protected fat + Zn and Cr. The finishing diets contained 84% concentrate and 25 ppm of sodium monensin. This study was last 112 days and meat quality variables were evaluated, such as: proximate composition, pH, tenderness, cooking loss, fatty acid profile, lipid oxidation, retail display, loin eye area, subcutaneous fat thickness, and marbling. There was no effect of treatments for marbling. Low EPD animals had higher backfat thickness with the addition of ZnCr, unlike high EPD animals increased backfat thickness with only corn processing (P=0,03). There was an interaction between treatments and EPD for final biceps femoris fat thickness (P<0,05), the percentage for fat (P=0,03), TBARS (P=0,03), SFA (P=0.02), Unsaturated (P=0,04), MUFA (P<0,01), PUFA (P=0,01), n-6: n-3 (P=0.02) in the meat. No differences were observed in shear force values for the different treatments (P>0,05), however, the aging time increases the tenderness. Therefore, the factors tested in the nutritional protocols did not change the percentage of intramuscular fat in the Longissimus muscle. (AU)

• FAPESP's process: 19/26951-8 - Effects of nutritional protocols for marbling on meat traits and beef quality of Nellore cattle finished in feedlot
• Grantee: Luana Doretto Felizari
• Support Opportunities: Scholarships in Brazil - Master