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Meat quality of beef cattle rearing in pastures associated with supplementation and finishing on pasture or feedlots systems

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Author(s):
Adriana Cristina Ferrari
Total Authors: 1
Document type: Master's Dissertation
Press: Jaboticabal. 2016-05-09.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
Defense date:
Advisor: Ricardo Andrade Reis
Abstract

The objective of this study was to verify if the growing phase influenced the meat quality of Nelore (bos indicus) beef finished on pasture or feedlot systems. The animals were kept during the growing phase, in Marandu grass pasture managed at different grazing height (15, 25 and 35 cm) in continuous grazing and variable stocking rate associated with supplementation strategies, and finished in the dry season in pastures with supplemented diet or feedlot system. The research was composed of two experiments, 2012/2013, Chapter 2 and year 2013/2014, chapter 3. In the first experiment, chapter 2, six treatments were evaluated: LHHS) growing on pasture of 15 cm height and 0.6% body weigt-BW supplementation; MHMS) rearing on pasture of 25 cm height and supplement 0 3% PC; HHLS) growing on pasture of 35 cm height and mineral, half os animals of each rearing treatment were finished on pastured associated with supplementation and other half finished on feedlot system with nine replications (animals) in each treatment. Samples of the M. longissimus thoracis et lumborum (LTL), from the left half carcass between the 12th and 13th ribs were removed, then packed in plastic film, refrigerated for 24 hours and then frozen at -20 ° C. The samples were analyzed for softness determinations (shear force) and cooking losses, the color of the meat and subcutaneous fat, pH, chemical composition, collagen content and the percentage of intramuscular fat in Spec-trofotômetro Near Infrared (NIR) FOSS FoodScan ™ and the fatty acid profile. The experiment was conducted according to a completely randomized design in a factorial arrangement (3 x 2), with three growing strategies (LHHS, MHMS or HHLS) and two finishing systems (pasture or feedlot) with nine replicates (animals) by treatment (n = 54), normality and variance analysis tests were applied (P <0.05), using the procedures PROC MIXED of SAS ® software. The finishing system influencied the fat color. Treatments with lower levels os supplementation produced meats with lower intensity of redness and higher intensity of yellowness. The average of pH were 6,23, that characterizes a meat DFD (dark, firm and dry) and masks the effect of treatment in the meat color, shear force, and cooking losses variables. Animal finished in feedlot system had more meristic acid than pasture finish In the second experiment, chapter 3, animal meat samples were collected from four treatments: MHHS- recreates in pasture 25 cm and 0.3% PC supplement; HHLS- recreates in pasture 35 cm and mineral supplement, finishing in pasture or confinement with six replications (animals) each treatment. On the transition phase water-dry (April, May and June), the supplementation level were increased, ie, multiplo supplement in the amount of 0.6% of the PC and protein of low consumption of 0.1% of the PC, to the height 25 cm and 35 cm respectively. In addition to the variables evaluated in the first experiment, this were also quantified the frequency and area of muscle fibers, the sarcomere length, the myofibril fragmentation and lipid oxidation. The data were analysed according a completely randomized design in a factorial arrangement (2 x 2), with two rearing systems (MHHS or HHLS) and two finishing systems (pasture or feedlot) with six replicates (animals) by treatment (n = 24) to evaluate the effect of rearing historic and finishing system on meat quality. Normality and variance analysis tests were used (P <0.05) using the PROC MIXED procedure of SAS ® software. Animals finished in pasture had higher concentration of linolenic acid, polyunsaturated acids and relation of ω6:ω3. Feedlot finishing had more palmitic acid and α linolenic acid than pasture. There was no significant diference on muscle fiber frequency and area, fat and meat color and chemistry composition. (AU)

FAPESP's process: 14/09932-6 - Quality of beef cattle recreated in pastures associated with supplementation and finishing on a pasture or feedlots sistem
Grantee:Adriana Cristina Ferrari
Support Opportunities: Scholarships in Brazil - Master