Thesis Abstract and Dissertation Abstracts
Relationships Of Residual Feed Intake And Feed Convertion Ratio With Carcass Traits, Metabolic And Blood Profile Of Nellore Bulls
Abstract Category: Science
Course / Degree: Veterinary Science/Master of Science
Institution / University: Universidade Federal do Paraná, Brazil
Published in: 2009
Feed efficiency is important for the profitability of production systems for beef cattle, although not given due importance in the past to selection for efficiency. Recently there has been an increased interest in the study for feed efficiency, especially the residual feed intake (RFI); these studies guided the first chapter of this dissertation. Given the potential use of the RFI and the feed conversion ratio (FCR) for selection in beef cattle, it is necessary to verify if those measures may bring changes in carcass traits or animal’s metabolism, with these objectives the second and third chapters were written, evaluating the correlation of RFI and FCR with carcass traits, measured by ultrasound, and metabolic and blood cells profile. Forty-six Nellore bulls (409 ± kg live weight and 22 month-old at the beginning of test) individually confined were evaluated for 84 days and being fed with silage of sugar cane and concentrate (50:50 of dry matter). Was measured the dry matter intake (DMI) daily, every 21 days the animals were weighed and thus obtained the values of average daily gain (ADG) and were also collected blood samples for analysis of metabolic profile and complete blood count (CBC). From the data for ADG, DMI and live weight was possible to calculate the RFI1 and FCR. At the beginning and end of experiment were measured, by ultrasound, carcass traits the ribeye area (AOL), subcutaneous fat thickness between the 12th and 13th rib (EGS) and subcutaneous fat thickness on the Biceps femoris muscle (EGP) and also estimated the gain of these traits, being the EGP used to calculate the final RFI2 along with the other variables used in the calculation of do RFI1.
According to the standard deviation of the RFI, the animals were divided into 3 classes of RFI (high, medium and low). Positive correlations were found with the RFI1 and EGP at the end and gain and also for the concentration of plasma urea (P0.05), as well as the classes did not differ (P> 0.05) for these variables. The classes of RFI2 differed only for the amount of eosinophils. The FCR was correlated (P0.05). The RFI as a measure of feed efficiency reduces food intake without altering weight gain or the size of adult animals, but this variable may bring negative effects on the deposition of subcutaneous fat of Nellore bulls. The FCR, as a selection criterion does not reduce food intake, increases weight gain of animals and body weight, and thus raise too much the size of adult animals.
Dissertation Keywords/Search Tags:
body composition, blood exam, feed efficiency, metabolism
This Dissertation Abstract may be cited as follows:
SANTANA, M.H.A. Relationships of residual feed intake and feed convertion ratio with carcass traits, metabolic and blood profile of Nellore bulls. 2009. Dissertation (Master of Science) – Universidade Federal do Paraná.
Submission Details: Dissertation Abstract submitted by Miguel Santana from Brazil on 26-Mar-2013 14:43.
Abstract has been viewed 2703 times (since 7 Mar 2010).
Miguel Santana Contact Details: Email: miguel-has@hotmail.com Phone: +551982507927
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