Autores
Sarah Figueiredo Martins Bonilha, Renata Helena Branco, Guilherme Fernando Alleoni, André Michel de Castilhos, Leopoldo Andrade de Figueiredo, Alexander George Razook
Resumo
Residual feed intake (RFI) is an efficiency measurement calculated as the difference between actual feed intake and predicted DMI based on metabolic BW and ADG. Some studies, using Bos taurus breeds, have found differences on carcass characteristics, mainly those related to fat content, on animals selected for low RFI, but there is no information about relationships between RFI and carcass traits on Nellore breed. Therefore, the objective of this work was to evaluate carcass characteristics of Nellore bulls classified in low and high RFI levels. Thirty three young Nellore bulls, with minimum RFI -0.640 and maximum RFI 0.690, were slaughtered and had their carcasses evaluated. Table bellow shows the least-square means of DMI; ADG; empty BW (EBW); HCW; dressing percentage (DP); hindquarter percentage (HQP); edible fraction percentage (EFP); rib-eye area (REA); and fat thickness (FT). Low RFI bulls had lesser DMI than high RFI bulls. No differences were detected for ADG, EBW, and HCW indicating that low and high RFI bulls had the same body size. For yield measurements (DP; HQP; and EFP) no differences were detected, but there is a tendency of low RFI (more efficient) bulls to have greater HQP than high RFI (less efficient) ones. No differences were found for REA and FT. Low RFI bulls ate less than high RFI bulls and had carcasses of the same size and fat content.
Table 1. Carcass characteristics of low and high residual feed intake (RFI) bulls
|
LOW RFI
(n=18) |
HIGH RFI
(n=15) |
P |
DMI, kg |
6.55a |
7.51b |
0.0485 |
DMI, %BW |
1.76a |
2.05b |
0.0079 |
ADG, g |
721a |
756a |
0.6954 |
EBW, kg |
368a |
362a |
0.7210 |
HCW, kg |
245a |
242a |
0.7938 |
DP, % |
62.3a |
62.3a |
0.9689 |
HQP, % |
46.5a |
45.1a |
0.0611 |
EFP, % |
80.1a |
80.3a |
0.5715 |
REA, cm2 |
74.8a |
75.6a |
0.8467 |
FT, mm |
3.56a |
3.22a |
0.3658 |
Within a row, means with a common superscript letter do not differ (P < 0.05) by least-square means adjusted for Pdiff.
2009 ASAS ADSA Joint Annual Meeting
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