Performance, carcass characteristics and meat quality of beef cattle for efficiency stratified by residual feed intake / Desempenho, características de carcaça e qualidade de carne de bovinos Nelore estratificados pela eficiência através do consumo alimentar residual

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

The supply of food is the highest cost input in livestock enterprises. Selection for feed efficiency in beef cattle was mostly ignored by the difficulty and cost of measuring individual consumption, besides the fact that efficiency is correlated with gain rate. An alternative index for measuring feed efficiency, not associated with increased adult size, would be the residual feed intake (RFI). In addition to assessing the genetic variability in Nellore to RFI, the objective of this work was to investigate the consequences of selection for this parameter of efficiency on carcass characteristics and meat quality of beef steers finished in feedlot. Nellore (n=75), progeny of 8 bulls of known pedigree, with approximately 18 months and weighting 394.4 ± 29 kg were kept in individual stalls after 15 days of adaptation receiving a 25% sorghum silage and 75 % concentrated diet. After the trial period of 85 days the animals were slaughtered to determine carcass characteristics and meat quality. According to the criterion RFI 0.5 standard deviation, 33% of the animals were classified as high-RFI, 28% as low RFI and 39% fit the group average RFI (-1.26 to 1.64 kg/day) and standard deviation (0.71 kg/day). RFI groups did not differ on hip initial and final weight (P>0.05). The animals of the low RFI had lower intake of dry matter and TDN (P<0.01) and were more efficient (P <0.05) when compared to animals of medium and high RFI. Differences in intake and feed efficiency between individuals most and least efficient was 1.74 kg DM/day, 1.49 kg TDN/day and 1.37 kg/kg. The daily weight gain did not differ between the groups with values of 1.153 and 1.215 kg/day for high and low RFI, respectively. There were no differences between groups of RFI on yield and hot carcass weight (P>0.01) and no effect of RFI on meat quality (P>0.10). There were no differences (P>0.05) among the progeny of bulls evaluated for height, initial weight, final body weight, daily weight gain, dry matter intake and feed efficiency. The progenies showed differences in carcass yield (P<0.05) and fat thickness (P<0.05). There was a tendency (P<0.10) to difference for ribeye area and hot carcass weight. The progenies showed differences on shear force (P<0.05). The myofibrillar fragmentation index was observed trend to difference (P=0.06). The lipid content and marbling scores were similar for the progeny (P>0.05). There was variation between animals for cattle feed efficiency measured as RFI. There was no relationship between RFI and performance, adult weight, carcass characteristics and meat quality of steers.

ASSUNTO(S)

consumo efficiency meat and meat products quality carnes e derivados - qualidade feed nellore cattle. beef cattle gado nelore. intake eficiência bovinos de corte alimentação animal

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