Relationship between bioimpedance and muscle mass in chilled lamb
carcasses
D.L. Hopkins, R.S Hegarty
NSW Agriculture, PO Box 242, Cowra, 2794, Australia
Proceedings of the New Zealand Society of Animal Production. 1995,
55: 117-119
The accuracy of multi-frequency bioimpedance analysis (MFBIA) as a
predictor of carcass composition in lambs was assessed in a small study.
Impedance and itsí components of resistance (R) and reactance (X) were
measured on 20 chilled carcasses from 8 month old second-cross Poll Dorset
x (Border Leicester x Merino) cryptorchid lambs. Impedance values were
transformed by allowing for path length in relation to frequency giving 2
indices E and F. Carcass weight, GR, C fat depth, and eye muscle area
(EMA) were also measured. The right side of each carcass was dissected
into fat (intermuscular and subcutaneous), muscle and bone. Carcass weight
explained 68% of the variation in the weight of muscle (r.s.d. = 0.34kg).
This was significantly improved by addition of C fat depth to the model
(r2=0.76, r.s.d. = 0.31 kg) or EMA, but was not affected by addition of GR,
E, F, R or X. The impedance derived value, E, was a significant predictor of
the percentage of muscle and with carcass weight achieved similar accuracy
to C fat depth alone. It is concluded from this study that impedance offers no
significant improvement over standard carcass measures for estimating
dissectible muscle mass or percentage. This may indicate that a refinement
of
methodology is required particularly for measurement of chilled carcasses.
Keywords: NZSAPAB;
lamb; impedance; muscle
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Last Updated 25-01-1997
