Fatness of lambs grazed on 'Grasslands Maku' lotus and 'Grasslands Huia' white clover

R.W. Purchas and R.G. Keogh

Department of Animal Science, Massey University, Palmerston North

Proceedings of the New Zealand Society of Animal Production. 1984, 44: 219-222

In 5 trials involving lambs grazing either lotus (L) or white clover (WC) in summer/autumn, those on L were consistently less fat. In trial 1 Romney wether lambs (n=12), grazed 62 days, had weight-corrected carcass fat depths C of 2.1 (L) and 3.4 (WC) mm. In trial 2 Romney hoggets (n+10) grazed 40 days, L had a lower side fat percent than WC at a similar weight. Trial 3 compared Romney lambs (n=20) of the same weight. After 80 days fat depths were significantly lower for L. In Trial 4 Southdown x Romney lambs (n=24), grazed for 45 days. Several measures of fatness were significantly lower in the L group after correcting for initial fatness and carcass weight. Trial 5 was similar to trial 4 (n=16), but continued over 76 days and the differences in fatness were greater. Growth rates of the lambs in these trials were in favour of the WC group by an average of about 15 percent.

The lotus tannin content was 10 to 30 g/kg DM. It is concluded that lambs grazed on pure lotus are likely to be less fat than lambs of the same weight grazed on clover, possibly because the protein of lotus is to some extent protected from rumen degradation by tannins, thus effectively increasing its protein content.

Keywords: NZSAPAB; Lamb fatness; pasture species; lotus; white clover; carcass composition

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Last Updated 03-05-1997