  The neutrino emissivity from two and three flavour quark matter is
numerically calculated and compared with Iwamoto's formula. We find that the
calculated emissivity is smaller than Iwamoto's result by orders of magnitude
when $p_{f}(u)+p_{f}(e)-p_{f}(d(s))$ is comparable with the temperature. We
attribute it to the severe restriction imposed by momentum conservation on the
phase space integral. We obtain an alternate formula for the neutrino
emissivity which is valid when the quarks and electrons are degenerate and
$p_{f}(u)~+~p_{f}(e)~-~p_{f}(d(s))$ is large compared to the temperature.
