Cattle grazing leucaena (Leucaena leucocephala cv. Cunningham)–pangola grass (Digitaria eriantha cv. Steudel) pastures in the Ord River Irrigation Area in north-west Western Australia, sometimes exhibit higher liveweight gains in the dry season when temperature and humidity are lower. Two factors have been suggested as causing this seasonal difference: the combined effect of the temperature and humidity, and the effect of the muddy conditions in the field associated with rainfall in the wet summer season.

An experiment over 81 days, from August to October 1995, was conducted to evaluate the effect of muddy conditions on the liveweight gain of cattle grazing a leucaena–pangola grass pasture. Replicated paddocks were grazed in a normal irrigated system during this dry season whereas other paddocks were flood irrigated twice weekly to create muddy conditions. Cattle grazing the muddy paddocks had a liveweight gain of 0.29 kg/steer.day, which was lower (P < 0.001) than the animals in the dry paddocks (0.57 kg/steer.day). These cattle spent less time grazing (41.9 v. 67.6% of animals grazing at three observation times, 0600, 1100 and 1500 hours, on each day over the whole 81 days; P ≤ 0.001). It was suggested that the muddy condition of the paddock was the primary factor causing this difference in liveweight gain and grazing behaviour.