Sixteen mature, ruminally cannulated wethers (average BW = 41 +/- 1 kg) were fed a low-quality hay diet with or without a cottonseed meal (CSM) supplement and the parasympathomimetic agonist slaframine (SF). Treatments were basal diet (Mitchell grass hay, 4.8% CP, 46.8% ADF) available on an ad libitum basis, basal diet plus SF (8 micrograms/kg BW, 2 x daily i.m. injection), basal diet plus CSM (41.0% CP; 100 g/d), or basal diet plus SF and CSM. Treatments were arranged as a 2 x 2 factorial within a replicated 4 x 4 Latin square with 20-d periods followed by a 10-d adjustment during which only the basal diet was fed. All measurements were performed within the final 10 d of each period. Slaframine increased salivary flow by 10 to 35% (P < .07), ruminal fluid dilution rate by 8 to 11% (P < .10), and pH by 3 to 4% (P < .001). A twofold increase (P < .05) in ruminal cellulolytic bacteria numbers occurred in SF-treated wethers. Despite these SF-induced changes in the ruminal environment, whole-tract apparent nutrient digestibility, N and mineral balance, and ruminal VFA concentrations were not changed. Cottonseed meal increased forage intake by 34 to 54% (P < .001) and DM digestibility by 30% (P < .001). Cottonseed meal supplementation of a Mitchell grass hay diet improved nutritional status and attenuated live weight loss.

A yearly management program for sheep in north-west Queensland has increased lambing percentage by > 20% compared with the district average. Greasy wool production of ewes over 4 years (1988-91) averaged 4.3 kg and wethers over 2 years (1990-91) averaged 5.7 kg. Managing sheep using this program increased wool production of the flock compared with the district average. The economic advantages of running breeding ewes or wethers was influenced by wool and sheep markets. During low wool prices ($2.82/kg net selling costs, 1990; $2.44/kg net selling costs, 1991) it was estimated that a 65% lamb weaning rate was needed for returns from the ewe and wether flock to be equal. Gross margins ($/DSE) for the ewe flock were 21.80, 17.07, 8.53 and 5.42 in years 1988, 1989, 1990, 1991 respectively and 5.82 and 5.01 for wethers in 1990 and 1991 respectively. Gross margin ($/DSE) of combined ewe and wether enterprises on properties representing the district, averaged 16.50, 14.20, 8.00 and 5.00 in years 1988, 1989, 1990 and 1991 respectively. The management program implemented at Toorak generated higher gross margins than the district average particularly during the years of higher wool prices.

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