Two digestion trials were conducted using sheep fed whole grains of triticale, wheat or maize on an equal amount or an isonitrogenous basis. Nine ewes were used in a 10-day collection period for each trial. Both trials consisted of three treatment groups of three animals each. Each ewe received daily either 1200 g of a diet containing 740 g (per kg diet) triticale, wheat or maize (trial 1) or 900 g of a diet containing 650, 650 and 600 g (per kg diet), respectively, of the above grains. Digestibilities of various nutrients, dry matter and organic matter were generally similar among treatments. However, apparent digestibility of crude fibre was significantly higher for ewes fed triticale than for those fed maize or wheat diets.

The effect of the high fecundity Booroola Merino gene (F) on wool production and live weight of Booroola x South Australian Merino rams classified as being offspring of FF, F+ or ++ Booroola sires was investigated. The characters studied were: greasy fleece weight in lambs, hogget (approx. 15 months old) greasy fleece weight and the associated scouring yield, clean fleece weight, fibre diameter, staple length and wool style; birth weight and live weight gains from birth to weaning in September (3 months of age), from September to the following March, and from March to September. There were no significant differences among sire genotypes in the characters studied. The results suggest that the F gene had no undesirable pleiotropic effects on wool and live-weight traits.

Computer simulation was used to study the effect of assortative mating in tandem selection. Selection was applied alternatively for each of two traits of equal economic importance, the mating being assortative for the trait not subjected to selection. Two heritabilities (0·2, 0·4), two selection intensities (20/40, 20]100) and three additive genetic correlations (0·50, 0, —0·50) were considered. Assortative mating gives a response which is 1·03 to 1·10 times that achieved when random mating is employed.

The effect of frequency of feeding on the efficiency of utilization of L-lysine hydrochloride supplements was studied in 30- to 60-kg pigs. The feeding regimes were: (A) once daily, (B) twice daily, (C) four times daily between 08.30 and 20.30 h, (D) four times daily at 6-h intervals. The response criterion was urinary-nitrogen (N) excretion during 5-day periods. Linear improvements in N utilization were seen in response to lysine supplementation: (a) of a mineralized barley diet (4·0 g lysine per kg to levels of 5·0 and 6·0 g/kg (trial 1)), and (b) of a barley-soya diet (5·5 g lysine per kg to levels of 6·8 and 8·1 g/kg (trial 2)). In both trials the efficiency of N use averaged over the three diets was significantly poorer with once-daily feeding than for the other three treatments, which did not differ significantly from each other.