Eighteen Large White gilts were allocated to one of three treatments so that there were six gilts on each treatment. The treatments were (1) daily exposure to a nasal spray of boar saliva reinforced with 16-androstene steroid pheromones, (2) daily exposure to a nasal spray of saline and a mature boar for 20 min, and (3) daily exposure to a nasal spray of saline only.

The experiment began when the gilts were between 158 and 165 days of age, and was terminated when they reached 240 to 247 days of age, the gilts were slaughtered soon afterwards.

The results indicate that if salivary pheromones operate in the overall effect of the male on puberty attainment in gilts, the effect is of minor significance. Exposure to a mature boar confirmed the phenomenon of the 'male-effect' on puberty attainment in gilts.

One hundred and twenty-five boars were given diets containing five levels of methionine: 1·5, 1·7, 1·9, 2·1 and 2·3 g methionine per kg diet, from 21 to 49 days of age. The mean weight gain of the pigs given the diet containing 1·5 g methionine per kg was 71 g/day and this increased linearly to 346 g/day for the pigs given the diets containing 2·3 g methionine per kg.

From 49 to 97 days of age all pigs were given a commercial pig grower diet containing 160 g protein per kg. Live-weight gains over this period increased linearly from 477 to 689 g/day with increasing methionine content of the starter diets. There was no compensatory weight gain.