The effects on sow reproductive performance of three feeding regimes (ration (R), ad libitum (A) and ration + straw (R + S)), in conjunction with partial barriers placed along the food trough, were investigated. Three groups of four sows were put on the regimes, in a group-housing system, over three consecutive gestations. Each trial lasted 13 days and took place during the first half of the gestation period. Sows on A ate about three times the amount of food that was allocated to them on R and R + S (2 kg per sow per day). Feeding regime did not affect any of the measures of reproductive performance (numbers of piglets liveborn, stillborn, weaned, birth and weaning weights). Sows of parity 7 and over had significantly fewer liveborn and more stillborn piglets compared with parities 2 to 6 (P < 0·05). It is probable that no adverse effects of the feeding regimes were found due to the short time that the sows were on them and because multiparous animals were used. It is suggested that the welfare of ration-fed sows, whose appetite is not satiated, is jeopardized and that this problem may be solved by the provision of fibrous foodstuffs.

Actaplanin, a complex of glycopeptide antibiotics produced by Actinoplanes missouriensis, was investigated as a performance enhancer when incorporated in the diet of lactating dairy cows at the rate of 960 mglday. In a trial with autumn-calving cows over two successive lactations, the milk yield of animals given diets incorporating Actaplanin (no. = 132 lactations) showed only a small (proportionately +0·038), nonsignificant increase in milk yield over the controls (no. = 121 lactations). Overall, there were no significant differences in milk composition, cow body weight or condition score changes, mastitis cell counts or in the majority of blood metabolites.

The lumbar joint, which is handled to assess body condition scores, was taken from 52 adult Rasa Aragonesa ewes with body condition scores between 1·5 and 4·5 and dissected into muscle, bone, subcutaneous and intermuscular fat. The subcutaneous fat in the lumbar joint was highly correlated with total fat in the body (r=0·97), confirming the value of this region for assessing body condition in Rasa Aragonesa ewes.

A comparison was made of three diets given to pigs after weaning at 28 days of age: control, control + 300 g spring peas per kg or control + 300 g spring peas + 1·2 g DL-methionine per kg. The latter diet led to similar food conversion ratio and better growth rate than the control diet. It seems therefore that provided diets are properly balanced for all limiting amino acids, spring pea (Pisum sativum subsp. hortense) can be used at least up to 300 g/kg in weaned pig diets.

Five hundred and fifty sucking New Zealand rabbits of three ages (1, 10 and 20 days) were used to measure metabolizable energy intake and heat production at five ambient temperatures varying between 12 and 36°C according to age. Critical temperatures and rate of heat production below them, decreased with age (32, 28 and 24°C; 20·8, 10·8 and 9·2 kJ/kg0·07 per day and °C at 1, 10 and 20 days of age respectively) as a result of the increase in thermal insulation. Energy retention also decreased below critical temperature at a similar rate to the increase of heat production, because rabbits could not increase their milk intake to meet their higher energy requirements.