Administration of exogenous progesterone (0-55 mg/kg live weight) and oestrone (0-275μg/kg live weight) during various discrete intervals between days 4 and 30 of gestation elicited variable results depending upon the time and duration of administration. Administration of the combined steroids early in gestation (days 4 to 20, trial 1; days 4 to 12, trial 2) tended to affect farrowing performance adversely. In general, advantageous effects on farrowing performance occurred when treatment with exogenous progesterone and oestrone was initiated at day 12 or later of gestation.

A general parabola constrained to pass through points (0,0) and (1,1) yields a linear one parameter (q) function which can be used to relate the fraction of maturity of organs or masses of tissue to the fraction of maturity of the whole animal. This is an empirical approach. It is often preferable to derive a function from a theory of the phenomenon under study. A theory of feeding and growth of animals is used to derive a non-linear one parameter (k) function which can be used to study the same data to which the linear q-function is applicable. The parameter, k is directly proportional to the fraction of total nutrients consumed by the animal which is allocated to the organ as the animal ages. If the fraction of nutrient allocated remains constant, the parameter k is constant and has the same properties as the parameter q. However there is nothing in the theory which constrains k to be constant, therefore, the q-function is of more general use than the q-function in the study of the relationship of the fraction of maturity of organs to that of the whole animal. Two cases are presented to illustrate this generality.

Growing pigs were fed in isolation, closed stalls or in small groups. Food intake was greatest under conditions of competition if the hierarchy was stable.

In an attempt to establish an ad libitum, labour saving feeding system 12 Large White primiparous sows were used to investigate the effects on food intake and digestibility of including oat husks in a conventional concentrate diet. The diet contained 500 g ground oat husks per kg diet and was compared with the undiluted concentrate given in restricted amounts during pregnancy (1·8 kg/day) and lactation (5·4 kg/day). The mean daily food intakes for the oat husk diet were 5·50 and 6·29 kg during pregnancy and lactation respectively. The apparent digestibility of the dry matter of the oat husk diet (0·58) was significantly lower than that of the concentrate (0·80), but values for apparent digestibility of nitrogen were similar (0·77 and 0·78, respectively).