“…The smallest pigs in this group tended to elicit an aggressive response from the oestrous gilt, or show aggression towards the gilt. (Bern, 1949 ;Beyer, de la Torre, Larsson & Perez-Palacios, 1975;Foote, Draddy, Breite & Oltenacu, 1977) and horse (Thompson, Pickett, Squires & Nett, 1980). The enlargement of the muscle surrounding the urethra, together with the excess fibrous stromal tissue in the accessory sex glands, would appear to be an expression of an anabolic effect of oestrone rather than an 'androgenic' effect.…”