Two experiments were conducted to determine if methallibure (ICI 33828), a hypothalamus-inhibiting dithiocarbamoylhydrazine (Malven, 1971) would prevent parturition.
In Exp. 1, thirteen pregnant Yorkshire, Poland China and Yorkshire × Poland China gilts were divided into three groups. Three gilts were assigned to be controls, four were fed 150 mg ICI 33828/gilt/day from the 100th to the 116th day of gestation and the six remaining gilts received ICI 33828 from the 100th day of gestation until parturition. Piglet numbers and weights were determined on the day of parturition.
In Exp. 2, fourteen pregnant Yorkshire or Poland China sows were randomly assigned to be untreated controls or fed 200 mg ICI 33828/sow/day from Day 100 of gestation until parturition. Piglet numbers and weights were obtained at birth and at 1 week of