Abstract
The farrow-to-farrow interval was analyzed for 8421 reproductive cycles in 5 herds. Females farrowing during June, July and Aug. had longer farrowing intervals than did females farrowing during the remaining months of the year. Primiparous sows had longer farrowing intervals during all seasons than did multiparous sows. This difference was most obvious for gilts farrowing from May through Aug.