at different intervals after pLH in jection were analysed with a logistic regression model (GLIMMIX procedure), which included the effect of treatment, week, parity order, and weaning-to-oestrus(WOI) interval. The logistic regression model used to ana-lyse the farrowing rate included the effects of treatment,week, parity order, WOI, boar, and semen age. Logisticregression models were also used to analyse the farrow-ing rate within each treatment according to the optimalinsemination period (between 0 and 24 h before ovulationor not), and the occurrence or not of semen backflow orbleeding during insemination.Oestrus length, the time of ovulation, the number ofpiglets born, and the number of piglets born alive wereanalysed using the MIXED procedure, with the means com-pared by the Tukey-Kramer test. In the models used for theanalysis of oestrus length and time of ovulation, WOI andoestrus length were respectively used as covariates. Thefixed effect of treatments, the random effect of the boar,the week of the study, and the age of the semen, in additionto the mean lifetime number of born piglets, as a covari-ate, were included in the models used for the analysis ofthe number of piglets born and the number of piglets bornalive