2.4. Statistical analysis
Synchronization and pregnancy rates were summarized in
tabular format using frequencies and percentages. The chisquare
test was used to compare synchronization rates
between groups. Pregnancy rates were analyzed using the
intent-to-treat population, which was defined as all animals
which were successfully synchronized and received an
embryo. Logistic regression analysis was performed to
compare all study outcomes (pregnant at day 23 after TET,
pregnant at day 48 after TET, pregnancy loss) between the
two study arms. In order to adjust the analysis for farm site
and year effect, those variables were included as covariates in
the logistic regression analysis models. All P-values are twosided,
with Pb0.05 indicating a statistically significant
difference. Data analysis was performed using SAS® version
9.2 software (SAS Corp. Cary, NC).