Estrus detection and transcutaneous real-time ultrasonography
was performed every 8 h (08:00, 16:00, and
24:00) beginning 8 h before pLH/saline treatment.
Estimated time of ovulation was determined as
described by Almeida et al. [22] adjusted for frequency
of ultrasonography. The relationship between duration
of estrus and timing of ovulation was determined by
dividing the time between onset of estrus and ovulation
by the total duration of estrus (% estrus). Gilts treated
with pLH were inseminated 32 and 40 h after treatment
with pooled Duroc semen processed on-site. Insemination
doses contained 3 109 motile and morphologically
normal spermatozoa, extended in 50 mL Beltsville
thawing solution (Minitube of America, Verona, WI,
USA). Control gilts were inseminated 16 h following
initial detection of standing estrus, and then every 24 h
with the same source and dose of semen, until the gilt
was no longer exhibiting estrus. All inseminations were
performed with semen that was