Two experiments were conducted in 17 dairy herds in NE Kansas to determine
the effectiveness of prostaglandin F2α (PGF) for reducing intervals to conception
for cows with silent or unobserved estrus. Cows that failed to be seen in heat so
they could be inseminated after calving (Exp. 1) and cows that did not return to
estrus after AI and were not pregnant when presented to veterinarian for
pregnancy examination (Exp. 2) were assigned alternately to be given PGF or to
receive no treatment after detection of a palpable corpus luteum. Cows were
inseminated at 72 and 96 hr after PGF treatment if not detected in heat. Intervals
from treatment to conception were reduced after PGF treatment. Cows with
unobserved estrus can be inseminated sooner and have shorter intervals to
conception if PGF is used for reproductive management in association with a
routine herd health program.
