Effect of Rectal Palpation on Pregnancy Rate of Nonlactating, Normally Cycling Mares1

Abstract

The effect of rectal palpation on pregnancy rate of nonlactating, normally cycling mares was studied over a 3-year period. Each palpation was conducted by an experienced followed by an inexperienced palpator and palpation time was not limited, and must be considered excessive in relation to routine breeding practices. In 1971, first-cycle pregnancy rates of mares palpated daily during estrus and mares palpated daily until 50 days of pregnancy were 25.0 and 27.3% compared to 50.0% for the nonpalpated, control mares; after four cycles the pregnancy rates were 75.0, 72.7 and 91.7%, respectively (P>.05). Daily palpation during early pregnancy was not detrimental to fertility, since no abortions or interruptions of pregnancy prior to the 50-day pregnancy examination could be attributed to palpation. Palpated mares had shorter (P<.05) durations of estrus than nonpalpated mares (5.6 and 5.9 vs 7.9 days). In 1972, first-cycle pregnancy rates for the two groups of mares palpated daily during estrus were lower (P<.05) than the pregnancy rate of control mares that were not palpated, 16.7, 16.7 and 61.1%, respectively.