Rectal examination at approximately 30 days of gestation in a mare can show which of the following?

Rectal examination at approximately 30 days of gestation in a mare can show which of the following?

• A. A large, fluid-filled uterus with no palpable conceptus
• B. A tense, small uterus with a ventral bulge at the base of the gravid horn
• C. No reproductive structures detectable
• D. A ventral bulge is felt at the base of the gravid horn

Answer: (D)

Rectal palpation around 30 days of gestation in a mare is most consistently marked by a ventral bulge felt at the base of the gravid horn. This bulge comes from the developing conceptus and placentation within that horn, which causes a localized enlargement that can be distinguished along the ventral aspect of the uterus. The uterus at this stage is not typically large or fluid-filled, so finding a large fluid-filled uterus would be unexpected. Likewise, the absence of any reproductive structures is not correct, since a palpable pregnancy signal—the ventral bulge at the base of the gravid horn—should be detectable. The description of a tense, small uterus is not the usual hallmark at this stage; the key finding is the ventral bulge associated with the gravid horn.

Rectal palpation around 30 days of gestation in a mare is most consistently marked by a ventral bulge felt at the base of the gravid horn. This bulge comes from the developing conceptus and placentation within that horn, which causes a localized enlargement that can be distinguished along the ventral aspect of the uterus. The uterus at this stage is not typically large or fluid-filled, so finding a large fluid-filled uterus would be unexpected. Likewise, the absence of any reproductive structures is not correct, since a palpable pregnancy signal—the ventral bulge at the base of the gravid horn—should be detectable. The description of a tense, small uterus is not the usual hallmark at this stage; the key finding is the ventral bulge associated with the gravid horn.