The following case study was prepared by James R. Crabtree BVM & S, CertEM(StudMed)., MRCVS. Independent Veterinary Consultant, Equine Reproduction & Stud Medicine.
You are presented with a 7-y-o Shire Horse maiden mare in late March; the owner wishes to breed as soon as possible. The mare is not teasing to a gelding she lives with and has a grade 2/5 cervix on palpation. The mare's uterus contains no oedema but has no tone. The mare's ovaries look like the following two images.
Question 1: At what stage of the cycle is this mare?
c). Early transition
d). Late transition
Question 2: What is your recommendation to the owner?
a). Administer a prostaglandin injection
b). Prescribe a 10 day course of oral altrenogest
c). Insert an intravaginal progestagen device
d). Re-examine in 2 days
e). Re-examine in 14 days
Question 3: Regardless of what is done above you are re-presented with the above mare 6 weeks later and her ovaries are still the same. What is your diagnosis?
a). Equine PPID
b). Karyotype abnormality
c). Seasonal anoestrus
d). Equine Hypothyroidism
Question 4: What is the best way to approach this case?
a). Hormone therapy
b). Give more time
c). Investigate for PPID
d). All of the above
Re-examine in 14 days
All the above
This mare was examined 2 and four weeks after initial presentation as it was deemed unlikely that she would respond to any therapy as she was still in anoestrus. The mare did not have any evidence of PPID and failed to respond to therapy with altrenogest and domperidone. The owner declined GnRH therapy on economic grounds. The mare failed to cycle all year and presented similarly the season after. Karyotyping failed to identify any abnormality. The mare spontaneously cycled late that season, ovulated and conceived to natural cover however suffered early pregnancy failure. Some are just left unexplained!