The use of prostaglandin applied in Bai Hui Acupoint on mare reproductive efficiency

Abstract

Prostaglandin F2α (PGF2α) is one of the most frequently used drugs for pharmacologic manipulation of the oestrous cycle in mares. Among its roles, PGF2α induces luteolysis, leading to an early oestrus return, which reduces the dioestrous phase and the inter-ovulatory intervals. Interestingly, mares are more sensitive to PGF2α than other domestic species, hence lower doses are used; even so, the side effects are still adverse and inconvenient for animals and breeders. Recent studies of acupuncture, a traditional Chinese medicine technique, have been performed as an alternative to decrease the PGF2α dose for mares. The efficacy described of applying lower doses of PGF2α at specific acupoints is similar to that obtained with the regular dose. Therefore, the objective of this study was to analyse the reproductive performance and characteristics of oestrus in embryo recipient and donor mares using different doses at the Bai Hui—an acupoint located on the dorsal midline, also known as ‘the point of one hundred meetings’, as its region of effect encompasses many nerve trunks, nerve endings and vascular networks—a useful veterinary acupuncture treatment for ovarian disorders. For this study, 76 Quarter Horse mares were randomly assigned to three experimental groups: Control (CTR)—Intramuscular (IM) administration of 5 mg PGF2α; Bai Hui 5 mg (BH5)—application of 5 mg at the Bai Hui acupoint; and Bai Hui 2.5 mg (BH2.5)—application of 2.5 mg at the Bai Hui acupoint. In the results, there were no differences regarding uterine oedema, pregnancy rate or body condition score among the groups. However, oestrous expression was lower (p < 0.001) in both BH groups compared with CTR. Lastly, the interval between application and ovulation was shorter in BH5 compared with CTR (p = 0.042). The results indicate BH5 and BH2.5 as viable alternatives to the IM administration.