Activin is secreted from equine uterine glands and plays important roles in establishment and maintenance of pregnancy in mares. This study aimed to localize activin receptors (ActRs) IA/B and IIA/B using immunohistochemistry in the uteroplacental tissues of seven pregnant Thoroughbred mares. At the time of tissue collection, the mares were at the following days of pregnancy: 88, 120, 161, 269, 290, 313, and 335 days. We fixed the uteroplacental tissues in 4% paraformaldehyde and obtained serial sections that were subsequently stained for analysis. All four isoforms of ActR were expressed in the uteroplacental tissues, including the endometrial epithelium, uterine glands, trophoblasts, and myometrium, throughout pregnancy. Our results suggested the potential role of activin in the uteroplacental tissues.

The distribution of Y chromosomal haplotypes in Japanese native horse populations was investigated to obtain genetic information on these populations. Here, 159 male/gelded horses from eight local populations were investigated, and three Y haplotypes (JHT-1, JHT-2, and JHT-3) were identified by analyzing five Y-linked loci. Five populations had only JHT-1, whereas two populations had only JHT-2. One population had JHT-1 and JHT-3. Based on the geographical distribution of these haplotypes and previously reported haplotypes for other Asian horses, JHT-1 is considered to be a major haplotype in ancestral native horses. The fixation of each haplotype suggests the influence of independent breeding and genetic drift in each population. These findings complement the results from previous genetic studies of Japanese native horses.

Branchial remnant cysts are an uncommon cause of masses of the throatlatch area in horses. Two methods of treatment have been proposed in literature, both with complications. This manuscript proposes a method (marsupialization and sclerotherapy) for the treatment of a cyst in a 1.5-year-old Arabian filly. Diagnosis was made by ultrasonographic, radiographic and endoscopic examinations, revealing an anechoic fluid-filled structure and a well-defined capsule not in communication with other structures. After emptying the cyst, the skin was sutured circumferentially to the cyst wall; it was then flushed first with a solution of ethanol and povidone-iodine, then with sterile saline. Eight months after surgery, the filly had no recurrence of the cyst and the stoma was healed.