Oesophageal muscular hypertrophy and pulsion diverticulum in a Friesian horse

A 13-year-old Friesian stallion was referred for evaluation of acute coughing and bilateral nasal discharge. Thoracic radiographs revealed dilation of the terminal portion of the oesophagus, forming a thin-walled outpouching containing soft tissue opaque material and gas. A diagnosis of oesophageal obstruction with an impacted diverticulum was made. Caudal oesophageal muscularis hypertrophy and an impacted oesophageal diverticulum were found on postmortem examination. Histological abnormalities included a thick caudal oesophageal tunica muscularis and an oesophageal diverticulum composed of mucosa, submucosa and adventitia. Muscular hypertrophy of the oesophagus with diverticulum formation should be considered in Friesian horses presenting with clinical signs of oesophageal obstruction. In this case, thoracic radiographs contributed to a premortem diagnosis, guided medical management and provided information on prognosis. Thoracic radiography can be used as a complementary test in the diagnosis of oesophageal obstruction when endoscopy is available and is a useful diagnostic alternative when endoscopy is not an option.

Immune-mediated hemolytic anemia associated with chronic fibrosing mediastinitis in an Arabo-Friesian horse

In this report, a ten-year-old gelding with immune-mediated hemolytic anemia associated with chronic fibrosing mediastinitis of unknown origin is described. The patient suffered from chronic weight loss and intermittent diarrhea for already several months. He was presented with severe anemia, anorexia and fever of a 24-hour onset. A direct Coombs test was highly positive for IgG auto-agglutination. No evidence of an underlying process was found on clinical examination. Post-mortem examination revealed green liquid material containing food particles in the cranial mediastinum and histology suggested chronic fibrosing mediastinitis. Even though perforation of the esophagus is a plausible cause, no signs of esophageal rupture were noted on macroscopic examination. This case shows that non-responsive, immune-mediated hemolytic anemia can be due to an undetected underlying disease, such as chronic mediastinitis.

The Genomic Makeup of Nine Horse Populations Sampled in the Netherlands

The spectrum of modern horse populations encompasses populations with a long history of development in isolation and relatively recently formed types. To increase our understanding of the evolutionary history and provide information on how to optimally conserve or improve these populations with varying development and background for the future, we analyzed genotype data of 184 horses from 9 Dutch or common horse populations in the Netherlands: The Belgian draft horse, Friesian horse, Shetland pony, Icelandic horse, Gelder horse, Groninger horse, harness horse, KWPN sport horse and the Lipizzaner horse population. Various parameters were estimated (e.g., runs of homozygosity and FST values) to gain insight into genetic diversity and relationships within and among these populations. The identified genomic makeup and quantified relationships did mostly conform to the development of these populations as well as past and current breeding practices. In general, populations that allow gene-flow showed less inbreeding and homozygosity. Also, recent bottlenecks (e.g., related to high selective pressure) caused a larger contribution of long ROHs to inbreeding. Maintaining genetic diversity through tailor-made breeding practices is crucial for a healthy continuation of the investigated, mostly inbred and (effectively) small sized horse populations, of which several already experience inbreeding related issues.