Heritability of Locomotor Stereotypies in Chilean Horses.

The Chilean horse is a breed of closed registry. Stall-walking and weaving are locomotor stereotypies that affect this breed, and genetic predisposition has been suggested for both conditions. The objective of the present study was to estimate heritability of stall-walking and weaving in Chilean horses. Owners of 2,098 horses registered in the Chilean horse Stud Book, which were or had been stabled for at least 1 year, were asked to provide for identification data of the animal and presence or absence of stall-walking and/or weaving. The Chilean Horse Stud Book was accessed online, to collect information on name and registration number of the sire and dam of each horse. The prevalence of stall-walking and weaving was calculated from the sample (n = 2,098). The database to estimate the heritability (h2) included all the sample horses (n = 2,098) and their sires and dams. Additionally, all the ancestors available in the Chilean Horse Stud Book were included in the database for 297 sampled horses including those with locomotor stereotypies. The genealogical database consisted of 7,187 individuals. The prevalence of stall-walking was 2.05% and prevalence of weaving was 1.43%, being more frequent in males (P < .05) for stall-walking. Heritability of stall-walking was low (h2 = 0.213 ± 0.08) and moderate for weaving (h2 = 0.435 ± 0.06). Heritability and prevalence of locomotor stereotypies found in the Chilean horse suggest that they are hereditary disorders, highly influenced by environmental factors.

Reemergence of H3N8 Equine Influenza A virus in Chile, 2018.

A new outbreak of equine Influenza A virus (IAV) was reported in Chile in January 2018, 6 years after its last report in 2012. Equine IAV was detected by rtRT-PCR, followed by virus isolation and full genome sequencing. Genetic characterization of equine IAV classified the virus within clade 1 of the Florida sublineage. Although this is the same sublineage that caused an outbreak in Chile in 2012, the virus has a high similarity to other cocirculating viruses that were recently identified in Europe and Asia. The Chilean 2018 equine influenza (EI) outbreak was caused by an H3N8 strain circulating globally that spread through horse movements.