The Reproductive Characteristics of the Mare in Subtropical Taiwan

다국어 초록 (Multilingual Abstract)

The objectives of this study were to document the reproductive traits of mares as influenced by the month of the year in Taiwan. Reproductive records, lactation traits, foal birth weight (FBW) and foal height (FBH) were collected from Holi Equine Station of Taiwan. The effects of month on these parameters were analyzed. The length of estrus (LE) was shortest in December each year. The increasing trend was recorded from January to September with a significantly (p<0.05) longer period of $12.4{\pm}0.4$ days in September than in January and February. A gradual shortening in LE was observed from September to December ($10.1{\pm}0.6$ days, p<0.05), when the shortest period of the year was observed. Mares showed signs of estrus throughout the year, but more than 80% were found in estrus during March through October. The FBW was significantly (p<0.05) affected by the breeding month of the year. The lowest foal weights were recorded in both September ($36.7{\pm}0.7$ kg) and December ($36.8{\pm}0.9$ kg), which were also significantly lower than those in other months except in March, August, and November. A trend of lower FBH from September to December (93.5-93.8 cm) than those from January to August was observed. The greatest FBH was in June (96.2 cm). Breeding months and onset of estrus of the mares exerted a significant effect on the incidence of agalactia during the lactation period. These analyses provide fundamental information on adaptive processes in respect to reproductive characteristics of mares, which indicated an extent of acclimation by these animals in subtropical Taiwan.