HAREM STABILITY AND REPRODUCTIVE SUCCESS OF MISAKI FERAL MARES

The stability of relationships between harem stallions and mares (cons ort relations) was investigated and the durations of inter partum inte rvals were determined in order to establish if there was any correlati on between the stability of consort relation and reproductive success of mares in Misaki feral horses. Thirty-four mares were observed conti nuously far more than 5 years. The lifetime stability was 80-100% (mea n 92.4%) for 16 mares, 60-79% (mean 70.4%) for 10 mares and 0-59% (mea n 27.9%) for 8 mares. The continuous length (years) of specific consor t relations was 2-10 years and was found to correlate significantly wi th lifetime stability. There was a significant positive correlation of lifetime stability with lifetime reproductive success for 34 mares ob served, and the correlation was higher when the data of 8 wandering ma res (<60% in lifetime stability) were omitted. The mean +/- s.d. deliv ery interval of 25 stable mares was 364.5 +/- 11.0 days, whereas that of 8 unstable mares and stable mares who changed stallions was 387.0 /- 40.2 days. There was a significant difference between delivery inte rvals of stable and unstable mares. Significant correlations between t he stability of consort relations and both the foaling rates and deliv ery intervals suggest that mares may obtain major reproductive advanta ges if they maintain long term and stable consort relations with a par ticular stallion throughout their reproductive life span.