This work aims to study the influence of some factors on the expression of the foaling heat in Arab mares. This study was held in Tunisia, from January to May 2018. For this, 59 Tunisian Arab mares were separated into 2 groups (young mares, age <15 years, n=41; and old mares, age ≥15 years, n=18), and monitored amid the post partum period. The parturition mode (eutocic, dystocic) was noted, and the onset of the foaling heat and its duration recorded. Follicular activity was monitored using ultrasonography to track the side at which the ovulation occurred. ANOVA was carried out using the software SAS (SAS Institute Inc.®) to study the effect of age and parturition mode on the onset of foaling heat and its duration. The Duncan test was used to compare the variations according to the age and the parturition mode. The onset of the foaling heat and its duration did not vary with the age class (7.5±0.2 vs 7.3±0.2 days; 5±0.5 vs 7.8±0.3 days), but had more important values in mares with dystocia (8±1.2 vs 7.4±0.2 days, p<0.05; 6±1.8 vs 5±0.5 days, p<0.05). Significantly more ovulations occurred in the left ovary than in the right one (55% vs 45%). Furthermore, silent heat occurred at the rate of 20%, while all females resumed an ovulatory function. Our results suggest that dystocia increase the onset delay of the foaling heat and its duration, and that the left ovary tends to retrieve its function faster than the right one.