Abstract. Since the morphology of the reproductive organs could be a wherefore of reproductive performance of Mangalica, this study was conducted to get some more information about the number of corpora lutea and the size of reproductive tract both in cycling and pregnant Mangalica pigs. Two experiments were carried out to investigate the reproductive tract of Mangalica gilts. In Experiment 1, reproductive organs of 66 gilts (12–15 month of age) were recovered immediately after slaughter to determine the number of ovarian features, the weight and diameter of the ovaries, and the weight and length of oviducts and uteri, respectively. In Experiment 2, 22 puberal Mangalica (M) gilts and 34 German Landrace (L) gilts were used following estrus synchronization and artificial insemination. Genital tracts were recovered by ovario-hysterectomy on day 1 (n = 8 M; 10 L), day 12 (n = 8 M; 22 L) and day 24 (n = 6 M; 2 L) of pregnancy and the number of corpora lutea, ovarian weight and diameter, and the weight and length of oviducts and uteri evaluated. Oviducts and uterine horns (day 1 and 12, respectively) were flushed or uterine horns were opened (day 24) for embryo recovery.

In Experiment 1, 58 gilts (88 %) were cycling ones with mean number of ovulation of 10.6 ± 3.1. In first estrous gilts (n = 8) it was 11.1± 2.5. No differences were observed both between left and right ovaries, and first estrous and cycling gilts. The number of corpora lutea were correlated with ovarian weight (r = 0.35, p<0.05). Oviduct length (24.4 ± 1.4 and 24.3 ± 0.5 cm) and weight (4.3 ± 0.4 and 3.2 ± 0.2 g), and uterine horn length (143 ± 13 and 143 ± 5 cm) were not different in first estrous and cycling gilts. Uterine weight was higher in first estrous compared to cycling gilts (358 ± 32 vs. 250 ± 12 g, p < 0.05). In pregnant Mangalica (M) and Landrace (L) gilts no breed*day of pregnancy interaction regarding the number of ovulation was found. Mean number of corpora lutea was 17.2 ± 1.2 (M) and 18.6 ± 1.3 (L). Length of uterine horns was reduced in pregnant M compared to L gilts (124 ± 5 vs. 188 ± 6 cm, p < 0.01). Uterus grows in length continuously between day 1 and 24 of pregnancy in Landrace but not in Mangalica sows (p < 0.01). Uterine weight as well increased earlier (day 1 to day 12) in Landrace in comparison to Mangalica (day 12 to day 24).

Results of this study support the concept that in Mangalica besides diminished ovarian and oocyte development, uterine conditions, especially growth restricted uterine development, may influence the initial process of early pregnancy and can be another reason of lower fecundity.