Table 1.

Coefficients of correlations (r) between the concentrations of estradiol (E₂) and progesterone (P₄).

Analytical Date	Group C	Group ZEN5	Group ZEN10	Group ZEN15
D1	0.105	0.445	−0.483	0.0
D2	0.767	0.0	0.0	0.594
D3	0.244	−0.231	−0.147	0.511

Key: Strength of linear correlations between the concentrations of E2 and P4 in the blood of pre-pubertal gilts on different analytical dates (D1 — exposure day 7; D2 — exposure day 21; D3 — exposure day 42) and in different groups where ZEN was administered once daily before the morning feeding (group C — placebo; group ZEN5 — 5 μg ZEN/kg BW; group ZEN10 — 10 μg ZEN/kg BW; group ZEN15 — 15 μg ZEN/kg BW).