Effect of the new fixed-time artificial insemination technology based on novel hormone preparations in gilts

This study evaluated the effect of a novel fixed-time artificial insemination (FTAI) protocol for gilts, which incorporates altrenogest tablets (ALT-T), long-acting recombinant porcine FSH (rpFSH), and recombinant hCG (rhCG). A total of 160 gilts were divided into the control (n = 80) and the new treatment (n = 80) groups. Control gilts received oral altrenogest solution (20 mg/day) for 18 days, followed by 1000 IU equine chorionic gonadotropin (eCG) administered 42 h post-treatment and 100 μg GnRH 80 h later. The new treatment group received ALT-T, 40 μg rpFSH + 200 IU rhCG, and 400 IU rhCG at equivalent time points. Both groups underwent dual inseminations at 24 h and 40 h after GnRH/rhCG administration. Hormonal profiles (altrenogest, FSH, E₂, P₄) showed no significant differences between the groups, except for a higher LH level (P < 0.05) during ALT-T treatment. Follicle sizes were comparable during the two types of altrenogest administration but became significantly larger in the control group 12 h pre-ovulation (6.99 vs. 6.57 mm, P < 0.05). There was no significant difference in reproductive outcomes between two groups including estrus rate (76.25 % vs. 76.25 %), pregnancy rate (88.52 % vs. 91.80 %) and farrowing rate (94.44 % vs. 94.64 %). Notably, the new treatment group exhibited superior litter productivity with significantly increased total born (13.81 vs. 11.80, P < 0.05) and live-born piglets (11.81 vs. 10.39, P < 0.05). These findings suggest that the new FTAI protocol achieves comparable synchronization efficacy while enhancing litter productivity compared to traditional regimens, supporting its use as an effective alternative for gilts reproductive management.