Intravaginal devices impregnated with medroxyprogesterone acetate avoid early parturition and synchronize farrowing in sows.

Two experiments were performed to evaluate the use of an intravaginal device (IVD) impregnated with medroxyprogesterone acetate (MPA) to avoid early parturition and synchronize farrowing in sows. In both experiments with IVDs, the gestation length, stillbirth rate, birth weight, colostrum yield, lactational litter performance, and subsequent reproductive performance of sows were assessed. In Experiment 1 (Exp. 1; n = 91), sows were assigned to four treatments to evaluate the minimum required MPA dose: without IVD (CONT; control), 400 mg (MPA400), 600 mg (MPA600), and 800 mg (MPA800) of MPA in the IVD. The IVD was inserted on day 110 of gestation and removed on day 115. No sows farrowed during IVD treatment. Gestation length was increased in treatments with MPA (116.4 days) compared to the control (CONT; 114.9 days; P < 0.01), without effects on piglet birth weight (P = 0.98). A lower percentage of deaths around the farrow (P = 0.02) was observed in the CONT (1.8%) compared to MPA treatments (6.8%). The dose of 400 mg of MPA, validated in Exp. 1, was used in Experiment 2 (Exp. 2; n = 84) to evaluate the performance of sows and piglets in a sow farrowing synchronization protocol. Sows were treated with MPA from days 110-114 of gestation with or without 0.168 mg of cloprostenol sodium (PGF2α), for luteolysis induction, at IVD removal. Thus, four treatments were considered: CONT - without MPA or luteolysis induction (no interventions); PGF2α - luteolysis induction on day 114 of gestation without MPA; MPA114 - MPA treatment till 114 days of gestation without luteolysis induction; MPA114 + PGF2α - MPA treatment and luteolysis induction on day 114 of gestation. The gestation length in treatments with IVDs was longer (P < 0.01) than CONT without a difference for PGF2α treatment (P = 0.46). No impact of IVD use on piglet birth weight (P = 0.67) and deaths around the farrow (P = 0.50) were observed. The colostrum yield (P = 0.65), immunocrit (P = 0.72), piglet performance during lactation (P = 0.81), and weaning-to-estrus interval (P = 0.21) were similar among treatments. In conclusion, the use of IVDs impregnated with 400 mg of MPA between days 110 and 114 of gestation prevented early parturition with no implications for piglet survival at birth, colostrum yield, or litter performance.

Reproductive performance of single fixed-time inseminated sows with semen doses submitted to different semen storage times.

This study aimed to evaluate the reproductive performance of sows submitted to single fixed-time insemination (SFTAI) using boars according to capacity for liquid in vitro semen preservation, type of extender, and storage time. Boars (n = 12) were classified into two groups based on progressive motility (PM) at 120 h of semen storage: low (PM - 64.5%) - and high-preservation (PM - 83.9%) capacity for semen storage. Weaned sows (n = 397, parity - 1 to 7) were inseminated (1.5×109 sperm cells) in a factorial design: two classes of boars (low- or high-preservation), two types of extenders (short- or long-term), and two semen storage times at insemination (24 or 72 h). An adapted triptorelin acetate protocol was used for SFTAI. Total sperm motility (TM) and PM at insemination were greater in high-preservation boars at 72 h compared with low-preservation boars at 24 or 72 h (P < 0.01). Short- or long-term extender did not affect (P ≥ 0.68) TM and PM in high-preservation boars; however, long-term extender improved these parameters in low-preservation boars (P < 0.01). Pregnancy and farrowing rates were not affected by groups (P > 0.05). Total piglets born (TPB) was reduced (P = 0.05) in low-preservation boars with 72 h of storage (13.6 ± 0.5) compared to high-preservation boars with semen stored for 24 or 72 h (15.2 ± 0.5 and 15.5 ± 0.5, respectively). The low-preservation boars reduced the TPB in sows submitted to SFTAI, and this reduction was greater using semen stored for 72 h.