Progesterone and estrogen concentrations in gilts with delayed parturition

Area of Science:

• Reproductive endocrinology
• Swine reproduction
• Animal science

Background:

• Progesterone is crucial for maintaining pregnancy.
• Understanding exogenous progesterone's effects on parturition is vital for swine production.
• Previous studies indicate potential complications with progestin use in late gestation.

Purpose of the Study:

• To investigate the impact of exogenous progesterone administration on gestation length and farrowing outcomes in gilts.
• To analyze progesterone and estrogen profiles during late gestation and parturition following progesterone treatment.
• To determine the relationship between progesterone levels, birth process, and stillbirth incidence.

Main Methods:

• Twelve pregnant gilts were divided into three groups: control (corn oil), progesterone treatment for 3 days, and progesterone treatment for 5 days.
• Exogenous progesterone (P4) was administered subcutaneously.
• Blood serum was analyzed for progesterone and estrogen concentrations prepartum.

Main Results:

• Progesterone treatment extended gestation length compared to controls.
• Live birth percentages were significantly reduced in progesterone-treated groups (48.8% and 2.5%) versus controls (87.4%).
• Exogenous progesterone altered endogenous progesterone patterns and suppressed prepartum estrogen levels.

Conclusions:

• Exogenous progesterone administration can delay parturition in gilts but severely compromises farrowing success.
• The disruption of natural progesterone and estrogen dynamics appears to impede the birth process.
• This hormonal imbalance contributes to a high incidence of stillbirths in gilts treated with progestins for parturition delay.