Attempt to control parturition in the sow using an oral progestogen

Area of Science:

• Animal Science
• Reproductive Biology
• Veterinary Medicine

Background:

• Prostaglandin F2 alpha analogues are common for inducing parturition in sows.
• A key disadvantage is premature farrowing, leading to suboptimal piglet outcomes.
• Maintaining gestation with progestogens offers a potential alternative for controlled farrowing.

Purpose of the Study:

• To evaluate the efficacy of an orally active progestogen, allyl-trenbolone, for controlling parturition timing in sows.
• To compare farrowing performance, piglet viability, and subsequent reproductive health in sows treated with allyl-trenbolone versus natural farrowing controls.

Main Methods:

• Experiment 1: 20 sows received 16 mg/day allyl-trenbolone from day 111 to 118 of gestation.
• Farrowing performance, interval from progestogen withdrawal to farrowing, stillbirths, and piglet weights were assessed.
• Experiment 2: 81 sows and 12 gilts were evaluated under commercial conditions with four treatment groups.

Main Results:

• Treated sows farrowed significantly later (118.2 days) than control sows (116.1 days) (P < 0.01).
• The interval from progestogen withdrawal to farrowing was 29.6 ± 4.8 hours.
• Stillbirths increased in treated sows (2.1/litter) compared to controls (0.4/litter), with no impact on piglet birth or weaning weights.

Conclusions:

• Allyl-trenbolone can delay farrowing in sows, but it is associated with increased stillbirths.
• Potential for subsequent reproductive malfunction warrants further investigation.
• Controlled farrowing via progestogen withdrawal may not be a superior alternative to natural farrowing due to adverse effects.