Post weaning oestrus and luteal function in primiparous and pluriparous sows

Area of Science:

• Veterinary Medicine
• Animal Reproduction
• Swine Husbandry

Background:

• Post-weaning anestrus is a critical factor affecting swine reproductive efficiency.
• Understanding the timing and patterns of ovarian activity resumption is crucial for optimizing breeding programs.

Purpose of the Study:

• To investigate the resumption of ovarian activity in primiparous and pluriparous sows following weaning.
• To determine the incidence of ovulation with and without detectable estrus ('silent heat').
• To evaluate the influence of season and parity on ovarian cyclicity post-weaning.

Main Methods:

• Progesterone determination was used to monitor ovarian activity in 33 primiparous and 52 pluriparous sows.
• Progesterone profiles were analyzed to assess the timing of ovarian activity resumption and ovulation.
• Data were analyzed to compare activity between primiparous and pluriparous sows and across different weaning seasons.

Main Results:

• Over 90% of pluriparous and 66% of primiparous sows resumed ovarian activity within 10 days post-weaning.
• Ovulation occurred within 10 days in 53.8% of pluriparous and 45.5% of primiparous sows, with 'silent heat' observed in 31% of all sows.
• Sows weaned between January and June exhibited better ovarian activity resumption compared to those weaned between July and December.

Conclusions:

• Swine ovarian activity resumes rapidly post-weaning, particularly in pluriparous sows.
• Silent ovulation is a significant factor in post-weaning reproductive cycles.
• Seasonal effects influence the ability of sows to resume ovarian activity, highlighting the importance of strategic weaning times.