Early embryo survival and development in sows with lactational ovulation

Area of Science:

• Reproductive biology
• Animal science
• Embryology

Background:

• Lactational oestrus and ovulation can be induced in sows through daily separation from piglets, known as intermittent suckling (IS).
• Understanding the impact of IS on early embryonic development is crucial for optimizing swine reproduction.

Purpose of the Study:

• To investigate the effects of two intermittent suckling protocols (IS12 and IS6) on early embryo survival and development in multiparous sows.
• To compare these effects against a control group with standard weaning procedures.

Main Methods:

• Multiparous sows were assigned to either IS12 (12h daily separation), IS6 (two 6h daily separations), or control (C, standard weaning) groups.
• Sows were inseminated during oestrus and slaughtered 23 days post-ovulation for embryo and uterine assessment.
• Parameters evaluated included pregnancy rates, embryo survival, and embryo/placental/uterine development.

Main Results:

• All treatment groups exhibited oestrus within 5 days; pregnancy rates were not significantly different across groups (75% IS12, 78% IS6, 94% C).
• Embryo survival rates showed no significant difference (IS12: 57%, IS6: 51%, C: 70%), though numerically lower in IS groups.
• Embryo and placental development were negatively affected in the IS6 group, with shorter placentas and smaller, less developed embryos compared to controls.

Conclusions:

• Intermittent suckling does not significantly affect sow pregnancy rates or embryo survival, despite numerical trends.
• Embryo development is negatively impacted by intermittent suckling, especially with more frequent separations (IS6), potentially due to physiological stress and lactation demands.
• Further research is warranted to explore the mechanisms behind reduced embryo development under IS conditions.