Sheep 201: The Lambing Process

Overview

• The lambing process has evolved over thousands of years.
• Most ewes give birth normally without assistance.
• Understanding the process helps determine when intervention is necessary.

Hormonal Control

• The lamb decides when to be born through hormonal changes.
• Signs of imminent lambing:
  • Ewe stops eating.
  • Distended udder and teats.
  • Dilated vulva.
  • Relaxation of muscles in the rump area.

Phases of Lambing

1. Cervical Dilation

   • Prepares the birth canal for delivery.
   • Lasts 12 - 24 hours.
   • Ends with mucous discharge signaling the start of labor.

2. Labor and Delivery

   • Increased uterine contractions.
   • Ewe lies down, a "water bag" appears and breaks.
   • Lamb's nose and front feet appear, then lamb is expelled.
   • Multiple births repeat this sequence.

3. Expulsion of Afterbirth

   • Afterbirth usually expelled 30-60 minutes post last lamb.
   • Retained placenta after 24 hours may indicate a problem.
   • Ewe eats placenta instinctively; discard to prevent disease.

Dystocia: Difficult Births

• Leading cause of lamb deaths.
• Causes include:
  • Abortion
  • Size disparity between lamb and ewe
  • Malpresentation
  • Cervix not dilating
  • Vaginal prolapse
  • Deformed lamb
• Assistance Guidelines:
  • Check if straining lasts over an hour with no result.
  • Use lubrication, gloves, and ensure hygiene.
  • Call for help if no progress in half an hour.

Types of Presentations in Delivery

• Normal Presentation:

  • Front feet, head between them.
  • Rare assistance, except in large lambs.

• Backwards Presentation:

  • Hind legs first; common in multiples.
  • Do not attempt to turn.

• Elbow Lock:

  • Elbows locked; push back slightly to free.

• Leg(s) Back:

  • Cup hooves, bring forward.
  • Use lambing rope if needed.

• Head Back:

  • Push back, turn head around.
  • Avoid pulling by jaw; use eye sockets.

• Disproportionate Size:

  • Large lamb/small ewe.
  • Use lubrication, gentle assistance.

• Breech Birth:

  • Rear legs tucked; reposition quickly.

Post-Lambing Care

• Minimal interference post-delivery.
• Ensure lambs breathe and nurse.
• Monitor for colostrum intake.
• Check no other lambs remain in uterus.

Common Complications

• Ringwomb:

  • Cervix fails to dilate.
  • Often requires caesarian.
  • Removal from flock may be necessary.
  • Possible genetic component.

• Dead/Deformed Lambs:

  • Often need veterinary assistance for removal.
  • Large issues may indicate breeding/nutrition problems.

Additional Notes

• Overfeeding or inappropriate sire choice can cause oversized lambs.
• Ewe lambs should reach 70% mature weight before breeding.
• Post-delivery, ewes should receive antibiotic injections if assisted.