Oesophageal Groove

BACK TO THE STOMACHS OF THE RUMINANT

Introduction

The oesophageal groove is present in newborn ruminants. It is a channel taking milk from the oesophagues into the rumen, omasum and then abomasum, bypassing the reticulum.

Histology

• Floor of groove smooth and pale

• Stratified squamous epithelium

Formation of the Groove

• Posture- lifting head to suckle

• Calcium ions from the milk

• Teat or teat-shaped experience

• The formation of the groove can be overridden, e.g. bucket feeding calves

Groove Closure

• Unconditioned reflex when the animal is eager for milk

• Water consumption does not usually iniatiate groove closure

• Age when the rumen becomes fully functional and the oseophageal groove closes differs between ruminants
  • In calves 20 weeks
  • In lambs 8 weeks
  • In deer 16 weeks
  • In goats 12 weeks

Function in the Adult Ruminant

• The groove is stimulated in adult ruminants by ADH

• The groove can also be closed in adult ruminants by the administration of drugs, e.g copper sulphate, which is of use to prevent drugs becoming diluted in the forechambers. Instead, it directs the drugs directly to the reticulum.