The Esophageal Groove

What it is and why it is so important

The esophageal groove is a curved muscle that lies in the throat of the calf. It’s job is to ensure that everything that enters the calf’s mouth ends up in the right place.

The Rumen. When a calf drinks water from a trough or eats meal and grains, the esophageal groove stays curved to direct these foods to the rumen for digestion.
The Abomasum. When a calf suckles on a cows teat the esophageal groove closes and forms a tunnel to direct the milk to the abomasum for digestion. This tunnel is small and cannot cope with the large volumes of milk caused by fast feeding.

It is vital to the health of the calf that all the milk goes into the abomasum. If milk enters the rumen through fast feeding or bucket feeding, It can cause a gut ache, as the enzymes in the rumen cannot digest milk. Milk in the rumen can lead to scarring on the rumen wall, which affects the long term production of that animal.

  • This demonstrates the esophageal groove when relaxed.

    groove1
    As a calf drinks water from a trough or eats grain or pasture
    (grass, hay, silage etc) the esophageal groove muscles are relaxed so 
    the food and water drops into the rumen.

  • This demonstrates the esophageal groove when a calf suckles from a teat.

    groove2
    The muscles tighten to form a tube to direct milk to the abomasum.
    Fast feeding can overflow the tube so milk can enter the rumen.

Nutritional Scours

Feeding calves at a natural slow speed can help avoid this problem

‘The initial digestion of milk occurs in the abomasum (or fourth stomach) and this progresses further in the intestines. Scours can usually be traced back to a failure of adequate milk digestion in the abomasum.
Nutritional scours is simply the end result of an over supply of lactose in the intestines, caused by milk moving too rapidly out of the abomasum, so it cannot be broken down quickly enough.
Nutritional scours often progresses to infectious scours, caused by a high population of pathogens. Pathogens use excess lactose as a nutrient source to increase in numbers. The rate in lactose digestion is then further reduced as a result of damage to the intestine walls by these pathogens.
This damage also causes body fluids to leak into the gut, thereby increasing the rate at which the calf dehydrates.
Nutritional scours can be caused by stress to the calf due to a breakdown in management routines.’
Source – Victoria Department of Primary Industries.

scours1