As it’s cow appreciation day on the 11th July, we thought we’d investigate the more specialised areas of the cow's anatomy – and we think you might be very surprised!
It is a common myth that cows have four stomachs – they only have the one, but it is split into four chambers. It is enormous! If all four compartments were filled at once, they could collectively hold around 67 gallons. If you can't envision this, imagine a toddler sized paddling pool filled up to its brim and you won't be far off!
The first, and the largest, part of the stomach is the rumen. Its job is to break down the food by fermentation. This is not done with acid or enzymes, but by microscopic organisms (rumen microbes); the cows’ stomach is one of the best in the world for productive and varied microbial habitats. There can be anywhere between 1 and 10 billion bacteria per ml.
Next is the reticulum. It is nicknamed a “honeycomb” due to its surface texture or the “hardware” stomach, as this is where objects such as nails, screws or pieces of fence that have been ingested accidentally are held. The main purpose of this section is to soften the grass and to form it into cud for further chewing.
The third compartment is the omasum, and it mostly absorbs water and only the finest particles of the digested food.
The final chamber is the abomasum where the cow uses its own enzymes and stomach acids to break down the food further before it passes to the small intestine. This is known as the “true stomach” as it does a similar role to stomachs that only have one compartment, such as ours.
The udder is also a very interesting creation. It essentially is a modified sweat gland and is split into four separate glands known as quarters.
The most fascinating part is the deep tissue of the udder contains alveoli, whose structure is very similar to those of the lungs! Each alveolus is surrounded by epithelial cells that are milk-producing, as well as muscle cells. Synthetisation of milk is continuous, and between milkings 60-80% of it is stored within the alveoli itself.
Cow related AnatomyStuff resources:
Further reading / sources
Physiology of the udder