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Why Holes in Cows in Their Sides / Cannula? A Quick Discussion

Why Cows Have Port Holes in Their Sides _ Cannula_ A Quick Discussion

Why Holes in Cows in Their Sides?

Why Cows Have Port Holes in Their Sides – Cows are ruminants. They have a complex digestive system and digestion physiology. Cannulation is basically the creation of holes at specific sites in cows for various purposes. Many cow farmers want to know about cannulation/hole drilling in cows, their purposes, and risk factors associated with it. Purposes are Why Holes in Cows in Their Sides

  • Research
  • Sampling for Digestion Digestibility Study
  • Lifesaving Relief
  • Transfer of Microbes
  • Giving of Medications quickly

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Port for Cannula

Here we will explain the purposes of cannula in cows with all necessary details.


The cannula is a porthole-like a medical instrument that helps in accessing the rumen of cows.

As it has already been cleared the cow has four parts of the stomach and carries a diversity of microbes that perform a number of beneficial functions in cows. Cannulation has been using for a long time in the animal world.

Researchers/farmers/observers cut the holes the sides of cows to evaluate the ruminal contents, flora (community of microbes), and for other research purposes.

The practice of rumen cannulation was first documented in 1928 by Arthur Frederick Schalk and R.S. Amadon of North Dakota Agricultural College

Installing a Cannula Port in Dairy Cow


Let’s enlist the proper purposes of these holes in cows for better understanding:

To assess the functioning of the gastrointestinal tract

To infuse any drug/medication to the cow’s stomach (medical cause)

For research goals especially to conduct digestibility trials (evaluate the digestibility of feeds)

To obtain samples of rumen digesta (ruminal content)

For the transfaunation purpose (transferring microbes from one cow to other)

Cows that have been undergone a surgical procedure and fitted with cannula is called cannulated cows.

It is noteworthy to know that there are various types of cannula according to their functions. Remember, these all cannulas have different purposes some are used for intestines, abomasums, and rumen.

T- Cannula
Reentrant Cannula
Abomasal cannula
Omasal cannula
Closed T cannula.

These Ports are Great. Personally, I have had Cancer for the last several years. My last Chemo set, the Doctors inserted a Port and a Tube down into my Heart. I was going into the Hospital daily for those treatments and they were able to inject the chemo quickly and much easier than Daily IV’s I had no problems at all with the port. Quite a Convenience.

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Installation of Cannula Port – University of Utah

Surgery Install


This is a lifesaving procedure that can become possible through the cannula. With the help of the hole in the donor cow, the rumen is easily approached and microbes are obtained from that cow. These essential microbes are transferred from that donor cow to the sick cow to improve her health.

Plus, through cannulation, ruminal microbes of a cow can also be easily studied. Interestingly, researches have revealed that the ruminal flora from cows not only helps the other cows but also it effectively helps the sheep and goats because they are also ruminants and have almost similar gastrointestinal tract.


This is very much important to know the temperament of a cow before going for cannulation. This point is much valid when you are doing cannulation for research purposes.

This surgical intervention is done when the cow is standing. Local anesthesia is given to that cow. The skin is cut to create a hole. Through that hole, the cannula is passed. This is all done to keep the hole open. A removable cap is also included for easy access. After a period of six months when healing is completed, the cow becomes ready for the desired purpose.


The cannula is also helpful in saving the life of a cow. In the severe cases of ruminal acidosis or other similar conditions, the cannula is passed in the cows to remove the extra ruminal contents and ease the cow from the ruminal troubles which can put her life into danger.

All along with that, this helps in infusion of various kinds of life saving drugs into the rumen of diseased cows.


Holey cows had been used in the area of nutritional research studies for a long time ago. Through this procedure, samples can be easily taken from the cow’s rumen to evaluate their digestibility and other parameters. Moreover, it also helps researchers in better understanding of the digestive physiology of cows and the impact of nutrients on the growth of microflora and overall health and well being of cows. This is why; cannulation has a wide range of applications in the field of animal research.


This is a very important question that is usually asked by the farmers. Like what are various risk factors that are associated with cannulation in cows. You know that after creating a hole in cows their internal organs become exposed to the outside environment.
If you have done the surgery nicely with all care and maintaining aseptic conditions, then chances of getting infection become less. With proper care and attention, cannulated cows can enjoy a healthy and happy life.

Additionally, this is important to note that while transferring the ruminal content/microflora from one cow to another cow can increase the spread of infectious diseases such as salmonellosis, Jones’s diseases, and other chronic bacterial infections. These infections can compromise the overall health and performance of the herd.

To deal with this situation, this is important to define a criterion for the donor cow and cannulate the cow with supreme health status and free health-related complications. For that select a cow of superior genetic potential and do regular testing to assess her health status.


Cannulation is a quite painful and uncomfortable process. Just imagine, cows are also living creatures and drilling holes in their sides is creating painful sensations in them. Although, this practice is widely used for various outcomes ethically this is not good for their overall health and life expectancy. However, according to some schools of thought cannulation is not a painful process but it just creates a time being discomfort in cows and also doesn’t impact the life expectancy of the cows.


Holes are created on the sides of cows for a number of medical/research purposes. This is kept in mind that surgery should be performed by only expert veterinarians and all precautionary measures must be kept in mind. Lastly, proper attention and care should be given to the holey cow, and in case of any complication; you should contact your veterinarian on emergency grounds.

Cattle Losses 2010

Cause of DeathPercentage of Total
Respiratory Problems26%
Unknown Reasons18%
Digestive Problems13%
Birth Problems/Calving12%
Metabolic Problems2%
Domestic Dogs.6%
Large Cats.5%
Theft .4%
List Prioritized of Cattle Deaths in 2010

World Cattle Breeder Associations

Cattle AssociationLocationLink
National Cattleman's Beef AssociationsUnited StatesNCBA
United States Cattlemans AssociationUnited StatesUSCA
Ohio Cattlemans AssociationOhioOCA
American Angus AssociationUnited StatesAAA
United Kingdom Cattle AssociationsUKUKCA
Australia Cattle AssociationsAustraliaACA


Alonso, F. R., W. J. Donawick, and E. P. Hammel. 1973. Cannulation of bovine abomasum: A surgical technique. Am. J. Vet. Res. 34: 447−448.

Gay, W. I., and J. E. Heavner. 1986. Methods of Animal Experimentation. Vol. VII. Research Surgery and Care of the Research Animal. Part A. Patient Care, Vascular Access, and Telemetry. Academic Press, Orlando, FL.

Komarek, R. J. 1981a. Intestinal cannulation of cattle and sheep with a T-shaped cannula designed for total digesta collection without externalizing digesta flow. J. Anim. Sci. 53:796-802.

MacRae, J. C. 1975. The use of re-entrant cannulae to partition digestive function within the gastro-intestinal tract of ruminants. In: I. W. McDonald and A.C.I. Warner (Ed.) Digestion and Metabolism in the Ruminant. Proc. IV Int. Symp. Ruminant Physiol., Sydney, Australia. pp 261−276

McGilliard, A. D. 1982. Surgical techniques-advances and cautions. In: F. N. Owens (Ed.) Protein Requirements for Cattle: Symposium. MP109:31−36. Oklahoma State Univ., Stillwater.