To answer the question, do dogs have blood types, we need first to ask ourselves do they have red blood cells, and if so, what are their purpose?
Do all Animals Have Red Blood?
Humans, like other species, have red blood cells. Their primary function is to carry oxygen (essential) to our body’s tissues so we can breathe. Additionally, they remove carbon dioxide (waste), bringing it to our lungs, which we then breathe out. So obviously, red blood cells are crucial to life.
The molecule that carries oxygen as part of the red blood cell isn’t the same for all species. Most species use the protein hemoglobin to carry oxygen; this leads to the red color of blood in most species. However, in some, that protein is different, known as hemocyanin (Lenfant & Johansen, 1965; The European Synchrotron, 2013). In animals that use this carrier, like octopuses, snails, spiders, and mussels, their blood is actually blue.
Do Animals Have Different Blood Types?
So, if not all species even have the same color blood, it makes sense that they would have different blood types, right?
Human Blood Types
Do you know your own blood type? What do you know about the alphabet soup that makes up the human blood system? Do the following sound familiar A, B, O, AB, negative/positive, or Rh factor?
There is one blood system in humans, ABO, and this breaks down to various blood types. According to the red cross (2020), humans basically have 8 common blood types, O+, O-, A+, A-, B+, B, AB+, AB-. Of these, O negative is known as the “universal donor”. (Please see definitions for underlined words). These letters represent proteins called antigens on the surface of the red blood cell. No antigens reside on O- blood, and this means that anyone can receive this type of blood in their first blood transfusion.
So, people with Group O blood have neither A nor B antigens on their red blood cells. This means people with A will have A antigens, B with B antigens, and AB with both A and B antigens on the surface of the cells (American Red Cross, 2020). These antigens are essential not in how your blood works but are critical when blood is given to others to minimize the risk of transfusion reactions.
A Few Definitions
To help make this alphabet soup less confusing, let’s back up for a second. We’ll define a few terms to make things understandable before moving on to animal blood types.
“An antigen is any substance that causes your immune system to produce antibodies against it”. It can be from various sources, like bacteria, allergens, pollen, a chemical, or they can form if a person receives a blood transfusion. When they develop, your immune system sees the substance as an intruder and tries to fight it off (US National Library of Medicine, 2020). Basically, it is anything that your body sees as foreign and mounts a response against (Merriam-Webster, n.d.).
So the letters represent the antigens found on the surface of a human or animal’s red blood cells.
An antibody is “any of various proteins produced in the blood in response to the presence of an antigen”. Antibodies attach to antigens (those things that are seen as foreign, hence, harmful, to the body) to remove them or render them safe (Collins, 2020).
Basically, a universal blood donor has a blood type that doesn’t have any antigens on the surface of the red blood cell (American Red Cross, 2020). This blood type, type O negative in humans or DEA 1.1 negative in dogs, is the type least likely to cause an adverse reaction in the body. It can be used in an emergency when a person or dog has never before received a transfusion.
Simply, one person or animal, the recipient, receives blood from another person or animal, the donor.
How do we define transfusion reaction? When someone receives blood that contains antigens that their body sees as foreign, it can cause an adverse reaction. Simply put, the body reacts to that letter (protein) because of receiving blood from a donor that isn’t compatible with its own blood. It can cause signs such as fever, hives, trouble breathing, even death. So the science of blood typing and matching blood, while not critical on the first transfusion, is vital in future ones.
Blood Types of Other Species
Non-human primates also possess the ABO Blood group as in humans, though, at the genetic level, there are variations (Segurel et al., 2012).
Cats have 1 blood group system with 3 blood types, A, B, and AB. But these are in no way the same as the As and Bs in human blood types. So don’t worry, if you ever need a transfusion, you won’t get cat blood (Cornell University College of Veterinary Medicine, [Cornell U], 2013-2020).
Cornell U. (2013-2020) states that in horses, we recognize over 30 blood groups, but of those, 8 are considered significant. Finally, looking at Cattle, they have 11 systems, while sheep have 7, and goats have 5.
So, yes, animals have blood types, and they are very different from one species to another.
Dog Blood Types
So, do dogs have blood types? In the 1970s, when first described, the dog blood type was coined Dog Erythrocyte Antigen (DEA). Since that time, other systems have been identified. These include Dal, Kai 1, and Kai 2. But the most important and widely studied remains the DEA system. This system provides for various subtypes, DEA 1.1, 1.2, 1.3, 3, 4, 5, 7. The ABO alphabet soup in human blood typing correlates to the DEA in dogs. The DEA refers to the specific antigen (a protein) that attaches to the red blood cell to identify it (Ebelt, Fuchs, Weber, Müller, & Giger, 2020)
As of 2020, greater than 13 known canine blood groups exist. Though we lack data about what the presence or absence of them all mean scientifically. While we have identified various subgroups, including DEA 3, DEA 5, and DEA 7, we do not usually appreciate transfusion reactions in dogs to these subtypes. Thus, DEA 1.1 remains the most important and well studied canine blood group (Ebelt et al., 2020).
Studies to tell us what blood type is most common in dogs haven’t been the top priority. But a recent study in Germany showed that of those dogs surveyed, 40.8 % were DEA 1 negative. Surveys recently completed in the USA, France, India, and Italy concur that this universal donor is most likely the most common blood group (Ebelt et al., 2020).
What about that negative or positive? “A dog can either be positive or negative for each specific DEA. If positive, the antigen of that blood type is present on the red cell surface [sig] and if negative, the antigen is missing” (Withnall et al., 2005).
But who cares, right? Why does it matter? This becomes important in transfusions. If a dog who is DEA 1.1 negative receives blood that is DEA 1.1 positive, antibodies may develop. If that same dog received another DEA 1.1+ transfusion later in life, the red blood cells could be rapidly destroyed. Additionally, those previously formed antibodies could lead to severe reactions, including death (Cotter, 2017). Thus, a positive dog could receive positive or negative blood without a problem, but the reverse is not valid.
Do Dogs Ever Need Blood Transfusions?
Everyone knows that humans donate and receive blood frequently. Blood transfusions help in trauma, surgery, and chronic diseases. Heard of the Red Cross? Receiving blood can mean the difference between life or death. The same holds true for animals.
Everyone has heard stories about dogs hit by cars or cats falling out 3 story windows and surviving. What they don’t always hear about is the blood transfusion that saved their life.
Whether hit by a train, or because of certain diseases like cancer or immune-mediated diseases that negatively affect the blood, sick and injured animals commonly need life-saving transfusions.
Canine Blood Banks. Can my Dog Donate Blood?
Without blood banks and blood donors, veterinarians would have difficulty saving some dogs’ lives. If you have a dog and you are interested in having your dog donate blood so that their blood will help other dogs in need, we salute you. “A single donation can help as many as four dogs” (Pet Blood bank UK, 2020).
While in no way a complete list, if you are ever interested in having your dog give blood to help another, check out the links below. You can learn if your dog is eligible and how blood is obtained.
In general, check local veterinary schools as many have donor programs. Also, some of the large referral practices (usually 24-hour facilities with specialists) have them. Finally, ask your local veterinarian if they are looking for donations or know where your dog can donate.
So as you can see, the answer to the question, do dogs have blood types is a resounding, yes! Understanding the science behind these blood types helps veterinarians save lives!