When we process our deer, whether at home or in the field, sometimes we notice small black or dark red spots on the meat and other tissue.
Some of those spots are regular occurrences – an aftermath of killing your deer, but others could have formed from other reasons.
If you are unsure, it is always best to consult your local veterinarian or wildlife biologist at DNR to check whether the meat is suitable for consumption.
What Are Black Spots On Deer Meat?
There are several types of black or dark red spots one can find on a deer. Their sources vary depending on the tissue they are found on.
Many hunters with a lot of experience have never seen black spots on the meat before, and it brings up a lot of questions as to whether the deer is sick and the meat safe.
The most common cause of black spots occurring in deer meat is blood spotting and is restricted only to muscles. This type of blood spotting has the medical name ecchymosis.
Ecchymosis in meat looks slightly different from an average bruise under your skin, but the principal working is the same: it is caused by small bleeding from the ends of the blood vessels causing dark bruising throughout the muscle.
Blood spotting can be found both on the surface of the muscle and inside, spread throughout in a random pattern, often reminding of a shotgun wound.
The spots are usually small in size, fractions of an inch in diameter, although in extreme cases, one can also encounter a more significant bruise, usually closer to the gun wound.
A deer shot with a bow dies from a blood loss and is usually not as stressed, while a deer shot with a gun sustains a lot more damage, and often the extreme pressure of the impact can cause weaker blood vessels to burst.
In other words, ecchymosis can result from hydrostatic shock.
Another reason blood vessels break, causing dark spots in deer meat, is stress level. Blood spotting can result when a deer doesn’t die quickly after being shot or when an animal is chased or wounded.
The stress levels rise and, with them, the blood pressure. Some deer have weaker blood vessels than others, and any rise in blood pressure can easily cause blood spotting.
The most often cause of stress-induced blood spotting seems to be from a headshot – while the deer’s brain dies, the heart still pumps the blood, raising the pressure in blood vessels.
Although this theory doesn’t have scientific proof, many hunters noticed black spots covering the entirety of the deer after a headshot.
Black spots are also often seen in the fat tissue. Those spots are called haemal lymph nodes and are a type of lymph node that occurs in blood vessels.
The black or dark red color results from the constant blood flow, as opposed to the regular lymph nodes, which are usually white, yellow, or gray and filled with lymph fluid.
The most common places one can find haemal lymph nodes are in the fat and connective tissues of the neck, close to the windpipe and esophagus.
After those, the next place to look for the haemal nodes is in the fat around the large blood vessels.
It could be the arteries that leave the heart, like the aorta, and the primary blood vessel inside the body cavity directly below or around tenderloins.
Haemal lymph nodes are also common enough to spread in the fat around the intestines and other organs like the kidneys or urinary bladder.
The black spots in the fat are considered secondary organs, but unlike primary organs, there isn’t any specified number of haemal lymph nodes.
Some individuals seem to have a lot even within the same species, and others may have few or even none.
This is why many hunters may never see haemal lymph nodes, even those with many years of experience.
Haemal lymph nodes are essential filtering organs for deers’ circulatory systems, and one can generally trim them out with the fat excess while processing the meat.
There are also black spots occurring in the internal organs, like the lungs and liver.
The black spots on the lungs can result from a few different sources, like pneumonia, lung parasite, or petechial hemorrhages. Depending on the source, one can find the spots covering the whole of the lungs or only a small part of one lung.
Liver flukes cause the black spots in deer liver. In an early stage of liver fluke infestation, the small flukes travel through the liver, leaving a trail that appears as black spots.
When the flukes grow, they create fibrous yellow-grey cysts oozing dark brown liquid.
There is also a case of tiny black spots in the abdominal region caused by abdominal worm infection. The worm (Setaria yehi) lives only in the abdominal cavity and doesn’t cause any harm to the organs.
The discoloration is often present due to the host reacting to the presence of the worm activity and can look like anything between a black rash with separate black spots distributed at random or a big group of tiny black spots that looks like a black bruise.
What Causes Black Spots On Deer Meat?
The black spots in the deer meat are caused by unexpected ruptures in blood vessels. The blood that comes out of the blood vessel is confined, forming small blood clots that appear black or dark red.
As mentioned before, the blood vessel rupture can result from a few different causes, like heightened blood pressure, high stress levels, or a hydrostatic shock from the bullet.
The reason for the lymph nodes is to filter and clean all fluids that circulate through the deer’s body. While regular lymph nodes are filled with lymphocytes and white blood cells, the haemal lymph nodes filter blood, similar to a spleen.
There is no documented research on what causes their appearance, in what numbers, and why some deer have them and others don’t.
Can You Eat Deer Meat With Black Spots?
In most cases, eating deer with black spots is safe.
The blood-spotted meat is safe for human consumption, although many hunters who encountered black spots in their deer meat say the quality is much lower than meat without the spots.
The meat appears to be much dryer and tougher than the usual cuts. It is also proven by meat processing factories dealing with processing other ruminants, like cows or sheep, who can also sustain black spots after increased stress levels.
To avoid discarding perfectly healthy meat, the deer that sustained black spots could be turned into burgers and sausages instead.
The haemal lymph nodes also do not pose any risk to human health. They are part of the deer’s anatomy.
Even though some of the deer may have quite a lot of haemal nodes, they are usually embedded in the fat tissue and are easily discarded during meat processing.
The same can be said for the worm in the abdominal cave of the deer. The worm doesn’t harm the deer and will not pose health issues for humans.
The tissue containing abdominal worms is usually discarded on the gut pile or with the leftover carcass of the deer.
One should not consume the liver containing liver fluke. Although there is a small chance of deer liver fluke contaminating the human body, there is no need for any risk, and the infected liver doesn’t look appetizing at all.
However, the meat from the infected deer is still suitable and safe for consumption.
There are a lot of suspicious spots and parasites that live inside the deer’s body, but not all of them are dangerous or contagious to humans.
Some black spots in deer meat, like ecchymosis of haemal lymph nodes, are harmless, and hunters can consume the meat safely, although the quality of the meat may not be the best.
In any case, even if the deer meat with black spots is safe for consumption, one should consult an authority if any doubts should arise. After all, it’s best to be safe than sorry.