Unit 10 - hard winter for deer

[Sam Menard]

I’ve been reading a lot lately about feeding/baiting and the deer digestive system. Deer rely on microbes in their rumens to break down food into useable energy. From what I learned, it can take a week or more for the digestive system to adapt to new foods - if introduced properly. It’s my understanding that the better way to help stressed deer is to pack trails and provide them with natural foods that they normally eat at this time of the year such as cedar bows.

A danger of feeding deer corn and other simple carbohydrates is acidosis which is a condition experienced by ruminants such as cattle, sheep and goats. Wild ruminants such as elk and deer appear to be more susceptible to this condition than traditional livestock species. Acidosis usually occurs when animals have consumed large quantities of cereal grains or other sources of readily fermentable starch, or have had their diet suddenly switched from a high roughage diet to a high concentrate diet. It will usually manifest itself in the herd in one of two ways – an acute case will usually be terminal, while milder cases can be turned around. There is also the possibility that some of the affected animals will be more susceptible to secondary infections.

Acidosis is caused by an increase in lactic acid-producing bacteria in the rumen and the rapid production of lactic acid. It commonly occurs when there is a sudden change in diet, or when animals gain access to large quantities of grain. Animals that are maintained on a high energy ration may normally be in a marginal state of acidosis due to the formation of lactic acid by the rumen bacterial flora. Therefore, ingredient changes, poor mixing of grains in the ration, or faulty feeding can produce acute acidosis in deer.

Excessive feeding of foods such as corn can be harmful and the consequences can be difficult to reverse and death can result in 2 to 4 days. The underlying problem is the rapid fermentation of starch in the rumen with the resultant production of lactic acid. The lactic acid is picked up by the blood stream in amounts that are high enough to generally disrupt normal body chemistry. Lactic acid can also pool in joints and heavily worked muscles resulting in severe tendonitis, arthritis and lameness. It has also been suggested, that very acid conditions in the rumen may damage the lining of the mucous membrane, allowing bacterial to enter the blood stream and reach the liver, injuring this organ as well.

Usually the greedy feeders are the first to be affected. Symptoms comprise of staggering and apparent blindness, subnormal or normal body temperatures. This will usually be followed in 24 to 48 hours by recumbency, and finally coma and death. A profuse diarrhea may develop in later stages. Milder cases can recover when the high grain or high concentrate ration is removed, and extra roughage is provided.

The severity of the signs depend largely upon the amount of cereal grains or concentrates eaten. In the first few hours, a full rumen and restlessness may be all that is seen. There are mild cases, that do not progress beyond simple indigestion. However, in severe cases there may be evidence of extreme agitation and some pain (crying and getting up and down). The animal will often stagger and even appear blind. Their appetite will decrease dramatically during the first day as will rumen contractions. The feces may become soft.
The temperature of the deer will become sub-normal unless the animal is exposed to the hot sun. As the lactic acid level in the blood and body fluids increases, circulatory collapse or shock will begin; this will increase the heart rate. Animals with a heart rate of less than 100 are more likely to respond to treatment than those with a heart rate of 120-140 or higher. Respiration rate increases and breathing becomes shallow, diarrhea usually develop and is profuse.

The excess lactic acid in the rumen causes a large amount of fluid to be transported into the rumen which causes dehydration. The rumen may feel full and doughy; if less grain was consumed, it may feel resilient because of increased fluid and gas. The rumen will have no contractions but, if you could listen, you might hear a lot of gas rising through the fluid. Usually after two days the animal will lie down and not voluntarily get up.

The challenge for deer in northwest Ontario is that they don’t yard up in the traditional sense. Deer up here congregate in extended family groups, or small buck groups, and seek out mature conifer stands. We don’t have deer yards (like the Lorring Yard), rather smaller and spread out concentration areas. In unit 10, there has been an abundance of logging over the past 20 years which has resulted in a loss of critical wintering habitat; thus reducing the carrying capacity on the range.

Given that we are halfway through March and we still have 3’+ of snow on the ground, likely deer have another 4 weeks of suffering to endure - which unfortunately will be too much. I will be surprised if there are more than 100 doe tags available for units 7B and 10 combined. The bright side is that with no more deer, the wolf numbers should finally starve… once they eat all the carrion and beavers.

[Sam Menard]

I was wondering why they aren't using hay - I thought deer eat that too. I figured maybe it was because of the ratio of calories/weight/volume of hay is so low that it makes it hard to deliver enough for it to be useful to the deer? Anyway, I assume they know what they are doing and chose the best option.

Deer will eat certain kinds of hay such as alfalfa. They don’t eat grasses such as Timothy due to high amount of lignin which they can’t digest. The problem of feeding hay is that it is very bulky which makes it difficult to get into the woods. Also, hay can be hard to come by at this time of the year. Like corn, hay is not a deer natural food so deer need to be introduced to it slowly in order for the microbes in their stomachs to adjust.

[Gilroy]

Great information Sam, has anybody expressed an opinion to a local MNR biologist up there and I wonder what they are saying? Mind you if they have "managed" the tree cutting in a way leaving very little winter cover you wonder who is managing what.

Even if hunters wanted to help out the deer and get permission to cut down some cedar that would help temporarily but you end up with even less winter cover.


I found this after a bit of searching.

https://www.ofah.org/wp-content/uplo...terFeeding.pdf