Fawn Growth is Key to Improving Deer Quality

A deer and a fawn stand behind a fence.

Nearly every day, I have a conversation with someone, either in person or over the phone, about feeding deer in hopes of improving the “quality” of their deer.  “Quality” in this case generally refers to an increase in body size and antler growth. However, improving the quality of a deer herd through improved nutrition, like improving the quality of a livestock operation, takes time. Particularly when it comes to your fawn growth throughout the seasons.

The main reason that time is involved in improving a herd of animals is that in order to see the fruits of your labor, you will have to give the young animals of today time to mature and express their full potential.  This is more so with native pasture deer because we can’t get yearling weights and average daily gains to compare animals to measure improvement in performance at various stages in their life.

Deer generally produce their first set of antlers in the first spring after they are born.  The larger the fawns are when antler growth starts, the greater potential for larger antlers they have.  If nutritional needs are met in following years, the larger fawns should continue to have larger than average body sizes and larger antler growth, up to their genetic potential.

In order to improve the quality of your deer herd, you must concentrate on the fawns each year. Because fawns will have the greatest requirement for nutrient density, if you meet their needs, you will be meeting, or exceeding the nutritional needs of the other classes of deer.

To determine the critical times of the year for nutritional needs of fawns, lets look at a fawn’s first year.  Actually we need to look at a fawns year plus two months.  The two months are the last two months of gestation the doe carries the fawn.  If during this time the doe is not able to get the nutritional intake she needs to maintain her weight and develop the fetus within, the fawn will be born undersized, with a depressed immune system, and with potentially weaker bones and teeth. All of these conditions will hinder the growth of the fawn in its first year.

If we figure that June is the average time of birth for fawns, then beginning in April you need to insure the does are getting the nutrients they need.  This doesn’t necessarily mean that they need a lot of supplement.  If your pastures have a good production of forbs and new browse growth, the does should be eating a diet with all the nutrients needed.  However, if your deer density is so high that forage intake is restricted at times, or if you don’t have the forbs and browse to give the nutritional intake, you will have to provide a supplement to make up the deficiencies.

Once the fawns are born the does experience their greatest nutritional needs of the year during lactation.  This is the most critical period of development for the fawns.  If their nutritional intake is deficient during this time, their growth will be below their genetic potential for most of their life.

So making sure the does have adequate nutrition is just as important during lactation as during late gestation.  The big difference during lactation is the protein requirement.  Generally the first limiting nutrient for lactation is protein because a molecule of milk is built around an amino acid.  If protein is short, there will not be enough amino acids to produce a large volume of milk.

Now lets look at when lactation takes place in deer, from June into September.  Hot temperatures, maturing forages, and declining nutritional quality in the forages, characterize this period.  The dairy cattle industry has proven that milk production peaks can be improved and sustained longer with better nutrition.  So to help the fawns grow as well as they are capable, you need to make sure the does have an adequate level of nutritional intake.

Since protein is most likely going to be the first limiting factor in milk production, the supplement used during this time should be one with a high protein level.  Depending on how much the does are eating, the protein level of the supplement should be from 20% to 32%.  How much they eat per day will depend on how much native forage the deer have available.

However, if you are trying to improve the quality of your deer, at this time you want the does to produce as much milk as they can to give the fawns as good a start in growth as they can get.  This good start is important because the rut and winter is coming.

The rut is important to the fawns not because they will be active in the breeding, but with all of the fighting of the bucks and the turmoil of bucks chasing the does, the fawns’ daily patterns are thrown off.  When their patterns are disturbed, the fawns may not eat as well as they normally do, and may get run away from feed stations by fighting bucks.

So the rut will be a period when the fawns do not grow as well as they could, unless they can get to a supplement that helps them to keep growing.  Again, a high protein supplement is called for to provide the protein needed for muscle development.  Also a high mineral intake is necessary to develop their bone structure and to prepare them for growing their first set of antlers next spring.

One mistake a lot of producers make is to inadvertently fence the fawns out of the deer feed pens.  Ranchers are so intent in keeping livestock, and especially feral hogs, out of the feed pens that they sometimes build pen fences too well.  If you consider the size of the 3 to 4 month old fawns, it’s easy to build a fence too tall for them to jump in just when they need the nutrients most.  So be sure to make your feed pens accessible to the fawns that will need the supplement as they approach and move into winter.

When winter arrives, the forage quality and quantity reaches its lowest levels.  At this time, those fawns that have grown the largest have an advantage over their smaller mates.

Rumen size is a function of body size.  A larger rumen will allow a fawn to eat more of a lesser quality forage in an attempt to get as much nutrient intake as possible.  So at the time of lowest forage quality, the animal that can eat more will do better.

Doing better during the winter is important because in late February, the fawns will begin to grow their first set of antlers.  Their body condition, mineral density, and health will all determine how many of the nutrients they ingest each day can be diverted to antler production.  If the fawns come out of the winter in poor body condition with a low mineral density because they have had to use tissues and minerals stored in the body, they will have to replenish these tissues and minerals before they can put substantial nutrients into antlers.

As the fawns reach a year of age and a new fawn crop is being born, they are expressing enough antler growth and body size to allow some comparison among their mates.  And while it is difficult to compare one year to another, if your supplementation program is working, you should see an improvement in body size and antler growth over fawns that weren’t supplemented.

These larger, more developed yearlings are now poised to continue to grow and express more of their genetic potential than they would have been if their nutrition had been more restricted.  In another 4 to 5 years, they will reach their peak production and you can finally measure how well your feeding program is accomplishing your goals.

It is impossible to feed one class of deer without feeding them all.  However, if you are feeding your deer in hopes of improving your “quality”, then you need to concentrate your feeding program on the needs of the fawns.  If you do, all other classes will have their nutritional needs met and will develop to their genetic potential.  And, over time, you will see the great benefit of giving these fawns the best first year possible.

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