Spring brings added excitement to deer farming. It is the season of fawns and antler growth which has the deer farmer anticipating the genetic potential of every animal on farm. Perhaps an account of the birth process would be in order as an explanation of this strange excitement that flows through the veins of deer farmers come springtime. Much has been written or documented on antler growth, but very little appears in the "textbook" on the birth of whitetailed or mule deer fawns. But the facts truly add an
interesting dimension to the understanding of the birth process of deer.

The Rut
A brief discussion of the rut is necessary as the foundation of the birth
process and factors affecting such have their beginnings during the fall
period of the rut. In Canada, the peak of the rut generally occurs in mid
November. The primary breeding phase generally lasts from 2 to 3 weeks,
however a second estrus will occur if successful breeding did not take place which helps to increase conception in the deer herd. As TR Michels (a well known writer/researcher) states, "does may be in estrus from 24 to 48 hours and recycle from 21 to 30 days later." A doe will often increase her physical activity (walking, pacing, etc) the day prior to breeding and will only accept the breeding buck in the peak of her estrus (about 24 hours). (Mule deer tend to breed almost 1-2 weeks earlier). Interestingly, John
Ozoga (a leading whitetail biologist), notes that "close confinement of bucks with does in small pens prior to the rut can stimulate females to advance their breeding date by eight to ten days." Doe fawns however, tend to have only a late estrus.

When we leave our white-tailed doe fawns in with the breeding pasture
animals, we remove the fawns by the end of December to avoid late
July/August fawns. Those that breed generally have achieved an optimum
weight between 85-110 lbs. Mule deer, however, may tend to mature later
because as a rule, it is very rare for mule deer doe fawns to breed and in
fact only an approximate 50% of mule deer yearlings will conceive. It has
been documented by Ozoga that whitetail doe fawns may mature earlier but
will typically breed later in the season and conceive fewer fawns. They
apparently also have fewer females in their first year than more mature
does. In farmed situations whitetail doe fawns which generally reach a 70%
weight of adult does and which receive excellent nutrition with low herd
density (stress factors) will tend to conceive well and may often produce
twins under ideal circumstances. Contrary to some concerns, under our
feeding system, we have not found any indication that does fawning in their
first year have any "stunted growth" but generally weigh the average (and often above average) mature weight. However, it is important to note, though that it is generally necessary to hand feed one of the offspring to ensure that the young mother does not lose excess condition through nursing twins.

Birth:
The gestation of whitetail/mule deer from conception to birth is 200 days
(give or take 10 days). Prior to giving birth, the does should be separated
into fawning pens and given adequate time to establish a hierarchy within
each doe pen. Although does vary in personality and aggression during this
highly territorial stage, most does, only days prior to fawning will drive
away most others as she begins to protect her prospective fawning area.
(Studies have shown that most matriarchs or more maternally experienced
does, tend to return to a traditional fawning area if given a choice.)

In addition to increased aggression to other deer and self isolation, signs and symptoms of an impending birth are pacing, udder enlargement ("bagging up") and contractions. Although "bagging" may begin two weeks prior to birth, when the udder is clearly and obviously full and "tight", fawning
should occur over a single day. Birth is imminent when contractions become noticeable. The doe will often lie down and throw her head back with neck
stretched out for each contraction, although she may get up between
contractions. Deer are very similar to goats/sheep in the birthing process,
in the positioning of the fetus and duration of delivery. Normal fawning
seems to take anywhere from 1-2 hrs and fawns should appear front hooves
facing downward followed by the muzzle in the "diving position". Once the
fawn's feet are visible, normal birthing should occur within the hour
provided the positioning is correct. Does may give birth standing or laying
and siblings may arrive 15-20 minutes apart. Although twins are most common,
triplets occur regularly as well. Even surviving quadruplets have been
reported by deer farmers, however these are generally related to artifical
insemination. In such rare cases, bottle feeding becomes necessary to
maintain the condition of the quad mother. Live fawns, to our knowledge,
have ranged in weight from approximately 3 lbs to 14 lbs, however the average weights range from 6-8 lbs (similar to human newborn weights). One of the most important aspects of a fawn¹s survival often hinges on birth weight. That is why when we tag fawns at birth, we also record birth weights.

Instinct:
After fawns are on the ground, the doe will spend her time consuming amniotic fluid, membranes and all traces of the afterbirth. Even the underlying vegetation generally will be eaten. The reason for this is that instinct requires the doe to protect her fawn by minimizing all odours (which in the wild could attract predators). Does will generally begin
cleaning the first fawn minutes after its arrival, however after the birth
of subsequent siblings she tends to turn her full attention on the strongest
of the fawns. Does have an uncanny sense of "survival of the fittest" and
occasionally, without the timely intervention of the deer farmer and a bottle feeding plan, the smallest or weakest may be found dead shortly after birth. Fawns are wobbly at first as they test out their legs, but usually within 30 min are capable of traveling quite a distance on pencil thin long legs. Dr. Harry Jacobson states that "at 3 days, most fawns can outrun a man, at 3 weeks they can outrun a coyote and at 6 weeks they have a good
chance of outrunning a bobcat or lynx."

Instinct plays an important part in the mortality rates of deer. For
instance, Ozoga also states that when in danger, fawns will instinctively
"freeze" by sinking to the ground with neck stretched out. This state is referred to as alarm bradycardia which is a depressed physiological state which lowers the fawn's heart rate, and breathing. This is a marvel of nature demonistrating the innate protective capabilities of deer. In the wild, the doe will also move sibling fawns as far as 100-400 ft apart. This
is once again an instinctual survival technique (and coupled with the spotted camouflage) is highly effective protection. Those species given to high postnatal mortality are naturally more prolific in births. Therefore, because deer multiply at such a rate, we can expect higher fawn mortality in a variety of ways. In the wild, fawn mortality through predation is usually
a major contributing factor. Since fawns are virtually odourless on their own and are promptly moved away from the birthing site, chance encounters with predators become the next obstacles to survival. Splitting up her fawns, a doe instinctively lessens the chance of losing all offspring to predators. A coyote may find one, but probably not all. Given the limited space on a farm, a doe still demonstrates this instinct, often moving fawns to opposite corners of a pen. Fawn survival rates (after weaning) on farm average 1.6 fawns per doe in whitetails and are generally a small percentage lower in mule deer (usually 1-1.5 fawns per doe).

Fawns will nurse immediately after testing their movement capabilities. Does
generally begin nursing their fawns while lying down, at which time, fawns
receive a concentrated colostrum-rich milk. Colostrum (first milk) is high
in protein and provides necessary antibodies to the young until their immune
system becomes more fully developed. According to Ozoga, deer milk is higher
in fat, protein, dry solids and energy when compared with cow¹s milk. While
fawns nurse, the mother grooms and cleans the them which is the beginning of
the bonding (imprinting) process. Does stimulate and consume fawn bowel
movements while nursing, another instinctual behavior favoring survival. In
the wild, the doe moves her fawn(s) further away from the site, after every
nursing session, as added protection, and the consumption of feces limits
odour-attracted predators. Does seem to imprint on their young quickly but
it may take up to 48 hours for a fawn to become fully imprinted on its
mother. This may be a significant factor when choosing to hand rear fawns.
Providing they have access to adequate milk supply white-tailed fawns often
double their birthweight within 2 weeks.

When will a doe require help?

The general rule of thumb, during fawning, is to not disturb does that are
ready to fawn but maintain observation at a distance, watching for signs of
trouble. There are very few does that will require help. Unlike cattle,
fawns rarely need human intervention. However, the most problematic part of
fawning may be the assessment of the rare delivery difficulties. Generally
this is a call the farmer must make based on beginning delivery time, fetal
positioning, or an obviously distressed doe. Often, as with domestic
livestock, the same doe may have trouble from year to year. So do not be
surprised if intervention is needed on the same doe more than once. We had
one doe this past year that required help in fawning. She had given birth to
one small (1 lb, fully formed) stillborn fawn and seemed to be in distress
with the 2nd fawn. We gave her a minimum of 2 hours once the hooves
presented and decided to handle her and pull the sibling. In retrospect this
waiting period was too long. Given the choice again, we would have
intervened within an hour if no progression seemed to be occurring. She was
very cooperative in handling and stood amazingly still in the squeeze as her
first live fawn was "pulled." It was necessary to pull with some steady
outward and downward force but once the front shoulders are out, the birth
process is very rapid. This first fawn had obviously been left too long as
she was very weak with dry hooves and muzzle. Given the possibility that
this doe may have been carrying triplets, we decided to check for a third.
We had to reach a full "hand to elbow" length into the birth canal to get a
grip on the front feet. Once again steady force had the fetus out within minutes. Once the fawns were out (and obviously moving), we cleaned off
their mouths and nose, wrapped them in cloth, and took them up to the house
for a warm bath and rub down. Having released the doe, we kept her in a smaller fawning pasture, ready at any time to handle her for medication if she began to show any signs of fever, infection or ill effects from her birthing experience.

Overall, the birth process of deer is generally an uncomplicated, unheralded event (as many deer farmers rarely witness the actual birth). However, constant observation of the fawning pens is important for tagging purposes and possible intervention in the rare delivery complication. The amazing miracle of birth is just one more reason farmers continue farming. The hope and anticipation of new beginnings in one (or two or three) spotted "small packages."

-Tara-Lynn Barks

Bibliography:
-Whitetail Country. John Ozoga., Willow Creek Press 1988
-The Wildlife Series: Deer. Edited by Duane Gerlach, Sally Atwater & Judith Schell ., Stackpole Books 1994
-AgFact (AgResearch) no. 105, June 1996 (www.diaa.org)
-“Chronology of the Rut” TR Michels (Trinity Mountain Outdoors)
-www.2farm.co.nz, Elise Mclellan “Birthing”