Doe's Reproductive Physiology and proper scent collection...
08-22-2005, 08:27 AM
#1
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Join Date: Aug 2005
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Posts: 24
Doe's Reproductive Physiology and proper scent collection...
Lets take a look at Doe's Reproductive Physiology....
The primary messengers, which allow all of the organs involved in reproduction to communicate and coordinate, are "hormones". Hormones are protein molecules that are produced by many organs and structures in the body, usually in response to an external stimulus (such as light or smell). Reproductive hormones rise and fall at appropriate times (cycles) to ensure the female behaviorally accepts the male (is standing heat) when ovulation is about to occur, and to ensure the uterus is ready to accept and nourish the fertilized egg. Hormones also "feedback" and decrease some reproductive functions when it is appropriate, so that the ovaries do not produce and ovulate eggs needlessly when an animal is pregnant. In animals which breed only during certain seasons of the year, these hormal reproductive cycles are turned on and off accordingly.
The hypothalamus is a gland located on the ventral (bottom) surface of the brain. The hypothalamus produces several hormones that are important in regulation of various body functions, including reproduction. The primary reproductive hormone produced by the hypothalamus is "Gonadotropin-Releasing Hormone (GNRH). GNRH is produced in response to daylight length (photoperiod) in animals that have a seasonal reproductive pattern. In deer, as the days get shorter and the length of daylight per day decreases, GNRH production in the hypothalamus increases, and levels of GNRH rise in the bloodstream.
The anterior pituitary gland is located in close proximity to the hypothalamus. Rising levels of GNRH stimulate the anterior pituitary gland to produce and release two hormones: Follicle Stimulating Hormone (FSH) and Leutinizing Hormone (LH). FSH stimulates the development of egg containing follicles on the ovary. LH promotes ovulation of these follicles and initiates the development of the corpus luteum after ovulation. Stimulation of the follicle by FSH is required before LH can be effective and cause a follicle to ovulate.
The ovary produces two reproductive hormones: Estrogen and Progesterone. As a follicle develops in the ovary, it secretes Estrogen. The primary function of Estrogen is to cause the behavioral signs of heat (estrus) or receptivity to the male. Once a follicle ovulates, the remains of the follicle wall develop into a Corpus Luteum, which then secretes Progesterone. The primary function of progesterone is to prepare the uterus for implantation of the fertilized egg. The Corpus Luteum must be stimulated by Estrogen before it can produce Progesterone. Because it would be wasteful for an animal, which has already ovulated and bred, to continue to produce follicles or to ovulate, rising estrogen levels inhibit the production of follicle stimulating hormone (FSH) and luetinizing hormone (LH), preventing both. Progesterone, produced by the corpus luteum during pregnancy, also inhibits follicle stimulating hormone (FSH) and the development of follicles.
The uterus also produces a reproductive hormone from its lining: Prostaglandin F2 Alpha. If an animal does not become pregnant, prostaglandin F2 alpha is produced, which destroys the corpus luteum and thus progesterone production, and allows a new estrous cycle to begin.
The cycle of follicle development, ovulation, corpus luteum formation, prostaglandin destruction of the corpus luteum, and its repetition until pregnancy occurs is known as the Estrous Cycle. In humans, the estrous cycle is called the Menstrual Cycle. The length of the estrous cycle varies, but is approximately 21 days in most deer. Breeding occurs during “standing heat” or “estrus”, which lasts only 18-24 hours in deer. If the animal is bred or semen introduced at the proper time, the ovulated egg is fertilized in the fallopian tube. After fertilization, the embryo implants in wall of the uterus. Implantation of the fertilized egg into the uterine wall prevents prostaglandin production and the corpus luteum continues to produce progesterone, the hormone which maintains pregnancy. The uterine wall then forms a Placenta to nourish and develop the fetus.
Temperate deer species only breed and have estrous cycles seasonally. This ensures babies are born at the time of the year when food is plentiful and the environmental conditions are more amenable to survival. Nature thus required a consistent, unquestionable cue which would signal the proper time to initiate the estrous cycle and breeding. The primary stimulus initiating the estrous cycle in white-tailed deer is shortened day length, which occurs in the fall.
In Review: It is an interaction of all the reproductive organs, glands and hormones, which results in the estrous cycle. The sequence of events of the estrous cycle starts with the production of GNRH. The production of GNRH stimulates the secretion of FSH and LH. The increased level of FSH stimulates the development of follicles with subsequent increased estrogen secretion. The increased estrogen level causes a decrease in FSH and an increase in LH. The increased LH comes in a pulse and causes the follicle to ovulate and release the ovum. This causes the female to enter “estrus” or “standing heat”. The remains of the follicular wall develop into a corpus luteum, which produces progesterone. If the female is not pregnant, the uterine wall produces prostaglandin F2 alpha which causes destruction (lysis) of the corpus luteum. The corpus luteum regresses and ceases the production of progesterone. The resulting decreased progesterone level stimulates increased secretion of FSH and LH, which starts the cycle all over again.
Can anybody explain why this is importantfor proper scent collection or does anybody want to know why this is important to know as a scent user?
The primary messengers, which allow all of the organs involved in reproduction to communicate and coordinate, are "hormones". Hormones are protein molecules that are produced by many organs and structures in the body, usually in response to an external stimulus (such as light or smell). Reproductive hormones rise and fall at appropriate times (cycles) to ensure the female behaviorally accepts the male (is standing heat) when ovulation is about to occur, and to ensure the uterus is ready to accept and nourish the fertilized egg. Hormones also "feedback" and decrease some reproductive functions when it is appropriate, so that the ovaries do not produce and ovulate eggs needlessly when an animal is pregnant. In animals which breed only during certain seasons of the year, these hormal reproductive cycles are turned on and off accordingly.
The hypothalamus is a gland located on the ventral (bottom) surface of the brain. The hypothalamus produces several hormones that are important in regulation of various body functions, including reproduction. The primary reproductive hormone produced by the hypothalamus is "Gonadotropin-Releasing Hormone (GNRH). GNRH is produced in response to daylight length (photoperiod) in animals that have a seasonal reproductive pattern. In deer, as the days get shorter and the length of daylight per day decreases, GNRH production in the hypothalamus increases, and levels of GNRH rise in the bloodstream.
The anterior pituitary gland is located in close proximity to the hypothalamus. Rising levels of GNRH stimulate the anterior pituitary gland to produce and release two hormones: Follicle Stimulating Hormone (FSH) and Leutinizing Hormone (LH). FSH stimulates the development of egg containing follicles on the ovary. LH promotes ovulation of these follicles and initiates the development of the corpus luteum after ovulation. Stimulation of the follicle by FSH is required before LH can be effective and cause a follicle to ovulate.
The ovary produces two reproductive hormones: Estrogen and Progesterone. As a follicle develops in the ovary, it secretes Estrogen. The primary function of Estrogen is to cause the behavioral signs of heat (estrus) or receptivity to the male. Once a follicle ovulates, the remains of the follicle wall develop into a Corpus Luteum, which then secretes Progesterone. The primary function of progesterone is to prepare the uterus for implantation of the fertilized egg. The Corpus Luteum must be stimulated by Estrogen before it can produce Progesterone. Because it would be wasteful for an animal, which has already ovulated and bred, to continue to produce follicles or to ovulate, rising estrogen levels inhibit the production of follicle stimulating hormone (FSH) and luetinizing hormone (LH), preventing both. Progesterone, produced by the corpus luteum during pregnancy, also inhibits follicle stimulating hormone (FSH) and the development of follicles.
The uterus also produces a reproductive hormone from its lining: Prostaglandin F2 Alpha. If an animal does not become pregnant, prostaglandin F2 alpha is produced, which destroys the corpus luteum and thus progesterone production, and allows a new estrous cycle to begin.
The cycle of follicle development, ovulation, corpus luteum formation, prostaglandin destruction of the corpus luteum, and its repetition until pregnancy occurs is known as the Estrous Cycle. In humans, the estrous cycle is called the Menstrual Cycle. The length of the estrous cycle varies, but is approximately 21 days in most deer. Breeding occurs during “standing heat” or “estrus”, which lasts only 18-24 hours in deer. If the animal is bred or semen introduced at the proper time, the ovulated egg is fertilized in the fallopian tube. After fertilization, the embryo implants in wall of the uterus. Implantation of the fertilized egg into the uterine wall prevents prostaglandin production and the corpus luteum continues to produce progesterone, the hormone which maintains pregnancy. The uterine wall then forms a Placenta to nourish and develop the fetus.
Temperate deer species only breed and have estrous cycles seasonally. This ensures babies are born at the time of the year when food is plentiful and the environmental conditions are more amenable to survival. Nature thus required a consistent, unquestionable cue which would signal the proper time to initiate the estrous cycle and breeding. The primary stimulus initiating the estrous cycle in white-tailed deer is shortened day length, which occurs in the fall.
In Review: It is an interaction of all the reproductive organs, glands and hormones, which results in the estrous cycle. The sequence of events of the estrous cycle starts with the production of GNRH. The production of GNRH stimulates the secretion of FSH and LH. The increased level of FSH stimulates the development of follicles with subsequent increased estrogen secretion. The increased estrogen level causes a decrease in FSH and an increase in LH. The increased LH comes in a pulse and causes the follicle to ovulate and release the ovum. This causes the female to enter “estrus” or “standing heat”. The remains of the follicular wall develop into a corpus luteum, which produces progesterone. If the female is not pregnant, the uterine wall produces prostaglandin F2 alpha which causes destruction (lysis) of the corpus luteum. The corpus luteum regresses and ceases the production of progesterone. The resulting decreased progesterone level stimulates increased secretion of FSH and LH, which starts the cycle all over again.
Can anybody explain why this is importantfor proper scent collection or does anybody want to know why this is important to know as a scent user?
08-22-2005, 11:02 AM
#3
Thread Starter
Join Date: Aug 2005
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Posts: 24
RE: Doe's Reproductive Physiology and proper scent collection...
As we now know from the reproductive physiology of the doe, the sequence of events of the estrous cycle starts with the production of GNRH. The production of GNRH stimulates the secretion of FSH and LH. The increased level of FSH stimulates the development of follicles with subsequent increased estrogen secretion. The increased estrogen level causes a decrease in FSH and an increase in LH. The increased LH comes in a pulse and causes the follicle to ovulate and release the ovum. This causes the female to enter “estrus” or “standing heat”.
Now lets take a closer look at the roles estrogen, testosterone and fall/winter metabolism plays on the mating and social ranking of white-tailed deer.
Estrogen
Once the doe’s come into their estrous cycle they produce vaginal secretions (including estrogen) that the bucks are able to smell. These vaginal secretions may be detected on the doe, or more likely in the urine the doe passes and leaves behind. Some researchers believe that bucks may come into breeding readiness when they perform the flehmen sniff and detect estrogen from a doe’s urine, and that this detection may ensure that both the bucks and does are ready to breed at the same time. This suggests that bucks may respond to estrous secretions or estrous urine as long as their testosterone levels are high, which may be as early as late August or early September, until after most of the does have been bred.
Bucks show interest in urination of females particularly during the rut and follow their investigations with a lip curl (Flehmen). Although somewhat ritualized, the purpose of the lip curl is to expose the scent to the vomeronasal or Jacobson’s organ, which assists the buck with his assessment of the doe’s reproductive stage and willingness to mate by the estrogen levels in her urine. The vomeronasal organ detects large non-volatile molecules. Because it has separate tracts to and stimulates different areas of the brain, it is properly considered the ‘sixth sense’.
Testosterone
It has been shown that a buck's testosterone level rises in the fall, and that dominant bucks have higher testosterone levels than subdominant bucks. Researchers have suggested that does can smell testosterone and protein levels in a buck's urine, and are able to determine the health of the buck by the smell; which allows the does to choose a healthy dominant buck to breed with. If this is true, urine from a healthy dominant buck should attract does, which may in turn attract bucks.
Since testosterone levels rise when the bucks begin to shed their velvet and make rubs and scrapes, and remains high as long as doe’s remain in estrous, urine with testosterone can be used throughout the rut. A buck in rut is curious about which other bucks are in its area, and may be compelled to check out any new buck scent in the area. However, because high levels of testosterone are associated with dominance, buck in rut urine may attract dominant bucks, but it may scare off subdominants.
Fall Metabolism Effects on the Buck
The higher protein levels in a buck’s urine, along with testosterone levels, give males their strong eye-watering rutting odor. As they stop feeding and mobilize fat, highly volatile ketones resulting from incomplete oxidation of fat appear in the urine. Odor therefore indicates quantitatively how hard the male is rutting and whether he is ‘spent’. The message may be significant tothefemales when selecting a mateand also to other males. When a dominant buck has an essence of being “spent” but with a strong essence of testosterone, it is more likely that a harder rutting buck in the area will investigate the scent and try to run the “spent” buck from the area. This is the distinction buck’s use to determine the over-all stamina of each other, hence the rub-urination before a full-blown fight.
Is all this making sense so far?
Now lets take a closer look at the roles estrogen, testosterone and fall/winter metabolism plays on the mating and social ranking of white-tailed deer.
Estrogen
Once the doe’s come into their estrous cycle they produce vaginal secretions (including estrogen) that the bucks are able to smell. These vaginal secretions may be detected on the doe, or more likely in the urine the doe passes and leaves behind. Some researchers believe that bucks may come into breeding readiness when they perform the flehmen sniff and detect estrogen from a doe’s urine, and that this detection may ensure that both the bucks and does are ready to breed at the same time. This suggests that bucks may respond to estrous secretions or estrous urine as long as their testosterone levels are high, which may be as early as late August or early September, until after most of the does have been bred.
Bucks show interest in urination of females particularly during the rut and follow their investigations with a lip curl (Flehmen). Although somewhat ritualized, the purpose of the lip curl is to expose the scent to the vomeronasal or Jacobson’s organ, which assists the buck with his assessment of the doe’s reproductive stage and willingness to mate by the estrogen levels in her urine. The vomeronasal organ detects large non-volatile molecules. Because it has separate tracts to and stimulates different areas of the brain, it is properly considered the ‘sixth sense’.
Testosterone
It has been shown that a buck's testosterone level rises in the fall, and that dominant bucks have higher testosterone levels than subdominant bucks. Researchers have suggested that does can smell testosterone and protein levels in a buck's urine, and are able to determine the health of the buck by the smell; which allows the does to choose a healthy dominant buck to breed with. If this is true, urine from a healthy dominant buck should attract does, which may in turn attract bucks.
Since testosterone levels rise when the bucks begin to shed their velvet and make rubs and scrapes, and remains high as long as doe’s remain in estrous, urine with testosterone can be used throughout the rut. A buck in rut is curious about which other bucks are in its area, and may be compelled to check out any new buck scent in the area. However, because high levels of testosterone are associated with dominance, buck in rut urine may attract dominant bucks, but it may scare off subdominants.
Fall Metabolism Effects on the Buck
The higher protein levels in a buck’s urine, along with testosterone levels, give males their strong eye-watering rutting odor. As they stop feeding and mobilize fat, highly volatile ketones resulting from incomplete oxidation of fat appear in the urine. Odor therefore indicates quantitatively how hard the male is rutting and whether he is ‘spent’. The message may be significant tothefemales when selecting a mateand also to other males. When a dominant buck has an essence of being “spent” but with a strong essence of testosterone, it is more likely that a harder rutting buck in the area will investigate the scent and try to run the “spent” buck from the area. This is the distinction buck’s use to determine the over-all stamina of each other, hence the rub-urination before a full-blown fight.
Is all this making sense so far?
08-22-2005, 01:35 PM
#6
Dominant Buck
Join Date: Feb 2005
Location: WC FL
Posts: 26,323
RE: Doe's Reproductive Physiology and proper scent collection...
Stony, I have been a Deer and Hog hunter for more than 50yrs.
Most hunters don't care to know, all they want to know is when
and where to kill a deer in a short week-end. They no nothing about
the animal they hunt, only what it looks like.
I have been to many seminars on these subjects.
They should know the light spectrum of a deers eye ability. Ask any hunter
how the Tatum in a deers eye functions. Most don't know.
Every gland by name and locationon a deer and what they use it for. Most don't know.
Movements and vocalizations and what they mean.Most don't know.
etc.,etc.,etc.,......
Heck, I've even taken seminars on entomology, they show you many signs in
the deer woods.
You're on the right page Stony, keep learning as much you can on the animals
you like to hunt! Thanks again!
Most hunters don't care to know, all they want to know is when
and where to kill a deer in a short week-end. They no nothing about
the animal they hunt, only what it looks like.
I have been to many seminars on these subjects.
They should know the light spectrum of a deers eye ability. Ask any hunter
how the Tatum in a deers eye functions. Most don't know.
Every gland by name and locationon a deer and what they use it for. Most don't know.
Movements and vocalizations and what they mean.Most don't know.
etc.,etc.,etc.,......
Heck, I've even taken seminars on entomology, they show you many signs in
the deer woods.
You're on the right page Stony, keep learning as much you can on the animals
you like to hunt! Thanks again!
08-22-2005, 02:07 PM
#7
Thread Starter
Join Date: Aug 2005
Location:
Posts: 24
RE: Doe's Reproductive Physiology and proper scent collection...
ORIGINAL: Rebel Hog
Ask any hunter how the Tatum in a deers eye functions. Most don't know.
Ask any hunter how the Tatum in a deers eye functions. Most don't know.
Do you mean the tapetum? The tapetum, which acts as a mirror and reflects the light not absorbed by the receptor cells when it enters the eye the first time back across the cells for a second chance. In other words, deer get to use the same light twice while humans get to use it only once.
None the less, still very good points to your post. I am willing to share my knowledge with fellow hunters, which could quite possibly make it possible to get their deer in a weekend. I know it works for my hunting buddy’s and me but we need to understand the deer's senses, reproductive cyclesand the communications that go along with them first. This is why I started off the way I did.
Thanks Rebel and looking forward to an ongoing discussion....
Come on all you guys, start asking some questions or giveme your thought!!!
My two fingers were going to fast!
08-22-2005, 03:52 PM
#9
Boone & Crockett
Join Date: Feb 2003
Location: Ponce de Leon Florida USA
Posts: 10,079
RE: Doe's Reproductive Physiology and proper scent collection...
The only part about your information I can't completely agree is the part about shorter days triggering the rut. There has to be more to it, either something in the genetics or something else. Where I now hunt, about 40 miles south of Montgomery, Alabama, the rut kicks in about the 15th of Jan. Just 30 or so miles east, in the Clayton, Alabama area, where I use to hunt, the rut kicks in about the first of Dec. I know of some pens in the area that have northern genetic deer in them and the rut hits late Oct. I understand that blackleg killed off a lot of deer in our area in the late 40's and 50's and they were reintroduced from a number of stocking areas. That may play into the answer.
08-22-2005, 04:06 PM
#10
Thread Starter
Join Date: Aug 2005
Location:
Posts: 24
RE: Doe's Reproductive Physiology and proper scent collection...
Very good question Timber. I'm curious as to when the bucks shed velvet in both of the locations you just described? Are the bucks shedding their velvet in the same time frame or are they spread out 45 day apart also?
Thanks
Thanks