emerged last month from her white room at the Denver Zoo into a maze of
logs and rope, leaning on her fists, both of them closed loosely as if
they cradled buzzing flies.
The 44-year-old Sumatran orangutan ate
some oatmeal and peanut butter in the exhibit, studied people on the
other side of the glass, and slipped her long fingers into a concrete
barrel full of bubble-bath. She scooped up drifts of foam and ate it,
giving her a white beard and mustache, and mugged like Lucille Ball for
She was back to her old self, said Cindy Cossaboon,
Sally's principal zookeeper, back to being a "very strong, stubborn
woman" who finds loud noises rude and who likes to comb the long,
coppery hair that shrouds her body and
work on Sally the Sumatran orangutan in June. The operation lasted six
hours and was "nerve-wracking" and "inspiring," said zoo veterinarian
Diana Boon. "It still gives me chills." Sally is back at the zoo and has
recovered from the ordeal. (Photo courtesy of Diana Boon, Denver Zoo)
gathers on her scalp in a rendition of the mop-top.
it not for a zoo veterinarian and a team of physicians from two Denver
hospitals, however, Sally would have died last summer.
compelled high-profile surgeons to rush to a bare-bones, old-fashioned
operating room, and launch into a lengthy, complex operation that likely
would have ended badly — death — had they made a single error.
doctors had never worked together before as a team. None had operated
on an orangutan before, nor were they especially familiar with the great
apes' anatomy. The surgery they performed may have been the first of
But they were not deterred.
"This was a patient in
need, and just like any other patient, there was something wrong and we
weren't sure what it was and we knew it needed to be addressed
quickly," said Ruben Alvero, a reproductive endocrinology and fertility
specialist at the University of Colorado School of Medicine. Alvero flew
back early from a conference in Florida to attend the surgery, driving
straight from the airport to the operating room. "We felt strongly we
had an obligation to the patient."
"Something was wrong"
Sally, the eldest of the Denver
filling her water bottle, Sally a 44-year-old orangutan carries her
water bottle in her mouth at the Denver Zoo on Friday, January 20, 2012.
She underwent a major surgery on her uterus last year. (Cyrus McCrimmon, The Denver Post)
five orangutans, has lived in Denver since 1996, arriving after stints
at the Albuquerque BioPark Zoo and the Cheyenne Mountain Zoo in Colorado
Springs, where she was born Dec. 1, 1967. She is one of only 212
orangutans in zoos in North America, and 684 around the world. In the
wild, Sumatran orangutans are critically endangered: Only about 8,000
Like most orangutans, Sally is solitary, preferring
time alone. She fills her days eating the vegetables and fruits that
comprise most of her diet — all of it weighed in precise amounts because
orangutans in captivity are prone to obesity. She cycles between
different environments: smaller, quiet rooms shielded from the public;
the indoor space, with the ropes and the meandering climbing structure
where Sally makes paint out of chalk and water to draw on the walls; and
the sprawling outdoor area, where the 130-pound ape often climbs a
cottonwood tree and watches traffic on East 23rd Avenue.
last winter Sally was good-natured, with "a lot of personality and a lot
of rules," said Cossaboon, who has worked with the Denver Zoo
orangutans for nearly 10 years. When Sally would see other orangutans
getting attention from zoo employees, she would demand at least equal
But a little more than a year ago sour moods began replacing Sally's normally upbeat, spirited approach to life.
"She wasn't interested in food, in playing," said Cossaboon. "We knew something was wrong."
the same time, her menstrual flow had become erratic. At first zoo
doctors weren't too alarmed — she was an elderly orangutan after all.
Most orangutans don't live much longer than 50 years in captivity (it's
shorter in the wild). But by January of last year, the volume of
discharge began to disturb zoo veterinarian Diana Boon. The ape started
showing signs of anemia.
In March, Boon called Preston Stubbs with
the Animal Hospital Specialty Center in Highlands Ranch, a veterinary
clinic known for its surgical staff. When she reported Sally's problem,
Stubbs offered his CT scan imaging equipment, free of charge.
The machine revealed a large mass in the abdomen, which they guessed was a fibroid, a benign tumor associated with
Prang of Denver studies Sally, a 44-year-old Sumatran orangutan at the
Denver Zoo, on Jan. 20. Sally started showing signs of illness early
last year. In the spring, a CT scan showed a large mass in Sally's
abdomen, which appeared to be a benign tumor. By summer, the ape had
stopped going to the bathroom and emergency surgery was the only option
for Sally's survival. (Cyrus McCrimmon, The Denver Post)
uterus. Biopsies confirmed the diagnosis. Boon placed Sally on a
regimen of hormonal therapy (using the same drugs human women use,
including a type of birth control), thinking the drugs would diminish
the size of the growth and help regulate Sally's menstrual cycles.
The strategy failed. And in June, Sally stopped going to the bathroom.
"It was an emergency," said Boon.
Surgery particularly high-risk
the spring Boon had formed what she called "Team Sally," a group of
five surgeons who work out of University Hospital and two
anesthesiologists from Children's Hospital. Should Sally need surgery,
Boon wanted physicians who had prepared for it.
She began getting
in touch with other zoos, to amass enough orangutan blood for the
operating room. If Sally's condition forced surgeons to cut open
Sally's belly and remove the growth, which had swelled into something
the size of a soccer ball, having blood on hand would be important. It
was major surgery.
But when Sally lost the ability to go to the
bathroom, Boon understood she had only days to live if the obstruction
wasn't removed. So on a Friday afternoon she fired off e-mails to the
team, telling them the surgery had to be done by Sunday. And they
wouldn't have blood.
"It had to be a bloodless surgery," Boon
said. "It was either this would work, or this wouldn't work and it would
be fatal for Sally."
And then, the group got a break. Covidien, a
Boulder company that makes a device called LigaSure that helps limit
blood-loss during surgery, donated the use of a machine for Sally's
Another snag loomed. The procedure demanded quite a bit of
rummaging around in Sally's abdomen. If a wayward blade nicked her
distended bowel, she would die; Sally would not understand how to use a
Six nerve-wracking hours
Dr. Monique Spillman, a gynecologic oncologist, to lead the team, and
Spillman began searching for information about orangutan anatomy
immediately. Unfortunately, she didn't find much — where human anatomy
is mapped in great detail, orangutans remain relatively uncharted.
Still, orangutan anatomy at least parallels that of humans. So
once Team Sally's far-flung members all finally stood in the zoo's
pale-blue operating room, and Spillman cut into the ape, things seemed
"What we first encountered was the
infected part," said Spillman. "It's like somebody took a bowl of
spaghetti and poured Super Glue all over it."
The huge fibroid
contained an abscess, a zone of infection, which explained why it was
growing so rapidly. Sticky adhesions on the fibroid attached it to
other things in the abdomen, like the bladder, the bowels and the
Methodically, patiently, the team picked its way
through the cavity, liberating organs from the fibroid one scrap of
flesh at a time.
The mood was intense and "collegial," said Julia Embry, a senior gynecologic oncology fellow.
was peeking in, no one made a decision without discussing it with
everybody else," said Embry, who grew up around animal surgeries — both
of her parents are veterinarians. "It just warmed your heart. I felt
honored and privileged. To look back at your life one day and say, 'I
was able to help this endangered species.' "
When they felt
confident the organs were safe again, the team turned over the procedure
to Alvero, who best understood female reproductive organs. Should the
uterus be removed? Alvero decided it should stay put — pulling it from
the abdomen would have added three more hours to the surgery, and could
have caused more harm than leaving it alone.
"It still gives me chills," said Boon of the "nerve-wracking, inspiring" six-hours of toil.
Cossaboon, the orangutan keeper, canceled a vacation to be with
Sally during the procedure. She couldn't watch from within the operating
room, though. Fear and anxiety overwhelmed her, and she paced outside
the room while the doctors worked.
Weeks later, Sally had
recovered enough that Cossaboon, who knows her better than anybody else,
could not tell she had just gone through such an ordeal.
Team Sally and their families returned to the zoo within the month, to see how she was doing.
was getting all pretty for us when we showed up," Embry said. "When the
zookeepers tried to get her to show us the incision, she just combed
her hair. She was primping for us."
Alvero said the reunion formed an even deeper connection between the team and Sally.
"You kind of saw there was some sort of understanding," he said. "Dare I say it? She seemed grateful."
Doug Brown: 303-954-1395 or djbrown@denverpost
Team of doctors
A team of five surgeons working out of University Hospital and two
anesthesiologists from Children's Hospital Colorado saved the life of
Sally, a 44-year-old orangutan living at the Denver Zoo.
Dr. Monique Spillman, gynecologic oncologist
Dr. Kian Behbakht, gynecologic oncologist
Dr. Henry Galan, maternal and fetal specialist
Dr. Ruben Alvero, reproductive endocrinology and infertility specialist
Most of us were taught
the importance of a balanced and nutritionally complete diet. But when
it comes to knowing what nutrients our pets need to grow properly and
stay healthy, we often come up short.
Many years ago, little
thought or research was put into the manufacture of pet food, or the
proper way to feed our pets. Eventually, in response to consumer demand,
the Association of American Feed Control Officials (AAFCO) was formed.
Their primary function was to publish feed regulations and ingredient
definitions. After much research, committee investigations and feeding
trials, nutrient profiles for pets were developed, and guidelines
This is still a work in progress. Despite
significant advances, the importance and proper levels of some nutrients
are still under investigation. The recommendations of AAFCO, for
instance, may change when additional information about nutritional
health in dogs becomes available.
For now, the minimum levels of nutrients that should be included
in pet foods are listed. In a few cases, excess amounts of certain
nutrients can be damaging so maximum levels are also listed in AAFCO
When buying pet food, choose only those products
that carry the statement "Formulated to meet the AAFCO Dog Food Nutrient
Profile for..." because they follow these guidelines. It is not a
requirement to meet AAFCO standards in order to sell pet food, so buyers
beware. Check the labels and compare products.
list is divided into two separate profiles. One profile is for growing,
pregnant or lactating dogs and one is for adult maintenance. The
nutrients are listed on a dry matter basis. What this means is that if
you are comparing products, the moisture content of the food must be
taken into consideration. If the food has 75 percent moisture, then the
remaining nutrients make up 25 percent of the food.
nutrient amount and divide by 0.25 to obtain an accurate dry matter
amount to compare to the nutrient guidelines or even to compare one food
to another. If the moisture content is 10 percent, then 90 percent make
up the rest of the nutrients. Divide each nutrient value by 0.9 in
order to get an accurate value.
Current AAFCO Dog Food Nutrient Profiles
For Adult Maintenance
Unless otherwise listed, all values are minimum requirements:
Vaginal hyperplasia is
an exaggerated response by the vaginal tissue to estrogen during certain
phases of the estrus (heat) cycle. The vaginal tissue becomes swollen
and may protrude through the vulva, or external female genital organ, as
a tongue-shaped mass.
Vaginal hyperplasia is most common in
young intact female dogs and is thought to be caused by estrogen
stimulation. There is a genetic predisposition to developing vaginal
The breeds most commonly affected include the Labrador retriever, Chesapeake Bay retriever, boxer, English bulldog, mastiff, German shepherd, St. Bernard, Airedale, springer spaniel, walker hound and Weimaraner.
What to Watch For
A protrusion of a round tissue mass from the vulva
Licking of the vulvar area
Failure to allow breeding
Baseline tests, including complete blood count (CBC), biochemical profile, and urinalysis, are usually within normal limits.
Careful inspection and examination of the vulvar area generally reveals a fairly classic appearance of overgrown tissue.
A biopsy may be recommended in an old bitch in order to rule out the possibility of cancer.
Management of vaginal hyperplasia can be difficult. If the patient can urinate, treatment is generally not an emergency and outpatient care
is recommended. If there is a blockage due to the mass, immediate hospitalization and intervention is necessary.
enough time, most all cases of vaginal hyperplasia are reversible, as
certain periods of the estrus cycle allow for it to resolve. Treatment
Daily cleansing of the affected area with saline washes
Lubrication with appropriate jellies
Padding the environment to avoid direct exposure to concrete or abrasive surfaces
Elizabethan collar to eliminate the possibility of excessive licking and chewing
Diapers to minimize exposure of the tissue to the environment and the patient herself
i quoted some paragraphs.... worth the ethical practice ^^
“There are four principles to keep in mind regarding appropriate antibiotic
use,” continues Dr. Muse. “One is that the correct choice of antibiotic needs to
be made for a particular infection. The second is the proper dose must be given.
Third is that the dose must be given at defined intervals because some
medications should be given once a day and others four times a day to achieve
consistent and effective tissue levels of the antibiotic. And finally, the
antibiotic needs to be given long enough to truly effect a cure.”
whew! finally found the term i've been looking for >< this is different from polyuria whick means large amount of urine.
"Pollakiuria: Mostly affects children between the age of 3-8 years, and causes frequent daytime urination, sometimes up to 10-30 times a day, usually with very small amounts of urine being produced at each time. Children with pollakiuria usually do not have other symptoms, and it is not known what causes it, although it may be linked to stress. No treatment is necessary and symptoms usually go away after about 3 months. It is also called Extraordinary Daytime Urinary Frequency Syndrome."
In general, female mice reach sexual maturity, and estrous cycles commence around 4 weeks of age. However, inbred strains often reach sexual maturity a little later than outbred strains. Consequently, many labs begin breeding females at 5-6 weeks of age.
Mice have a 4-5 day estrous cycle that is divided into four phases-proestrus, estrus, metestrus and diestrus.
Proestrus: Ovarian follicular development occurs. Estrus: Female is sexually receptive to male; ovulation occurs; duration 6-10 hours. Metestrus: Corpora lutea forms; mature eggs move through oviduct into uterus. Diestrus: Follicles begin to undergo rapid development for next ovulation; previous ova are eliminated.
Ovulation usually occurs 3-5 hours after onset of the dark cycle. Males will generally copulate with females in estrus at about the midpoint of the dark period. In addition, the estrous cycle is profoundly affected by the light cycle (hours of light and dark); interruption of the dark cycle can affect reproductive performance. In general, breeding mice should be maintained on a 12:12 cycle (12 hrs light: 12 hrs dark).
Each phase of estrus can be identified by the appearance of vaginal epithelium and vulva. It is possible to identify females in estrus by examining the color, moistness and degree of swelling of the vagina, see below.
Proestrus: Vagina is gaping; tissues are reddish-pink and moist; numerous longitudinal folds or striations visible on the dorsal or ventral lips.
Estrus: Vaginal signs similar to above, but tissues are lighter pink and less moist; striations are more pronounced
Metestrus: Vaginal tissues are pale and dry; dorsal lip less edematous; whitish cellular debri may line the inner walls and/or partially fill the vagina.
Diestrus: Vagina has small opening; tissues are blue and very moist.
The Effect of Pheromones on the Estrous Cycle
Pheromones are scents emitted by mice that cause behavioral and physiological changes in other mice, both same and opposite sex. Pheromones can produce significant influence on reproductive performance of mice and can be used to an investigator's advantage.
Below are several pheromone-induced reproductive effects:
Suppression of estrus in grouped females Group housed female mice tend to stop cycling and display either pseudopregnancy (Lee-Boot effect) or anestrus. This phenomenon can be exploited in some strains by grouping females together before exposure to a male (see below).
Induction of estrus by a male (Whitten effect) Whether a female mouse is housed alone or in an all female group, exposure to a male has an immediate effect upon her cycle. A new estrus cycle is initiated in group housed females, while individually housed females begin to cycle regularly. To utilize this effect, single or group housed females are exposed to a male, or male mouse urine (dirty bedding). A majority of females will then be in estrus the 3rd night after exposure to the male mouse.
Male-induced pregnancy block (Bruce effect) Pregnancy can be blocked during the preimplantation period by exposure to a strange male. Exposure to a male of a different strain than original male causes failure of implantation, followed by return to estrus in 4-5 days.
Superovulation regimens are commonly used to maximize the number of ova released at a particular ovulation, such as collection of ova for production of transgenic animals. A combination of Pregnant Mare's Serum Gonadotropin (PMSG) and Human Chorionic Gonadotropin (HCG) is often used. For more information on superovulation regimens, please contact the Transgenic Mouse Facility at 824-8579.
Mixing Breeding Pairs
Breeding animals should be mixed by placing a female mouse (or mice) into a male's cage. Placing a male into a female's cage often results in lack of mating and may result in the female mouse attacking the male.
The ejaculate from the male's accessory sex glands forms a short-lived, white to yellowish plug in the vagina of the female. Presence of a vaginal plug is often used to determine if copulation occurred between mice. By checking female breeding mice each morning, the presence of a vaginal plug allows one to estimate the approximate time of mating as the middle of the preceding night.
It is important to remember that the presence of a vaginal plug indicates that a mating took place, and does not mean that a pregnancy will result from the mating. It should also be remembered that lack of a vaginal plug does not always mean that mating did not take place, as the plug may have already dislodged. It is common to check for plugs early in the morning, as most matings take place during the dark cycle each evening.
External visualization of the vulva and plug. However, deeper plugs may be missed by this method.
Use of a small forceps to gently part the vulvar lips to identify the plug in the vagina.
Use of a blunt probe (i.e.: capillary tube, glass rod) to examine the vulva and vagina for presence of a plug.
Pregnant mice will fail to return to estrus and will not breed when placed with male mice.
Abdominal distention is apparent in most mice by 12-14 days of gestation. Mice with large litters may show distention slightly earlier.
Palpation of the uterus: By days 12-14 a small "string of pearls" may be palpated. Palpation takes practice, patience and a soft touch.
Gestation in mice varies slightly by strain and ranges from 19-21 days. Smaller litters are often carried longer than larger litters.
Postpartum Estrous and Delayed Implantation
Mice have a fertile estrus that occurs 12-24 hours after delivery (postpartum). If a mating takes place, the embryos resulting from the postpartum mating undergo developmental arrest and delayed implantation. Consequently, the delivery date of the pups from the postpartum mating may be delayed 4-5 days.
Handling Pregnant Females
Near term females with greatly distended abdomens should be disturbed as little as possible. Rather than lifting them the tail, it is recommended to gently lift them in the palm of the hand. Care should also be taken to insure the mouse will not jump out the handler's cage and injure itself.
Cage Preparation: If possible, it is recommended to minimize disturbances to the female within 2 days of delivery and for 2-3 days after delivery. If the female is singly housed, or paired with a male, the cage should be changed 2-3 days before delivery and nesting material added to the cage. The cage should then be left undisturbed for 2-3 days after delivery. If the female is housed as part of a harem, it is recommended that the female be separated into a single cage several days prior to delivery. Delivery in a harem cage may result in an overcrowded cage and occasionally results in trampling and death of the pups.
Nesting material: Nesting material is not required for successful rearing of pups, but it may aid in decreasing cannibalism in nervous dams and strains with a history of cannibalism. Nesting material also helps create a warm microenvironment for the pups during the early neonatal period. Popular nest material includes Kimwipes, cotton nestlets and shredded paper towels. The dams will usually shred the material and create a nest. Nests also allow easy transfer of young litters between cages at cleaning time. The whole nest can be gently grasped and transferred between cages with little disturbance to the mouse pups.
Occasionally, mice experience difficulties during delivery (dystocia) and a cesarean section (C-section) is required. C-sections can also be used as a method of rederiving mice that are contaminated with certain viral, bacterial and parasitic agents. If you have questions about performing C-sections in mice, please contact Veterinary Services.
Foster rearing involves transferring pups from one dam to another to be raised. It is performed for many reasons, including strain history of poor maternal behavior, maternal neglect, poor milk production by the dam, death of the dam, excessively large litters and experimental dam.
Selection of foster dams: The best candidate for a foster mom is a strain with a history of good maternal behavior. Generally, outbred strains (e.g. CD-1) are usually better foster moms than inbred strains such as C57BL/6.
Age of pups: Ideally, a foster mom should have a litter of her own that is within approximately 1 day of age as the pups to be fostered. In addition, it is also recommended to select a dam that has successfully raised a litter previously.
Suggested procedure for cross fostering:
Remove the foster dam from her cage, while leaving her pups in the original cage. If the size of the foster dam's original litter must be decreased to allow room for the incoming pups, this should be performed now. In general, the final litter size should be between 6-10 pups, depending on the strain.
Transfer the pups to be fostered to the foster cage. Mix the foster pups with the original pups to pick up their scent, and the scent of the foster mom. Many find it successful to hold all the pups (foster and original) in their cupped hands to mix them up and thoroughly mix the scents. Also, if the fostering pups are cool, warming them in your hands may increase the likelihood of acceptance by the foster mom.
Place all the pups in the foster mom's original cage. If nesting material is available, place all the pups in the nest.
Return the foster mom to her cage. If she has not rejected the litter in 10-15 minutes, she will usually continue to care for them.
Identification of fostered pups: If it is necessary to identify the fostered pups to allow subsequent separation from the foster dam's original litter, several options are available. The easiest method is to select a foster dam (and litter) with a different coat color. If the coat color is the same, procedures such as tail snips or ear notching can be performed to identify the foster animals.
Nutrition of the Pregnant Mouse
Most outbred, and many inbred strains perform well with standard rodent chow. However, a few inbred and mutant strains may require a higher fat (and protein) diet for breeding and lactation, and "breeder" diets are available for this purpose. The increased fat in such diets may increase body weight and rate of gain during pregnancy compared to regular rodent diets. However higher fat diets may cause male mice to become obese and lead to poor breeding performance. Please contact ULAR for information on ordering higher fat diets.
Breeding Life Expectancy
Reproductive performance of female mice tends to decrease with increasing age and number of prior pregnancies. Few females of inbred strains, with the exception of FVB/N, will produce more than five litters. And, irrespective of past reproductive history, most inbred females exhibit greatly reduced fecundity by the age of 8-10 months. Reproductive characteristics for specific strains of mice are usually available from commercial vendors. See section I below for reproductive characteristics of selected inbred strains.
Outbred mice and F1 hybrids will routinely surpass inbred strains when comparing reproductive performance. Productive matings (those resulting in live offspring) often approach 100% in outbred animals, the age of first mating can be as early as 5 weeks, and the females may remain fertile up to 18 months of age.
They are cheap, easy to look after and don't take up much room. They're also very sociable creatures, so you might want to get more than one mouse. Make sure they're the same sex though – otherwise you could end up with a large family of mice very, very quickly!
A baby mouse is called a pinky, or a kitten
A female is called a doe
A male is called a buck
It’s very important to keep males and females separate
Mice live for one to two years. They can start having babies at 6-8 weeks old and have 5-10 in each litter (pregnancy lasts 3 weeks). Babies are born hairless with their eyes closed. One mother mouse can produce over 100 babies a year.
NEVER pick up a mouse by its tail
Caring for mice
Mice are quite intelligent, so they need other mice or toys to play with. They also need regular exercise to stay healthy.
Boys tend to fight. If you’re planning on having a couple of boys make sure they are the same age and preferably from the same litter.
Mice are constant eaters, so food and water should always be available
Commercial mouse pellets (from pet shops) are the best way to ensure your pets are getting all their nutrients.
The RSPCA reckon that pellets should make up around 90% of the diet and be supplemented with fresh vegetables (not lettuce or celery), a small amount of fruit (like apples), oats or wholemeal bread. They like to chew carrots too.
Mice love to gnaw things, so the hard pellets are good for their teeth.
Dandelions, nasturtium, clover, comfrey and herbs like basil, mint and sage are also good for mice.
Mice will eat everything, whether it’s good for them or not. So you can feed them all sorts of foods as treats. They’ll eat cheese, bread & butter, jam sandwiches, eggs, popcorn, banana chips. Seeds and nuts are ok as treats sometimes but they’re high in fat. Special mouse seed mix is available at some pet shops. Dairy products can cause stomach upset in some mice.
No raw onion, peanut butter, human chocolate
It’s important to keep food & water bowls clean. Do not use plastic bowls - they will get chewed and small pieces could be swallowed. Lots of people use a special inverted water bottle – they’re cleaner and don’t spill.
If you’re keeping your mice in an aquarium make sure you have a wire top for ventilation. Mice need a lot more air than fish!
If you let your mouse out of its cage for a run around, be very careful that it can’t chew telephone or electrical cables. Not only could the mouse be killed, it could cause a major electrical fire.
Kitty litter can be used to cover the bottom of the cage to absorb the smell of wee (the recycled newspaper type is recommended)
Mice like to have a nesting box – this can just be an shoe box – and should have some paper towel or cloth in
Every once in a while you hear a story about a hen that changed into a
cock. Such stories are often meet with skepticism, but sex reversals
do, in fact, occur, although not very frequently. To date, however,
spontaneous sex reversal from male to female has not been reported.
In spontaneous sex reversal, only the phenotype3 is altered. Genetically, the bird remains a female, but externally it appears male.
Differences between the sexes
A young chicken is called a chick. A male chicken is a cock or a
cockerel, depending on its age. Similarly, a female chicken is called a
pullet or a hen. The age at which a pullet becomes a hen and a cockerel
becomes a cock depends on what type of chicken is being raised.
Purebred poultry producers have very age-specific definitions. A
chicken is a cockerel or pullet if it is less than one year of age.
After one year of age, the chicken is referred to as a hen or cock. In
the commercial chicken industry a female chicken is called a hen after
it begins egg production (around five months of age). A sexually mature
male chicken (again, around five months of age) is referred to as a
The observable differences in secondary sex characteristics between the
male and female chicken are referred to as sexual dimorphism.
The male has a larger body, comb, and wattles than the female.
In single-comb birds the male's comb will be turgid and stand erect, whereas the female's may flop over on one side.
The male has a larger, more developed spur than does the female.
Roosters crow, while hens do not.
In multicolored varieties, the male will have more variety of coloring in his plumage than the female.
The male has longer and more pointed hackle feathers than the female.
The male and female both have main tail feathers, but only the male has saddle feathers.
As often happens, there are exceptions to these
differences. Males of two breeds of chicken, the Campine and the
Sebright, for example, have female plumage. The female plumage pattern
is dependent upon the presence of estrogen to femininize the feather
follicle and direct feather formation to produce more rounded feathers
in the hackles and tail. These two breeds possess a single gene
mutation that codes for excessive aromatase production in several
tissues, including the feather follicles. Since aromatase is the enzyme
responsible for the conversion of androgens to estrogens, the feather
follicles of males of Sebright and Campine breeds have excess estrogen
production. The level of estrogen in the feather follicles is
sufficient to femininize the growing feathers. Castration of Sebright
or Campine males removes the source of androgens for conversion to
estrogen in the feather follicles causing their female plumage to
revert to the male phenotype.
CREDITS: From Poultry Science & Production, by R.E. Moreng and J.S. Avens
Figure 1. Parts of the male chicken.
CREDITS: From Poultry Science & Production, by R.E. Moreng and J.S. Avens
Figure 2. Parts of the female chicken.
Genotype or Phenotype?
Sexual differentiation in birds is directed by the presence or absence
of the W chromosome, similar to the Y chromosome in humans.
Genetically, male birds are homozygous, ZZ, and the female bird is
heterozygous, ZW. This is opposite from mammals where the male is
heterozygous, XY, and the female homozygous, XX.
Within a few days after fertilization, the female chicken embryo can be
identified by the accumulation of primordial germ cells in the left
gonad (primary sexual gland). By the tenth day of incubation, the
gonads are sufficiently differentiated to be recognized upon autopsy.
Throughout embryonic development, however, there are no external
characteristics that identify the sex of the chick. At hatch, male and
female chicks are the same weight and, with the exception of specific
genetic variants in down color or feather length, neither males nor
females exhibit any distinguishing secondary sexual characteristics.
The acquisition of secondary sexual characteristics as birds mature is
a consequence of the hormonal secretions from the testes and ovary. The
development of secondary sexual characteristics, representing the
phenotypical expression of the sex genes, is dependent upon the
production of both androgens and estrogens.
Androgens are required to induce growth of the comb and wattles in
roosters. They are also responsible for full expression of the
characteristic voice of the rooster. The growth of spurs, however, is
independent of testicular and ovarian secretion. Their growth is
determined by the genetic sex of the bird.
The female plumage color is dependent upon the presence of estrogens to
femininize the feather follicle and direct feather formation to produce
a more rounded feather in the hackles and tail. In breeds of chickens
that are sexually dimorphic for feather color, the estrogens are also
responsible for the reduction in pigmentation in many of the feather
How does sex reversal occur?
Most cases of spontaneous sex reversal are the result of a disease
condition which has resulted in damage to the left ovary. Typically,
female chickens only have one functional ovary, the left one. The right
ovary and oviduct are present in the embryonic stages of all birds, but
typically do not develop in chickens.
In general, spontaneous sex reversal has been described as the result
of pathological conditions (e.g., ovarian cyst or tumor, diseased
adrenal glands) which cause the left ovary to regress. Residual tissue
in the right ovary proliferates in the absence of a functional left
ovary. This regenerated right gonad is known as an ovotestis and may
contain tissue characterisitics of the ovary, the testes, or both.
There are reports of these ovotestes producing semen capable of
fathering offspring. Most, however, will never lay an egg or sire
The "ovotestes" are steroidogenically functional and secret androgens,
as well as estrogen. As a result, the bird develops male secondary
characteristics. So while the bird is genotypcially female, it will be
This document is FACTSHEET PS-53, one of a series of the Department of
Animal Sciences, Florida Cooperative Extension Service, Institute of
Food and Agricultural Sciences, University of Florida. First published:
November 2000. Please visit the EDIS website at http://edis.ifas.ufl.edu.
Jacqueline Jacob, poultry extension coordinator, and F. Ben Mather,
poultry extension specialist, Department of Animal Sciences,
Cooperative Extension Service, Institute of Food and Agricultural
Sciences, University of Florida, Gainesville, FL 32611.
There is an interesting analogy from nature that can be applied to Hezzbollah in Lebanon.
There is a parasite out there that has multiple hosts. A heron, a snail, and a frog. The parasite starts its cycle in the heron and works it way to snails. From the snails it finds tadpoles and does an interesting thing. It causes the infected tadpole to develop malformed legs as it transforms from tadpole into a frog. Hence you get frogs with multiple legs, short useless legs, missing legs, and other variations on the messed up leg theme.
Why? Because the parasite needs to work its way back into the gut of a heron so it engineers crippled frogs that are easy prey for herons.
Same goes for the current situation with Lebanon. Lebanon is infected with the parasite of radical Islamism and it is mutating Lebanon to cause Israel to attack it thereby making Lebanon more prone to takeover by Hezzbollah and radical Islamists.
Ironically what is the cure? Hezzbollah admits is underestimated the Israeli response, half-... responses the kind Israel usually engaged in were what they were hoping for. Another bombing of a Hezzbollah safehouse, another film crew filming healthy children being rushed to the hospital and the world once again lambastes Israel.
In order for Lebanon to excise the parasite it must be cooked clean. That is the once the frog of Lebanon is kissed by the fire it will turn into the prince it once was.