SHB Category: B, Reproduction Flashcards
Left off with question #555 on page 77 Pages 39-91
When a stallion extends his neck upward and curls his upper lip during the teasing process, what is the action called?
Flehman reflex or olfactory reflex
What term describes a mare that is not pregnant and was not bred in the previous or current season?
Open mare
A colt is considered a cryptorchid if its testes have not descended by what age?
15 months
What are the designated sex chromosomes of the stallion and the mare?
Stallion-XY, Mare-XX
What is the most common cause of abnormal sexual behavior leading to infertility?
Mismanagement
What is the term for a mare that is not pregnant but was bred in the previous or current season?
Barren mare
What is the term for a mare that is nursing a foal?
Wet mare
What injection should be given to the mare and foal after parturition?
Tetanus antitoxin
What term describes a mare that has never been bred?
Maiden mare
What controls the expression of traits of the horse and are located on chromosomes?
Genes
How long does an ovum live after ovulation if pregnancy does not occur?
12-24 hours
What is the recommended age to wean foals?
4-6 months
What is the expulsion of the fetus prior to 300 days of gestation?
Abortion
What is the length of the average gestation period?
335-340 days
At what age does the mare’s reproductive abilities start to decrease?
After 16 years
What is the initial step in breeding a mare?
Restraining the mare
When is the optimal time to breed a mare?
Just before ovulation
What is the first thing that should be done when a foal is first born?
Check if it’s breathing
Why should straw be used in a foaling stall?
Shavings and similar materials will stick to the wet nostrils of a newborn foal and may suffocate it
What is the best test of a breeding animal?
Type of offspring it produces
Most mares should be kept in a box stall for how long prior to foaling?
1 week
The rupture of the follicle refers to what?
Ovulation
What term describes the techniques of estrus detection?
Teasing
How long does estrus period usually last in a mare?
5-7 days
The age of puberty in stallions is what?
11 1/2 months to 16 3/4 months
What is the first defecation of a foal following parturition?
Meconium
What is another name for the prepuce?
Sheath
What is the first heat period following parturition called?
Foal heat
What is the relationship of 2 fillies that have the same sire and dam
Full sisters
What is foal heat?
First heat period following foaling
What is the most difficult part of parturition?
Passage of the shoulders of the foal
Name 3 primary types of gene actions that affect the horse’s traits
Dominance, co-dominance, partial dominance
What is the simplest method of bringing a mare into estrus prior to the natural breeding season?
Artificial lighting
Which inherited lethal was originally called the Fredericksborg Lethal?
Lethal White gene, W
What is the term for characteristics that ultimately result in death?
Delayed lethals
Horses have 33 different chromosome strings, the X and Y chromosomes are called sex chromosomes, what are the other ones called?
Autosomes
Which gene is responsible for mottled, varnish roan, blanket with spots, blankets, frost, leopard, and a few leopard spots in horses?
Leopard gene, Lp
Why are all roan colored horses heterozygous Rnrn?
All homozygous roan horses die in early fetal development and are never born
What is the term for a condition that results in embryonic death?
True lethal
What is the external opening to the mare’s reproductive canal?
Vulva
Name a breed of horse that is homozygous for the Dn gene.
Fjord horse
What is a synthetic progestin compound that does not interact with the mare’s natural progesterone and is used to regulate estrus early in the breeding season?
Regumate
The foal should be assisted up and guided to the mare’s udder if the foal is not nursing in what amount of time?
2 hours
What color are the foal’s hooves at birth?
Cream or White
The foal can only absorb the antibodies in the colostrum for how long?
36 hours after birth?
What is usually applied to the naval stump to cause closure of the urachus?
Silver nitrate or it is sutured
What is the name of the hormone that signals the start of the reproductive season?
Gonadotropic releasing hormone
Stallion spermatozoa do not move in the twisting progression like other sperm, how does it move?
In straight lines
What is it called when organs or tissue project through an abdominal opening and usually occur in the naval or scrotum area?
Hernia
What kind of bedding is preferred for a foaling stall?
Straw
Which hormone stimulates the growth of follicles?
FSH
What is a major site for bacterial invasion into the newborn foal’s body that should be treated with an iodine solution to prevent infection?
Naval stump
Most traits in horse are influenced by what type of gene action?
Quantitative
If there is an orphan foal, what can be put over the foal to disguise its odor, so another mare will let it suckle?
Oil of Linseed or Whiskey
What are the accessory sex glands of the stallion?
Seminal vesicals (vesticular glands), Bulbourethral (cowper’s gland) and prostate gland
The 2 basic types of gene actions are quantitative and qualitative, which is most common?
Most traits in horses are influenced by quantitative gene actions
What type of genetic action is when many genes have an effect on the same trait and they are added together to produce that trait in a horse such as speed?
Quantitative gene action
What are the accessory sex glands of the stallion?
Seminal vesicles, bulbourethral gland (cowper’s gland), prostate gland
Name the 2 types of genetic hernias
Umbilical and inguinal
What are the gonads?
Ovaries and testicles
What phase of the estrous cycle occurs when the mare’s attitude towards the stallion varies from non-interest to complete resentment?
Diestrus
What is the term for characteristics that predispose an animal to disease conditions because of environmental factors, but do not in themselves cause disease?
Partial lethal
What is the powerful middle layer of the uterus that is responsible for contractions which expel the foal at birth?
Myometrium
Where is the site of spermatogenesis and production of testosterone?
Testes
Which genetic lethal can be traced to the Percheron stallion, Superb, that causes death as a result of the failure to elimante feces?
Atresia coli (severed large intestine)
What is the main body of the penis called?
Shaft
What is the term for the secretions of the testes, epididymis and accessory glands mixed with spermatozoa?
Semen
What is the name of the enlarged pre-ovulatory follicle?
Graafian follicle
What are the 2 classifications of abortions?
Infectious and non-infectious
What type of genetic action is when a particular trait is influenced by a single pair of genes or maybe 2 or 3 pairs of genes such as the dilution of bay to buckskin?
Qualitative gene action
Blood type is an example of which gene action?
Co-dominance
How long does the stallion semen last in the mare’s reproductive tract after ejaculation?
Usually 48 hours but can last up to 5 days
What is the more common term for the rupture of the chorio-allantoic membrane during pregnancy?
Breaking of the water bag
What is the 6-8 inch long muscular mucous membrane-lined tube which communicates the vestibule of the vulva to the cervix?
Vagina
Name the wedge-shaped area of the ovary from which ova are shed.
Ovulation fossa
What is the mare called that carries a fertilized egg to term that was removed from another mare?
Recipient mare
How long will sperm survive?
24-30 hours after ejaculation
How may bacteria enter the foal’s blood system?
Via the umbilical cord
What hormone causes receptive behavior patterns observed in mares during heat and acts to prepare the uterus for receiving the embryo?
Estrogen
What is the name of an enlarged preovulatory follicle
Graafian follicle
How soon after ovulation can pregnancy be diagnosed by ultrasound?
11-14 days
What phase of the mare’s estrus cycle comes after she ovulates?
Diestrus
What is the gene for roaning?
RN
What term describes nonidentical genes that are located at the same physical position on a chromosome?
Alleles
Name the substance in colostrum that is very important to the health of newborn foals.
Antibodies or immunoglobulin
Why would you put a stallion under artificial light?
Increase testicular activity
At what time do most mares foal?
Between 7 PM and 7 AM
Which of the pinto patterns is considered to be dominant?
Tobiano
Milk production varies greatly among mares but peak lactation might be expected when?
8-12 weeks after birth
What reproductive hormone is secreted by the hypothalamus in response to environmental cues such as day length?
Gonadotropic releasing hormone (GnRH)
Name the 2 basic methods of collecting the embryo from the donor mare and transferring it to the recipient mare.
Surgical and non-surgical
In the stallion, the hormone FSH exerts its effect on which cells?
Serloli cells
Spermatogenesis is made up of a series of events leading to the release of spermatozoa. How many days are required for these events to occur?
57 days
What does the word genotype mean?
Genetic make-up of an animal
What does the word phenotype mean?
The outward appearance of the animal
What is the hormone necessary for normal sexual behavior and function in the stallions?
Testosterone
Peak lactation in a nursing mare usually occurs when?
8-12 weeks after parturition
What term describes any foaling problem that prevents delivery of foal by the mare’s efforts alone?
Dystocia
Colts are usually carried about how much longer than fillies during gestation?
2-7 days
On which chromosome does the gene for hemophilia ride?
X chromosome
What acts as a physical barrier between the vagina and the uterus?
Cervix
What phase of the estrous cycle occurs when the mare’s attitude toward the stallion varies from noninterest to complete resentment?
Diestrus
How long can semen be stored in a refrigerator prior to its use for AI?
Up to 24 hours
What hormone is responsible for milk let down and contractions during parturition?
Oxytocin
How often can a stallion’s semen be collected without interfering with the stallion’s ability to produce sperm?
Up to 3 times daily for short periods
What is dystocia?
Any foaling problem that prevents delivery of the foal by the mare’s efforts alone
How many chromosomes do horses have?
64 or 32 pairs
Brood mares can be protected against rhinopneumonitis by immunization with an inactivated vaccine during which months of pregnancy?
Third, fifth, seventh, and ninth
Urine on the naval stump due to the failure of the urachus to close is called what?
Previous or persistent urachus
Lack of treatment or presence of urine on the naval stump may lead to infection, which can in turn lead to what problem?
Naval ill
Define the term seasonally polyestrus
Reproductive habits of the mare in which she undergoes multiple estrous cycles only during a circumscribed portion of the year
What is it called when there is a transfer of an embryo from one female to another which carries it to term?
Embryo transfer
What is the mare called that has a fertilized egg removed from her and placed in another mare?
Donor mare
The genetic material is located within what cell structure?
Nucleus
What is the ability to pass on characteristics and qualities to offspring?
Prepotency of genes
What is the production of spermatozoa called?
Spermatogenesis
What is the study of hormones and their effects?
Endocrinology
The lethal problem called white foal syndrome will occur when breeding parents of what color together?
2 overo colored parents
What condition does the Caslick operation prevent?
Pneumovagina (windsucking)
What is the length of the gestation period for the American Miniature Horse?
11 months
Why would oil of linseed or whiskey be poured over an orphan foal?
To disguise foal’s odor so another mare will let it nurse
Why don’t females suffer from X-linked hereditary disease?
Females have to be homozygous for trait to suffer from it and would have to receive abnormal gene from both parents. Most affected males do not live to reproductive age and therefore do not sire foals.
What is the term used when EVR causes a high percentage of mares on one farm to abort?
Abortion storm
What is the major advantage of artificial insemination?
More mare per season can be bred
What is the tube that extends from the tail of the epididymis to the urethra?
Vas Deferens
When do ‘wax beads’ appear on the teats of a mare?
A few hours to 2-4 days before foaling
Which pinto pattern is associated with the lethal white foal syndrome?
Overo
What is a cryptorchid?
Animal with one or both testes undescended into the scrotum
What are the 2 parts of the uterus?
Hom and body
What types of chromosomes are the X and Y chromosomes?
Sex chromosomes
What happens to the offspring of roans and white horses whose genetic pattern is homozygous?
They die in early fetal development
What is the initial step in an embryo transfer?
Synchronizing the ovulations of donor and recipient mare
Why are all white horses heterozygous?
Because white homozygotes die early in development
What is a common cause of death in older pregnant mares?
Uterine arterial hemorrhage
What is mastitis
Inflammation and infection of the udder
What is another name for convulsive syndrome?
Barker, dummies or wanderers
When is a mare usually anestrus?
In winter/during shorter daylight hours
The short estrus period soon after foaling is called what?
Foal heat
Describe 2 methods of estrous manipulation.
Photostimulation (artificial lighting during winter months that results in earlier than normal initiation of a mare’s estrus.) Hormonal/Endocrine Control (using hormones to control the mare’s reproductive cycles)
What hormone is responsible for stimulating ovulation and supporting the initial stages of corpus lutuem development?
LH
Which gland signals the start of the reproductive season by producing a chemical signal in the form of gonadotropic releasing hormone (GnRH)?
Hypothalamus
What is the term for the oil product of the sebaceou glands that build up in the end of the penis?
Smegma
Give 2 good reasons for having a mare’s immunizations up-to-date prior to foaling.
Higher concentration of antibodies to foal through colostrum, antibodies protect foal from disease
Name 2 basic colors that the color ‘chestnut’ is recessive to
Black and bay
Conception rates are highest when the mares are bred when?
1-2 days prior to ovulation
What is one of the most common uses of human chorionic gonadotropin?
To stimulate follicles to ovulate
What is the time period that occurs during the winter months when a mare is in sexual inactivity?
Anestrus
At what stage of pregnancy does the mare’s nutritional need increase?
Last 3 months of gestation
What is hemolyze?
Red blood cells that clump together
What is the most frequent cause of twin abortions?
Fetal malnutrition due to insufficient surface area for placenta attachment
How long does it take for the foal’s immune system to become functional and to be able to produce significant levels of antibodies to guard against diseases?
2-4 months
What is the medical procedure used to close the mare’s vulva to prevent her from sucking air and debris into her reproductive tract?
Caslick operation (episoplasty)
What process is used to prevent aspirating air and contaminants from entering the vulva of mares?
Caslick operation
When does a mare’s reproductive ability begin to decrease?
Usually after 16 years of age
What is the first step in freezing horse semen?
Collecting a gel-free semen
What is the name of the hormone responsible for testosterone production in the stallion?
LH- luteinizing hormone
What is the relationship of foals how have the same sire but are out of different dams?
Paternal half-sibs or half brother/sister
Name the 3 basic models of artificial vaginas.
Fujhira, Missouri, and Colorado
During parturition, what happens at the end of stage one that prepares the birth canal for the delivery of the foal?
Rupture of the water bag (chorion or chori-allantoic membrane)
What are foals called that suffer from Neonatal maladjustment syndrome?
Dummy or convlusive foals, Barker, Wanderer
What are the 3 methods of castration?
Primary closure method, closed technique, and open technique
What are the 2 most common methods used to manipulate the estrous cycle?
Artificial lighting and hormone stimulation
What is the best choice for bedding in a foaling stall prior to parturition?
Straw
What is the best choice for bedding in a foaling stall prior to parturition?
Straw
What is the ‘book’ of a stallion?
Mares to be bred to a stallion
What is the most popular method of pregnancy diagnosis?
Rectal palpation
Mares that have chronic infections for air being aspirated into the vagina are called what?
Windsuckers
What type of response results from behavioral urinalysis by the stallion or teasing a mare to determine if she is in estrus and involves a curling of the upper lip of the stallion?
Flehman response
What is either of the 2 upper projections in the Y-shaped uterus of the mare, connection the Fallopian tubes to the body of the uterus?
Uterine horn
What is the length of the average estrous cycle?
21-23 days
Within 24 hours after ovulation, the corpus luteum begins to secrete this hormone.
Progesterone
Describe a teasing mill used to detect mares in estrus.
Special pen for the stallion surrounded by individual pens for individual mares that are being teased
What term describes the failure to show behavioral signs of estrus?
Silent heat
If a Rh positive foal nurses on an Rh negative mare with antibodies in her milk, what will happen to the foal?
It would die
What part of the ovary contains the ova when a filly is born?
Cortex
During the first 3 months after foaling, a mare will produce how much milk per their body weight?
Up to 3% of their body weight
What is the book of a stallion?
Mares to be bred to the stallion
What is the usual dilution ratio for AI?
1:1 or 1:4
What is generation interval?
Average time between the birth of animals and birth of their replacements
How does the length of daylight hours affect the breeding season and the reproductive response of the stallion and the mare?
Longer daylight hours (16 hr.) stimulate the reproductive systems, shorter hours suppresses and decreases hormones needed for reproduction
The lethal problem called white foal syndrome will occur when breeding parents of what color together?
Two overo colored parents
What is the heritability estimate when looking at the horse’s traits?
Percentage of a horse’s expressed traits that is due to genetics
What are the 3 main colors of horses that provide the basis for most of the other colors in color genetics?
Bay, black, and chestnut
What does flagging of the stallion’s tail indicate?
Ejaculation
Name the hair-like projections that line the mare’s oviducts and are responsible for transporting ova down the oviduct.
Cilia
How long does it take after castration before all spermatozoa in ejaculations to be nonmobile and pregnancy is unlikely to occur?
7-8 days
What is the name of the procedure used to identify mares in estrus?
Teasing
What is the short estrus period soon after foaling called?
Foal heat
The ovaries are responsible for the production of which 2 female hormones?
Estrogen and progestrerone
What is the scientific name for the sheath?
Prepuce
What is the most popular method of pregnancy diagnosis?
Rectal palpation
What is the term for the number of spermatozoa which can be collected per a 24-hour period from a stallion and is determined by collecting the stallion daily for 7 days?
Daily sperm output (DSO)
A brown discoloration of the placenta with meconium in it may indicate what?
Foal may have had a low oxygen supply during birth
When would breeding on the foal heat be appropriate?
Only if mare had a normal delivery and reproductive tract is normal
What is the physical makeup and appearance of an organism as determined by its genes and environment?
Phenotype
How long does it take the fertilized ovum to migrate to the uterus?
6 days
How should the navel cord of a newborn foal be treated?
Navel cord should be dipped in a tincture of iodine (metaphen, merthiolate, iodine, and glycerine)
What is the multi-layered, hollow, Y-shaped organ in the female reproductive system?
Uterus
What are the finger-like projections from the end of the infundibulum that surrounds the ovary?
Fimbriae
What is endometritis?
Infections of the uterus (inflammation of endometrium, the mucous membrane of the uterus)
What is the primary function of the scrotum?
Temperature regulation of the testes
Which organ is considered to be the ‘master organ’ of the male reproductive system because it is the site for production of spermatozoa and testosterone?
Testes
What is the term used to describe the sexual drive?
Libido
Out of the colors black, bay, and chestnut, tell which one is recessive and which one is dominant to the others.
Chestnut is recessive, black is dominant
Which 2 hormones stimulate the gonads?
FSH and LH
What 2 structures are found on the ovarian end of the Fallopian tube?
Infundibulum and ampulla
What term describes the minimum number of spermatozoa produced within a 24-hour period?
Daily sperm production (DSP)
What are the 3 parts of the sperm cell?
Head, neck, and tail
What is the fluid portion of the semen consisting of testicular, epididymal, and accessory sex gland secretions called?
Seminal plasma
How long after parturition is it before the placenta is passed?
10-15 minutes
Which hormone can be used on pregnant mares to cause abortions?
Prostaglandin
Testicles are usually descended into the scrotum by what age?
birth to 15 months
Fetal development is greatest during the third trimester but most of the body weight gained during pregnancy occurs when?
Second trimester
At what age does the average filly reach puberty?
12-15 months
Colostrum contains a high level of immunoglobulins, why are these important to the foal?
Foals are born with no protection from diseases, immunoglobulins are antibodies to protect the foal against disease
What is the destruction of red blood cells of the foal by the serum antibodies in the mare’s colostrum?
Neonatal isoerythrolysis (hemolytic icterus, foal jaundice)
Usually ‘wax beads’, which are actually drops of colostrum, appear on the mare’s udder about how long prior to foaling?
2-4 days before foaling
What is the name for the thin, transparent membrane that surrounds the foal at birth and must be removed so the foal can breathe?
Amnion
What is the length of time required for spermatogenesis and epididymal maturation in the stallion?
About 65 days
What is a non-infectious disorder of the central nervous system in about 1-2% of newborn foals with gross abnormal behavior?
Neonatal maladjustment syndrome (also called convulsive syndrome)
What virus is the most devastating bacterial cause of pneumonia in foals?
Rhodococcus equi (Pronounced road-o-cock-us)
What vaccine should be given to brood mares at the fifth, seventh, and ninth months of pregnancy?
Rhinopneumonitis
What primary sex organs produce the germinal sex cells as well as the sex hormones?
Testicles and ovaries
Diarrhea is a common problem of foals, but a squirting type of diarrhea can dehydrate a foal and lead to death within what amount of time?
Within hours
What is pneumovagina?
When air and contaminants are sucked into the mare’s reproductive tract
Which highly contagious disease causes about 90% of all foal diarrhea outbreaks and usually occurs in foals about 70 days old?
Rotavirus
What are the 2 basic techniques of collecting the embryo from the donor mare and transferring it to the recipient mare?
Surgical and non-surgical
Approximately how many days longer is a mule fetus carried than a horse fetus?
10 days
What is the genus and species of the true zebra?
Equus zebra
Name a septicemia that settles in the foal’s joints.
Navel ill or joint ill
What happens when there are 2 dominant white genes in a horse?
It is lethal
What are the 3 most genetically common colors of horses?
Black, bay, and chestnut
Name the type of anemia that occurs in a newborn foal if it has a different blood type than its dam.
Neonatal isoerythrolysis (foal jaundice, Rh factor)
What is the most common cause of infertility in mares?
Pneumovagina or wind sucking
At what age does the mature ovary reach its maximum size in the mare?
3-4 years old
What is the distensible muscle that acts as a physical barrier between the vagina and the uterus?
Cervix
What is the only hybrid shown to be fertile?
Crosses between Przewalski’s horse and the horse
What is the term for blood stream infections?
Septicemia
Which hormone initiates lactation?
Prolactin
What is a funnel-like membrane that surrounds the ovary and catches the egg when it is released by the ovary?
Infundibulum
Name 3 modes of inheritance.
Autosomal recessive, autosomal dominant, and X-linked
What are the 2 basic types of genetic actions?
Quantitative and qualitative
What is dystocia?
Any foaling problem that prevents delivery of the foal by the mare’s efforts alone
What is the effect of LH on the mare?
Stimulates ovulation, supports the initial stages of corpus luteum development
How many chromosomes are responsible for the sex of the foal?
1 pair (2 chromosomes)
Why is it preferable to break the umbilical cord rather than to cut it?
usually have less bleeding
Approximately how many days does it take the fertilized ovum to migrate to the uterus?
Six
What is the primary environmental cue regulating season reproductive activity in the mare?
Length of daylight
What is an allele?
Nonidentical genes located at the same physical position on a chromosome
What 2 ovarian hormones control the estrous cycle?
Estrogen and progesterone
What is the main function of the scrotum?
Encloses the testicles and serves as a thermo-regulator
WHat is the most common term for episioplasty, which is the artificially sealing by sutures of the labia of the vulva together?
Caslick operation
What is the function of the vesicular glands in the stallion?
Responsible for secreting the ‘gel fraction’ to the semen
Name the hair-like projections that line the mare’s oviducts and are responsible for transporting ova down the oviduct.
Cilia
Name the parts of the stallion’s reproductive system.
2 testes, epididymis, urethra, penis, accessory glands (cowper’s, seminal vesicle, prostate)
The epididymis can be divided into 3 segments, name them.
Head (caput), body (corpus), tail (cauda)
In mare management, mares can be classified into what 5 types during the breeding season?
Pregnant, open, barren, maiden, and wet
What are the 2 types of cryptorchids and which will usually be infertile?
Unilateral and bilateral, bilateral is usually infertile
Name 3 factors that affect the stallion’s ability to produce spermatozoa.
Testicle size, seasons of the year, age
What are the 3 muscles associated with the scrotum and spermatic cord that contract during cool weather to draw the testes close to the body to raise the testicular temperature?
Tunica dartos and cremaster
The uterus is suspended within the body cavity by 2 tough, sheet-like structures called what?
Broad ligaments
What are the 3 distinct layers of the uterus?
Serous (outer layer), myometrium, endometrium (innermost layer)
What is agalactia?
Lack of milk production
What is the definition of GnRH?
Stimulates secretion of gonadotropins
What is the definition of FSH?
Gonadotropin exerting its effect on Sertoli cells
What is the definition of LH?
Gonadotropin exerting its effect on the Leydig cells.
What is the definition of Inhibin?
Inhibitory effect on FSH
What is the definition of Testosterone?
Responsible for libido
What is the definition of Testosterone?
Responsible for libido
What is the definition of Melatonin?
Inhibitory effects of GnRH
