Category B: Reproduction--DONE Flashcards
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 is the recommended age to wean foals?
4-6 months
What term describes a mare that is not pregnant and was NOT bred in the previous or current season?
Open Mare
What term describes a mare that has never been bred?
Maiden mare
At what age does the mares reproductive abilities start to decrease?
After about 16 years
How long does estrous period usually last in a mare?
5-7 days
What is a weanling?
Young horse of either sex that has just been taken way from it’s mother usually 6 months up to one year
What is the female parent of a horse called?
Dam
How many testicles does a stallion have?
two
What is a colt or filly under one year old?
foal
What is a filly?
Female foal up to 3 years of age
What is an altered or castrated horse called?
gelding
What is the primary sex organ of the mare?
Ovary
What is the primary sex organ of the stallion?
testicles
What is the most easily recognized phase of the estrous cycle?
Estrus
What is the scientific name for the womb?
Uterus
How many sperm does it take to fertilize a singe egg?
one
Name the 2 specialized sex cells that join to start the development of a foal.
Ovum and sperm
the 2 basic types of gene actions are quantitative and qualitative, which is most common?
Most traits in horses are influenced by quantitative gene action
What is the term for characteristics that ultimately result in death?
Delayed Lethal
What is the study of hormones & their effects?
Endocrinology
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
Wat is the external opening to the mares reproductive canal?
Vulva
What is a major site for bacterial invasion into the newborn foals body that should be treated with an iodine solution to prevent infection?
Naval stump
What is the more common term for the rupture of the chorio-allantoic membrane during pregnancy?
Breaking of the water bag
What is the primary function of the scrotum?
Temperature regulation of the testes
What are the 3 most genetically common colors of horses?
Bay, black, and chestnut
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
At what time do most mares foal?
Between 7pm and 7am
What type of gene 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 type of gene 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
What is the 6-8 inch long muscular mucous membrane-lined tube which communicates the vestibule—— of the vulva to the cervix?
Vagina
Why would you put a stallion under artificial light?
Increase testicular activity
Which 2 hormones stimulate the gonads?
FSH and LH ———
What is the term for a condition that results in empryonic —-death?
True lethal
Horses have 33 chromosome strings, the X and Y chromosomes are called sex chromosomes, what are the other ones called?
Autosomes
Where is the site of spermatogenesis——- and production of testosterone?
Testes
Why don’t females suffer from X-linked heredity diseases?
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 and therefor do not sire foals
Which pinto pattern is associated with the lethal white foal syndrome?
Overo
What is the name of the hormone that signals the start of the reproductive season?
Gonadotropic releasing hormone—
What type of chromosomes are the X and Y chromosomes?
sex chromosomes
Fetal development is greatest during the third trimester but most of the body weight gained during pregnancy occurs when?
Second trimester
Which gene is responsible for mottled, varnish roan, blanket with spots, blankets, frost, leopard and a few leopard spots in horses?
Leopard gene, LP
What is the length of the gestation period for the American Miniature Horse?
11 months
What happens to the offspring of roans and white horses whose genetic pattern is homozygous?
They die in early fetal development
What is the average length of the mare’s estrous cycle?
4.5-7.5 days
Blood type is an example of which gene?
Co-dominance ———-
What is the name of the enlarged pre-ovulatory——– follicle?
Graafian follicle
What is the main body of the penis called?
Shaft
What is the simplest method of bringing a mare into estrus prior to the natural breeding season?
Artifcial lighting
Most traits in horses are influenced by what type of gene action?
Quanitative
Name the 2 types of genetic hernias.
umbilical and inguinal
What are the gonads?
Ovaries and testicles
What hormone causes receptive behavior patterns observed in mares during heat and acts to prepare the uterus for receiving the embryo?
Estrogen
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
Which hormone stimulates the growth of follicles?
FSH
How often can a stallion’s semen be collected without interfering with the stallions ability to produce sperm?
Up to 3 times daily for short periods
What is the powerful middle layer of the uterus that is responsible for contractions which expel the foal at birth?
Myometrium
What is the general term for the secretion of the testes, epididymis and accessory glands mixed with spermatozoa?——
Semen
What are the 3 types of qualitative gene actions?
Dominance, co-dominance, and partial dominance
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
Name 2 basic colors that the color ‘chestnut’ is recessive to .
Black and bay
What is the medical procedure used to close the mare’s vulva to prevent her from sucking air an debris into her reproductive tract?
Caslick operation (episoplasty)
When does a mare’s reproductive ability begin to decrease?
usually after 16 years of age
During the first 3 moths after foaling, a mare will produce how much milk per their body weight?
Up to 3% of their body weight
The ovaries are responsible for the production of which two hormones?
Estrogen and progesterone
What i mastitis?
Inflammation and infection of the udder
What is the name of the procedure used to identify mares in estrus?
Teasing
At what stage of pregnancy does the mare’s nutritional need increase?
Last 3 months of gestation
What are the 2 basic types of genetic actions?
Qualitative and quanititative
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 are the 3 main colors of horses that provide the basis for most of the other colors in color genetics?
Black, bay, and chestnut
Why are all roan colored horses heterozygous Rnrn?
All homozygous roan horse die in early fetal development and are never born
What part of the ovary contains the ova when a filly is born?
Cortex
What reproductive hormone is secreted by the hypothalamus in response to environmental cues such as day length?
Gonadotropic releasing hormone (GnRH)
In the stallion, the hormone FSH exerts its effect on which cells?
Sertoli cells
What is the short estrus period soon after foaling called?
Foal heat
Why are all white horses heterozygous?
Because white homozygotes die early in development
How does the length of daylight hours affect the breeding season and the reproductive response of the stallion and the mare?
Longer daylight horses (16 hrs) stimulate the reproductive systems, shorter hours suppresses and decreases hormones needed for reproduction
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
When is a mare usually anestrus?
In winter/during shorter daylight hours
What is the term for the oil product of the sebaceous glands that build up in the end of the penis?
Smegma
Conception rates are highest when the mares are bred when?
1 - 2 days prior to ovulation
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 are the 2 most common methods used to manipulate the estrous cycle?
Artificial lighting and hormonal stimulation
What is the heritability estimate when looking at the horse’s traits?
Percentage of a horse’s expressed traits that is due to genetcis
What kind of bedding is preferred for a foaling stall?
Straw
When do ‘wax beads’ appear on the teats of a mare?
a few hours to 2 - 4 days before foaling
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 chorio-allantoic membrane)
A brown discoloration of the placenta with meconium in it, may indicate what?
Foal may have had a low oxygen supply during birth
What acts as a physical barrier between the vagina and uterus?
Cervix
Name the wedge-shaped area of the ovary from which ova are shed.
Ovulation fossa
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)
Name 3 modes of inheritance.
Autosomal recessive, autosomal dominant and X-linked mode
What is the fluid portion of the semen consisting of testicular, epididymal and accessory sex gland secretions called?
Seminal Plasma
Which hormone can be used on pregnant mares to cause abortions?
Prostaglandin
What is a colt?
Young male horse under 4 years of age
What is the term used to describe the sexual drive?
Libido
What vaccine should be given to brood mares at the fifth, seventh and ninth months of pregnancy?
Rhinopneumonitits
What is the length of time required for spermatogenesis and epididymis maturation in the stallion?
About 65 days
Colostrum contains a high level of immunoglobulins, why are these important to the foal?
Foals are born with no protectoin from diseases, immunoglobulins are antibodies to protect the foal against disease.
Which highly contagious disease causes about 90% of all foal diarrhea outbreaks and usually occurs in foals about 70 days old?
Rotavirus
What virus is the most devastating bacterial cause of pneumonia in foals?
Rhodococcus equi (Pronounced road-o-cock-us)
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 are foals called that suffer from Neonatal Maladjustment syndrome?
Dummy or convulsive foals, Barker, Wanderer
What is it called when organs or tissue project through an abdominal opening and usually occur in the naval or scrotum areas?
Hernia
Name a breed of horse that is homozygous for the Dn gene.
Fjord horse
Usually ‘wax beeds’, 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 hormone necessary for normal sexual behavior and function in stallions?
Testerone
What is endometritis?
Infections of the uterus (inflammation of endometrium, the mucous membrane of the uterus)
What are the finger-like projections from the end of the incunabulum that surround the ovary?
Fimbriae
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
What is the production of spermatozoa called?
Spermatogenesis
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 the multi-layered, hollow, Y-shaped organ in the female reproductive system?
Uterus
What is the distensible muscle that acts as a physical barrier between the vagina and the uterus?
Cervix
Name the hair-like projections that line the mare’s oviducts and are responsible for transporting ova down the oviduct.
Cilia
The short estrus period soon after foaling is called what?
Foal heat
Brood mares can be protected against rhinopneumonitis by immunization with an inactivated vaccine during which months of pregnancy?
Third, fifth, seventh and ninth
Which organ is considered to be the ‘master organ’ of the male reproductive system because it is the for production of spermatozoa and testosterone?
Testes
Colostrum is secreted during which period post-parturition?
First 24-28 hours
What term describes the minimum number of spermatozoa produced within a 24-hour period?
Daily sperm production (DSP)
About how long is a mare pregnant before giving birth to a fully developed foal?
11 months
Name the only 2 places where single chromosomes exist.
In sex cells, sperm and egg
What is the term for a female foal?
Filly
What sex has the genotype XX?
Female
How many ovaries does the mare have?
Two
