Reproduction Flashcards
What term is used to describe the genotype of a horse that has one dominant gene or one recessive gene, such as large “A”, small “a”?
Heterozygous
When the paired genes are not identical, the animal is said to be what?
Heterozygous
When the paired genes are identical, the animal is said to be what?
Homozygous
What is the difference between homozygous and heterozygous?
Individuals that are homozygous for a particular gene have only one allele to pass to their offspring and heterozygous individuals can pass either of the two different alleles.
How many pairs of chromosomes are located in the body cells of the horse?
32 pairs
What is the normal sex genotype for the mare and stallion?
Mare-XX Stallion-XY
How many pairs of chromosomes are responsible for the sex of the foal?
One pair
What are two types of genetic action?
Qualitative and quantitative
What are qualitative genetic actions?
A particular trait is influenced by a single pair of genes
What is quantitative gene action?
A trait is influenced by a number of genes that all have some influence on the trait
What type of gene action will result in an intermediate state between two parents?
Co-dominance
What is another word for paired genes?
Alleles
What is the heritability estimate?
The percentage of a horse’s expressed trait that is due to genetics
True or False? Black is recessive to bay
True
What is the rule of genetics regarding the mating of a chestnut stallion to a chestnut mare?
They will produce only a chestnut foal
What is the exterior opening to the mares’ reproductive canal?
Vulva
What is the part of the mare’s reproductive tract that is shaped like a catchers mitt with finger-like projections?
Infundibulum
The ovarian end of the oviduct is called what?
Infundibulum
What is the convex side of the ovary called?
Hillus
Name the three layers of the uterus.
Serous, myometrium, and endometrium
What is another term for the complete heat cycle of a mare when she is ready to conceive?
Estrus
How long does the average heat of the estrous cycle last in a mare?
5-7 days
What term describes the mare’s seasonal estrous cycle?
Polyestrous
The estrous cycle consists of two stages, one lasting 5-7 days, the other lasting 14-16 days. What are the names for these stages?
Estrus and diestrus
In mares, what are the gonads?
Ovaries
What are the ovarian hormones that control the estrous cycle?
Estrogens or progestins
What is “silent heat”?
The failure to show behavioral signs of estrus
When is a mare’s conception rate highest?
Prior to ovulation
How can a mare’s heat cycle be manipulated without the use of hormones?
Use of extended daylight
At what age does a mare’s reproductive ability decrease?
16yrs
What is the most effective method for detecting a mare in estrous?
Teasing
What is a teasing mare?
The checking of a mare for signs of estrus by watching her reaction to a stallion
When a mare is teased or subjected to urinalysis to determine if she is i estrus,a curling of the upper lip occurs. This response is called what?
The Flehmen response
What two hormones can be used to synchronize mare’s estrous cycles?
Prostaglandin and human chorionic gonadotropin
What reproductive hormones is secreted by the hypothalmus in response to enviromental cues such as day length?
Gonadotropc releasing hormone(GnRH)
What hormone stimulates the growth of follicles?
Follicle stimulating hormone or FSH
What does FSH do?
Stimulates the growth of follicles
What is the term used for a solid mass that forms in te follicle after the egg has left and produces progesterone which helps to maintain pregnancy and prevents other follicles from developing during pregnancy?
Corpus luteum
What is the average age of a filly at puberty?
12-15 months
A mare that has never been bred is called what?
Maiden
A mare that has never become pregnant is referred to as what?
Maiden
True or False? An open mare is a mare without a foal on her side.
False, not pregnant
When is conception rate highest?
When bred one to two days prior to ovulation
What is the normal length of gestation?
324 days, plus or minus 20 days(11 months)
What are the major causes of mare infertility?
Uterine infecions
What is the definition of a “wet mare”
A mare that is nursing a foal
When should a mare receive the most nutrients during gestation?
During the last three months
Any birth of a foal of less than how many days gestation is considered premature?
320 days
What are the pieces of amphorus material found in the allantoic fluid during pregnancy?
Hippomanes
Feeding excessive amounts of what substance to a mare can cause an enlarged thyroid in a foal?
Excess iodine
What is the weight of a normal placenta?
13-14lbs
How many holes should be present in the placenta after foaling?
One
Is straw or shavings better bedding for foaling?
Straw
When during the pregnancy should drugs such as vaccines and dewormers be withheld from the mare?
The first sixty days and the last thirty days
What period of time during a mares pregnancy would not be a good time to de-worm her?
During the last 30 days of gestation
For maximum protection for the foal, when should a mare be immunized for tetanus and encephalitis?
About thirty days prior to foaling
What is another name for difficult birth?
Dystocia
What is the final stage of the foaling process?
Expulsion of the placenta (fetal membranes)
What is the foal’s first fecal material called?
Meconium
What is meconium?
Dark green, brown to black, tarry stools formed prior to birth
What categories of horses have the greatest calcium needs?
Young animals and lactating mares
What is one way to start respiration on a new born foal?
Blowing into the mouth, working it ribs and vigorously rubbing its body
At what temperature should you store colostrum?
-15 to -18 C
What are the three major types of immunoglobulin present in a mare’s colostrums?
IgG, IgM, 19A
How long after parturition is a mares peak lactation period?
8-12weeks after parturition
What is the term that means a mare has no milk?
Aglactia
How much milk does a mare produce during her first three months after foaling?
3% of their body weight
What is the name of the principal immunoglobulin in mare’s milk?
Immunogloblin G (IgG)
When do milk yield energy and fat content peak in mares?
Only within the first 36hrs after birth
It will take until how many days until a foster mare will show maternal behavior toward an orphan foal?
Ten
Why would whiskey or linseed oil be poured over a newborn foal?
To disguise the odor of an orphan foal so that a foster mother will allow it to suckle.
How many days after foaling should creep feeding be started due to a decrease in milk production by the mare?
90 days
How much weight does a foal gain per day up to the age of three months
2.25-3lbs
What percentage of all foals get pneumonia?
About 9%
What is the minimum size for a stallion or foaling stall?
12ft by 14ft is recommended
What percentage of a mare’s body weight does a foal weigh?
8-10%
What is fed to a foal, beginning a few days after birth, to reduce the stress of weaning?
Grain and hay
When should foals be dewormed?
6-8 weeks after birth and then every 2 months after that
At what age is a foal weaned?
4-6months
What are the three signs of foal or neonatal septicemia?
Decreased appetite, generalized weakness, weakened suck reflex, mild dehydration
What complication can cause influenza to be fatal in young foals?
The development of pneumonia
What is the common name for botulism in foals?
Foal Shaker Syndrome
Limb deviations in foals can be caused by what?
Genetic predisposition, nutrition deficiencies, cramping of a big foal in the uterus
Name three parts of a stallion’s reproductive tract.
Testes, epidiymides, two deferent ducts, urethra, penis, accessory sex gland( bulb urethral, prostate, and vesicular
What is the master organ of the male’s reproductive system?
Testes
What are the accessory sex glands that contribute to stallion’s semen?
The vesicular glands
In the stallion the hormones FSH exerts its effects on which cells?
Sertoli cells
What is the ultimate proof of semen quality?
Conception rate
How many days are required for spermatogenesis and epididymal maturation in the stallion?
65 days
How long is spermatogenesis?
57 days +/- 5 days
What does the acronym D.S.O. stand for?
Daily sperm output
How are testes kept cool during hot weather and warm during cold weather?
The scrotum and spermatic cord contract and release the testes toward or away from the body
What do the initials A.I. stand for?
Artificial Insemination
Give three advantages to using artificial insemination?
1) To prevent injury to the stallion 2) To prevent injury to the mare 3) To be able to breed more mares per season 4) Mares with Caslicks can be bred without infection
An animal with one or both testes undescended into the scrotum is called what?
A cryptorchid or ridgeling
Colts are considered cryptorchid if the testes have not descended after what age?
15 months of age
What term is used to designate a castrated male horse?
Gelding
Which sex of horse generally has more consistent behavior and performance?
Geldings
What are two advantages to gelding a horse?
Several geldings may be kept in a paddock; geldings are easier to care for; less prone to injury and easier to haul because of their attitude.
Name three types of breeding contracts?
Stallion Service Contract, Foal Sharing Agreement, Mare lease
What is the most often used breeding contract?
The Stallion Service Contract
Name the parts of the uterus.
Body and two horns
