Module 3- Reproduction and Breeding Flashcards
Is the process of getting genetic material from male to genetics materials from the female through the union of sperm and egg cells.
Reproduction
Have reduced the efficiency of reproduction
Manipulation and confinement
Several factors contributing to poor reproductive performance
1.Reproductive anatomy
2.Long time period before the embryo can safely implant in the uterus
3. Variable hormonal system synchronizing the whole process
Reproductive organ of stallion
Two testes (each suspended by a spermatic cord and external cremaster muscle)
Two epididymis
Two deferens ducts
Penis
Associated muscles
What are the accessory sex glands in Stallion?
Paired Vesicular Glands
One prostate Gland
Paired bulbourethral glands
Outside of reproductive tract of stallion
Scrotum
Prepuce
Penis
Is an outpouching of the skin, divided into two scrotal sacs by a septum
Scrotum
The testes of stallion should be what?
Should descend from abdominal cavity through inguinal canal into the scrotum between the last 3 weeks of gestation and the first 2 weeks after birth.
What will happens if the testes does not descend before closure of inguinal ring?
Cryptorchid testis stays in the abdominal cavity that can lead to infertility
The three parts of ejaculation
Erection
Emission
Ejaculation
Is stimulated by teasing stallion.
The penis lengthens and stiffens through engorgement with blood.
Occurs in strong pulsatile contractions
Erection
During this the semen, which contains spermatozoa and fluid from the cauda epididymis plus fluids from the accessory gland arrived in pelvic urethra.
Emission
During this mating process semen is expelled through the urethra.
Reproduction in the stallion is also under hormonal control.
The hormones directly include FSH, LH, and testosterone.
Ejaculation
Full reproductive capacity is not reached until what age in stallion?
4 years old
No spermatozoa production occurs until a stallion is well over what age?
1 year old
The stallion reproductive capacity will then remain constant until what age?
20 years old
It influenced sperm output and sperm production
Season
Testicular size
Age
Frequency of ejaculation
The three best months for testicular size, development, function in stallion
May, June and July
This months the testes are regressed
September through February especially November and December
Volume per ejaculate in millimeters
60 to 100
Sperm per cubic millimeter
150-300 million
Total sperm in Ejaculate
5-15 billion
Starting in mid-to late December the stallion should be exposed to how many hours of light and hours of darkness
16 hours of light
8 hours of darkness per day
This would prevent the stallion being sensitive to increasing light
Stallion has to be normally exposed to the decreasing daylight in the fall to eliminate a photoreceptory condition.
Do lead to early burnout and a decline in performance at the end of the breeding season
Artificial photoperiods
The mare reproductive anatomy is characterized by ?
Simple uterus
Placenta arrangement
Inefficient cervical closure
Mare reproductive organs
Ovary, Fallopian tube, cervix, vulva and vagina
These structure are suspended within the abdominal cavity via ligament and connective tissue to the abdominal wall.
Uterus
The elongated shape of the uterus and uterine horns causes the uterus to what?
Drain inefficiently, predisposing this organ to infections.
Maintain pregnancy by retaining the embryo and it’s membrane within the uterus and preventing entry of bacteria.
Closure of the cervix
Is vital for embryo survival by preventing infection.
Maintenance of cervical seal
Closure of the cervix is controlled by what? This has been cited as a possible cause for early embryonic death.
Hormonal levels and can be unstable.
Is attached to the endometrial lining of the uterus by the innumerable tiny villi that project into the lining, forming a shallow one-cell thick fusion through which the placenta transfer the embryo’s blood, oxygen, and nutritional needs
Placenta
Stimulates release of progesterone
Corpus luteum
What will happen if hormonal balance is not achieve?
Mare will have problems cycling, conceiving, maintaining pregnancy, delivering a foal, and providing adequate milk supply.
Controls all phase of reproductive tract stimulation and inhibition.
Hormonal Balance
Occurs after mare ovulates and is responsible for the production of the corpus luteum and it’s production of progesterone.
Luteal phase
What causes mare to come into heat and ovulate?
Strong follicle-stimulating phase of her cycle
Are released to destroy the corpus luteum, reduce progesterone, and allow the mare to cycle again.
Prostaglandins
Relaxes the uterus to allow the embryo to implant and new pregnancy to be established
Progesterone
Maintain pregnancy by keeping follicle stimulating hormone and estrogen in check. thereby preventing the mare from coming back into estrous and disrupting the newly established pregnancy.
Progesterone
A animal that comes into estrous several times a year but does not cycle all year round.
Polyestrous
Times of year with irregular and sub-fertile cycles
February and March
Are called breeding transition momths
September and October
When a mare begin cycling in the spring their estrous lasts for how many days?
6 to 8 days
The length of estrous in most mares at the peak of the season in may or June
3 to 4 days
Produce the hormone estrogen, which causes the signs of sexual receptivity.
Follicles
The time when a primary follicle is ready to shed an egg nature enough for the fertilization form the ovary, occurs late in the estrous, no more than 2 days before the mare goes out of heat.
Ovulation
After ovulation, the now eggless cavity in the follicle fills up with a blood clots and is now called what?
Corpus hemorrhagicum
Produces the hormone progesterone, which corresponds with diestrus.
Corpus luteum
During this stage the cervix relaxes and is soft and rose pink.
Estrous
In this stage the cervix protrudes into the vagina; it’s pale pink and tightly constricted; secretion are scant, viscous, and sticky
Diestrus
At the time of ovulation, the follicle in large mares may be as large as what?
65mm in diameter
By this day the follicle may be detected by rectal palpation and by ultrasound.
Day 20
It can estimate follicular size and can also differentiate between a young corpus luteum and soft follicle, even though these structures feel similar during rectal palpation.
Ultrasound
If the fetus is aborted before this day the mare continue to show signs of being pregnant, due to special tissue secreting the hormone that maintain pregnancy, until day 120.
Day 45
Puberty age of mare
15 to 24 months
But can early as 1 year of age and as late as 4 years of age
The mare normal estrous cycle
21-22 days
The mare usually goes into winter anestrus between what months?
November, February and March
The first 5-7 days when a mare displays behavioral signs of sexual receptivity to the stallion are called?
Estrous
What is the behavior or mare when teased with a stallion
Will raise her tail and urinate
Labia will open to expose the clitoris, while she assumes a mating position
During this phase the behavior pattern is that of sexual rejection of the stallion .
During this stage the mare will switch her tail, pin her ears back, kick and move away from the stallion when she is teased
Luteal phase or diestrus
Diestrus lasts at what days?
14-15 days
The ovum leaves the ovary and enter the ovary ducts
Fertilization
The ovum is visible for how many hours?
8-12 hours
The spermatozoa coming up the oviduct can live?
24-48 hours
The time involved for the spermatozoa to travel down to the oviduct and reach the ovum
4-6 hours
Based on time constraints, breeding is recommended within what day?
1 or 2 days before ovulation
By this hour the embryo settled at one part of the uterus, where is implants
16-18 hours
After the egg is fertilized, it travels down the oviduct and enter the uterus in what day?
5-6 days
Is the premature termination of pregnancy before 300 days of gestation
Abortion
From ovulation parturition the average length of gestation is ?
335 days plus or minus 2-4 weeks