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
Termination after 300 days of gestation
Stillbirth
What causes abortion?
Bacteria and viruses
Consideration for breeding include
Appearance
Pedigree
Hereditary disorders
Disposition
Conformation
Performance
Factors that relate to the mare’s reproductive potential
Age
Previous athletic use
Breed
General Health
Status
Nutrition
Past breeding records
In this age the mare may have some abnormal cycling pattern.
2-3 years old
Anatomical changes in mare after multiple foals
Changes in vulvu and vagina predisposing for pneumovagina and urine pooling
The very large draft breeds the show a greater tendency to reproductive failure
Miniature breed
Mare that has never been breed
Maiden mare
A mare that was either not breed the previous season or did not conceive in the previous season
Barren or open mare
Mare that has foaled during the current breeding season and is nursing sa foal
Wet mare
It includes past breeding records and are all helpful information in reproductive evaluation
Previous foaling data:
Gestation length
Any complications
Cycling patterns from previous years
Previous reproductive surgery
Previous uterine infection
Treatment
Evidence of early embryonic death in previous season.
It includes Previous medical events such as chronic obstructive pulmonary disease (heaves) leading to
coughing and difficulty breathing, cardiac disease, or pain from laminitis or tendinitis will all influence
reproductive potential.
General Health
Has been used for pregnancy diagnosis since early 1980s and is used in addition to rectal palpation
may also provide diagnosis of conditions that cannot be felt by rectal palpation.
Ultrasound
Is inserted into the rectum and moved across the reproductive tract
Ultrasound probe
In this mare ultrasound study of the ovaries can distinguish between follicles, corpus
hemorrhagicum, corpus lutea, ovarian cysts, and tumors.
nonpregnant mares
Ultrasonography is useful in what?
normal reproductive cycle
diagnosing diseases of the ovaries and uterus
early detection
of pregnancy
diagnosing twins
diagnosing embryonic death
determining length of gestation
It where cysts or an infection can be diagnosed
Uterus
With ultrasonography the diagnosis of pregnancy is possible in what day of gestation?
14 days
With ultrasonography the fetal heartbeat can be detected in what day of gestation?
Day 22
(Should be routinely looked from day 25 on)
With ultrasonography it is possible to determine the sex of foal at what day of gestation?
Day 60 to 70
Effect of short breeding season
Reduce the number and sexual individuality of the stallion will affect his Siring ability
Should be fed like a horse at hard work
Breeding stallion
Feed requirements of breeding horse
1½ pounds of grains
1 pound of hay per 100 pounds of body weight
Regular exercise of stallion usually result in what?
Sexual vigor (libido)
Fertility
Two methods used in breeding horse
Hand mating
Pasture mating
reduces labor, affords convenience to the owner, “catches” shy breeding mares, and creates an opportunity for
a high settling percentage. It has the disadvantage of reducing the number of mares a stallion can serve, and it
obscures breeding dates. Some risk to the stallion exists.
Pasture mating
is practiced under wide variety of
conditions, ranging from rather casual selection of mares and
sanitation conditions to operations that are highly supervised
with a veterinarian in attendance
Hand mating
2 kind of breeding stall
Teasing stall
Breeding stall
What stall should be used in when stallion is hand mated
Teasing stall
aside from nutritional requirements, should be paid attention regularly for Reproduction and Breeding For the pregnant mare.
dental and hoof care
usually do not need shoes, but if they are shod, the
shoes should be removed a few weeks before foaling to protect the foal at birth. A good exercise program is
recommended.
Broodmares
vaccination program should include what?
Vaccination against rhinopneumonitis (3rd, 5th, 7th, 9th)
Tetanus
Equine encephalomyelitis
Influenza (4 weeks prior to foaling)
During this time of gestation the mares abdomen takes on the pendulous enlarged characteristics of pregnancy.
Final two months of pregnancy
It does not allow transfer of maternal antibodies to the fetus
Placenta
The foal intestine will absorb the antibodies only during what hour?
First 24 hours after birth
Stimulates the udder to produce milk
Prolactin
Hormonal inadequacies is a common occurrence if the mare is consuming what?
It produce chemical toxin to horse
Fescue grass
Hormone that enables contraction of uterus and milk let down
Oxytocin
bacterial infection of the mammary glands (udder) and/or the urogenital tract.
Mastitis, metritis Agalactia
It becomes relaxed prior to parturition
Tail, head, croup and perineal are
Loosen the ligament of the pelvis
Relaxin
Signs of impending parturition (7)
Large, pendulous abdomen or sudden change in position of foal
Udder enlargement
Waxed teats
Relaxation of the tail, head, croup, and perineal area
Enlarged abdominal milk veins
Loss of appetite
Change in personality
Change in gait of a pregnant mare occurs when?
1 to 2 months before giving birth
It can be used to predict the foal’s arrival time
Milk Calcium concentration
Waxed teats of a pregnant mare occurs when?
2 weeks to just hours before foaling
Relaxation of tail, head, croup and perineal area occurs when?
1 month to 2 weeks before foaling
Enlarged abdominal milk veins occurs when?
2 months 2 weeks before foaling
Does not occurs in all mares, but if present, depressed appetite usually occurs during last months of gestation
Loss of appetite
Change in personality behavior will change when?
4-2 weeks before foaling
. The best predictor of foaling
time
knowledge of the mare’s gestation length and behavior during previous pregnancies.
equipment or supplies that will be
needed during and/or after foaling:
- Four to five ounces of an iodine solution in a sterile jar
- Tail bandages or 3-inch gauze bandages
- Roll of sterile cotton
- Package of gauze squares (3” or 4” square)
- Adhesive tape (1 inch wide)
- One pint povidone-iodine compound
- Six to eight clean towels
- Enema tube, soap, and lubricant
- Seamless pail
- Large animal thermometer
Three stages of labor
Stage 1. The uterus begins to contract, the foal moves into position to be born, and the cervix relaxes in stage 1
Stage 2. This is the time of intense labor contractions that push the foal through the birth canal.
Stage 3. Stage 3 is complete when the placenta and fetal membranes are expelled.
Sign of labor in stage 1
restlessness
Tail switching
pacing
Sweating over the
neck, chest, and flank
Stage 1 of labor ends when?
when the allantois, or fetal membranes, are pushed through the cervix by the advancing
fetus and rupture, releasing amniotic fluid (breaking water).
Situation that causes dystocia
1.mare become
exhausted in the middle of labor and be unable to push the foal out,
2. A foal will not fit through the birth canal 3. Any
deviation from the front-legs-first, head-facing down-between-the-knees posture
4.The presence of twins is a possibility when labor becomes extended.
5.The entire foal may also be completely backward, or breech
may have a blue tongue and bluish-white nasal mucus.
Newborn foal
What to do to a new born foal?
1.As soon as it is
born, the fetal membranes should he cleared away from the foal’s head so that breathing can start.
2. The
umbilical cord should be allowed to break on its own.
3.Once this has happened, the foal’s navel should be
immediately treated with an iodine solution to prevent entrance of pathogens through the opening. In
some instances, the navel will bleed after the umbilical cord has broken.
4. The cord should be tied shut
with a length of sterile umbilical tape, gauze, or string
The
membranes usually are passed how many minutes after the foal’s birth.
5 to 45 minutes
an inflammation of the
uterus. And is an infection that may result in laminitis or death.
Metritis
It should be inspected after it has been passed
to ensure it is complete and there are no tears or pieces missing.
The placenta
a soft, dark-brown body of tissue it is floating among the membranes.
hippomane
It happens after the membranes have been properly expelled, the mare’s uterus will undergo involution, during
which the uterus returns to its nonpregnant size
Immediately postpartum
Without infection or trauma the uterus will involutes with how many days?
10 days
a term used to describe a symptom of abdominal (belly) pain, which in horses is usually caused by problems in the gastrointestinal tract
Colic
They ovulate more slowly than younger mare
Older mare
May cause abdominal pain and colic like symptoms
Involution
It is the most critical hours for both mare and foal.
For this reason they should be keep in what?
24 hours
a clean, quiet environment where they can be observed frequently
It should be avoided in the first few weeks of lactation
Damp or wet environment
It is when A mare needs special attention during the first week after delivery. The perineal region will be bruised
and sore. Defecation may be painful.
Postpartum mare care
may loosen the
stool and make defecation less painful
Bran, beet pulp, more salt, or other laxative-type feeds
Decreased appetite and water intake may cause what?
Decreased milk production
During this time of lactation the mare’s energy requirements are double normal maintenance levels, and she needs larger amounts
of concentrates and high-quality hay.
first 3 months of
lactation,
The mare’s uterus continues to involute through how many weeks after delivery?
first 2 weeks
a dark brown fluid may be seen on the vulva. This odorless discharge in vulva
lochia
About what day of postpartum, the
mare’s reproductive tract needs to be examined by a veterinarian if she is to be rebred.
the 7th or 8th day
is relatively common during the first week postpartum
Colic
It is a more serious condition occurring
immediately postpartum. This condition,
occasionally seen in mares over 15 years of age, is usually fatal.
internal bleeding
Cause internal bleeding
rupture of the middle uterine artery.
Symptoms associated with a middle uterine artery rupture
colic
pawing
anxiousness
profuse
sweating.
gums may also look pale or white.
At this day of postpartum most mares will come into heat.
6 to 12 days postpartum
In rebreeding it is the first estrous after is part of
the uterine involution process. Unless uterine involution is practically complete, conception is unlikely in a mare
bred during this heat.
These mares run a greater chance of developing uterine infections and scarring since the uterus is most
susceptible to infection during the first 30 days after foaling
foal heat
It slows down the involution process, and the uterus
will be unable to support embryo life.
uterine or vaginal bruising, damage, or swelling
The conception rate for mares bred during their foal heat is only how many percent?.
40 percent
Excessive or improperly timed breeding attempts increase the chances of what?
uterine infections
- The fertile egg is released from a follicle on the ovary during the mare’s estrous usually occurs on when?
7th and again on the 30th day after delivery
(A mare usually goes out of estrous within 1 day after ovulation, although there is variation between mares.)
The mare ovulate without showing
any external signs of estrous.
Silent heat
What causes silent heat?
Mares who have just foaled is their concern for their foals.
Their maternal instinct is stronger than the instinct to display estrous
The hormone that stimulates milk production (lactation), may inhibit estrogen and the hormones necessary for ovarian activity
Prolactin
is more common if the mare is on a substandard diet and in a negative energy balance.
Lactational inhibition of ovarian activity
Transporting the Mare
If the mare is to be transported to the stallion, she should arrive well before the onset of her second heat.
The ideal body condition score of a mare before second heat estrous
5
is a method of quantifying the amount of subcutaneous fat cover.
Condition score
Management of equine reproduction involves the use of what?
photoperiods and hormones
The designated birth date of foals of many performance breeds in the Northern Hemisphere is?
January 1
is used to induce follicular activity
artificial lighting
A mare requires approximately how many days of artificial lighting before ovulation occurs.
60 days
To induce ovulation in early February, the artificial lighting has to start in late November or early December.
Uses of hormones
Hormones can be used to make a mare short cycle, or come in season early.
to ensure that a mare will ovulate within 24 to 48 hours after being bred.
Mares becoming pregnant early in the
year are more likely to lose their fetuses because of what?
extreme fluctuations in hormone level
stimulates uterine contractions in childbirth and lactation after childbirth
Also increases production of prostaglandins
Oxytocin
control processes such as inflammation, blood flow, the formation of blood clots and the induction of labour.
Prostaglandins
assist in reproduction, feeding, social interactions and maternal-neonatal bonding in mammals.
Pheromones
stimulates follicles on the ovary to grow and prepare the eggs for ovulation. As they increase in size, they begin to release estrogen and a low level of progesterone into your blood.
Follicle stimulating hormone
helps control the menstrual cycle. It also triggers the release of an egg from the ovary. This is called ovulation
stimulates Leydig cells in the testes to produce testosterone, which acts locally to support sperm production.
Luteinizing hormone
Makes up 20% of the estrous cycle
Follicular phase
Makes up the 80% of the estrous cycle
Luteal phase
Causes the decline in progesterone
Luteolysis
Causes follicle to produce estrogen
Gonadotropin (FSH AND LH)
Ovulated follicles undergoes transformation to become what?
Corpus luteum
