Repro Exam 2 Flashcards
For a breeding soundness exam in dogs and bitches, what should be tested for?
Brucella canis
This causes orchitis: epididymitis and testicular atrophy in males.
Also causes abortion in females
Brucella canis
Translucent sperm samples usually have a
low sperm concentration
This species has a large gel fraction in its semen that must be removed before further processing the semen
Stallion
Sperm motility in which sperm are able move in a more or less straight line
Progressively motile
Sperm motility is greatly affected by environmental conditions. Must be protected from temperature shock during processing and must be kept at what temp?
100F
Coats the head of the sperm
contains enzymes necessary to help sperm penetrate and fertilize ovum
acrosome
Primary abnormalities are those that occur on what part of the sperm?
head
With this sperm abnormality, sperm may remain motile, may retain ability to fertilize ovum, but zygote usually dies due to genetic abnormalities
Primary abnormality
Secondary abnormalities occur in what part of the sperm?
mid-piece
Secondary abnormalities of sperm occur during what process?
They are normal and usually disappear during maturation in the epididymis.
spermatogenesis
These are seen microscopically when sperm have a secondary abnormality.
They are the first to appear and the last to disappear
cytoplasmic droplets
Tertiary abnormalities occur in what part of the sperm?
tails
This abnormality is usually the result from damage during storage or transportation in epididymis or ductus deferens.
Can also be due to poor technique during evaluation procedure.
Tertiary abnormalities
One major advantage of AI is
numerous females can be inseminated from a single ejaculate
Semen shipped long distances
Control of venereal and other disease
Improved record keeping
These are all advantages of what?
AI
Increased labor time to detect estrus
need for trained labor
additional veterinary intervention
these are disadvantages for
AI
This is used to dilute semen aid is survival and longevity of sperm maintain viability over time provide adequate nutritional components provide good pH buffering protect against bacterial contaminants non-toxic
semen extenders
These products can be used as: Egg yolks (no egg whites) gelatin milk fruit juice glycerol commercially prepared
semen extenders
Bull semen is packaged in what
plastic straws
Granulosa cells sticking to the oocyte are called
the cumulus
What step is this in the fertilization process?
one sperm penetrates the oocyte membrane.
Then the oocyte finishes the 2nd meiotic cell division and expells the extra chromosomes into a small cell
Step 1
What step is this in the fertilization process?
male & female haploid nuclei fuse to make the new diploid nucleus.
Step 2
Fertilization of older oocytes increases or decreases chances of an abnormal embryo resulting
increases
A mare’s oocyte can only be fertilized for how long?
6-8 hours
A bitch’s oocyte can only be fertilized for how long?
> 4 days
This is the final step of sperm maturation
It occurs in the female reproductive tract
Capacitation
Packet of enzymes in the acrosome on the from of the sperm head
Hyaluronidase
These digest away the granulosa cells surrounding the egg.
Enzymes form acrosome
How many sperm must reach the “egg” to digest away this cell coat
Several
Aged spermatozoa are more or less able to fertilize an oocyte
less able
Sperm retain ability to fertilize an oocyte for a variable period of time. Most lose ability in
24-48 hrs
Equine sperm lose ability to fertilize in
3-5 days
Canine sperm lose ability to fertilize in
4-11 days
One or more spermatozoa penetrate cumulus, acrosomal enzymes released will dissolve part of
zona pellucida
What is the purpose of the receptor proteins on the cell membrane of the ovum?
The receptor proteins are species specific and bind with the proteins on the head of the sperm
This triggers a change in oocyte membranes
Prevents entry by other spermatozoa
Fusion
What is the end product of fertilization?
zygote
Rapid cell division without increase in size
Cleavage
Where does cleavage occur?
Inside the uterine tube before the zygote reaches the uterus
These small, normal sized cells produced by cleavage are now called
blastomeres
When the clump of cells reaches 16, the name changes from zygote to
Morula
At first, morula is a solid structure. As cells continue to divide, the cells move towards the outside edge and attach tightly and pump water into the middle of the clump. The middle becomes a fluid filled cavity called a
blastocoele
Morula cells are ______, if the morula divides = twins
Totipotent
Chemicals are segregated into appropriate region of the morula by continued process of
partitioning
As cleavage is completed, morula becomes a
blastula or blastocyst
Large hollow ball composed of a double layer of cells. Formerly called the morula
Blastula
The inner mass of cells at one end of the blastula is called the
blastocoele
The single layer of cells at the other end of the blastula is called the
trophoblast
The period of time when cells are in the process of forming specific organs is called
Differentiation
Differentiation begins with the formation of 3 germ layers
Endoderm
Mesoderm
Ectoderm
During differentiation, the blastula becomes the
gastrula
Through gastrulation, the gastrula becomes a
2-layered cup, results in the three layers
This process finishes the 3 layers: ectoderm, mesoderm, and endoderm
Gastrulation
Ectoderm will become
epidermis of skin: hair, feathers, nails, hooves, mammary glands, sweat & oil glands, tooth enamel
Nervous system
Endoderm will produce
Inner linings of the gut
linings of: lungs, liver ducts, pancreas & other glands, urinary and gall bladder
Thyroid gland (pouches off the gut)
Anterior pituitary gland (pouches off the gut)
Mesoderm produces:
dermis of skin dentine layer of teeth muscles & skeleton heart, blood, vessels kidneys gonads
Mammals, birds, and reptiles have water sacs and are called
Amniotes
How do mammals, birds & reptiles produce the 3 germ layers?
First has to make a placenta, amniotic sac and other membranes, then the germ layers can be made
The union of sperm and egg. Sperm’s haploid set of chromosomes combine with egg’s haploid set of chromosomes and forms a diploid zygote. What is this?
Fertilization
The cells associated with the oocyte when it is released from the ovary are called?
Granulosa cells sticking to the oocyte are called the cumulus.
Where do sperm become motile?
Tail of epididymis
What is the significance of the cytoplasmic droplet in the sperm?
Found in the midpiece
occurs during spermatogenesis
normal, generally disappear during maturation in epididymis
first to appear & last to disappear
What is the final maturation step in the sperm called?
Capacitation
Where does the final maturation step in the sperm occur?
Occurs in female reproductive tract
For what length of time are the ova of bitches, mares, cows, sow, & ewe viable?
Dogs: 4 days Mares: 6-8 hours Cattle: 8-12 hours Sow: 8-10 hours Ewe: 16-24 hours
For what length of time are the sperm of dogs, horses, cattle, swine & sheep viable?
Dogs: 4-11 days Horses: 3-5 days Cattle: 1-2 days Swine: 1-2 days Sheep: 1-2 days
What is the zona pelucida & why is it significant?
Specialized extracellular matrix surrounding developing oocyte. Thought to be formed by secretions from the oocyte & follicle granulosa cells. Allows only one sperm to fertilize the oocyte
Where does fertilization occur?
Uterine tube
What and where does cleavage occur?
Cleavage: rapid cell division without increase in size
Occurs inside the uterine tube before the zygote reaches 16 cells
This extra-embryonic membrane surrounds yolk early in differentiation. It contains nutrients used during early development
Yolk sac
This extra-embryonic membrane is the innermost membrane. It forms the ectodermal amniotic membrane which surrounds fetus & amniotic fluid and protects embryo and fetus
Amnion
This extra-embryonic membrane is an outpouching of the hind gut. It will contain the embryo’s waste fluid.
Allantois
This extra-embryonic membrane is the outermost membrane. It becomes the placenta.
Chorion
When is an embryo considered a fetus?
When formation of organs & organ systems is complete.
What is the general appearance of bull semen?
Creamy white, occasionally yellow. If it smells like urine, no good. Relatively uniform & opaque, homogenous, no chunks
What is the general appearance of stallion semen?
Greyish white, gel fraction
What is the general appearance of boar semen?
Greyish white, occasionally pink tinged
What is the general appearance of dog semen?
Greyish white, never yellow or pink
What is the placentation type in canines & felines?
Endotheliochorial zonary placenta: chorion is in contact with the endothelium of the dams’ blood vessels along a band or zone that encircles the fetus.
What is the placentation type of equine?
Epitheliochorial diffuse: chorionic villi (microcotledons) cover entire placenta & project into crypts (microcaruncles) scattered over the entire endometrium.
What is the placentation type of bovine?
Epitheliochorial cotyledonary: chorion is in direct contact with the epithelium of the uterus (endometrium) in mushroom like areas called caruncles.
Which species has a large gel fraction in its ejaculate?
Stallion
Project inward from the surface of the uterus
Chorion in direct contact with endometrium in these areas
Caruncles
Portion of chorion that attaches to the caruncles
Cotyledons
Together, the maternal caruncle and fetal cotyledon are called the
placentome
Structure derived from fetus; source of PMSG; arranged in circular or horseshoe pattern near junction of gravid uterine horn and body; development begins around day 25, cells from chorion grow into endometrium.
Endometrial cups
In which species do endometrial cups form?
Equine
What is the significance of endometrial cups?
secrete Pregnant Mare Serum Gonadotropin (PMSG)
What is Pregnant Mare Serum Gonadotropin?
Also called Equine Chorionic gonadotropin; has FSH & LH like activity; luteotrophic
What does PMSG do?
Causes development of additional follices that lutenize & secrete progesterone to support pregnancy. Proves conception occurred if detected in mare 50-120 days after breeding.
Hormone produced by canine placenta; can diagnose pregnancy as early as 21 days
Relaxin
When can puppies be palpated in the abdomen of a pregnant dog? When can they not be palpated?
Palpable between 20-35 days and after 50 days.
After 35 days, swellings become softer & uterus enlarges & becomes protected by ribs. Larger bitches, bitches with tense abdomens or few pups are hard to palpate.
What findings on palpation of a cow or mare would suggest that they are pregnant?
Cow: gently forcing fist in & out of lower portion of R flank; fetus (in uterine horn) rocks from side to side. Hold first firmly in flank & feel calf bump into it
Equine: rectal palpation - 17-19 days: high uterine tone, tightly closed cervix, no dominant follicle; 28-30 days: bulge in uterine horn.
When is it possible to detect puppies in the uterus of a dog with radiographs?
Calcification of fetal skeletons begins 43-46 days after LH surge, approximately 20-22 days before parturition; at 50 days can usually get a puppy count
What are some advantages and disadvantages of using ultrasound to diagnose pregnancy?
Can confirm fetal viability as well as early pregnancy & see heart beating. Used frequently to diagnose equine pregnancies. Diagnostic too that doesn’t contain radiation.
About how early could you diagnose pregnancy in a bitch using ultrasound?
20 days after LH surge
What mineral, when supplemented too much, can lead to eclampsia in a bitch?
Calcium
What are the characteristics of a good whelping area for a bitch?
Familiar, private, free from drafts & moisture, prevent temp extremes
Should pregnant mares be vaccinated?
Yes - vaccinations late in pregnancy boost antibody levels in mare’s colostrum
What minerals should be supplemented in a mare’s diet?
Copper and zinc
Why should mares be taken to an “equine maternity ward: 30 days prior to foaling?
Allows adequate time for exposure to resident pathogens (colostrums will be protective)
allows adequate time for mare to acclimate & feel comfortable in new surroundings
What kind of bedding is recommended for mares about to foal?
Straw
Should pregnant mares be dewormed?
Yes, regularly throughout pregnancy
When do mares typically foal?
12am - 6 am
What are some premonitory signs of birth in mares?
Mammary activity: udder enlarges 1 month prior, nipples fill w/colostrum 24-48 hrs before, dried colostrum may accumulate on nipple end (waxing)
Sacrosciatic ligament relaxation, relaxation & elongation of vulva, may have decreased appetite, mild colic symptoms last weeks of gestation
After parturition, there is a discharge from the vulva. What is this called? How can you know if it is normal or not?
Lochia
Greenish or reddish brown is normal
Should not smell rancid
What are signs of dystocia in a dog?
Illness in dam; bloody, foul smelling or greenish vulvar discharge; prolonged pregnancy; obvious difficulty in delivering
What hormone can be administered to increase the strength of uterine contractions?
Oxytocin
Explain the feeding strategies for dogs in early, mid, & late pregnancy, lactation & weaning.
First 5-6 weeks: normal maintenance diet
Last 3-4 wks: increase amount 25-30% by whelping time, diet should be more nutrient dense, smaller meals at greater frequencies.
Lactation: keep amount increased through this time
Weaning: reduce rations by 90% for 1-2 days & lactation will stop
What is the cause of parturient paresis?
Caused by hypocalcemia, heavy lactation uses up lots of calcium, lack of calcium in body can cause flaccid paralysis (no muscle tone)
What hormones are involved with milk production?
Placental lactogen, prolactin, somatotropin (bovine growth hormone), insulin, cortisone
What hormones are sometimes used in the dairy industry to increase milk production in a cow?
Somatotropin (BGH)
Prolactin
Can the composition of cow’s milk be changed by making changes in the diet
Yes, milk comes from the cow’s plasma in their blood
What environmental factors influence sperm motility?
Temperature - must be kept at 100F
The most important factor in evaluating a bull’s fertility is?
Circumference of testicles, Direct correlation between circumference size & fertility
Sperm motility is graded from 1-5. What do those numbers mean?
5 = excellent, motility >80% 4 = very good, motility 70-80% 3 = good, motility 50-70% 2 = fair, motility 30-50% 1 = poor, motility <30%
Theoretically, how many cows could be artificially inseminated from a singe bull ejaculate?
300-500 cows/ejaculate
What is pregnancy toxemia?
Associated with relative lack of carbohydrates or alteration in carbohydrate metabolism. Adipose tissue mobilized to meet energy needs. Ketones are produced. Liver cells undergo adaptive changes due to alterations in metabolism. Metabolic acidosis (ketoacidosis) & severe systemic illness result.
When do pregnancy toxemia typically occur?
late in pregnancy
Explain vaccine strategies as they relate to breeding mares.
vaccinations late in pregnancy boost antibody levels in colostrum. Tetanus, EEE, WEE, WNV (and Potomac Horse Fever) should be given 4-6 weeks prior to foaling. Vaccines for rhinopneumonitis & equine influenza & strangles may be given late in pregnancy if possibility of exposure.
Explain vaccine strategies as they relate to breeding bitches.
Avoid vaccination unless substantial risk of exposure to disease. If she is unvaccinated, can use a killed virus.
What is “red bag”
placenta
What hormones are produced by the fetus at the end of pregnancy?
Cortisol (stress hormone) removes progesterone block of placenta, causes placenta to release PGF2 alpha which further decreases progesterone levels
Know the gestation times for dogs, cats, pigs, cows, horses.
Dogs: ~57 days after cytologic diestrus onset
Cats: 65 days
Pigs: 114-116 days (3 months, 3 wks, 3 days)
Cows: 273-290 days
Horses: 325-355, avg is 340-345
Know the terms for act of giving birth in the different species.
Cows: calving; sheep: lambing; goats: kidding; horse: foaling; pigs: farrowing; dogs: whelping; cats: queening or kittening
What stage of parturition?
Uterine contractions & gradual dilation of cervix
Stage 1
What stage of parturition?
Expulsion of fetus due to uterine contraction & voluntary pushing.
Stage 2
What stage of parturition?
Expulsion of fetal membranes
Stage 3
How many mammary glands do cows, bitches & mares have?
Cows: 4
Mares: 2
Bitches: 5 pairs or 10
What is the major carbohydrate and protein in milk?
Carb: lactose
Protein: Casein
What happens to the body temperature of bitches immediately prior to giving birth?
Will drop 1 or more degrees 8-24 hrs prior to whelping
What is normal body temp of a dog?
100-102
What is colostrum?
First milk, supplies antibodies to neonate
Why does colostrum have to be the first thing a calf or foal ingests?
If they drink milk 1st, they will not be able to receive the antibodies in the colostrum. Since all of their protection for the first few months comes from the colostrum, they will not be protected against disease if they do not ingest colostrum first.
Know the causes of dystocia.
Fetus too large
Malpresentation of fetus (turned)
Fetal pathology (hydrocephalis, ankylosed joints, shortened tendons, etc)
Dam: uterine muscle weakness, hypocalcemia, low oxytocin level, uterine rupture or torsion
Why is exposure to radiation or drugs early in the development of an embryo so devastating compared to exposure later in development?
Risk to developing fetus is highest early in pregnancy since most development is taking place early on.
How does age affect an oocyte or sperm?
Fertilization of older oocytes increases changes of an abnormal embryo which will probably not implant
Aged sperm are less able to fertilize oocyte
What hormones does the placenta produce?
Relaxin & estrogen
What is external ballottement
Gently forcing fist in & out of lower protion of right flank. Fetus rocks from side to side
What is the AM/PM rule?
A cow should receive AI 12 hours after being observed in estrus. If a cow is observed in estrus in the AM, she should be given AI in the PM.
How does electroejaculation affect sperm?
It has the lowest quality of sperm of all the collection techniques.
