Animal
Breeding & Reproduction
A. Discuss the meaning and importance of reproduction in
animal agriculture
B. Describe benefits of using genetically superior animals for
breeding
C. Define common terms and describe the function of
reproductive organs
D. Compare estrous cycles and gestation of different species
and list common signs of breeding readiness
E. Describe signs of parturition and dystocia
F. Describe the purpose and benefits of reproductive
technologies
Why is it important for
animal producers to
understand principles of
animal breeding?
A.
Discuss the meaning and importance of reproduction in animal agriculture
Importance of Reproduction
• Producers rely on successfully reproducing
young for economic success
–
–
–
–
Cow/Calf Operation without calves?
Hog farm without piglets?
Sheep farm without lambs?
Dairy farm without calves?
A.
Discuss the meaning and importance of reproduction in animal agriculture
Importance of Reproduction
• Our food supply would be in jeopardy
without sound animal reproductive
practices
Should any or all animals be
used for breeding?
B. Describe benefits of using genetically superior animals for breeding
Choosing Superior Animals
• Responsible Animal Breeding:
– Only breed animals with desirable
characteristics to be passed on:
• Natural selection would eliminate most genetic problems, but
artificial selection does not
• It is our responsibility to be responsible animal breeders
B. Describe benefits of using genetically superior animals for breeding
Choosing Superior Animals
• Responsible Animal Breeding:
– Improve the next generation
• Hybrid Vigor
• Eliminate poor characteristics
• Improve efficiency of food production
C. Define common terms and describe the function of reproductive organs
Terminology
• Pregnancy -- carrying a fetus
• Fertilization -- the union of the EGG and
SPERM nuclei
• Conception - occurrence of fertilization
• Ovulation - release of an ovule from the
female.
• Gestation - the time from fertilization or
conception of a female until she gives birth
C. Define common terms and describe the function of reproductive organs
Terminology
• Ovaries - FEMALE reproductive gland in
which eggs are formed and hormones are
produced.
– Egg or Ovule- Female Reproductive Cell
• Testes - MALE reproductive gland that
produces sperm and testosterone.
– Sperm- Male Reproductive Cell
– Semen- Fluid that carries sperm
C. Define common terms and describe the function of reproductive organs
Female Reproductive Organs
C. Define common terms and describe the function of reproductive organs
Female Reproductive Organs
Vagina
Cervix
Vulva
Ovaries
Uterine Horns
Uterus
Fallopian Tube
Infundibulum
C. Define common terms and describe the function of reproductive organs
Female Reproductive Organs
•
•
•
•
Vulva- opening of reproductive tract
Vagina- channel for birth and copulation
Cervix- divides vagina and uterus
Uterus- Where fetus grows & receives
nourishment
• Fallopian Tube- where fertilization
occurs
• Ovaries- produces eggs and hormones
C. Define common terms and describe the function of reproductive organs
Male Reproductive Organs
C. Define common terms and describe the function of reproductive organs
Male Reproductive
Organs
Prostate Gland
Cowper’s Gland
Sigmoid
Flexure
Epididymis
Seminal Vesicle
Vas Deferens
Testicle
Scrotum Sheath
Penis
C. Define common terms and describe the function of reproductive organs
Male Reproductive Organs
•
•
•
•
Testes - produce sperm and testosterone
Epididymis - collects and stores sperm
Vas deferens - transports sperm
Penis - places sperm in female
• Cowper's Gland
• Prostate Gland
• Seminal Vesicle
produce semen
• Scrotum - protects testes & maintains temp.
• Sheath - opening of reproductive tract
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Estrous Cycles
• Estrous Cycle:
– Time between periods of estrus, or “heat”
– Often influenced by of hours of light in the day
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Estrous Cycles
• Estrous Cycles by Species:
Species
Estrous
Cycle
Length of
Estrus
(heat)
Ovulation
Cow
21
12-18 hours
10-14 hours after estrus
Mare
22
6-8 days
1-2 days before estrus ends
Doe (goat)
21
30-40 hours
At end of estrus
Doe (rabbit) Constant
Constant
8-10 hours after mating
Sow
20-21
40-72 hours
Mid estrus
Ewe
17
24-36 hours
Late estrus
Dog
-
9 days
1-2 days after estrus begins
Cat
14-21
5 days
24 after mating
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Estrous Cycles
1- Estrus- also known as
“heat.” The period of time
when female is receptive to
male and conception can occur.
-Hormone: Estrogen
2- Metestrus- follows
estrus. Usually when ovulation
occurs
-Hormone: LH (leutenizing hormone)
1-Estrus
2-Metestrus
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Estrous Cycles
3- Diestrus- Period of
cycle when system assumes
pregnancy.
1-Estrus
4-Proestrus
-Hormone: Progesterone
4- Proestrus- If not
pregnant, body prepares to
begin cycle again
-Hormone: Progesterone drops
3- Diestrus
2-Metestrus
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Breeding Readiness
Cattle-
Horses-
• Standing to be mounted
or trailing other cattle
• Clear, viscous mucous
from vulva
• Swelling of vulva
• Restlessness
• Restlessness whinnying
• Frequent urination in
small amounts
• Backing up and pushing
on fences or other objects
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Breeding Readiness
Pigs-
Sheep-
• Erect ears
• Moist vulva
• Standing or “Locked up
Response” when touched
• Seeking out and standing
for ram
(symptoms are much less
noticeable than other species)
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Breeding Readiness
Chickens-
Rabbits-
• None
• Sperm from a rooster can
be viable in a hen for up
to 30 days. Once
inseminated, it’s stored
until the next egg is
produced
• None
• Does ovulate at presence
of sperm, not on a cycle
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Gestation
• Length of PREGNANCY.
• Begins with FERTILIZATION and ends
with parturition (birth).
• All animals have different gestation
lengths. Usually the LARGER the animal,
the LONGER the gestation.
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Cattle Gestation
• Gestation- 283 days or 9 Months
• Breeding Season- Dairy: Year round, Beef: Summer-Fall
• Cycle: Year round, every 21 days
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Sheep & Goat Gestation
• Gestation: 145-150 days or 5 months
• Breeding Season- Fall/Winter (dairy goats year round)
• Cycle: Late fall when days get short
“Short day breeders”
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Pig Gestation
• Gestation- 115 days
OR 3 months, 3 weeks, 3 days
• Breeding Season- year round
• Cycle- Year round every 21 days
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Horse Gestation
Gestation- 336 days or 11 months
• Breeding Season- Spring
• Cycle- Spring/Summer when days are long
•
“Long day breeders”
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Rabbit Gestation
• Gestation- 30 days
• Breeding Season- Year round
• Cycle- Constantly, year round
D. Compare estrous cycles and gestation of different species and list common signs of breeding readiness
Chicken Gestation
• Gestation- 21 days (incubation)
• Breeding Season- Year round or spring
• Cycle- Year round, but more productive when days are long
E. Describe signs of parturition and dystocia
Parturition
• Parturition- The act of giving birth
• Signs:
–
–
–
–
–
Milk develops in udder
Abdomen drops
Nesting
Restlessness or pacing
Abdomen muscles contract (just before birth)
E. Describe signs of parturition and dystocia
Stages of Parturition
• Stage 1 –
– Preparatory Stage (Labor)
• Stage 2 –
– Delivery of Fetus
• Stage 3 –
– Expulsion of the placenta
• Stage 4 –
– Period of Rest
E. Describe signs of parturition and dystocia
Dystocia
• Dystocia- Difficulty giving birth
• Causes:
–
–
–
–
Presentation
Oversized fetus
Multiple births
Exhaustion, uterine contractions stop
• Solutions: Call vet or assist
yourself
– Cesarean Section (c-section)
– Assist manually
E. Describe signs of parturition and dystocia
Dystocia
• Birth Presentations
Breech
Normal
Head Back
Upside down &
Backward
Leg Back
IV. Female Reproductive Hormones
A.
Gonadotropin
• Causes puberty
• Produced in the pituitary gland
• If pituitary is removed, individual
remains infertile, no sexual cycle
B. Follicle Stimulating Hormone (FSH)
• Promotes egg and follicle growth
•
Follicle releases estrogen, primary
female hormone
C.
Progesterone (P4)
• Produced by corpus luteum
•
Major production beginning in day 5 or 6 of
pregnancy
•
Maintains pregnancy
•
If animal does not become pregnant, level drops
by day 16-17 of cycle, P4 levels increase after
ovulation and remain high until the end of
diestrus
•
If pregnancy occurs, P4 levels remina high until
just before parturition.
•
Promotes development of mammary glands
D.
Estrogen
• Primary female hormone
• Group of hormones produced by
follicles and placenta
• Initiate growth of mammary glands and
ducts
• Levels peak at the beginning of
standing heat
E. Relaxin
• Produced by ovaries
• Causes relaxation of pelvic ligament for
parturition
F.
Lutenizing Hormone (LH)
• Produced by pituitary
• Needed for ovulation and development
of corpus luteum
F.
Prostaglandins
• Produced by various tissues in the body and appears
to be secreted by the uterus just prior to birth
• PGs are commercially produced and used to
synchronize estrus and treat silent heats
H.
Prolactin (PIH)
• Produced by anterior pituitary
• Needed to begin lactation
• Maintains lactation
I.
Oxytocin
• Released by posterior pituitary
• Causes milk let down
• Helps uterus recover after birth
V. Effects of hormones produced by ovaries
and testes
A.
Ovaries
• Estrogen
brings female in to heat
Aids in moving sperm and egg together by
increasing contractions of the female
reproductive tract
Stimulates cell growth in the uterus in
preparation for the embryo
•
Progesterone
Prevents ovulation and causes heat period to
end
B.
Testes
• Testosterone
Affects sex drive
Causes growth and development in male
reproductive tract
Necessary for maturation and survival of sperm
Breeding Systems
I. Breeding Systems
A. Straightbreeding-mating animals of same
breeds
B. Crossbreeding-mating animals of different
breeds
C. Considerations
1.
2.
3.
4.
Type of operation
size of herd
money available
goals of owner
II. Types of Crossbreeding
A.
1.
2.
3.
Purebred Breeding
Characteristics of a particular breed
BOTH parents must be purebred
Able to register in breeds association
a. Color disqualifications
b. Recessive gene traits
4. Linage is traceable for several
generations
5. Homozygous-identical genes for a trait
6. Provide foundation stock for
crossbreeding
B. Inbreeding-mating of related animals
1. Closebreeding-animals are closely
related and have more then one common
ancestor.
2. Linebreeding-animals more distantly
Related and can be traced back to one
common ancestor.
3. Inbreeding increases genetic purity
4. Undesirable traits become more visable
5. Selection and culling is made easier
6. Desirable traits are more closely
grouped
7. Requires careful planning and culling
8. This system is expensive
9. Used by Universities and Seedstock
breeders.
C. Outcrossing-mating of animals of different
families within the same breed.
1. Animals are not closely related
2. Bring in desirable traits
3. Most animal breeding
D. Linecrossing-mating animals from two
different lines in same breed
E. Grading Up-mating of purebred sires to
grade females.
1. Grade Animal-any animal not qualified
for purebred registration.
2. Improves the quality of herd animals
3. Less expensive
4. Improvements based of quality of sire
used
5. Greatest amount of improvement
D. Crossbreeding-mating two animals of
different breeds.
1. Result is a hybrid
2. Results in improved traits
3. Dominant genes cover recessive
undesirable traits.
4. Heterosis-Superior traits that result
from crossbreeding
5. Is used mostly in market livestock. Not
Dairy
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
• Any method of reproduction that is not a
natural method
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Artificial Insemination
Collecting and placing sperm from the male
to the female reproductive tract without
natural mating
VI. Advantages of Fertility Testing Bulls
A. Prevents loss of calf crop
B. Increase calf crop
C. Provides means of selecting
bulls
D. Provides means of culling bulls
from herd
E. Shorten calving season
F. Increases profit
VII. Causes of sterility and delayed
breeding in bulls
A. Poor semen
B. Physical defects or injuries
C. Psychological problems
D. Infection and disease
E. Poor management and
feeding
F. Inherited abnormalities
VII. Parts of a sperm cell
A. Head
B. Neck
C. Middle Piece
• The middle piece of the sperm cell
stores energy for the sperm cell
D. Tail
• The tail propels the sperm
IX. Types of Abnormal Sperm
A.
Tailless Head
B.
Two Heads
C.
Abnormal Shaped
Head
D.
2 tails
E.
Coiled Tail
F.
Abnormal Middle
Piece
X. Evaluating Quality of Bovine Semen
A. Color--Acceptable color ranges from
milky to creamy
Note: This indicates sperm per cubic millimeter of
500,000 or above. Other colors indicating less
than 500,000 sperm/cu. mm. would be opalescent
(cloudy) to watery.)
B. Foreign material--Blood or pus in the
semen indicates a serious problem and
is unacceptable; bedding, dust or fecal
material should be disregarded
(Note: Pus may appear as snowflakes around the
edges of a tilted vial.)
C. Wave pattern
(Note: This is best determined by placing a thick drop of
semen on a slide under a microscope on low power and with
reduced light.)
1. Acceptable
a. Very good - 4 - Dark, distinct waves
moving rapidly
b. Good - 3 - Waves apparent, with
moderate motion
2. Not acceptable
a. Fair - 2 - Waves barely distinguishable
b. Poor - 1 - No waves, but motile sperm
are present
c. Very poor - 0 - No waves and no sperm
motility
D. Progressive motility (Able to move
spontaneously)
1. Acceptable samples should have a progressive
motility exceeding 50 percent
2. Ratings
1.
2.
3.
4.
5.
Very good - 5 - 80-100% motile sperm
Good – 4 - 60-80% motile sperm cells
Fair - 3 - 40-60% motile sperm cells
Poor – 2 - 20-40% motile sperm cells
Very poor - 1-0-20% motile sperm cells
XI. When to check a bull for fertility
A. Just before breeding season
A. Soon after breeding season
XII. Fertility Problems
A.
Sterility
1.
Animals unable to reproduce
2.
No remedy
B.
Age
1.
2.
3.
C.
Fertility levels decrease as age
increases
Female--Eggs not produced
regularly
Male--Reduced sperm concentration
Deformities--Deformed parts of
reproductive tract
Example: Undescended testicles
D.
Temperature
1. Male--High temperatures can end sperm
production
2. Female--Heat stress reduces size and number
of offspring
E.
Condition
1. Temporary infertility when animals not in good
general condition
2. Abrupt change in nutritional levels, overfeeding
and underfeeding can all reduce fertility
F. Freemartin
1. Heifer born twin to a bull
2. 90% infertile
G. Silent heat
1. Shows no signs of estrus
2. Caused by improper hormone release
3. Causes cyst
H. Chronic buller
1.
Caused by hormone imbalance
2.
Female seems to stay in heat
3.
Conception does not occur
I. Disease and infections
1.
Can cause death of fetus
2.
Can prevent conception
XII. Advantages of Pregnancy Testing
A. Cuts winter feed bills
B. Identifies pregnant cows
C. Provides means of culling cows
D.
Increases profit
A. Example: Setting goal of 90 to 95%
calf crop within 30 days
(Note: Slaughter cows will bring a
higher return if known to be open.
Purebred animals will bring more
money if known to be safely with calf.)
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Artificial Insemination
Step 1: Collect & Store Semen
-Collect Semen
-Extend sample and place in straws
-Store in liquid nitrogen
XIV. Equipment used in inseminating
A. Frozen Semen Storage Tank
1. Liquid nitrogen storage (-320 F)
2. Several straws stored for long periods/
B. Thaw Tank
1. 95 degree water
2. About a minute
C. Breeding Guns
1. Insert Semen into female tract
D. Plastic Gloves
B
A
D
C
F. Insemination Tube
1. Covers straw and gun
2. Protects semen and eases
insemination
G. Semen Straw
1. Stores Semen
2. Protection
H. Straw clippers
1. Cuts end of straw
XV. Errors in placing inseminating tube
Reproductive Technologies
Advantages of Artificial Insemination
1-Wider selection & use of outstanding sires
2-Rapid Genetic and herd improvement
3-Overcome physical barriers to mating
- Examples: Aggressive behavior or injuries
4-Danger of the bull is eliminated
5-Eliminate cost of purchasing and keeping a bull
Reproductive Technologies
Disadvantages of Artificial Insemination
1-Skilled Technician or training required
2-Very close supervision of females is necessary
to accurately determine stage of estrus.
XVIII.Other types of Fertility Aid
A. Sexed Semen
1. Collected and prepared to produce all male
or female offspring.
2. About 90% Accurate
3. Cost about 4 times more
B. Estrous Synchronization
1. Bringing a group or single animal into heat
2. Use of synthetic hormones
3. Shots or implants
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Embryo Transfer
The transfer of fertilized egg(s) from a donor
female to one or more recipient females
Utilizes genetics of superior FEMALES by
producing more offspring per year than by
natural breeding methods
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Cloning
Producing an EXACT genetic copy of an
organism
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Cloning “Scamper”
•Charmayne James was first Million Dollar
Cowgirl, 1990
•11 Consecutive Barrel Racing Championships
•First WPRA Member listed in Guinness Book
of World Records, 1987&92
•WPRA Record Most NFR Qualifications, 19
(consecutive)
•All won on her beloved horse, “Scamper”
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Cloning “Scamper”
Few people involved in the horse industry haven't heard the legendary story of Gill's
Bay Boy, affectionately known as "Scamper," and his jockey and partner Charmayne
James who together set the world of pro rodeo on fire beginning in 1984. Scamper
came to Charmayne as an untrained young prospect with a renegade reputation and
was best known in those days for bucking off ranch cowboys. At the tender age of 14
Charmayne did the inconceivable. She trained and cared for Scamper and in the
process revealed the limitless potential concealed beneath his common exterior. With
dedication and careful attention to conditioning Charmayne produced an equine
legend whose historical achievements will not soon if ever be duplicated. The young
horsewoman was herself a prodigy honing her training skills to take Scamper from
the anonymity of the feedlot to the spotlight of the rodeo arena. The two inevitably
raced to unforgettable performances in arenas from Houston to Las Vegas and most
everywhere in between along the way. Scamper and Charmayne's list of accolades
together are endless and include Scamper's induction into the PRCA Hall of Fame, as
well as Charmayne's place in the National Cowgirl Hall of Fame, National Cowboy
Hall of Fame, and Texas Cowboy Hall of Fame, among others.
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Scamper’s Clone: “Clayton”
F. Describe the purpose and benefits of reproductive technologies
Reproductive Technologies
Is cloning new?
Mule cloned at USU in
2003
“Dolly” cloned in
1996
Bell Quiz
Objective A, B, & C
1. Why is successful animal reproduction
important to the finances of farming and
ranching?
2. How would it effect our food supply if animal
producers were NOT successful at reproducing
their animals?
3. Should all animals be used for breeding?
4. What is the male & female reproductive cell?
5. What 3 glands produce semen in the male
reproductive tract?
Bell Quiz
Objective D
1. What is the difference between “estrous”
and “estrus?”
2. How long is the gestation of a sheep or
goat?
3. How does daylight effect the estrous cycle
of some animals?
4. What is unique about a rabbit’s
reproductive system that allows them to
reproduce quickly?
Bell Quiz
Objective E
1. What is the definition of dystocia?
2. What does the word, parturition mean?
3. Name 3 signs that could indicate that an
animal will give birth soon.
4. What purpose does the placenta serve in
the growth and development of a fetus?
5. Describe a normal birth presentation of a
calf.
Bell Quiz
Objective F
1. What reproductive technology is used to
enhance the # of offspring a superior SIRE
can have
2. What reproductive technology is used to
enhance the # of offspring a superior DAM
can have
3. What are 2 benefits of Artificial
insemination?
4. What are 2 disadvantages of Artificial
Insemination?