REPRODUCTION AND BREEDING
REPRODUCTION AND BREEDING
OBJECTIVES Discuss Expected Progeny Differences
(EPDs). Discuss genetic engineering and its
effect on animal agriculture. Label the major parts of male an female
reproductive systems. Identify animals by gender. Identify methods used in artificial
insemination of animals.
WHY? Why is genetic engineering important to
know about? Why should we be able to ID animals by
gender? Why should we know about
reproduction? Why should we know about artificial
insemination?
WHAT? What is expected progeny difference?
What is genetic engineering?
What are different methods of AI?
EXPECTED PROGENY DIFFERENCE
A prediction of future progeny performance of one individual compared to another individual within a breed for a specific trait.
For registered animals. In BW the lower the number the better.
EPDSBull A Bull B DIFFERENCE
BW (Birth Weight)
-2 +3 5 LBS.
WW (Weaning Weight)
40 70 30 LBS.
MA (Milking ability)
27 10 17 IBS.
OTHER EPDS
STAY STAYABILITY IN MARKET
CED CALVING EASE
YW YEARLING WEIGHT
EPDS Ex) MA: Milking ability
Daughter of Bull A are expected to wean calves which weigh 17 pounds heavier than calves of the daughters of Bull B.
GENETIC ENGINEERING The direct human manipulation of an organism's
genome using modern DNA technology. Involves the introduction of foreign DNA or
synthetic genes into the organism of interest. The introduction of new DNA does not require
the use of classical genetic methods, however traditional breeding methods are typically used for the propagation of recombinant organisms.
An organism that is generated through the introduction of recombinant DNA is considered to be a genetically modified organism.
1973• First organisms genetically engineered were bacteria
1974• Mice genetically engineered for insulin.
1982• Insulin-producing bacteria were commercialized.
1994• Genetically modified food start being sold commercially.
1997• Vacanti mouse was first introduced.
GMO Science, mice, and patents
The most commonly genetically modified animal is almost certainly the mouse. It is small, short-lived and sufficiently similar to humans to be an almost ideal laboratory animal. As a result, mice have not only been cloned and modified, they have led to an actual industry in the production of "knockout mice," that is, mice with a particular gene or set of genes inactivated for research purposes.
Trans Genic Inc asserts, "Currently, we are able to produce almost 1,000 strains of Knockout
GMO "Pharming"
Cattle, sheep, goats, chickens, rabbits and pigs have been genetically modified with the aim of producing human proteins that are useful, generally as medicines. The gene transfer process is typically very inefficient, and cloning is seen as another way of propagating the GM animal.
A 1999 USDA report cited estimates that there was a $24 billion market for human proteins, and theoretically 600 transgenic cows could supply the worldwide demands for some drugs. In practice, however, several companies that have pursued this line have gone bust, and the profit potential seems less than it once did.
Genetic modification of animals in order to improve the prospects of organ transplants is also being investigated.
GMO Genetically modified fish as pets
A tropical fish genetically modified to glow in the dark went on sale in Taiwan in 2003 for about $17 each. A different variety of zebrafish, called "GloFish," which were created in Singapore, reached the United States market in January 2004. The distributor says that GloFish were originally developed to fluoresce only in the presence of pollutants, but that is not the form in which they are being sold. They cost about $5 each, and are intended to live in aquariums, but can breed and, in the right conditions, live in the wild.
The Food and Drug Administration (FDA) approved the sale without ceremony. A coalition led by the Center for Food Safety filed suit against the decision, but sales went ahead. In California, the Fish and Game Commission initially banned the fish but later agreed to hold hearings at the request of the distributor.
GMO Allergy-free cats?
A company called Transgenic Pets, in Syracuse, NY, was widely reported in 2001 to be working with scientists at the University of Connecticut to "remove the allergen gene" from cats. The company hoped to raise $2 million and sell the modified animals for $1,000 each. Funding problems ended the project.
REPRODUCTION The process by which new organisms
are derived normally involving the union of the male and female sex cells.
Female sex cells: Egg or ovum
Male sex cells: Sperm
MALE
Testicles - produce spermatozoa & male hormone Testosterone
Scrotom - sack which carries testiclesfunctions as a heat regulator
Monorchid - one fertile testicle Cryptorchid - both testes remain in body
cavity (sterile) Castration - removal of testicles
lack sex drivegain weight quicker
Epididymis - tube connects to testes storage of spermatozoa (200
billion at a time) spermatozoa mature as they
migrate through Vas Deferens - tube connects to
epididymusif removed, can't reproduce = vasectomy
Urethra - begins at bladder and continues through penis
Sigmoid Flexure - "S" shape in urethra allows for extension of penis outside of body for reproduction
FEMALE
Vulva - exterior portion of reproductive tract
provides visual signs of heat Vagina - between vulva & cervix
Cows & Ewes: semen is deposited hereMares & Sows: semen is deposited in the
cervix
Cervix - "Mouth of the womb" opening into uterus at birth cervix stretches to allowbaby
to pass (most painful part) during pregnancy cervix becomes
blocked with a mucous plug to prevent infection
Uterine Horns - two branches of uterus Fallopian Tube - uterine horn
becomes a small tubelined with cilia which aid in egg
migration
OVARIES located at end of fallopian tubes possesses large number of eggs in all
stages of development this is all the eggs she will ever have,
unlike the male very few eggs reach maturity if not fertilized, the egg is reabsorbed by
the body
WHAT DOES "IN HEAT" MEAN? Heat is the time when a female is
receptive to the male and will allow breeding to take place
Heat is actually divided into 4 phases of the cycle.
ESTROUS CYCLE:Proestrus: ovary is about to release an
eggEstrus: female receptivityMetestrus: uterus prepares for pregnancy
fertilized egg attaches to uterus
Diestrus: longest period of cycleinactive
Estrous Cycles stop after conception, and begin soon after Parturition (birth)
CATTLE Mature Male (not castrated) Bull
Mature Female Cow
Young Male Bullock
Young Female Heifer
Newborn Calf
Male (Castrated) Steer
Group Herd
Act of Parturition Calving
Duration of heat 14 hours
Length of Estrous cycle 12; 18-24 days
Time of ovulation in (days) relation to heat
10-14 hours after end of estrous
Gestation period 281; 274-291
Age at puberty (months) 8-14
SWINEMature Male (not castrated) Boar
Mature female Sow
Young Male Boar3
Young Female Gilt3
Newborn Pig
Male (Castrated) Barrow
Group Herd, drove, or sounder
Act of Parturition Furrowing
Duration of heat 2-3 days
Length of Estrous 21; 18-24 days
Time of ovulation in (days) relation to heat
18-60 hours after estrous begins
Gestation Period 113; 111-115
Age at Puberty 5-7
3. Shoat refers to a young pig of either sex under one year of age.
SHEEP Mature Male (not castrated) Ram
Mature female Ewe
Young Male Ram Lamb
Young Female Ewe Lamb
Newborn Lamb
Male (Castrated) Wether
Group Flock
Act of Parturition Lambing
Duration of heat 30-35 hours
Length of Estrous 16; 14-20 days
Time of ovulation in (days) relation to heat
1 hour before end of estrous
Gestation Period (days) 150; 140-160
Age at Puberty (months) 4-8
POULTRY
Chickens Turkeys
Mature Male (not castrated)
Cock Tom or Gobbler
Mature female Hen Hen
Young Male Chick Jake
Young Female Chick Jenny
Newborn Chick Poult
Male (Castrated) Capon
Group Flock Flock
Act of Parturition NA NA
Duration of heat NA NA
Length of Estrous NA NA
Time of ovulation in (days) relation to heat
NA NA
Gestation Period (days)
21 Day Incubation 28 Day Incubation
Age at Puberty (months)
4-6
ONE EGG It takes 25-27 hours for a chicken to
produce one egg
DOGS (CANINES)Mature Male (not castrated) Dog
Mature female Bitch
Young Male Puppy Dog
Young Female Puppy Bitch
Newborn Pup
Male (Castrated) Castrate
Group Pack
Act of Parturition Whelping
Duration of heat (6-12 avg) 2-21 days
Length of Estrous 3.5-13 Months; (6 month avg)
Time of ovulation in (days) relation to heat
Usually 1-3 days after first acceptance of male
Gestation Period (days) 63; 58-68
Age at Puberty (months) 5-24
CATS (FELINES)Mature Male (not castrated) Tom
Mature female Queen
Young Male NA
Young Female NA
Newborn Kitten
Male (Castrated) Gib
Group Bevy
Act of Parturition Littering
Duration of heat 6-7 days
Length of Estrous 18; 14-21 days
Time of ovulation in (days) relation to heat
Stimulated by male
Gestation Period (days) 63; 62-64
Age at Puberty (months) 4-18 (breed variability)
GOATSMature Male (not castrated) Buck
Mature female Doe
Young Male Buck Kid
Young Female Doe Kid
Newborn Kid
Male (Castrated) Wether
Group Band
Act of Parturition Kidding
Duration of heat 42 hours
Length of Estrous 21; 15-24 days
Time of ovulation in (days) relation to heat
Near end of estrous
Gestation Period (days) 151; 140-160
Age at Puberty (months) 4-8
HORSESMature Male (not castrated) Stallion
Mature female Mare
Young Male Colt
Young Female Filly
Newborn Foal
Male (Castrated) Gelding
Group Herd
Act of Parturition Foaling
Duration of heat 6 Days
Length of Estrous 21; 16-30 days
Time of ovulation in (days) relation to heat
1-2 days before end of estrus
Gestation Period (days) 336; 310-350
Age at Puberty (months) 10-12
ARTIFICIAL INSEMINATION
Process by which sperm is placed into the reproductive tract of a female for the purpose of impregnating the female by using means other than sexual intercourse or natural insemination.
ARTIFICIAL INSEMINATION Pros
Quality Sires: AI makes superior sire semen to be available to hundreds of female cows. Artificial insemination
in dairy cattle, leads to sires of inheritance for butter fat and milk production. Prior to AI, only few cows could
have the advantage of good bulls.
Decreased Costs and Increased Safety: Bulls are bigger and stronger than cows and generally quite difficult to
handle around the farm. AI eliminates the need to have a bull on the farm, as semen can be easily transported.
They can also be stored for a long period of time. Since maintaining males costs quite a bit, AI decreases the
overall costs on the farm.
Reduction in Disease Transmission: The transfer of venereal diseases is quite likely to happen during natural
mating. Certain pathogens can be transferred via the semen into the female, during AI as well, however, the
screening done after semen collection prohibits this transfer.
Genetic Selection Improvement: Since one male's semen is more than enough to produce hundreds of
offspring, the best few males can be selected for breeding. This helps maintain the vigor of the cattle breed.
Artificial insemination in beef cattle helps maintain the genetic pool, thereby obtaining the right strain of beef
cattle, required for meat production. Bulls of high genetic merit are available with AI.
ARTIFICIAL INSEMINATION
ConsArtificial insemination in cattle requires
dexterity, patience, knowledge, experience, as well as specialized equipment.
Improper sterilization of equipment,
unsanitary conditions, etc.
Preservation of semen sometimes difficult..
ARTIFICIAL INSEMINATION
REVIEW
What is expected progeny difference?
What is genetic engineering?
What are different methods of AI?