as101 exam 3

What hormone and part can help maintain pregnancy?

-CL

-progesterone

What is necessary in order for reproduction to be successful?

-Reaches puberty

conceives

maintains pregnancy

undergoes successful parturition

offspring survive

uterus undergoes involution

esperience postpartum estrus and conceive agian

What factors affect reproductive performance?

-Nutrition

environment

-Anatomical differences in reproductive tract

endocrine system imbalance

diseases

What is the average percent calf crop in the U.S, what should it be, and what is the main cause of this?

-85%

should be 90%

nutritional management is the main cause

What are the environmental factors that affect reproductive performance?

-Temperature

humidity

seasonality

What is an example of an endocrine system imbalance?

A castrated male looks and acts different because he has less hormones

What are some diseases that affect reproductive performance?

-Brucellosis

metritis

vibriosis

leptospirosis

trichomoniasis

IBR

What is the BCS for cattle and what score is ideal?

-1 to 9

5 is ideal

When cattle are over conditioned/fat, what problems can they encounter?

Increased dystocia due to fat around tract

Are over conditioned cattle common or rare?

Rare

Where would you most likely see over conditioned cattle?

-Show animals

hobby farmers

Flushing

Increase the level of nutrition around 30 days before breeding to increase the rate of ovulation in the herd

What animals is flushing effective for?

-Heifers

ewes

girlts (sometimes)

Under conditioned

-Thin cattle

main focus is survival

What are the two biological goals of animals?

-Survive

reproduce

Why must a female carry a certain percentage of body fat to reproduce?

Because physiological mechanisms that are involved in reproduction do not function if an animals life is threatened due to the availability of food

What is the management problem producers face regarding reproduction?

-Want a cow every 12 months

takes 283 days for gestation

leaves them 82 days for uterus involution and rebreeding

cows don’t show estrus until 45 days after postpartum

have 2 estrous cycles (21days) to breed

What is the relationship between percent of cows showing estrus and their body condition at calving?

-Nutritional advantage

-As the days progress, more cows are showing estrus that have good body conditions compared to the thin and moderate conditioned cows

-Better BCS, show estrus quicker

How should the cattle go into calving season?

In gaining condition preferably with a BCS of 5 or above

Why do cattle lose weight between weaning and calving?

Because the nutritional demands are high for lactation which makes it likely for the cow to lose weight

What is the recommended diet for cattle when reproducing, and what is it called?

Feed them hay, silage, and range cubes beginning 30 to 60 days before calving and continue until the cattle is rebred, called 120 critical days

What is the goal of the 120 critical days?

Feed to gain weight (not to fatten)

What critical needs do first calf heifers have that requires they get extra nutrients?

-They will be lactating for the first time

-They are still growing

-Uterine involution to prepare for the next pregnancy

Why do you separate first calf heifers from the main cow herd?

So mature mama cows don't bully them and so they can get the correct amount of feed

What should you do with replacement heifers?

-Separate then from the main herd

-Provide excellent grazing or supplemental feed

For replacement heifers, what percent of their expected mature weight do you want them to reach, and how old are they when they begin to breed?

Reach 65% of their expected mature weight at breeding at 13 to 15 months

Energy

The dietary component that is usually limiting

What are the strategies used for optimizing reproductive efficiency?

-Artificial insemination

-Super ovulation

-Embryo transfer

How old is AI?

Very old, goes back to the 14th century

What is the percent of AI matings in the turkey industry?

95%

What is the percent of AI matings in the dairy cattle industry?

80 to 90%

What is the percent of AI matings in the beef cattle industry?

8 to 10%

What is the percent of AI matings in the horse industry?

40 to 50%

What is the percent of AI matings in the swine industry?

80 to 85%

What is the percent of AI matings in the sheep industry?

Less than 5%

What industries are predominately AI?

-Turkey

-Dairy cattle

swine

What industry rarely uses AI?

Sheep

What are the advantages of using AI?

-Maximum use of genetically superior sires

-Greater selection of affordable sires

-Use deceased, incapacitated, or dangerous sires

-helps reduce diseases

improves management

What are the disadvantages of using AI?

-Increases labor, management, and facilities

accentuate poor genetics by using an inferior sire

need good technicians

What is used in the AI industry to synchronize estrus?

-Lutalyse

estrumate

synchromate B

The future of AI would be better if we could do what?

-Successfully sex semen

-Breed lactational anestrous cows (skip heat)

What are two ways of collecting semen?

-Artificial vagina

-Electroejaculator

When is the artificial vagina used?

When mounting females or training to mount dummies (phantom mare for stallions)

What animals do you use the artificial vagina on?

-Bulls

stallions rams

-Stallions

-Rams

How do you collect semen for swine?

Apply pressure by a gloved hand

Electroejaculator

A probe that is inserted into the rectum that electrically stimulates the animal and causes ejaculation

What happens if you collect semen too frequently?

The number of semen per ejaculate decreases

After collection, what do you evaluate the semen for?

-Volume

-Sperm concentration

-Sperm motility

-Sperm abnormalities

During semen processing, what do you do?

-Evaluate semen

-Mix semen with an extender that dilutes to a greater volume (adds volume) and makes the semen last longer

How long does fresh semen last?

1 to 2 days

How long does frozen semen last?

Indefinitely

What animal is it not useful to freeze its sperm?

Boar

When is the best time to inseminate?

The sperm and the ova at the site of fertilization at the peak of their fertility

How long is the fertile life of the ovum?

12 to 24 hours it is capable of being fertilized

How long is the fertile life of the sperm?

24 hours in the female tract but 12 hours is required for capacitation (maturation) so fertility is limited to the last 12 hours

How long does it take to transport sperm?

Approximately 5 minutes

When do cows, ewes, and sows ovulate?

One day after estrus begins

When do mares ovulate?

One day before the end of estrus

What is the length of estrus for ewes?

1 to 2 days

What is the length of estrus for sows?

1 to 3 days

What is the length of estrus for mares?

4 to 6 days

What is the length of estrus for cows?

16 to 20 hours

When should you inseminate cows, ewes, and sows?

AM PM rule, 12 hours after the onset of estrus

When should you inseminate mares?

Palpate to determine follicle size and then decide when to inseminate

Where is the site of semen deposition in cows and mares?

Uterus

Where is the site of semen deposition in sows?

Cervix

Does deposition in the uterine horn increase or decrease the probability of conception and why?

Has lower conception due to uterine trauma and possible infection

Superovulation

Hormone treatment of the female to induce multiple ovulations for multiple births or embryo transfer

Whys is multiple births not a practical procedure?

-Decreases gestation length

-Decreases birth weights

-Increases calf loss at parturition and after

-Increases retained placenta

What are the advantages of embryo transfer?

-Increases reproduction of valuable dams

-Decreases time for proof of dam through a greater number of progeny

-Extends reproductive life of injured or older dams

-Makes it easier to transport exotic breeds or proven stock to restricted or underdeveloped areas

What are the disadvantages of embryo transfer?

-Costly

-The offspring are not necessarily genetically superior

-The success rate is variable and not guaranteed (can get 0 or 15 to 20 embryos in a flush and some do not take)

What is commonly used to induce superovulations in cattle?

-FSH

-Gonadotropins (FSH/LH combination) such as eCG and hCG

PMSG (eCG)

-Pregnant mare serum gonadotropin (equine corionic gonadotropin)

-Contains mostly FSH activity

-Has some LH

-Obtain from pregnant mare serum

hCG

-Human corionic gonadotropin

-Contains mostly LH activity

-Has some FSH

-Used in combination with FSH or PMSG

-Obtain from pregnant women

Prostaglandins

-Used to synchronize the estrous cycles of the donor cow and recipient cows

-Resemble hormones in their actions but are chemically different

-They are produced by many tissues in the body

What prostaglandin will be used for reproduction?

PGF 2 alpha