BAP DAIRY EXAM MIZZOU

What are the top 5 dairy states?

California, Wisconsin, idaho, Texas, and New York

What state has the most dairy cows?

California

What is the average production of milk in the United States?

22,000-25,000lbs

When do cows make the most milk?

Early lactation

What country has the most dairy cows nationally?

India

When do cows reach their peak in milk production?

60 days

What is the difference between stress and strain

Yes the stress is the milk producing, but strain is what it does to their body

Where do most of dairy cows energy go?

Towards making milk

What is selection index in dairy cows?

A series of traits that we select for. Selecting a healthy cow that makes a lot of milk.

What roles to genomics play?

We can increase milk production and conception rate with this over time because we are selecting for both.

What is the first step in making milk?

Heifer has to get pregnant first. You have to have a calf to make milk.

What is ovulation?

The release of the female gamete (the egg) from the ovary.

When is the first ovulation?

This is when they reach puberty.

When do heifers reach puberty? Why do dairy cows reach puberty before beef?

8 months of age and that is because they are fed better than beef cows

How often do cows and heifers ovulate?

Every 21 days

Why do we care about puberty?

Heifers generate no income for the farm because you have to feed them for two years before they start making milk.

When do we breed heifers?

14 months of age so that they can start making milk as 2 year olds.

What does the cervix do?

Provide a barrier between the vagina and the uterine body.

Why is the uterine body important?

This is where we deposit sperm in artificial insemination

What does it mean that the cow has a bicornuate uterus?

It has two uterine horns joined by the uterine body.

What is the oviduct?

This is the structure at the end of the uterus that leads to the ovary. It picks up the egg after ovulation and it is important because that is where fertilization and early embryonic development occur.

What are the two important structures on the ovary?

Corpus luteum and follicles.

What are the functions of the follicles?

Make estrodial and grow the egg/ ovulate the egg

What are the resting pool of follicles called?

Primordial follicles

What is a follicle with one cell layer called?

Primary follicle

What is a follicle with two cell layers called?

Secondary follicle

What are the two layers of the follicle called?

Granulose cell later and theca cell layer

What is it called once there is fluid in the follicle?

Tertiary follicle, they go through recruitment selection and dominance.

What follicle comes after the territory follicle recruits and selects dominant follicles?

Preovulatory follicle

What is atresia?

Follicles die through this process

How many follicles are on the ovary?

Over 100,000 but prob will only use 50 in a lifetime

What is estradiol?

This is a hormone type of estrogen that is most potent with estrogen. It comes from the follicle and it is a steroid.

What does estradiol do?

It causes the LH surge and brings the cow into estrus.

What is the corpus luteum?

A structure on the ovary that makes progesterone

What is progesterone?

This is a steroid that comes from the CL and it is essential for establishing and maintaining pregnancy.

What is the hypothalamus in reproduction?

A part of the base of the brain and they release GnRH

What are the cells that make LG and FSH?

Gonadotrophs

What does GnRH stand for? What does it do?

Gonadotropin releasing hormone which acts on the anterior pituitary and causes it to release LH and FSH. Used in reproduction management as a contraceptive and to cause ovulation.

Where are the a lot of the hormones that control reproduction?

The base of the brain

What is the portal blood system?

Delivers GnRH to the pituitary.

What hormone causes milk let down?

Oxytocin

What is LH?

This is luteinizing hormone and it is released in a big surge. It causes follicles to mature and ovulate

What is FSH? What does it do?

It is a follicle stimulating hormone and stimulates the small follicles on the ovary and causes them to develop

What is an LH surge?

Once the follicle grow, this surge causes ovulation

What do you have to have to develop follicles?

A follicular wave

Describe a follicular wave.

Under control of FSH. It begins with recruitment of a group of follicles to participate, then out of that group one follicle is selected and the rest die through atresia, and then the selected follicle becomes dominant which means no other follicle can develop on both ovaries. But if the dominant follicle becomes atretic and dies, the second wave begins.

How long does a follicular wave last?

7-10 days

What does it mean when the FSH is going up and down?

When there is a dominant follicle on the ovary FSH is low (estradiol and inhibin suppresses FSH), and when it is high you're starting a wave.

How could you tell if a cow is in estrus?

If the cow is standing when mounted, tail chalking, activity monitors, estrotect trackers, protreck reader.

What are some changes to the cow during estrus?

Decrease in rumination, increase in activity

How many follicular waves does a cow normally have?

Two to three. Day 0 is estrus Day 1 is ovulation. CL regresses day 17 or 18 and they are back in heat by day 21. So they have a 21 day cycle.

What is artificial insemination?

Most dairy cows are not mated by bulls. Semen is collected, diluted, placed in to straws, frozen in liquid nitrogen, thawed on farms, and deposited into the uterine body.

What has AI meant to the dairy industry?

It has led to rapid genetic improvement, eliminated STDs, reduced injury to cows and heifers, and greater safety for farm workers.

What is a bull stud?

Bulls that live together on a farm. The company operates the stud collects bulls, freezes semen, and sells the semen to the farmers.

Can frozen semen be shipped?

Yes anywhere in the world.

Where are the major bull studs located?

Wisconsin

How many sperm per ejaculate?

10 billion sperm

How many sperm per straw to achieve maximum fertility?

20 million sperm

How many straws per ejaculate?

500 straws

How much is semen worth per straw?

$20 per

What is colostrum?

This is the first substance that comes out of a cows mammary gland after birth. It is rich in antibodies, vitamins, growth factors, and beneficial hormones.

When should a calf consume colostrum?

Right after birth. You have 12 hrs before gut closure

Is the consumption of colostrum active or passive immunity?

Passive because the calf does not make it itself.

When is puberty reached in bulls?

When they can get a cow pregnant

What is the role of prostaglandin?

To bring the cow into heat by regressing the corpus luteum.

Where does fertilization occur?

In the oviduct

Why do we use heat detection?

So that we know when she is going to ovulate

When do we breed the cow?

12 hours after heat, and then it takes 16 hours for the semen to mature

When do cows ovulate after coming into heat?

They ovulate 30 hours after in heat

How do we evaluate sperm?

Concentration by volume and morphology

How long does it take heifers to come into heat after prostaglandin injection? Cows?

2-3 days for heifers, and 3-5 days for cows.

What is the role of IFNT?

This blocks prostaglandin release then the CL doesn't regress and maintains throughout pregnancy.

What are the three ways you can test for pregnancy in a cow?

Palpation, ultrasound, blood test

What does PAG stand for?

Pregnancy-associated glycoproteins

What are the two driving points of lactagenisis?

Prolactin and glucoricoids.

What does GH do?

It is important because it drives glucogenisis and lipolysis

Where is milk synthesized?

Mammary epithelial cells

What are the major components of milk?

Water, fat, protein, lactose, ash

What are the building blocks of milk?

Water, glucose, fatty acids, glycerol, amino acids

What is milk mostly made up of?

Water

What animal is highest in fat content?

Marine animals

What structural carbohydrate is not digestible by the rumen?

Lignin

What are the two types of microbes in the rumen?

Bacteria and protozoa

What makes milk fat?

Acetate and buterate

What is the gaseous energy loss?

Methane

What makes glucose?

Propinate, glycerol, amino acids

What is the purpose of digestion?

To break the stuff down into useable parts

What are the three stages of digestion?

1. Break down complex carbs into simple sugars

2. Break them down further into VFA'S

3. Metabolism of pyruvate

What is rumination?

This is when the cow chews the food regurgitates the food and then chews it again before swallowing

What is lactose?

Milk sugar

What is RUP?

Rumen Undigestible Protein

What is RDP?

Rumen Digestible Protein

What is NPN

Non-protein Nitrogen

What are the three types of parlors?

Herringbone, parallel, and rotary

How often do you milk?

3x a day

Why do you have to milk so often?

Because when the mammary system is full, it stops making milk

What is the biggest cooperative?

It is in Kansas City, DFA

How long is standard lactation?

10 months

When is peak lactation?

2 months

Do first lactation cows produce more or less milk than 2nd or 3rd lactation cows?

Less