Dairy Cow Repro

Question 1

What does the dairy cow lactation curve look like?

Answer 1

Reverse nike swoosh

Question 2

What is the time frame (expressed in days in milk) in which you want to get a cow pregnant?

Answer 2

60-100 days–> cows that get pregnant during this time frame spend more time in early lactation and make more milk

Question 3

Why do dairy cows ever go to the dry lot?

Answer 3

Because they are pregnant
- even if not producing milk they are carrying valuable cargo (their own replacement)

Question 4

How does low reproductive efficiency affect profitability?

Answer 4

1. Long calving interval results in less milk and fewer calves born
2. Increased culling due to repro failure, decreased genetic process, increased needs for replacements meaning fewer heifers to market
3. Low conception rates increases semen costs and vet bills
4. Extended low production or dry period can result in over conditioned cows with repro or other health problems

Question 5

What percent of dairy cow operations use AI only?

Answer 5

25-50%

Question 6

What percent of dairy operations are bull bred only?

Answer 6

10-25% of herds
- often not as well managed

Question 7

What are the 4 things that happen during the days open?

Answer 7

Voluntary waiting period, heat detection, conception, culling

Question 8

What is the definition of days open?

Answer 8

Number of days from freshening until a cow becomes pregnant again

Question 9

What is the definition of calving interval?

Answer 9

Days open plus the gestational length

Question 10

Define the voluntary waiting period

Answer 10

The period of time from freshening until you start breeding a cow needed for uterine involution
- traditionally 60 days but many owners have reduced this to 45 (but decreases fertility)

Question 11

If not using a timed AI program, when should you breed cows for the first time?

Answer 11

As soon as possible after VWP (must watch for heats very closely and use PGFs aggressively)

Question 12

If using TAI, how long should days to first service be?

Answer 12

70-90 DIM (depends on herd postpartum health, weight loss after calving, resynchronization protocol

Question 13

What factors influence the heat detection rate?

Answer 13

The technique used, the breeding program, the incidence of anestrus, the stocking rate, the environment, the foot care program, the facilities and the people that work there

Question 14

What is the disadvantage of the tail stripe system for heat detection?

Answer 14

You have to chalk every single cow (even those already bred) and you are looking for a negative rather than a positive. Also head locks are required in most cases

Question 15

Why do pedometers work for heat detection?

Answer 15

Cows move around significantly more when they are in heat.

Question 16

Is it better to be more efficient or more accurate with heat detection?

Answer 16

you need both, but high efficiency will come at the cost of low accuracy

Question 17

What are some ways to improve heat detection?

Answer 17

1. Put more effort into heat detection
2. Use drugs (OvSynch)
3. Use a bull

Question 18

Define conception rate.

Answer 18

% of breeding’s that result in a pregnancy

Question 19

What is pregnancy rate the product of?

Answer 19

Heat detection multiplied by conception rate

Question 20

Is it better to breed earlier or later after standing estrus is observed?

Answer 20

Earlier! often you dont detect heat right away after it starts

Question 21

How is the calving interval affected by the pregnancy rate?

Answer 21

It decreases!

Question 22

What are the only two ways to improve pregnancy rate?

Answer 22

Improve conception rate and/or heat detection