Herd Fertility

Question 1

What are the farmer’s targets in terms of herd fertility?

Answer 1

365 day calving intervals
Maximum milk production
Minimum culling

Question 2

What is the voluntary waiting period?

Answer 2

The earliest service date after calving. Set by the farmer e.g. won’t serve any cows until 45 days after calving

Question 3

What is the difference between calving interval and calving index?

Answer 3

Calving interval = for the individual

Calving index = average for the herd as a whole

Question 4

What are the pros and cons of using a calving index?

Answer 4

Pros:
Useful benchmark figures

Con:
Only historic
Only includes cows that got pregnant and calved

Question 5

How long after calving does the uterus return to normal?

How long after cavling is the earliest service date?

Answer 5

28 days

42 days - for involution and ovarian cycle to resume (50-55 more realistic)

Question 6

What can prolong the earliest possible service date?

Answer 6

Disease e.g. RFMs

Question 7

What is conception rate?

Answer 7

Number of pregnancies achieved per 100 services

Question 8

Targets for:

1. Calving index
2. Earliest service date
3. Calving to service interval
4. Calving to conception interval
5. Conception rate for first service
6. Conception rate for all services

Answer 8

1. 365
2. 50
3. 65
4. 85
5. 60%
6. 55%

Question 9

When should you interfere for:

1. Calving index
2. Earliest service date
3. Calving to service interval
4. Calving to conception interval
5. Conception rate for first service
6. Conception rate for all services

Answer 9

1. > 380days
2. <42days
3. > 75 days
4. > 95 days
5. <55%
6. <50%

Question 10

What is calving to first service interval influences by?

Answer 10

VWP
Postpartum issues e.g. RFM
Return to ovarian cyclicity
Oestrus detection

Question 11

Why is timing to first service critical?

Answer 11

Too soon after calving, you get lower pregnancy rates

Too later and you prolong calving interval

Question 12

How is timing to first service measures? Cons?

Answer 12

1. Mean interval between calving and 1st service over a period of time.
   - Cows not served missed out
   - Large spread not seen
   - Unusual VWP
2. First service submission rate

Question 13

What is the first service submission rate?

Answer 13

Proportion of cows served within 24 days of earliest allowed service date

Question 14

1st service submission rate example

2 served between calving and 50 days post calving
15 served 50-74 days post calving
3 served after 74 days post calving

What is the submission rate?

Answer 14

15/20 serves within 24 days of VWP (50days)

= 75% first service submission rate

Question 15

What is the calving to conception interval influences by?

Answer 15

Oestrus detection

Pregnancy rate

Question 16

What impacts oestrus detection?

Answer 16

Submission rate
Interoestrus interval
Accuracy

Question 17

When are interoestrus intervals relevant?

Answer 17

When a cow has more than 1 service (in between servies)

Target is 18-24 days

Question 18

How can you improve the accuracy of oestrus detection?

Answer 18

Milk sample at time of aI
Test for progesterone levels
(should be low - less than 5ng/ml)

Question 19

What is the 120 day in calf rate?

Answer 19

% of cows pregnant at 120days post calving

Target => 64%

Question 20

What is the 210 days not in calf rate?

Answer 20

% of cows not pregnant 210days post calving

Target = <7%

Question 21

Which cattle do you want to examine during a routine visit?

Answer 21

Problem animals e.g. RFM, metritis
Postcalving checks
Irregular interoestrus intervals
PDs
Pregnant and odd event