Infertility in the herd

Question 1

List 4 things we can use in sheep to analyse last seasons performance

Answer 1

Lambing %
Weaning %
Length of lambing period
Barren ewes

Question 2

what is the target length of lambing period

Answer 2

95% of ewes should be within 2 cycles (ie 35 day period)

Question 3

what is the target barren ewe rate

Answer 3

<2-3%

Question 4

List 2 ways to monitor this seasons performance in sheep

Answer 4

Use of raddle - ewes returning to serve, or not getting served
Use of scanning- estimates lambing %

Question 5

what are the major targets in a seasonal calving beef herd

Answer 5

90% herd should calve within 9wk period with 65% in first 3 weeks
<5% barren/empty cows

Question 6

How do we generally analyse last breeding season

Answer 6

look at calving distribution- can use data from CTS online

Question 7

what is the normal voluntary wait period in a dairy cow

Answer 7

45 days

Question 8

Why not just monitor calving index and culling then- when analysing fertility in dairy cows

Answer 8

Very slow to respond to changes
Don’t show where the problem is

Question 9

What makes up good fertility

Answer 9

are cows getting served- return to cyclicity and heat detection
when served are they getting pregnant- conception rate

Question 10

How do we measure heat detection in dairy cattle

Answer 10

first service submission rate

Question 11

what is first service submission rate

Answer 11

% of cows getting first serve within 24 days of VWP ending

Question 12

what should be the target first service submission rate in dairy cows

Answer 12

80%

Question 13

what do inter-service intervals look at in dairy cows

Answer 13

looks at heat detection for subsequent oestrus cycles

Question 14

What does a inter-service interval of 25-35 mean

Answer 14

Abnormal return, inaccurate heat detection or LED

Question 15

What does a inter-service interval of 36-48 days mean

Answer 15

return after missed heat

Question 16

What does a inter-service interval of 49+ mean

Answer 16

multiple missed heats
or
fetal death

Question 17

What does a inter-service interval of 0-17 days mean

Answer 17

Short return
inaccurate heat detection
(or follicular cysts- but this would just be an individual)

Question 18

What does a inter-service interval of 18-24 days mean

Answer 18

Normal return
correct oestrus detection

Question 19

List 5 things that can reduce oestrus expression in dairy cows

Answer 19

lameness
environment
nutrition
use of bull
genetics

Question 20

List 6 things that can affect oestrus detection in dairy cows

Answer 20

time observing
timing of observation
training
technology
heat detection aids
use of bull

Question 21

What is the target conception rate in dairy cows

Answer 21

> 35-55%
but is associated with milk yields
higher targets for lower yielding herds

Question 22

what is conception rate

Answer 22

proportion of serves leading to a pregnancy - outcome ideally via PD

Question 23

List 4 nutrition factors that can affect conception rate in dairy herds

Answer 23

energy balance
micronutrients
SARA
? excess protein

Question 24

List 5 AI related factors that can reduce conception rate

Answer 24

technique
semen quality
semen storage
thawing and handling
timing of AI

Question 25

List 4 disease factors that can affect conception rate in dairy cows

Answer 25

lameness
herd level infectious disease (BVD/ IBR/lepto)
Uterine bacterial disease
Venereal (e.g. campylobacter)

Question 26

What is the 21 day serve (insemination) rate

Answer 26

proportion of eligible cows served every 21d
measures submission

Question 27

what is the 21 day pregnancy rate (fertility efficiency)

Answer 27

proportion of eligible cows becoming pregnant every 21d
Measures overall repro performance=looks at submission + conception

Question 28

List 4 possible limitations in managing and monitoring fertility

Answer 28

Lack of data
poor data quality
lack of skill/time
no access to software