Infertility in the herd Flashcards
List 4 things we can use in sheep to analyse last seasons performance
Lambing %
Weaning %
Length of lambing period
Barren ewes
what is the target length of lambing period
95% of ewes should be within 2 cycles (ie 35 day period)
what is the target barren ewe rate
<2-3%
List 2 ways to monitor this seasons performance in sheep
Use of raddle - ewes returning to serve, or not getting served
Use of scanning- estimates lambing %
what are the major targets in a seasonal calving beef herd
90% herd should calve within 9wk period with 65% in first 3 weeks
<5% barren/empty cows
How do we generally analyse last breeding season
look at calving distribution- can use data from CTS online
what is the normal voluntary wait period in a dairy cow
45 days
Why not just monitor calving index and culling then- when analysing fertility in dairy cows
Very slow to respond to changes
Don’t show where the problem is
What makes up good fertility
are cows getting served- return to cyclicity and heat detection
when served are they getting pregnant- conception rate
How do we measure heat detection in dairy cattle
first service submission rate
what is first service submission rate
% of cows getting first serve within 24 days of VWP ending
what should be the target first service submission rate in dairy cows
80%
what do inter-service intervals look at in dairy cows
looks at heat detection for subsequent oestrus cycles
What does a inter-service interval of 25-35 mean
Abnormal return, inaccurate heat detection or LED
What does a inter-service interval of 36-48 days mean
return after missed heat
What does a inter-service interval of 49+ mean
multiple missed heats
or
fetal death
What does a inter-service interval of 0-17 days mean
Short return
inaccurate heat detection
(or follicular cysts- but this would just be an individual)
What does a inter-service interval of 18-24 days mean
Normal return
correct oestrus detection
List 5 things that can reduce oestrus expression in dairy cows
lameness
environment
nutrition
use of bull
genetics
List 6 things that can affect oestrus detection in dairy cows
time observing
timing of observation
training
technology
heat detection aids
use of bull
What is the target conception rate in dairy cows
> 35-55%
but is associated with milk yields
higher targets for lower yielding herds
what is conception rate
proportion of serves leading to a pregnancy - outcome ideally via PD
List 4 nutrition factors that can affect conception rate in dairy herds
energy balance
micronutrients
SARA
? excess protein
List 5 AI related factors that can reduce conception rate
technique
semen quality
semen storage
thawing and handling
timing of AI
List 4 disease factors that can affect conception rate in dairy cows
lameness
herd level infectious disease (BVD/ IBR/lepto)
Uterine bacterial disease
Venereal (e.g. campylobacter)
What is the 21 day serve (insemination) rate
proportion of eligible cows served every 21d
measures submission
what is the 21 day pregnancy rate (fertility efficiency)
proportion of eligible cows becoming pregnant every 21d
Measures overall repro performance=looks at submission + conception
List 4 possible limitations in managing and monitoring fertility
Lack of data
poor data quality
lack of skill/time
no access to software
