Infertility in the herd Flashcards
Principles of monitoring fertility in populations
What data do we need to monitor fertility, at a basic level?
“Aggregated” data, e.g:
▪Total numbers of ewes bred, lambs born live
▪Total number of piglets produced per year
- Fairly crude measures
- hard to judge data quality/accuracy
- may be all you have
What data do we need to monitor fertility? (more detailed than basic)
▪ Animal ID data
▪ Event records, e.g:
– Inseminations
– PDs
– Parturition events
- Generally more accurate
- better insights from data
- analysis can be more automated
Paper records (for data storage)
- More useful for “aggregated” measures using totals
- Very labour intensive for anything more detailed
On-farm software (for data storage)
- Usually good detail/accuracy
- Useful for day to day management on farm
Central database (for data storage)
- Easy to access
- usually less detail and sometimes accuracy
How can we analyse data?
DIY methods
* Flexible and customisable
* Time consuming
* Only option for simple “totals” data
Using the platform where the data lives
* Easy to access
* Multiple systems to be familiar with
* Some not very good at analysis
Specialist analysis software
* Relatively simple to use
* Only one system to get used to
* Can bring together lots of sources of data
* Ideal
How to monitor fertility in sheep - last season’s performance
▪ Lambing %
– (lambs born alive / ewes put to ram) x 100
– Target 120-200% (lowland>upland>hill)
▪Weaning %
– (lambs weaned / ewes put to ram) x 100
▪ Length of lambing period
– 95% should be within 2 cycles (ie 35 day period)
▪Barren ewes
– (1-(ewes lambing / ewes put to ram)) x 100
– Target <2-3%
How to monitor fertility in sheep - this season’s performance
- Use of raddle
– identifies ewes returning to serve
– identifies ewes not served - Use of scanning
– Identifies empty ewes at end of breeding season
– estimates lambing %
How to monitor fertility in beef cattle
Almost all herds seasonal calving
Major objectives:
▪ One calf per cow per year
▪ 90% herd should calve within 9wk period with 65% in first 3wks
▪ <5% barren/empty cows
Easy to analyse last breeding season
Calving distribution
▪ Can get data from CTS online
Can be difficult to work out what’s going on this season
- Vast majority of herds run bull(s) with cows
- No need for stockpeople to detect oestrus
- Usually no recording of serves/heats
– Often have PD session after end of breeding season (+/- at/during)
- Can use chin markers: rest their head on them before serving (like raddle marker)
Beef cattle breeding goals
- % of cows served being empty should be less than 5%
- aiming for 65% of cows served in the 1st 3wk block of the calving season
- aiming for 90% of cows in the first 9wks of the calving season (i.e.
How long is the voluntary wait period?
~45d
Parts of the dairy production cycle
- voluntary wait period (farm policy/choice)
- calving-1st serve interval
- calving-conception interval (wanting it to be as close the a year as possible)
- gestation period
- calving interval/index
- lactation
- dry period
How long is the gestational period in cows?
- ~280d
How long is the dry period in dairy cows?
~50d
Calving index and culling
- Farm culling policy can affect or “manipulate” calving index
– This is often seen in seasonal calving herds
-> Cows not pregnant at the end of a set “breeding season” each year are culled
Why not just monitor calving index and culling in dairy cattle?
- very slow to respond to changes
- doesn’t show where the problem is
What makes good fertility?
- return to cyclicity
- heat detection
- serving cows
- conception rate
- when served are they getting pregnant?
Measuring heat detection
First service submission rate
- Are cows getting their first serve “on time”?
- % of cows getting first serve within 24 days of VWP ending
- Target 80%
Inter-service intervals
0-17d from previous
- short return
- inaccurate heat detection
- or follicular cyst
18-24d from previous
- normal return
- correct oestrus detection
- 19-26d suggested to be a better normal range
25-35d from previous
- abnormal return
- inaccurate heat detection or LED
36-48d from previous
- return after heat missed
49+d from previous
- multiple missed heats
- foetal death
Heat detection - what goes wrong?
Expression
- lameness
- environment
- nutrition
- use of bull
- genetics
Detection
- time observing
- timing of observation
- training
- use of bull
- technology
- heat detection aids
Measuring conception rate
Proportion of serves leading to a pregnancy
- Outcome ideally via PD
– Can also use non-return to serve or next calving
- Sometimes known as “pregnancy rate”
- Target >35-50%
– Associated with milk yield
– Higher targets for lower yielding herds
Conception rate - what goes wrong?
Nutrition
- energy balance
- micronutrients
- SARA
- excess protein?
AI related
- technique
- semen quality
- semen storage
- thawing and handling
- timing of AI
Disease
- lameness
- herd level infectious disease (IBR/BVD/lepto)
- uterine bacterial dz
venereal (e.g. campylobacter)
Bull
- true infertility
- lameness
- lack of libido
NEB likely to be most common cause
Harder to fix than submission rate
Monitoring fertility - 21d pregnancy rate
every 3wks measure
- number eligible to serve
- number served
- number in calf
- % of eligible cows served
- % of eligible cows getting in calf
21d-serve rate (aka 21d insemination rate):
- proportion of eligible cows served every 21d
- Measures submission
- blue line on graph
21d-preg rate (aka fertility efficiency):
- proportion of eligible cows becoming pregnant every 21d
- Measures overall repro performance
- green line on graph
Limitations in managing and monitoring fertility
- lack of data
- poor data quality
- lack of skill/time
- no access to software
