Basic HTML Version
F A R M S K I L L S
SEMEN QUALITY & SEMEN
HANDLING
What are the chances of achieving a
pregnancy from each straw you are
currently inseminating with
?
Reproductive success is massively
multi-factorial and influenced by:
l
Infectious disease;
BVD, IBR etc
l
Nutrition - weeks earlier;
at time of
follicular recruitment as well as at
insemination
l
Uterine health;
subclinical endometritis
may be present in 60% of uteri that
otherwise appear clean and healthy
l
Social stress;
group changes have a
major impact on conception rate as stress
hormones rise and feed intakes potentially
fall. This includes separation of cows
waiting for insemination
l
Concurrent disease,
e.g. lameness
and mastitis
l
Environment;
ventilation and heat
stress effects
l
Semen quality
This latter factor is all too often taken as read.
How good is the quality of the semen in the
straw you have just inseminated
?
Poorly
maintained liquid nitrogen flasks and slipshod
thawing technique may be robbing you
of vital pregnancies despite faultless AI
gun position. Flask maintenance is
critical - essentially glorified thermos flasks,
one sharp knock may be all that is required
to damage vacuum and trigger rapid thaw
of all contents. They just don't last forever
and poorly maintained second hand flasks
may represent a real risk of failure. Simple
dipstick tests to check levels regularly are
the responsibility of the flask owner, not the
supplier of liquid nitrogen.
Strict thawing technique pays a big return:
l
Never take a straw completely out of
the goblet.
l
Identify and record straw location for
rapid location.
l
Work 'below the frost line' in the neck
of the flask wherever possible.
l
Immerse straws removed from the flask into
the thaw-bath within 2 seconds.
l
Remove semen straws from the
thaw-bath within 15 minutes, as quality
will deteriorate if left longer than this.
l
Thaw one straw at a time.
l
Use a thermometer to check thaw-bath
water temperature is between 35-37
o
C
(as directed for sexed semen).
l
Thaw quarter cc straws for at least
20 seconds and half cc straws for
40 seconds.
l
Ensure thermal protection for straws
after thawing; consider use of 'chemise
sanitaire' insulated sleeves in cold
conditions.
But how good is the quality of semen about to
be used
?
Although good production controls
are in place for most semen leaving AI studs, it
may take a long journey around the world with
multiple repackaging risks for semi-thawing
before semen reaches your farm flask. Tracking
conception success on dairy management
systems such as Interherd may highlight poor
performance by some bulls. At Bishopton
Breeding, we test thaw straws from batches to
assess motility over two hours post-thaw as well
as morphology and acrosome integrity. These
factors are strongly linked with conception
success and are surprisingly variable.
DIY AI offers a great opportunity to take
control of reproductive performance in your
herd. Attention to detail and overall herd
health are critical for success.
Chris Hodgson,
Providence Farm,Crayke,
near Easingwold, North Yorkshire
Dairy farmer, Chris Hodgson, farms 250
acres in partnership with his parents,
milking 100 Holstein Friesian cows with
60 followers. His cows average 8,700
litres and he currently has a calving index
of 390 days. All cows and heifers
at Providence Farm are inseminated
artificially and in May 2010 Chris took
part in a 3 day workshop at Bishopton
Vets so he could start to be able to AI
stock himself as well as through a local
AI technician.
Since going on the workshop, Chris has
seen positive results in his conception
rates and also appreciated learning
more about the steps vets, farmers and
AI technicians take to improve herd
fertility. The first two cows he AI-ed were
diagnosed as pregnant first time, which
was a boost to his confidence although,
as Chris observed, no two cows are
the same!
‘I'd always had a good relationship
with my AI technician, but was interested
to know how AI worked. I'd heard about
the Bishopton DIY AI course through my
local Grassland Society, and so applied
to go along. Since going on the course,
I have become more aware of heat
detection and how I can help improve
fertility on the farm. It has been a struggle
at times, and serving heifers especially is
tricky, but I'm pleased with the way that
my DIY AI skills are having a positive
benefit to the herd's fertility.’
Chris also finds the fact that you can
choose when to service the cows a real
benefit. At the moment, he AI’s the cows
on a night time when all the jobs are
done and he is quiet and can concentrate
on his technique. Going forward, Chris
is looking to build on his skills over the
coming months and to further improve
conception rates. He is also hoping to
move to sexed semen to help boost his
follower numbers.
FARMSKILLS
CASE STUDY
FARMSKILLS
CASE STUDY
Matthew Webster,
Webster and Trewhitt,
Sunny Bank Farm, Whixley, North Yorkshire.
‘FarmSkills courses give you the upper hand
on timing on the farm; now I can AI a cow
or trim a cow's foot when I want to and
when the animal needs it; I don't have to
wait for someone to come and do it for me.’
WINTER 2010 ISSUE
LIVESTOCK MATTERS
20