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HERD FERT I L I TY
AUTUMN 2015 ISSUE
LIVESTOCK MATTERS
16
Confidence to breed
without seeing heat
For Richard Pilkington of Shordley Hall Farm
near Wrexham, cows that were not seen
bulling were being given synchronisation
treatments to bring them into oestrus. But they
would only be served if they were seen in
heat. ‘It didn’t seem right to be AI-ing them
without actually witnessing the heat,‘ explains
Richard. ‘It went against everything we’ve
always done!‘
The 250-cow herd calves all year round and
is currently yielding 9,500 litres on twice a
day milking.
To overcome the challenges of spotting heats,
Richard had invested in activity collars for
the cows back in 2007. He upgraded
these two years later to include rumination
monitors. These give a 24-hour picture of a
cow’s health and results are analysed to give
an index of health, helping Richard and his
staff focus their care.
But with silent heats, despite these extra
monitoring devices, some cows would go
unserved until the next heat, automatically
delaying new pregnancies by at least
another 21 days.
Owen explains: ‘Because Richard was
wary of the fixed time AI, he was missing
opportunities to get the cows in-calf.
‘With a fixed time AI protocol, all interventions
will result in a service rather than the more
traditional ‘wait and see’ approach where
animals exhibiting silent heats have no chance
of conceiving, and every chance of requiring
further hormone treatment. This not only results
in higher treatment costs but substantially
decreases farm profitability through increasing
the number of days empty and extending
calving intervals.‘
Owen persuaded Richard to take part in a
trial in which the outcome of a range of two
different intervention approaches would be
assessed, and the value of Fixed Time AI
demonstrated.
The trial took place last year with breeding
decisions being made for the four months from
August, and involved Owen making weekly
fertility visits.
Cows were assigned to one of three
treatments according to Owen’s clinical
assessment of the state of the ovaries, and
body condition and general health of the
cow. Those in good health and showing heat
were AI-ed as usual.
Cows in good body condition with evidence
of a corpus luteum and an apparently normal
follicle development were put onto an
ov-sync programme which would bring them
into oestrus at a known time so they could
be AI-ed at a fixed time.
The third treatment was given to cows which
had not been seen bulling after 50 days,
and had a history of post-partum disease,
condition loss, or poor follicle presence.
These were given a synchronisation
programme that included an intra-vaginal
device (IVD+prog) to improve progesterone
levels and improve reproductive function.
The AI-ed cows would be examined seven
days later to ensure response to the initial
treatment, and continuation of the next
stage of the programme i.e. administering
prostaglandin for the ov-sync for treatment
and checking visible evidence of follicular
development in the IVD+prog treatment.
Cows were then PD-ed at 28-35 days after
service. The results are shown in the table
(note: direct comparisons cannot be made
between the two synchronisation programmes
due to the differences in cow health).
Owen explains: ‘Conception rates were
significantly higher in the synchronisation
programmes with the Fixed Time AI – 43%
and 36% compared to just 26% by normal
AI service.
‘Also, of the cows that received the intra-
vaginal device, and hence the extra
progesterone, 55% exhibited heat and so
only 45% received a true blind service.‘
In this trial, 66 cows out of 183 were not
showing signs of heat, and were assigned to
one of the two synchronisation programmes
and were served using FTAI.
‘This represents the potential to produce 10.5
more pregnancies per 100 cows in animals
which without fixed time AI would not have
been served. For Richard Pilkington’s herd, that
represents an extra 22 pregnancies per year.‘
Another significant finding was the days to
conception achieved using the synchronisation
programmes: 32 and 39 days
(see
table below)
.
Owen explains: ‘This indicates that those cows
not conceiving to the first blind service, did
conceive at the next oestrus. So the treatments
would have had a positive effect on their
reproductive functioning.
Richard Pilkington comments: ‘I did take a lot
of convincing, but the proof is there. I think it
would also be beneficial to be using the
intra-vaginal devices in the cows not seen
bulling, but am currently weighing up the
cost:benefit of this.‘
Owen adds: ‘In healthy cycling cows, with
normal follicular dynamics, it is easy to get
great results. But when dealing with cows that
are stressed and not cycling properly, then
tailoring specific treatments for different animals
gives far better results. And together with Fixed
Time AI, then overall, fewer medicines are
being used to achieve pregnancies.‘
‘So synchronisation programmes are a
management tool and not blanket therapy.
Communication needs to be very good
between the farmer and vet, but every farm
stands to gain something from their use.‘
Service type
No. served
CR%
Heat detected %
Natural service
117
26
100
Ov-sync (healthy cycling cows)
44
43
27
Sync and IVD+prog (problem cows)
22
36
55
Service type
Blind service % Days to conception
Natural service
0
Ov-sync (healthy cycling cows)
73
32
Sync and IVD+prog (problem cows)
45
39
CR = conception rate; IVD – intra-vaginal device
Left to right:Owen Tunney-Richard Pilkington
Cows with rumination collars