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Ridgeway "M" Kit |
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Ridgeway "Dropper" Kit |
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Target Kits |
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RIDGEWAY - Advice on using
On-Farm Progesterone assays |
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Progesterone is produced by the
ovary and is high at mid-cycle and
in pregnancy. It is low at heat or
if the cow is anoestrus. Milk
progesterone test kits are a simple
and economic method of measuring
progesterone in milk. Strong colour
is produced with low progesterone
and a slight colour with high.
Progesterone assay may be used in a
number of ways to investigate or
improve reduced fertility in a dairy
herd.
Sampling at day of observed heat.
All samples taken on this day should
show low progesterone. Samples from
20 cows would amply determine if
heat were being wrongly interpreted.
Sampling at day 19 after service.
If it has previously been determined
that heat is being correctly
identified (see above) sampling on
this day will give early warning of
return to service in 8/10 cows by
showing a low level of progesterone:
such cows should be carefully
observed for return to service.
Sampling at day 24 after service.
Cows apparently pregnant at day 19
(above) should be re-tested at day
24: this is statistically the best
day for determining positive
pregnancy but used on its own will
only identify most non-pregnant cows
too late for service at that heat.
Weekly sampling. Samples
taken on a weekly basis can give
information on whether cows are
showing regular heat cycles: cows
should show a low level of
progesterone indicative of heat at
least once in 3-4 samples. On the
other hand if all samples are low
the vet should be consulted about
anoestrus. This will occur in some
cows after calving. If all samples
are high the vet may conclude that
there is a cystic corpus luteum (but
beware, the animal may be
pregnant!). If evidence of normal
heat cycles is seen, then heat
detection may be slipping.
Heat Prediction. Samples are
taken every other day from day 15 or
16 after a previous heat (or low
level of progesterone during weekly
sampling). When a new low level of
progesterone is seen cows are
observed closely for signs of heat
or a "Kamar" device is affixed.
Alternatively, the cow is served
"blind" on the day after the low
value. This may result in increased
double services if the cow is seen
bulling on a following day.
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Address: Ridgeway
Science, Park Farm Buildings, Park
Lane, St Briavels, Glos, GL15 6QX |
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