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WORKING
TOGETHER
FOR A HEALTHIER FUTURE...
5
LIVESTOCK MATTERS
COPPER TOX I C I TY
Copper: a deficiency will depress cattle fertility, but too much
can kill. Vet Kirsty Ranson from Westmorland Veterinary
Practice had a challenge on her hands to fathom out why Neil
and Evonne Sowerby’s cows would suddenly drop dead. And
another challenge to convince them that cows were receiving
toxic levels of copper and dietary changes were needed.
Veterinary surgeon
Kirsty Ranson
XLVets practice
Westmorland Veterinary
Group
KIRSTY RANSON, WESTMORLAND VETERINARY GROUP
Copper in cattle diets:
too much can kill
Fertility issues
At Townhead Farm near Appleby, Neil and
Evonne milk 150 cows averaging yields of
nearly 10,000 litres/cow. Kirsty began
working with them in September 2013, first
helping them to control BVD in the herd.
The following summer, herd fertility was still
disappointing. Kirsty explains: ‘Heat expression
was poor, pregnancy rate was 10-15%
instead of the target 20%, and submission
rate was 35-40% instead of around 60%. Dry
matter intakes were also low. So something
wasn’t right somewhere.’
Poor fertility can be caused by a lack of
copper. In Cumbrian soils, copper can be
bound up by other elements like molybdenum,
sulphur and iron, making it unavailable to the
animal, thereby creating a deficiency.
Also, a minerals analysis of Neil’s silage had
shown copper level was low.
Neil’s dairy rations were formulated by a
nutritionist; cows received concentrate
(containing copper) fed to yield in the parlour,
and had ad-lib access to a TMR consisting of
grass silage, a concentrate blend, and a
mineral premix. To ensure copper was not
deficient in the diet, Neil sourced the mineral
premix separately, choosing one which was
high in copper, to aid fertility.
Investigations start
In the spring of 2014, several cows, in quick
succession, died suddenly whilst grazing.
‘They seemed healthy cows,’ says Neil. ‘One
of them had just milked really well in the
parlour, and then an hour later…she was
dead!’ Although sent for postmortems, no
explanation was found.
In July 2014, on a routine visit, Neil asked
Kirsty to take a look at some cows which were
looking ‘sick’. ‘They were depressed,’ explains
Neil. ‘Their coats were rough and milk yields
had dropped. But we couldn’t pin the reason
on anything – maybe it was a case of mild
acidosis.’
Kirsty Ranson with Neil and Evonne Sowerby