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(UPBEAT COUNTRY MUSIC)
Over the last few years,
cattle producers in the West Midlands
have been reporting problems with pregnancy toxaemia, or ketosis,
in the cow herd.
We'd like to use this presentation
to discuss some of the causes of ketosis
and to discuss some of the strategies
that cattle producers can adopt to reduce this problem.
Cows have a high energy requirement
in late pregnancy and early lactation,
when the energy requirement's not being met by the nutrient intake,
the cows start to break down their own body reserves
to meet the deficit.
If the rate of breakdown of the fat is too fast,
then toxic waste from the breakdown process accumulate
and cause the signs associated with ketosis,
which the cows get disorientated, they stop eating,
they might go down and gradually go into a coma and die
if treatment is not begun early.
Cows with damaged livers
or reduced appetite
are most susceptible to ketosis.
There are two fairly common pasture plants in the West Midlands
which can cause liver damage -
the pasture legume blue lupins,
when it is affected by the fungal toxin phomopsin,
and the pasture species Paterson's curse.
Fortunately, the cause of the liver damage can be diagnosed
by post-mortem and laboratory testing.
In 2011, there were eight cases of chronic liver damage
submitted to the Animal Health Laboratories in South Perth.
These were differentiated
into four cases being contributed
to Paterson's curse poisoning,
two cases diagnosed as lupinosis,
one case where both
Paterson's curse and lupinosis
were associated
with the chronic liver damage,
and a single case of saponin toxicity in some younger cattle.
The mortality in the herds affected with ketosis
that were submitted to the laboratory ranged from 1-2%.
Most of the cases were in cows of more than four years of age.
The good news is that the liver is one organ that is able to regenerate.
For example, if half the liver is removed in a healthy animal,
the animal will have full liver functional capacity within a month.
After an acute case of liver damage
where the cause is identified and removed early,
the cattle have a good chance of having full liver functional capacity
in 6-12 months.
However, if the liver is being continually exposed to a liver toxin,
this results in the cumulative damage to the liver
and an inability to recover.
The pasture weed Paterson's curse
contains a toxic compound, pyrrolizidine alkaloid.
This is present in all parts of the plant,
including the stem and the leaf and the flowers,
and it's present in the green material and in dry material,
including baled hay.
The toxicity increases at flowering and when the plant is stressed.
After spraying, the palatability of the plant increases
and also increases the incidence of poisoning.
The pyrrolizidine alkaloid damages the liver cells.
It damages the DNA of the liver cell
and it can damage the blood supply to the liver cells.
The extent of this liver damage
and the fact that the plant is toxic year-round
makes it hard for the liver to regenerate
when cattle are grazing pastures containing Paterson's curse
for extended periods.
Blue lupins are a useful feed source and fix atmospheric nitrogen.
However, after summer rain,
they may develop a fungal toxin, phomopsis, on the stem
and cause a disease known as lupinosis.
Sheep are more susceptible to lupinosis than cattle,
however the sheep livers recover more rapidly than cattle livers.
The phomopsis toxin affects the liver cells
and it also suppresses appetite.
In late pregnancy,
cattle with a reduced appetite are more susceptible to ketosis.
When cattle are grazing blue lupins
and have chronic liver damage associated with lupinosis,
they may not be clinically affected,
but they probably will be a little bit ill thrifty and fail to gain weight.
The livers can remain cirrhotic for a long period of time.
However, they are generally fully functional within 12 months.
When sheep have been affected by lupinosis,
once they've recovered and start to eat again,
those sheep that have got to this stage
will normally regenerate quite well within six months.
The best way of preventing ketosis in cows
is to provide them a good source of energy in late pregnancy
and early lactation.
Green pastures with at least two tonnes of feed on offer
provide sufficient energy.
If the pastures don't have this much feed,
it's important to provide a good quality energy supplement.
This might be a high energy grain or a very good quality hay.
If you know that your cows have some liver damage
or you suspect they might have
from previous exposure to lupins or Paterson's curse,
then it is a good idea not to use a high-protein supplement
such as lupins.
Also, in late pregnancy,
it's important not to graze pastures containing old blue lupin stalks
because if they do get some lupinosis at this stage of pregnancy,
their appetite will be reduced
and they are more likely to go into ketosis.
If there are some old blue lupin stalks in the paddock,
the alternative is to provide a really good, high quality roughage
so that they don't eat the stalks.
It is most important
that if producers have Paterson's curse in their pastures,
they aim to control it.
The plant is a weed
and doesn't provide any value to the pasture.
Blue lupins, on the other hand, provide a good feed source.
They put nitrogen back into the soil,
and blue lupins can be grazed strategically to avoid liver damage.
The sort of strategies that you can adopt
is to remove cattle from blue lupin paddocks after summer rain.
The cattle are more likely to eat the stalks after summer rain
when they're wet and the other dry feed is also wet.
But gradually, over summer, with incidences of summer rain,
the amount of phomopsin toxin on the stalk will increase.
Also remember
that when you're feeding cattle in a blue lupin paddock,
it's important that there is an alternative roughage source
so they aren't tempted to eat the blue lupin stalks.
Cattle producers with a current ketosis problem in their cow herd
associated with chronic liver damage
may wish to adopt a culling strategy to reduce the problem.
What you can do is, prior to joining, you can bring the cow herd in
and draft off the bottom 10%-20% of the herd
and then do a blood test on these cows
to assess the liver-functioning capacity.
Or, because most of the cases that we're seeing of ketosis
are in cows of more than four years of age,
you may wish to reduce the age at which you cull your cow herd.
Adopting one of these culling strategies,
in combination with controlling Paterson's curse on the property
and strategically grazing blue lupins,
should reduce the problem of ketosis in your herd.