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EWE NUTRITION
The consequences of inadequate
ewe nutrition follow through
into the survival and growth
rates of lambs.
Russell explains: ‘For instance, a ewe's
milkiness, is influenced by her energy
and protein status, and directly impacts
on lamb survival rates. Where these are
low then not only will her milk yield be
low but her colostrum - an essential
factor in lamb survival - will also be poor
quality. This then predisposes lambs to
more neonatal diseases such as joint ill
and watery mouth.’
Joe says: ‘Ultimately, the aim has to be
to maximise the number of lambs reared
per ewe tupped.
‘So always assess silage quality and
body condition score the ewes. Ask
your vet about metabolic blood profiling.
Ask yourself whether you are feeding the
same quality and quantity as last year,
and previous years, and whether that's
the right approach to be taking.
‘Making informed decisions - from
knowing the nutritional status of ewes
- allows a more economic use of
concentrates, and promotes good
lamb viability, maximising the lambs
per ewe that are reared.’
Good nutrition
Consequences of poor ewe
nutrition in last 4-6 weeks
of pregnancy
Joe explains: ‘Ewes should always be scanned
at between 60 and 90 days of gestation,
so that they can be grouped and managed
according to the number of lambs they are
carrying. But in addition, in the last three
weeks, it's crucial to determine the energy
and protein status of each management group
to tailor feeding regimes.’
Russell adds: ‘Ewes that are in poor condition
are more likely to succumb to twin-lamb
disease, which is frequently fatal. However,
metabolic blood profiling can be carried out
for the whole flock for less than the cost of a
dead ewe. So it really is worth doing!’
Blood sampling needs to be carried out
around three weeks before lambing is due
to start. Any earlier than this and ewes are
not yet in the high risk period. Any later, and
it will be too late to make the required
nutritional adjustments.
Energy status is determined by measuring the
levels of beta-hydroxybutyrate (BHB) in the
blood. These increase when the animal
is short of energy and mobilising its body
fat reserves.
Joe explains: ‘Ewes showing low energy status
need to have their feed ration increased.
However, ewes can only consume a maximum
of around 2-2.5% of their bodyweight in dry
matter. That's around 1.6-2.0kg of DM for an
80kg ewe. So the ration must be of an energy
density to enable this.
‘If there is a big variation between ewes in
a group, then a review of the feeding system
may be needed. Is there enough trough
space
?
Can the shy feeders (the thin ones) be
run in a separate group
?
In some cases, it
may be necessary to feed ewes three times
each day instead of two, to ensure they have
the appetite to consume the required rations.
In late pregnancy, a shortfall of protein will
reduce the ewe's milk production and this
impacts on lamb health and growth too.
‘So a ewe's protein status is also important
and again metabolic blood profiles are
invaluable,’ says Joe. ‘Two measures are used:
urea levels indicate short term protein status,
whilst albumin levels represent the longer term
historic picture. If albumin levels are low but
urea level is normal, this indicates the pres-
ence of parasites, e.g. liver fluke or worms.
‘Where urea level is low, but albumin is not,
then the remedy is straightforward - simply
increase dietary protein intakes, e.g. feed
more cake and/or increase the protein
content of the cake.’
In the ewe:
l
Twin-lamb disease
l
Hypocalcaemia
l
Mastitis
l
Poor quality colostrum
l
Less milk produced
l
Fewer lambs reared
In the lambs:
l
Lighter birthweights
l
Reduced survival rates
l
Hypothermia in newborns
l
Water mouth/rattle belly
l
Joint ill/navel ill
l
Scour
l
Pneumonia
l
Longer time to finish
The lambing season may be over for
pedigree breeders in Gloucestershire this
year. However, Russell has some advice
on preparing for the next lambing season.
‘Over a 12-month period, breeding ewes
will tend to spend three months rearing
lambs, have four months of being dry, and
then five months of being pregnant. They
need to be managed so that their body
condition scores can be raised or lowered
to the targets - as shown in the EBLEX chart
below, in a gradual and 'safe' manner.
‘So when the lambs are weaned, ewes
should be condition scored again. Thin
ewes can then be given extra feed or
good grazing so that they can regain
condition and be fit again for tupping -
this will help increase the potential number
of lambs conceived.
Post-lambing advice
Hill ewes
Body condition score targets
Upland ewes Lowland ewes
At weaning
2.0
2.0
2.5
At tupping
2.5
3.0
3.5
Mid-pregnancy and
at lambing
2.0
2.5
3.0
(Source: EBLEX)
Ewes eating silage
SPRING 2013 ISSUE
LIVESTOCK MATTERS
12