Page 14 - Livestock Matters - Winter 2012

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Improving animal performance
and reducing physical losses is
key to ensuring sheep farming
is profitable.
When financial margins are tight maximising
ewe productivity is essential. The more live
lambs they give birth to and rear, the greater
the returns will be.
Yet recent data from a lambing project
carried out in Wales suggest losses of around
10-25% between scanning ewes and the sale
of their lambs. Generally, most occur during
pregnancy or in the first week of life.
Farmers are often surprised to find out just
how many lambs they do lose. This is partly
because many are not visualised as dead
animals, i.e. they either die inside the ewe,
or are aborted as foetuses.
Infectious abortions continue to account for
a significant percentage of losses on lowland
farms. Weather is also an important factor
- impacting on ewe condition leading up to
lambing, and affecting lambs at birth.
Reducing lamb losses has to take various
factors into account, including the farming
system, ewe body condition, nutrition, health
planning and stockmanship. The target is to
optimise scanning percentage, i.e. the number
of embryos created, and to minimise lamb
losses up to the point of sale.
Why are losses occurring?
The first step is to look at and analyse farm
records to understand what is happening now.
Comparing scanning, lambing and rearing
percentages between years, and with national
benchmarks, highlights where problems occur
and indicates where action is needed.
Five key measures will indicate
where the problems lie:
REDUCING LAMB LOSSES
WORKING
TOGETHER
FOR A HEALTHIER FUTURE...
13
LIVESTOCK MATTERS
lamb losses
Reducing
The total number of ewes/ewe lambs put
to the tup.
A
Ewes tupped
Calculated from the results of pregnancy
scanning.
B
Lambs scanned
When compared to lambs scanned, this
indicates how many lambs have been lost
during pregnancy through absorption or
abortion. When compared to the number
of lambs born dead, it can highlight health
problems such as underlying infectious
abortion or nutritional deficiencies.
C
Lambing percentage
When compared to lambs born, this
shows how many lambs are lost during
the first days of life. A fall in numbers
could indicate underlying health problems,
hygiene issues or problems with
colostrum intake.
D
Lambs turned out
Comparing rearing percentage or lambs
weaned/sold, to lambs turned out, gives
an indication of mortality during the lambs’
first few months. These are more likely to
be related to health problems such as
inadequate control of worms and infectious
diseases. Rearing percentage is the
number of lambs divided by the number
of ewes put to the tup x 100.
Where ewes lamb outdoors 'lambing
percentage' and 'lambs turned out' may
be replaced by a figure for 'lambs tailed'.
This is generally done a couple of weeks
after lambing, but is still an important
measure. The target for tailing could be
based on the 'lambs turned out' figure 1.
E
Rearing percentage
Katie Brian
EBLEX Project Manager
A Ewes tupped
100
100
100
Lowland Upland Hill
B Lambs scanned
195
175
116
C Lambing percentage
183
166
112
D Lambs turned out
172
156
104
E Rearing percentage
168
151
100
Lamb losses
Scanning to birth (B-C)
12 (6%)
9 (5%)
4 (3%)
Birth to turn-out (C-D)
11 (6%)
20 (6%)
8 (7%)
Turn-out to weaning/sale (D-E)
4 (2%)
5 (3%)
4 (3%)
Birth to sale (C-E)
15 (8%)
15 (9%)
12 (10%)
Scanning to sale (B-E)
27 (14%)
24 (14%)
16 (14%)
Figure 1: Performance standards for different
sheep farming systems
Photos kindly supplied by NADIS