CAFRE Development Service

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Level II Agricultural
Business Operations
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Overview of the production cycle of a ewe
Appropriate management of the flock pre
mating to achieve optimum performance
Identify the most suitable option for selecting
replacements
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Unlike cattle sheep have a distinct breeding
season linked to day length
As day length decreases sheep begin to come
on heat
Different breeds will cycle at slightly different
times
Breeding season affects choice of breed
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Lowland breeds and crosses cycle – Aug – Feb
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Hill breeds – Oct – Jan
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Some breeds, e.g., Dorset Horn can breed
almost any time of year (for early lambing
systems, mate in July)
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When in season a ewe comes on heat every
16 – 17 days
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Each heat lasts for 24-36 hours
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Gestation period 147 days (21 weeks)
July/Aug
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The number of eggs shed at each ovulation
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Affects number of lambs born to the ewe
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A number of factors affect the ovulation rate
◦ Breed – in general terms ewes of hill breeds
have lower ovulation rates than those of low
ground breeds
◦ Nutrition
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Age – ovulation rate is low in the ewe lamb, rises
to peak at about 4 years of age, stays the same
for a few years and then drops.
Body condition – ewes in poor condition have
lower ovulation rates
Stage of breeding season – ovulation rate is low
at the beginning and end of the breeding season
and highest at the midpoint
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Starts at weaning
Ensure ewes have enough time to recover
between weaning and mating
Assess ewe body condition
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Condition scoring is method of estimating the
condition or 'nutritional well being' of a ewe
It requires an assessment of the amount of
muscle and fat covering the backbone and the
short ribs of each sheep
This gives a picture of the sheep’s store of
energy
Use body condition scoring to guide your feeding
management pre-mating and throughout
pregnancy.
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Wean lowland ewes July-mid August
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Hill ewes no later than end of September
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This give ewes time to gradually gain condition
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Ensure ewes are appropriately dried off
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May sort off culls at this stage for marketing
◦ Bad udders etc.
Prolapsed
Records / ear notch
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No lambs
Poor mother
Poor milker
Hard to lamb
Dead lambs
Rejected lambs
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Reassess body condition ideally 8-6 weeks
before mating date
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Feed ewes accordingly to achieve desired BCS
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Check udders/teeth/feet etc
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Treatments
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Cast/culls
Sward height
DM intake Kg per
day
2.5 or below
5–7
1.3 – 1.4
3.0 – 3.5
4
0.8 – 0.9
4+
3
0.7
Ewe body condition score
Low
Optimum
High
• Monitor condition regularly until rams go in and
adjust feeding to avoid excessive loss or gain in
condition
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Not needed for ewes BS >3.0
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Very fat ewes = increased barrenness
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Very thin ewes = low lamb numbers
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Increase by 1 body score takes about 6 weeks on
good grass at 7-9 cm
◦ (appox. 8-12kg for mature lowland ewe)
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If grass is short can offer additional feed
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Check feet, footbath, cull persistently lame
sheep
Crutch dirty/long tailed ewes
Dose for liver fluke as per vet advice
Vaccinations
If dipping, do this 1 month before tupping
Where possible carry out all management tasks
at least 2 weeks prior to tupping
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Clostridial & Pasteurella (Hep P+)
Two vaccines given 4-6 weeks apart
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Toxoplasa abortion
Live vaccine –up to 1 month prior to tupping.
Lasts 2-3 years (Toxovax)
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Enzootic abortion
Live vaccine – up to 1 month prior to tupping.
(Enzovax, Chlamydophila)
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Assess mineral status of ewes
• Blood sample 6-8 weeks before mating (Selenium, Cobalt,
Iodine)
• AFBI research found 50% hill ewes sampled had
inadequate selenium (Se) status
• Benefits of Se supplementation of ewes
– Se supplementation 4-6 weeks before mating improves
ewe fertility
– Higher growth rates, heavier lambs at weaning
– Ewe body weight and condition maintained more
efficiently, higher overall lamb output
• Methods of supplementation
– Injectable, boluses, drenches and feed additives
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On average 10% of ewes in a flock fail to rear lambs
Ewe and lamb deaths contribute to the biggest loss
in productivity (37%)
Older ewes are more prone to ewe deaths,
abortion/stillbirths, lamb deaths
Hence replacing/culling these ewes becomes
necessary
before
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A ewe should be replaced
unproductive season
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Typically after 5 crops
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Important to record and identify problem ewes so
they don’t get a reprieve
◦ Ear notch/tag
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Replacement rate
◦ Typically 20% for lowland flock
◦ Potentially 25 – 30% on a hill farm
she has an
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Prolific
Strong maternal ability
Good milker (lamb growth)
Produce quality lambs with good growth rate
Hardy / disease resistance
Reasonable size / conformation
Minimum cost to feed and treat
Easy lambing
Durable
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Keep your own ewe lambs
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Purchase ewe lambs
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Purchase sucked hoggets
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Purchase dry hoggets
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Draft ewes
Advantages
 Disease risks are lower
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Quality – greater control
over management
Disadvantages
 Management can be
complex
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Potential to improve ewe
type - maternal sires
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Good records
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Cheaper?
Breeding policy must
be planned
Cheaper?
Advantages
 Replacements can be
bought as shearlings
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Disadvantages
 Higher risk of disease
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No control over the
rearing phase
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No prior knowledge
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Autumn sales are fixed
Hybrid vigour
Less complex
recording?
Less time consuming
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Little time for
introduction to flock
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Conception rates are lower
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Lamb mortality can be high due to
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There is a greater risk of mismothering
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Good feeding is essential to
◦ 90% or less
◦ average litter size of 1.0-1.2
◦ Lambing difficulties, small lambs, lack of milk etc
◦ Sustain growth of the ewe lamb
◦ Enable the production of adequately sized lambs and
sufficient milk.
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May be cheaper than gimmers/hoggets
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Extra crop of lambs (if lambed)
◦ Harder to lamb/manage
◦ Easier to manage following year if lambed
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Need to be 60-70% of mature weight going to the
ram
Can stunt growth
Extended lambing season
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Two aspects of flock health must be considered
when introducing replacements
1. If bought in – must not be allowed to bring
diseases such as scab or enzootic abortion into the
flock
2. They have to be protected against the main
causes of losses, such as clostridial diseases,
pneumonia and infectious abortion
1.
Yard all sheep (rams and ewes) on arrival for 24-
2.
Treat asap
48 hours
 Worm treatment
 Fluke treatment
 Vaccination – Clostridial diseases, sheep scab, Toxovax,
Enzovax
 Foot care – Inspection and footbath
3.
Quarantine – turn out to pasture previously
grazed by own flock and keep isolated for 3
weeks
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Size, length, conformation
Legs and feet
Mouth and teeth
Wool
Reproductive organs
Breed characteristics
EBVs (Scan weight)
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Body score 3.5 – 4 (Feed meal 8 - 10 weeks prior
to tupping)
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Handle testicles – Should be hard without bumps
or lumps, check for epididymis
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Mouth – Check for broken mouth
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Temperature and wellbeing
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Feet
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Brisket sores
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Management of the mating period
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Management of the mating period
1. Select mating date so that lambing coincides
with spring grass!
http://www.tvsp.org/gestation.html
2. Restrict mating period to 35-42 days to reduce
lambing period and minimise lamb weight
variation
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1 mature ram: 40 ewes
(A fit, 2 shear, ram will cope with more as will
certain breeds – e.g. Highlander/Primera)
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Ram pool, 3 rams – 150 -200 ewes
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Raddle/harness crayon colour should be changed
regularly
◦ More frequent changes gives more control of feeding
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Excessive repeats (25-30%+) indicates a problem
with ram fertility
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Vasectomise at least 8 weeks before they are
needed
Use one teaser for 100 -150 ewes
Put teasers in for 17 days max
Remove before fertile rams are introduced
Alternatively:
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Run entire rams on opposite side of secure
fence line for 14 days before introducing to
ewes
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Maintain body score (3.5)
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Embryo floats about in uterus
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Don’t dramatically increase or decrease
feeding
Avoid unnecessary handling and stress
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Ewes served at the correct body score is the 1st
step in achieving a high lambing percentage
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Carry out a ram MOT early and use rams at
correct ratio
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Manage nutrition carefully after mating
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Remove culls and obtain replacements
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Use appropriate vaccines and drenches
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Nutrition of the pregnant ewe
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Getting the feeding right to reduce lamb and
ewe mortality
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What to look for in a good ewe feed
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Simple rations
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Level of concentrate feeding required
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