Level II Agricultural Business Operations. Overview of the production cycle of a ewe Appropriate management of the flock pre mating to achieve optimum.

Level II Agricultural Business Operations

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

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

Lowland breeds and crosses cycle – Aug – Feb

Hill breeds – Oct – Jan

Some breeds, e.g., Dorset Horn can breed almost any time of year (for early lambing systems, mate in July)

When in season a ewe comes on heat every 16 – 17 days

Each heat lasts for 24-36 hours

Gestation period 147 days (21 weeks)

July/Aug

The number of eggs shed at each ovulation

Affects number of lambs born to the ewe

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

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

Starts at weaning

Ensure ewes have enough time to recover between weaning and mating

Assess ewe body condition

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.

Wean lowland ewes July-mid August

Hill ewes no later than end of September

This give ewes time to gradually gain condition

Ensure ewes are appropriately dried off

May sort off culls at this stage for marketing◦ Bad udders etc.

Prolapsed

Records / ear notch

No lambs Poor mother Poor milker Hard to lamb Dead lambs Rejected lambs

Reassess body condition ideally 8-6 weeks before mating date

Feed ewes accordingly to achieve desired BCS

Check udders/teeth/feet etc

Treatments

Cast/culls

Ewe body condition score

Sward height

DM intake Kg per day

Low 2.5 or below 5 – 7 1.3 – 1.4

Optimum 3.0 – 3.5 4 0.8 – 0.9

High 4 + 3 0.7

• Monitor condition regularly until rams go in and adjust feeding to avoid excessive loss or gain in condition

Not needed for ewes BS >3.0

Very fat ewes = increased barrenness

Very thin ewes = low lamb numbers

Increase by 1 body score takes about 6 weeks on good grass at 7-9 cm ◦ (appox. 8-12kg for mature lowland ewe)

If grass is short can offer additional feed

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

Clostridial & Pasteurella (Hep P+) Initially two vaccines given 4-6 weeks apart

then an annual booster 4-6 weeks pre lambing

Toxoplasa abortion Live vaccine –up to 1 month prior to tupping.

Lasts 2-3 years (Toxovax)

Enzootic abortion Live vaccine – up to 1 month prior to tupping.

(Enzovax, Chlamydophila)

• 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

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

A ewe should be replaced before she has an unproductive season

Typically after 5 crops

Important to record and identify problem ewes so they don’t get a reprieve◦ Ear notch/tag

Replacement rate◦ Typically 20% for lowland flock◦ Potentially 25 – 30% on a hill farm

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

Keep your own ewe lambs

Purchase ewe lambs

Purchase sucked hoggets

Purchase dry hoggets

Draft ewes

Advantages Disease risks are lower

Quality – greater control over management

Potential to improve ewe type - maternal sires

Good records

Cheaper?

Disadvantages Management can be

complex

Breeding policy must be planned

Cheaper?

Advantages Replacements can be

bought as shearlings

Hybrid vigour

Less complex recording?

Less time consuming

Disadvantages Higher risk of disease

No control over the rearing phase

No prior knowledge

Autumn sales are fixed

Little time for introduction to flock

Conception rates are lower ◦ 90% or less ◦ average litter size of 1.0-1.2

Lamb mortality can be high due to ◦ Lambing difficulties, small lambs, lack of milk etc

There is a greater risk of mismothering

Good feeding is essential to ◦ Sustain growth of the ewe lamb◦ Enable the production of adequately sized lambs and

sufficient milk.

May be cheaper than gimmers/hoggets

Extra crop of lambs (if lambed)◦ Harder to lamb/manage◦ Easier to manage following year if lambed

Need to be 60-70% of mature weight going to the ram

Can stunt growth Extended lambing season

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 24-48 hours

2. Treat asap Worm treatment Fluke treatment Treatment for sheep scab Vaccination – Clostridial diseases, Toxovax, Enzovax Foot care – Inspection and footbath

3. Quarantine – turn out to pasture previously grazed by own flock and keep isolated for 3 weeks

Size, length, conformation Legs and feet Mouth and teeth Wool Reproductive organs Breed characteristics EBVs (Scan weight)

Body score 3.5 – 4 (Feed meal 8 - 10 weeks prior to tupping)

Handle testicles – Should be hard without bumps or lumps, check for epididymis

Mouth – Check for broken mouth

Temperature and wellbeing

Feet

Brisket sores

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

1 mature ram: 40 ewes(A fit, 2 shear, ram will cope with more as will certain breeds – e.g. Highlander/Primera)

Ram pool, 3 rams – 150 -200 ewes

Raddle/harness crayon colour should be changed regularly◦ More frequent changes gives more control of feeding

Excessive repeats (25-30%+) indicates a problem with ram fertility

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:

Run entire rams on opposite side of secure fence line for 14 days before introducing to ewes

Maintain body score (3.5)

Embryo floats about in uterus

Don’t dramatically increase or decrease feeding

Avoid unnecessary handling and stress

Ewes served at the correct body score is the 1st step in achieving a high lambing percentage

Carry out a ram MOT early and use rams at correct ratio

Manage nutrition carefully after mating

Remove culls and obtain replacements

Use appropriate vaccines and drenches

Nutrition of the pregnant ewe

Getting the feeding right to reduce lamb and ewe mortality

What to look for in a good ewe feed

Simple rations

Level of concentrate feeding required