Sheep husbandry

Where are sheep found?

In areas that receive lots of rainfall and have high grass growth.

Which countries have the largest sheep population?

China, India and Australia

What is the stratified system of sheep production?

A three-tiered system of raising sheep that is based on altitude and grazing conditions. It enables farmers to exploit a wide range of environments and combine the characteristics of different breeds to produce sheep suited to different areas and production systems.

In a stratified system what happens on the hills?

Hill breed sheep produce lambs which replace the flock, draft ewes which are removed and raised in the uplands, and store lambs which are raised for meat production in the lowlands.

In a stratified system what happens in the uplands?

Upland/Longwool breed sheep are crossed with draft ewes from the hills, and the offspring halfbred sheep are farmed upland or raised for breeding and meat production in the lowlands.

In a stratified system what happens in the lowlands?

Lowland sheep are crossed with the halfbred sheep or upalnd sheep to produce meat lambs.

What are some hill sheep breeds?

Hill breeds are hardy, small and have a low litter size (1 or 2 lambs). They have a strong mothering ability and require minimal input.
Examples include Scottish Blackface, Swaledale, Welsh Mountain, LLeyn, Kerry Hill

What are some upland/longwool sheep breeds?

Upland breeds have a bigger frame and a larger litter size (2 lambs normally) and a faster growth rate.
Examples include the Teeswater, Border Leicester, Blue-faced Leicester and Wensleydale.

What are some Halfbred/Mule sheep breeds?

Halbreds have a moderate frame and large litter size. They grow quickly and have a strong mothering ability. Examples include the North Country Mule, Scottish Mule, Greyface.

What are some lowland/down sheep breeds?

Lowland sheep have a large size and good carcass conformation. They grow quick but are less hardy and require more input.
Examples include the Suffolk, Southdown, Texel, Beltex, Charollais.

Aside from a stratified system, what are some other popular systems of sheep production?

- Closed purebreed flocks
- Crossbreed flocks
- Store lambs
- Crofting
- Direct hill breed x lowland lamb production

What is the EUROP system of carcass grading?

EUROP system is based on the appearance of the carcass.
Carcass conformation - should be a convex shape, ranked from E (excellent) to P (poor).
Fat class - ranked from 1 (low) to 5 (high). 4 and 5 both have a low and high class attached to them.

What may cause a carcass to lose value?

- Abcesses
- Bruising
- Arthritis
- T.ovis cysts
- Dirty carcass
- Liver condemnations

What are the current financial schemes available to UK farmers?

- Environmental Land Management Schemes
- Animal Health and Welfare Grants
- Annual Health and Welfare Review

When are sheep most likely to ovulate?

In Autumn due to decreased daylight hours. In the dark, melatonin production increases which triggers ovulation.

How long is the oestrus cycle in a sheep?

Approximately 17 days

How long are tups left with ewes?

For two cycles, 34 days.

How many ewes should there be per ram?

1 ram per 40 ewes.

How long is a ewe's gestation?

147 days (around 5 months)

What is the typical target age to wean a lamb?

Between 12-16 weeks, ideally 100 days after birth.

What is the conception rate of sheep?

90%
After tups have been with the ewes for 2 cycles, if the barren rate is more than 2% it is a cause for concern.

How do sheep farmers cope when grass demand exceeds supply?

- Use adipose reserves in animals, allow them to lose condition.
- Conserve forage when it is in excess and make silage and hay.
- Move sheep to graze somewhere grass growth is better.
- Change lambing and sale dates so they better align with grass growth.
- Grow cover crops like swedes, fodder beet, turnips to feed sheep when grass growth is poor.

At what stage is grass ready to be grazed?

At the 3 leaf stage.

What is continuous (variable) grazing?

Sheep graze only area of land for an extended period of time. This is cheap and low input but decreases forage yield. Weeds may build up and manure may be unevenly distributed.

What is rotational grazing?

Sheep graze one area of land for a certain amount of time before moving on. This increased productivity and means manure is more evenly distributed. This requires more input and is more expensive, as fencing and water provisions are greater.

What is paddock grazing?

Sheep graze different paddocks for different amounts of time. The grazing season is extended and manure is evenly distributed. This is expensive in terms of labour, fencing and water provision.

What is stocking rate?

The number of sheep per unit of land. According to the NSA, typical stocking density on productive grass is 6 to 10 sheep per acre.

What is the typical livestock unit for sheep?

Between 0.04 and 0.12, larger for larger breeds or breeding ewes.

How might you assess grass growth?

You can measure kg of dry mass per hectare (kg DM/ha) using a compressed sward stick, mechanical rising plate, electronic rising plate meter, grasshopper sensor, or qualitatively - would you be able to see golf balls?

What is the optimum body condition score of a tupping ewe?

3 to 3.5. Below 2, reproductive performance is reduced and fewer eggs are ovulated.

What is flushing?

Providing an increased plane of nutrition like fresh pasture or concentrates to boost ovulation, 3 weeks prior to tupping.

What is the optimum body condition score of a ram at tupping?

3.5 - 4. During tupping, rams pay less attention to eating and require more energy to get around the flock. Too fat rams will have a decreased sperm count and be lazy.

How much body condition score can ewes lose between tupping and weaning.

Lowland ewes can lose an entire BCS from 3.5 to 2.5.
Hill ewes can only lose 0.5 from 2.5 to 2.0.

How much body condition score can ewes lose in the last month of lambing/ start of lactation?

Ewes with BCS of 2.5 or more can lose up to 0.5.
Ewes with a BCS less than 2.5 cannot lose condition.

What are the risks of an overly thin ewe?

- Lamb death
- Uterine inertia (unable to push out lamb)
- Twin lamb disease/ Pregnancy toxaemia
- Mastitis

What are the risks of an overly fat ewe?

- Dystocia
- Poor lamb/ewe bonding
- Prolapse
- Twin lamb disease/ pregnancy toxaemia

What is the ideal BCS of a ewe one month prior to lambing?

3 to 3.5. It is important to maintain condition rather than gaining/losing in late pregnancy.

What is the target DLWG for lambs pre-weaning?

300g/day. Within the range of 200 to 500g/day.

What is the target DLWG for lambs post-weaning?

200g/day. Within the range of 100 to 350g/day.

What are the advantages and disadvantages of indoor lambing?

Advantages: Protection from inclement weather, lower risk of hypothermia, easier to supervise and intervene, allows pasture growth.
Disadvantages: Higher labour requirement and more expensive, increased disease risk.

What are the advantages and disadvantages of outdoor lambing?

Advantages: Lower labour requirement, less disease risk, lower cost.
Disadvantages: Increased risk of hypothermia and starvation, more losses as a result of dystocia, sufficient pasture needed, only suitable later in the year.

Why might ewes be culled after lambing?

- Age
- Poor condition
- Damage to udder
- Lameness
- Illness
- Difficulty lambing

When should replacement ewes be purchased if required?

In enough time that they can be quarantined for at least 28 days and then get used to the environment and diet.

At what weight can ewes be bred?

When they reach 2/3 of their adult weight. They have a barren rate of 20% compared to 2% in adult ewes.

How to tell if a ram is fit for breeding?

- Not lame
- Body condition of 3.5-4
- Two even testes
- Good testicular tone
- Minimal scrotal circumference of 30-36c, depending on breed.

What are the signs that a sheep is healthy and happy?

- Bright
- Ears pricked
- High head carriage
- Smile
- Good fleece
- Normal flock behaviour

What are the signs that a sheep is sick?

- Laying down
- Drooped ears
- Low head carriage
- Thin
- Reduced rumen fill
- Diarrhoea
- Lameness
- Increased respiratory effort
- Reluctance to move
- Clenched cheek muscles
- Drooping eyelids
- Cud spillage

What is the 5-point plan approach to lameness managment?

A holistic approach to managing lameness. Including avoidance, treatment, quarantine, vaccination and culling.

What are some common causes of abortion in sheep?

- Enzootic Abortion in Ewes (EAE)
- Toxoplasmosis
- Campylobacter
- Salmonella
- Listeriosis

What are some common sheep intestinal parasites?

- Coccidosis
- Cryptosporidiosis
- Liver Fluke
These parasites can be minimised by moving sheep between pastures so they do not shed too many eggs in one place and parasite burden is kept low.

What is liver fluke?

Common in wet, marshy areas as it is relies on the Mud snail to replicate. Prevention includes effective use of flukocides, avoidance of highly contaminated areas, habitat modification to reduce contamination.

What is Nematodirus?

A worm that is spread between lambs. The previous year's lambs shed it and it waits on the pasture until the following year's lambs arrive. If the weather has been cold and suddenly warms up, there is a mass hatch of nematodirus and lambs can become sick. The SCOPS forecast predicts the likelihood of this.

What are some common sheep external parasites?

- Flystrike
- Sheep scab. Mites make the sheep so itchy that they lose wool, weight and it can be fatal. Prevention includes treating bought-in sheep with MLs or dipping them in inorganophosphates and quarantining them.
-Lice
- Ticks
- Chorioptic mange
- Keds
- Midges

What is clostridial disease?

Examples include tetanus, black disease, black leg, pulpy kidney etc.
The most important prevention is vaccination.

What is pasteurella?

A bacteria that causes infections of the lower respiratory tract. This can be vaccinated against. Outbreaks are more common at certain times of the year, and changes in diet, transport, weather also increase the incidence.

What are iceberg diseases?

Diseases that present in such a way that you only see the tip of the problem. For examples:
- Chronic wasting disease
- Johne's disease
- Maedi-visna
- CLA (Caseous lymphadenitis)
- OPA (Ovine pulmonary adenocarcinoma)
- Scrapie (TSE)
Most of these diseases require infected animals to be culled.

What are disease accreditation schemes?

Exist for diseases that cannot be identified in a single test or can be present in a flock even though sheep test negative. An accredited flock is one that has not had a specific disease for a certain number of years, making it very likely the disease is not present in the flock.

What are some zoonotic diseases of sheep?

- Orf
- EAE
- Toxoplasma
- Salmonella
- Campylobacter
- Cryptosporidiosis
- E.coli

What vaccines are available to sheep?

- Clostridial
- Pastuerella
- EAE
- Toxoplasma
- Orf
- Mastitis
- Johne's
It is common to give 2 injections 4-6 weeks apart initially, and then once yearly. Some vaccines only need to be given once.

What is hefting/heafing?

The instinct which some sheep have of keeping to a certain heft (small local area). This instinct is learnt from ewes to their lambs.

What is the deadweight of a lamb?

Generally, 42-50% of the lamb's bodyweight. It does not include the head, wool, feet, entrails, organs.