BulletinExtraAutumn 2013

Providing ewes with adequate energy and protein in the last few weeks before lambing has a huge influence on subsequent flock performance. Making sure there is plenty of forage and a consistent diet during this time is critical.

It can be difficult to know exactly what ration is most suitable. This leaflet offers some good basic guidelines, but a professional nutritionist will be able to offer more precise advice.

Feed planning for ewes in late pregnancy and early lactation, during the housed period

Take a stepped approach to feed planning

Compiled by Kate Philips, ADAS

Feed requirement – feed supply = surplus or deficit

Step 1 - Calculate feed intake

First work out dry matter intake (DMI), ie how much the animals will eat

How much feed ewes will eat drives all rationing calculations

DMI is difficult to predict accurately and varies according to many factors such as breed, liveweight, weather conditions, ration type and feeding system

Table 1 provides an approximate guide to DMI for ewes at different stages of production, but on-farm measurements should be used where possible.

Feed intake is easiest to predict on a Dry Matter (DM) basis, since the DM of feeds varies widely. However, for practical rationing and planning there is a need to convert DM back to fresh weight or ‘as fed’.

For example, if a 70kg ewe eats approximately 2% of her bodyweight in DM each day in late pregnancy, that is 1.4kg of DM. Assuming high quality silage of 30% DM, this equals 4.7kg of fresh silage.

Note: DM content of forages varies greatly, but most ‘dry’ feeds such as compounds, concentrates and cereals are between 86 and 90% DM.

Table 1: DMI as a % of bodyweight

Stage of production Intake requirements (% of bodyweight)

Dry 1.5

Late pregnancy 2

Early lactation 3 +

Mid-late lactation 2.5

Nutrient requirements The total nutrient demand will depend on:

The number of ewes and length of feeding period

The physical requirements of the ewes, eg liveweight, litter size, body condition score

See tables A, B, C, and D for approximate guidelines

Metabolisable protein requirements are very complicated to calculate precisely, so a simple rule of thumb is shown in Table D using crude protein (CP) levels in the diet.

This is a rough guide and fails to take into account all the different types of protein, and whether they are degraded in the rumen or pass through to be digested in the small intestine.

For most ewe rations, rumen degradable protein is the major source of protein required. However, digestible undegradable (bypass) protein is also needed for ewes expecting twins or triplets, in late pregnancy and early lactation.

Step 2 - Consider feed availability and quality

List the current feeds available on the farm and their quantity and quality (DM, ME and CP as a minimum), eg silage, hay, cereals

Have conserved forages analysed by a reputable laboratory

Assess forage stocks by weighing a number of bales (large and small) or by measuring the volume of silage in a clamp

Other EBLEX publications and tools can provide a guide to the value of other feeds. However, there is no substitute for analysing the actual feedstuffs the sheep are going to eat, as there can be much variation within feeds, even of the same type

Step 3 - Formulate a ration

The most critical information needed is the quantity and quality of forages to be used, as this will dictate the amount of supplementary feed required.

Formulate a ration to the mid-point of the lambing period. If the lambing period is generally longer than three weeks split into different periods.

Dry matter intake of forages varies widely according to DM, digestibility and fermentation characteristics, ie pH and ammonia content.

Table 2 shows the daily DMI (percentage of liveweight) of different forages.

For example a 70kg ewe from 12 to three weeks pre-lambing on good silage would eat about 1.6% of her bodyweight as silage, ie 70 x1.6/100 = 1.12kg DM.

If the silage was 25% DM she would eat (1.12 x100/25) 4.5kg of fresh silage, which would meet all her energy needs up to about six weeks before lambing.

In the last three weeks before lambing, she would eat a little less silage as the lambs grow bigger inside her. She would then be eating 1.4% of her bodyweight, ie 70 x 1.4/100 = 1.0kg DM.

ME (MJ/kgDM)

Weeks 12–3 pre-lambing

Weeks 3–0 pre-lambing

Weeks 0–3 of lactation

% of LWT % of LWT % of LWT

Straw 6.5 1.0 0.8 n/a

Average hay 8.5 1.5 1.1 1.2

Good hay 9.5 1.8 1.4 1.5

Poor silage 9.5 1.4 1.2 1.3

Good silage 10.5 1.6 1.4 1.6

Table 2: Daily forage DMI as a % of ewe liveweight by twin-bearing ewes in pregnancy and lactation, when fed concentrates

Again if the silage was 25% DM this would be equivalent to (1.0 x 100/25) 4kg of fresh silage, and the ewe would need about 0.5kg of a good compound feed to make up the shortfall, depending on her body condition.

The total intake of silage for a period of eight weeks pre-lambing would therefore be about 250kg fresh weight per ewe.

For a three week period in early lactation silage intake would rise again and an additional 100kg fresh weight of silage would be needed, along with any necessary supplements to make up the energy and protein deficit that silage alone cannot provide.

Single bearing ewes would eat slightly more silage and need less supplements, while triplets would eat less silage and need more supplements close to lambing. Using the twin-bearing ewe estimates for a lowland flock would be a good compromise when planning a ration.

Unlike high quality grass, very few silages or hays are of high enough quality to provide pregnant and lactating ewes with all their energy and protein needs. They will need supplementing with straights or compound feeds.

Formulating a ration will define the daily requirements for different feeds per head and can be used to work out requirements over a specific time period.

Step 4 - Define the feeding period

How many days will the ewes need conserved forage and supplements before housing?

How many days will the ewes be fed indoors before lambing?

How many days will ewes need to be fed after lambing?

It is a good idea to formulate the rations well before the planned housing date and buy supplies in good time.

Step 5 - Calculate total feed requirements

Multiply the daily requirements of the ewes (carrying singles, twins and triplets), by the number of animals of that type and then by the number of days each group is to be fed.

This will give the total amount of each feed required for each defined feeding period. These can then be compared with actual feed stocks.

The total amount of silage or hay eaten will depend on the feeding period – from when it is introduced before housing to stopping in early lactation. This will vary each season, depending on the weather and grass availability.

On average allow about 150kg of hay per Mule ewe or 300 to 500kg of silage (depending on the DM). Straw-based systems work well for housed ewes that are fit at housing, and a daily allowance of 1.5kg of straw per ewe (eating and bedding) is needed, plus concentrates.

Remember to take into consideration possible wastage.

Step 6 - Take action to address feed deficits

If there appears to be a shortfall of feed once the calculations have been done, action can be taken to fill any deficits, sooner rather than later.

Options to manage any deficits in feed availability include:

Buying and/or sourcing more feed – including additional grazing or root crops

Looking for alternative types of feed

Weeks pre-lambing Total

8 6 4 2 1 (kg/hd)

Singles Silage 4.6 4.6 4.6 4.6 4.6 258

Compound 0 0 0 0 0.2 1.4

Twins Silage 4.6 4.6 4.5 4.1 4 249

Compound 0 0 0.15 0.4 0.5 8

Triplets Silage 4.6 4.6 4.3 3.9 3.7 242

Compound 0 0 0.25 0.6 0.75 13

8 6 4 2 1 (kg/hd)

Singles Silage 4.2 4.2 4.1 3.9 3.9 230

Compound 0 0 0.1 0.25 0.3 5

Twins Silage 4.2 4.1 3.8 3.5 3.4 218

Compound 0 0.15 0.3 0.6 0.75 16

Triplets Silage 4.2 4 3.7 3.3 3.1 211

Compound 0 0.2 0.45 0.8 0.9 21

8 6 4 2 1 (kg/hd)

Singles Hay 1.4 1.4 1.4 1.3 1.3 77

Compound 0 0 0 0.15 0.25 3

Twins Hay 1.4 1.4 1.3 1.2 1.1 74

Compound 0 0.2 0.3 0.55 0.7 16

Triplets Hay 1.4 1.3 1.2 1.1 1.1 70

Compound 0 0.2 0.45 0.75 0.9 21

Grass silage – clamp (25% DM, 10.5 MJ/kg DM) (ration kg/head/day)

Grass silage – big bale (40% DM, 10.0 MJ/kg DM) (ration kg/head/day)

Good hay (9.5 MJ/kg DM) (ration kg/head/day)

8 6 4 2 1 (kg/hd)

Singles Hay 1.1 1.0 1.0 1.0 1.0 57

Compound 0.15 0.25 0.35 0.5 0.5 18

Twins Hay 1.1 1.0 0.94 0.87 0.84 55

Compound 0.2 0.4 0.6 0.85 0.95 29

Triplets Hay 1.0 1.0 0.91 0.82 0.78 52

Compound 0.25 0.5 0.7 1.0 1.1 35

Average hay (8.5 MJ/kg DM) (ration kg/head/day)

Mule type ewe 70kg – BCS 3.0 (unshorn, indoors). Compound feed assumed to be 12.5 MJ/kg DM

Example diets

Here are some example rations for feeding different types of stock and displayed ‘as fed’.

Multiple factors will affect the exact nutrient requirements of stock and the performance achieved on a particular ration, so these rations should only be used as a guide.

Note: as there will be a spread in lambing dates slightly more feed might be required and forage should ideally be available ad-lib.

Guidance on energy and protein requirements of ewesTable A – Dry matter intake (DMI) and metabolisable energy (ME) requirements (MJ/d) for housed pregnant ewes for a diet of 11 MJ/kg DM

Table B – Dry matter intake (DMI) and metabolisable energy (ME) requirements (MJ/d) of housed, lactating ewes for diet of 11.5 MJ/kg DM.

Table C – Estimates of ewe milk yield (kg/d) by month of lactation

No allowance made for liveweight gain in the ewe except in the fleece. For 50g/day liveweight gain in addition to the foetus, add 2.5 MJ of ME. Subtract 1 MJ of ME for a liveweight loss of 50g/day in late pregnancy for ewes in condition score greater than 3.

Note: these figures are provided for guidance only and will vary according to breed, genetic potential, weather conditions, sex and animal health.

Number of weeks before lambing

7 5 3 1

Ewe wt No. lambs expected DMI ME DMI ME DMI ME DMI ME

50kg 1 0.7 7.9 0.8 8.7 0.9 9.8 1.0 11.2

2 0.8 8.8 0.9 10.1 1.1 11.9 1.3 14.2

60kg 1 0.8 9.1 0.9 10.0 1.0 11.2 1.2 12.8

2 0.9 10.1 1.0 11.6 1.2 13.7 1.5 16.3

70kg 1 0.9 10.2 1.0 11.2 1.1 12.6 1.3 14.4

2 1.0 11.4 1.2 13.1 1.4 15.3 1.7 18.3

3 1.1 12.0 1.3 14.0 1.5 16.7 1.8 20.3

80kg 1 1.0 11.3 1.1 12.4 1.3 13.9 1.4 15.9

2 1.1 12.6 1.3 14.4 1.6 17.0 1.8 20.2

3 1.2 13.3 1.4 15.5 1.7 18.5 2.0 22.5

Milk yield (kg/d)

1.0 2.0 3.0

Liveweight change g/d

DMI ME DMI ME DMI ME

60kg ewe 0 1.3 15.6 2.1 23.7 2.8 32.2

-50 1.2 13.8 1.9 22.0 2.6 30.3

-100 1.0 12.1 1.7 20.2 2.5 28.5

Lowland ewes outdoors +0.3 MJ/d, ewes on hills +1.1 MJ/d

80kg ewe 0 1.5 17.5 2.2 25.6 2.9 33.9

-50 1.4 15.8 2.1 23.8 2.8 32.0

-100 1.2 14.0 1.9 22.0 2.6 30.2

Lowland ewes outdoors +0.4 MJ/d, ewes on hills +1.5 MJ/d

Month of lactation

Litter size Type of ewe 1 2 3

One lamb Hill 1.25 1.05 0.70

Lowland 2.10 1.70 1.05

Two lambs Hill 1.90 1.60 1.10

Lowland 3.00 2.25 1.50

©Agriculture and Horticulture Development Board 2013.

EBLEX is a division of the Agriculture and Horticulture Development Board.

Tel: 0870 241 8829

Email: brp@eblex.ahdb.org.uk

www.eblex.org.uk

For more information contact:EBLEX BRP

Agriculture and Horticulture Development Board

Stoneleigh Park, Kenilworth, Warwickshire CV8 2TL

All copies of EBLEX BRP manuals and many other helpful tools are available to view at www.eblex.org.uk Or email brp@eblex.ahdb.org.uk or call 0870 241 8829 to request free hard copies.

Table D – Approximate guidelines for crude protein levels for ewe rations

Stage of production CP% in DM

Dry 12–14

Late pregnancy 15–16

Early lactation 16–20

Mid to late lactation 14–16

Crude protein levels take no account of protein quality and hence should only be used a guide to dietary protein levels. A professionally formulated ration is recommended.

Pregnant ewes should be offered consistent diets through late gestation to help avoid metabolic problems such as pregnancy toxaemia and hypocalcaemia. Ensure there are no significant changes in feed in the last three weeks before lambing. Any changes that are made should be introduced gradually.

• BRP Sheep Manual 12 – Improving ewe nutrition for Better Returns

• BRP Beef and Sheep Manual 5 – Making grass silage for Better Returns

• BRP Beef and Sheep Manual 8 – Planning grazing strategies for Better Returns

• Year round feeding the ewe for lifetime production

• The Home-Grown Forages Directory

• The Mini Feeds Directory

• The Cereals Directory

• EBLEX Blends Calculator (online)

EBLEX BRP publications and tools can provide a guide to the value of other feeds.