Ewe nutrition requirements through the production year
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Getting ewe nutrition right is not only critical to the health of the ewe and her lambs, both present and future, it is also pivotal when it comes to profitability.
Nerys Wright, knowledge exchange manager for AHDB Beef & Lamb says sheep liked a steady, consistent feed and it was important to keep the rumen pH stable.
“Our job is to feed the bugs that live in the rumen and those bugs will feed the sheep for us.”
See also: Advice on flushing ewes with a low body condition score
There are key times throughout the production year when it is important to check body condition score (BCS) and adjust diet accordingly to keep the ewe at optimum condition to produce and wean a strong lamb:
Tupping
Target BCS: 3.5 for lowland, 3 for upland and 2.5 for hill
“It is important to say that this [BCS target] is not a flock average, it is an individual ewe target,” Ms Wright says.
BCS needs to be checked before tupping to aim for these targets. It doesn’t matter whether scoring is done with full EID or by syphoning ewes off into different groups to feed them accordingly, but the important factor is putting a hand on the animal.
It takes six to eight weeks to gain one unit of condition, so it is too late at tupping time to realise they are not at the right score.
Ms Wright says it would appear that while you can regain condition fairly quickly, you cannot undo the damage of falling behind on BCS because the follicles are set a long time before mating. Therefore, nutrition requirements need to be determined at weaning (see below).
“Take care with flushing and definitely do not hold them back to flush them. It should be a back-up plan,” Ms Wright advises. “We know it has little effect if the ewe is already in good condition.”
Mid-pregnancy
Target BCS: 3.5 for lowland, 3 for upland and 2.5 for hill
It is key to maintain diet throughout this time, avoiding any sudden changes.
Maintaining body condition scores and weight up to scanning will have a positive effect. Up to BCS 4, we see a linear curve of benefit. At BCS 4 and above, scanning results will drop off.
Late pregnancy
This is when 75% of foetal growth takes place. Nutrition is key to support the ewe’s immune system, udder development and colostrum production.
Nutrition in late pregnancy will determine what the ewe can produce in lactation.
Energy requirements in late pregnancy (MJ) |
|||||
Ewe liveweight (kg) |
Number of lambs |
Time to lambing |
|||
Seven weeks |
Five weeks |
Three weeks |
One week |
||
50 |
1 |
7.9 |
8.7 |
9.8 |
11.2 |
2 |
8.8 |
10.1 |
11.9 |
14.2 |
|
60 |
1 |
9.1 |
10 |
11.2 |
12.8 |
2 |
10.1 |
11.6 |
13.7 |
16.3 |
|
70 |
1 |
10.2 |
11.2 |
12.6 |
14.4 |
2 |
11.4 |
13.1 |
15.3 |
18.3 |
|
3 |
12 |
14 |
16.7 |
20.3 |
|
80 |
1 |
11.3 |
12.4 |
13.9 |
15.9 |
2 |
12.6 |
14.4 |
17 |
20.2 |
|
3 |
13.3 |
15.5 |
18.5 |
22.5 |
Pre-lambing checks
Approximately three weeks before lambing is a good time to seek veterinary advice on blood sampling ewes (ideally twin- and triplet-bearing) for:
- BHB – this shows if the body is mobilising fat to meet energy needs
- Urea – shows a same-day protein deficiency
- Albumin – long-term indicator of protein levels
Any deficiencies require the feeding plan to be assessed. It isn’t a case of just adding concentrate: the overall ration should be analysed.
Lambing and lactation
Target lambing BCS: 3 for lowland, 2.5 for upland and 2 for hill
Ewe demand doubles almost immediately when they have lambed, so if they are housed they should have ad-lib food to ensure they don’t run out, alongside plenty of water.
They reach peak milk yield at 3-4 weeks after birth, so attention is needed in this window.
In years where grass growth is slow or if it’s really wet, ewes will fill up on water so it is important to look at where help is needed in the four weeks after lambing.
Ewes can milk off their back if body condition score is there, but if it is not and food is not either, it will affect lamb growth.
See also: 8 ways livestock farmers can manage a grass shortage
Eight weeks post-lambing
Target BCS: No more than 0.5 loss since lambing
Target lamb weight: 20kg
This is a good time to check ewe condition and lamb weights to determine weaning date.
While the recommendation is to wean at 90 days (just over 12 weeks), with flexibility for circumstances such as ewe lambs and thin ewes, Ms Wright said many people were still weaning at 14 to 16 weeks and this could affect the subsequent lambing.
“There needs to come a point when you wean to focus on lamb growth and ewe condition for the next tupping.”
Weaning
Ewes should be grouped by BCS at weaning so that feed can be adjusted accordingly to get them in the right condition for tupping.
Energy and dry matter intake targets for BCS gain |
||||
|
Requirement for body condition gain from weaning to mating |
|||
Lowland breed – aiming to be 70kg at mating |
0.5 |
1 |
1.5 |
2 |
Weight gain required over 100 days (kg) |
3.5 |
7 |
10.5 |
14 |
Daily ME requirement for weight gain (MJ) |
3.5 |
7 |
10.5 |
14 |
Daily ME requirement for maintenance (MJ) |
8.4 |
8.4 |
8.4 |
8.4 |
Total daily ME requirement (MJ) |
11.9 |
15.4 |
18.9 |
22.4 |
Daily grass requirements (kg DM) |
1.19 |
1.54 |
1.89 |
2.24 |
Hill breed – aiming to be 50kg at mating |
0.5 |
1 |
1.5 |
2 |
Weight gain required over 100 days (kg) |
2.5 |
5 |
7.5 |
10 |
Daily ME requirement for weight gain (MJ) |
2.5 |
5 |
7.5 |
10 |
Daily ME requirement for maintenance (MJ) |
6 |
6 |
6 |
6 |
Total daily ME requirement (MJ) |
8.5 |
11.0 |
13.5 |
16 |
Daily grass requirements (kg DM) |
0.85 |
1.1 |
1.35 |
1.6 |
Source: AHDB “Feeding the ewe” manual |
Forage
Ms Wright says it is important to review supplementation needs each year, depending on forage available.
“Based on how much quality and how much quantity you have, you need to pick your supplement on that gap. Some people tend to pick the same supplement each year and in a year when it’s not needed, you can save money if you can avoid it where possible.”
Therefore, farmers need to:
- Calculate how much forage is available for winter
- Get forage analysed for quality and supplement to fill any shortfalls.
The five things farmers should look at on a silage analysis report are:
- Dry matter percentage (DM%)
If silage is too wet (less than 25% DM), ewes find it difficult to eat enough to meet their needs. Clamp silage should be above 25% DM and bale silage should be above 30% DM.
- D value (digestibility)
The higher the D-value, the less concentrates are needed for ewes pre-lambing. A D-value of 60 would be good for hay and 70 would be good for silage.
- Metabolisable energy (ME)
A good silage result would be above 11 MJ/kg DM and hay would be above 10 MJ/kg DM
- Crude protein (%)
Silage should be 14%-plus and hay 12%-plus
- pH
Acidic silage (below pH 4) can restrict how much a ewe will eat
Compound feed
Compound feed should not be high in fibre. It is more important that it is a good source of starch and sugar.
Ms Wright says it is important to shop around and ask for ingredients lists. A compound feed should be 12-12.5 ME MJ/kg, but legally this does not have to be on the label, so you need to request this information.
“You pay for what you get. It might be worth spending an extra £10/tonne and feeding less of it.”
Nerys Wright was speaking at a National Sheep Association webinar.