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Seventy per cent of foetal growth occurs during the last six weeks of pregnancy.  To prevent excessive use of the ewe’s own tissues the diet needs to provide all the nutrients she needs.  Also if feed requirements are met, it will help to prevent other problems such as hypocalcaemia (milk fever) and pregnancy toxaemia (twin lamb).

The ewe also needs nutrients for:

  • maintaining and growing the unborn lamb(s)
  • developing the udder and milk production
  • producing good quality colostrum
  • to avoid metabolic disorders, such as twin lamb disease.

Thin, pale fore-milk indicates poor pre-lambing feeding whilst thick, yellow colostrum suggests the ewes have been well-fed.

At this time, the ewe’s energy and protein requirements increase rapidly; more than doubling for those carrying twins. However, as the lambs grow and take up more room inside, ewe appetite reduces by about 30%.  It is therefore important to increase the nutrient density of the ration to keep pace with foetal growth.  Supplementary concentrate feeding should complement the forage offered, and should be gradually increased either by step rate or flat rate feeding.                       

Feeding in late pregnancy

Meet the rapid increase in ewe energy and protein requirements in the final eight weeks of pregnancy through careful nutritional management, appreciating that mortality is invariably highest in lambs with a low birth weight and/or born to ewes in poor body condition.

Be aware that the ewes need to be fit (BCS of 3-3.5) at lambing time, and their condition should have remained stable from tupping; lean ewes (BCS <3) should be given preferential feeding.

Ensure a daily supply of minerals and vitamins is provided to maintain body functions, as readily available body reserves are limited; a good supply of vitamin E during pregnancy increases lamb vigour.

Good quality silage will supply much of the nutrients needed, however a source of DUP such as soyabean meal should also be fed.  Trough space is also important at this time to ensure all ewes have access to feed including ewe lambs and older ewes.  Studies have shown that feeding barley will lead to increases in the fatness of the ewe, but not the birth weight of the lambs.  Providing sufficient energy in the diet will ensure good milk production when the lambs are born.

It’s important to analyse the silage to ensure that concentrate feeding is matched to specific needs.  Also if there is a mineral deficiency supplementation will be needed for that element.

Whilst better feeding just before mating improves lambing percentage, few farmers seem to realise the responsiveness of the ovary to that feeding may depend on the nutrition the ewe received as an embryo. They are less aware of the lifetime effects of their feeding regimes.

Ewes underfed in late pregnancy produce lambs with low reserves of brown fat used specifically for protection against hypothermia, – longer term there are effects on wool follicles reducing wool yield.  Any effects of under nutrition during pregnancy will be greater in fast growing breeds.  In late pregnancy due to rumen restriction the ewe adapts by increasing food passage rate and increasing protein absorption by 15%.  High energy content of the diet is critical as efficiency falls with lower ME supply.  Cereals are a good source of energy but high levels of cereals, particularly wheat, can cause acidosis so the inclusion of a digestible fibre source, such as molassed sugar beet pulp at around 20% is desirable.  Cereals can be fed whole with hay, but should be processed with silage.  The inclusion of molasses will provide readily available energy, aid palatability and carry minerals.

The minimum metabolizable energy (ME) in a compound should be 12 MJ/kg DM and good quality ingredients should be used to achieve this with no reliance on low energy by-products.

Feeding levels

No. of lambs expected 6–8 weeks prior to lambing 4–6 weeks prior to lambing 2–4 weeks prior to lambing 0–2 weeks prior to lambing
1 300g
2 200g 300g 600g
3 200g 500g 900g

For crossbred ewe offered good quality precision chop silage (10.8 MJ per kg DM of Metabolizable Energy and 14% Crude Protein).

Concentrates should start being fed 2 weeks earlier and be 200g per day higher than the figures in table, if the ewes are in poor condition, the forage is of different quality or it is not precision chopped. Also if the concentrate intakes are higher than 500g per day, the feed should be equally split into two feeds. Check with a nutritionist before any major changes to diet formulation or nutrition are made. 

Protein nutrition

It is important to feed DUP (bypass protein) sources such as soyabean meal and not just consider crude protein levels.  A supplement of 100g of soya a day for each lamb carried, depending on the sheep breed and ration quality, for the last 3-4 weeks of pregnancy.  This should improve lamb birth weights and immunity to parasites.

Twin Lamb Disease (Pregnancy Toxaemia)

Thin or over fat ewes carrying multiple lambs can be at risk due to inadequate levels of available energy.

Ensure:

  • all ewes are at optimum body condition
  • stress is minimised
  • all sheep are getting their share of concentrates.
  • dividing ewes into groups depending on the number of lambs they are carrying and feed accordingly.
  • young ewes and shy feeders may need to be kept in a separate group.

Acidosis

Acidosis is where there is a marked decrease in rumen pH due to feeding:

  • high levels of concentrate in one feed or
  • inadequate forage or
  • too much rapidly broken down starchy ingredients, such as finely ground cereal.

This causes:

  • a decline in fibre digestion
  • lower feed intake
  • reduced performance.

Never feed more than 0.5kg concentrate per feed, and if feeding cereals avoid over-processing them.

Immunity

A ewe with poor immunity will not be able to pass on beneficial antibodies to her lamb via the colostrum, leaving the lamb vulnerable to infections in the first few weeks of life.  15% of lambs die around the time of lambing, by increasing birth weight and colostrums quality these figures will improve.

Colostrum is formed in the last 4-6 weeks of pregnancy – and antibodies from the clostridial vaccine will be passed on to provide immunity to the lamb.  Better feeding can boost antibody levels by 25%.  Good nutrition will also ensure the ewe stays fit around lambing as well.

Complete diet or TMR

A complete diet or TMR is where the forage and concentrates are mixed together and fed out from a feeder wagon.  TMR is the ideal way to feed ewes, as it provides a constant diet throughout the day, with no large shifts in rumen pH associated with concentrate feeding once or twice a day.  These can be formulated to meet the increasing needs of the pregnant ewe, but the advice of a competent nutritionist is strongly recommended.

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