Supplementary feeding in sheep

With many ewes across the Murray at the point of lambing, it may be a good time to discuss supplementary feeding in late gestation and early lactation.

Supplementary feeding is used when the available feed does not meet appropriate energy, protein and fibre requirements.  Supplementary feeding does not aim to provide a complete, balanced ration, where substitution feeding is required more specific nutrition advice should be sought.

There are some standard rules of thumb that can be adapted to focus on late gestation and early lactation ewes.

The nutritional requirement of the ewe is the most important thing to know when considering supplementary feeding, in particular, the energy requirement with some consideration to minerals:

• A pregnant 50 kg ewe, single pregnancy will require 11-14.2 MJ/ME (metabolisable energy) from 16-20 weeks gestation; the twin bearing equivalent will require 12.8-18MJME
• Protein requirements are around 8% of the ration for both maintenance and gestation however increase during lactation
• During lactation body condition defines the protein requirement – the higher the body condition, the higher the protein requirement; concurrently raising twins requires a higher level of protein than singles.

The second consideration is the volume of feed the animal can actually consume.  A late gestation ewe may need to consume 4 kgs of feed to meet the requirement but physically cannot consume this volume.  During lactation, while the energy requirements remain high the capacity to consume feed is greatly increased.

Rule of thumb:

• Choice of feed – hay v’s grain: grain is high energy but also highly fermentable compared to slower digested fibre.
• How much do I feed? – knowing the nutrient value of the feed commodity allows you to calculate the volume required based on the animals' needs.  In late gestation, focus on meeting energy requirements while focusing on protein and energy requirements during lactation. Remember to consider the limitations of physically consuming the volume calculated.
• When do I start feeding?  – when the first animal loses a body condition score
• Start feeding at 50g per head per day increasing by 50-100g per head per day.  Allowing 2 weeks to reach the total volume required, increase the delivery by 50-100g per head per day.  This will allow rumen microbes to adapt to the change in diet and reduce the risk of acidosis.
• Cereal grains have altered Calcium: Phosphorus ratios - ewes in late gestation and early lactation have a high calcium requirement; 1-1.5% ground limestone should be added to supplementary grain.

For further advice please contact your local district veterinarian.