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Don’t Forget About ERDP

29 January 2019

Some of those producers short of forage are turning to straw and old (often poor) hay to fill the gap.  In these situations it can be easy to think the supply of the energy on offer will be enough in the early stages of pregnancy when the requirement is still fairly low.  However, it’s important not to overlook protein requirement.   These alternative forages are low in protein and will not be sufficient to meet the demands of the rumen bugs.  In order for the rumen bugs to digest the forage they must have a supply of effective rumen degradable protein (ERDP).  This is the proportion of protein that is degraded in the rumen as opposed to Digestible Undegradable Protein (DUP) which bypasses the rumen for absorption in the intestine.

Rations based on these lower quality forages (less than11%CP) will need to supplement with a small amount of ERDP.  The cheapest source being urea is not always the easiest to feed unless given in liquid form.  Another alternative is offering a high Non Protein Nitrogen block.  In a TMR situation adding a high 40% or 65% crude protein urea-based liquid may be suitable to get the balance right.  Other good ERDP protein sources like straight soya, beans, rapeseed meal and wheat distiller’s grains would be suitable for these poor quality forage rations.   Unlike those with a higher proportion of DUP (e.g. protected soya).   If during feeding, the ewes are particularly aggressive, not milking well enough or too stiff in the dung, review protein supplementation (sources and amounts).

Poppy Frater & Mary McDowell

Sheep eating hay

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