Protein sources and TMR feeding

Results:

1. Ewe live weight and body condition score were unaffected by the main protein source fed in late pregnancy at any stage between housing in January and weaning in July
2. Performance of twin lambs offered creep feed was consistently above 300g/day between birth and eight weeks of age on all treatments
3. Lamb birth weights, 4 week weights, 8 week weights and the associated daily liveweight gains did not differ between treatments
4. The study demonstrated that rapeseed meal, wheat distillers grains and beans can all be used as substitutes for soya bean meal in the diets of twin bearing and rearing ewes in complete diets based on good quality grass silage; the ewes in this study were very fit at housing in January and the silage was of good quality (around 10.8 MJ/kgDM) which meant supplementary feed was only introduced 4 weeks pre-lambing and fed at a relatively low level (up to 0.45 kg/hd/day at lambing). On a poorer silage (10.0 – 10.3 MJ/kgDM) supplementary feed would be introduced sooner (from 6 weeks pre-lambing) increasing gradually to around 0.75 kg/head at lambing
5. Total supplementary feed costs (excluding minerals) were highest for the Barley/soya group (£2.96/head); the cheapest diet was the Barley/WDDG diet (£2.57/head) thus achieving a saving of £0.39/head
6. Estimated supplementary feed costs for ewes fed poorer silage were calculated to be approximately twice those calculated in this study resulting in a cost differential between the most expensive and cheapest rations of £0.80/head

The Challenge

Diets for pregnant ewes generally include some soya bean meal to provide the high quality protein needed to meet digestible, undegradable protein (DUP) requirements, and soya is often included in creep feeds for lambs and various other mixes.  However almost all soya is imported into the UK from South America and there is a need to evaluate other protein sources that can be grown in the UK to improve the long term sustainability of UK sheep production. Anecdotally some major retailers have expressed concern over the use of soya in ruminant diets and would prefer to see the meat they purchase in the future to have been produced without the need for soya.

The Project

• To compare alternative protein sources (beans, rape, wheat distillers grain) to soya bean meal for pregnant ewes on TMR
  To demonstrate the benefit of EID in collecting data
• To follow the performance of the lambs through to sale

This will provide information for a growing number of TMR feeders on how to provide high quality and sustainable protein to pregnant ewes.  It will also provide lamb performance data to see if there are any effects on diets during pregnancy on subsequent growth rates and days to slaughter.

Six treatments (soya, beans, soya and beans, rape, WDDG, and WDDG and soya) will be evaluated as part of a grass silage and fodder beet based TMR.  There will be 40 ewes per treatment, and ewes would be randomised and allocated by age.  All animals will have EID tags, and the lambs will be weighed at birth, 4 and 8 weeks, weaning and sale.