Evaluating a bi-crop of peas and beans to replace bought in protein for pregnant ewes and growing and finishing beef cattle

One of Robert Lyon’s main drivers at Lower House Farm is to increase farm resilience while reducing the farm’s carbon footprint. The growing of barley at Lower House Farm provides enough starch energy to feed the 500-600 pregnant ewes and grow and finish the 130-150 Belgian Blue heifers on site annually. However, a protein concentrate blend is mixed with the rolled barley to make up the protein shortfall in the ration. 

To work towards self-sufficiency in protein, Lower House Farm will trial incorporating bought in peas and beans in the pregnant ewe ration for winter 2023/24 and use home-grown peas and beans in winter 2024/25. The bi-crop of peas and beans will be crimped and incorporated into 2024/25 winter rations for both beef cattle and pregnant ewes.

With Lower House Farm growing 3.6ha of barley annually, the introduction of a pulse break crop will fit well into the rotation. Being a nitrogen fixing crop, no nitrogen fertiliser would be required for the following crop, and the different tap root type structure may provide benefits to soil structure.

Peas and beans can be used in ruminant diets as a useful source of energy and rumen degradable protein. Peas contain around 26% protein in the dry matter and beans around 29%. They are both high in energy, containing 13.6 to 14 MJ/kgDM with over 40% starch. The level of inclusion in cattle and sheep diets will largely depend on the level of protein in the base forage and the need for additional fermentable carbohydrates. 

Analysis of forage and other feeds (home grown barley, protein concentrates, peas & beans) will be used to formulate the winter diets for 2023/24 and 2024/25. The financial impact, carbon footprint and animal performance will be monitored and analysed to compare the incorporated peas and beans diet with the control diet containing soya. The cost of buying in, in comparison with home-grown peas and beans will also be assessed. 

Through driving improvements in sustainability, the project will contribute to the Sustainable Land Management outcomes by:

• Reducing the farms greenhouse gas emissions
• Support improvement in maximising carbon storage and sequestration whilst reducing the whole-farm carbon footprint
• Maintaining and enhancing the ecosystem at Lower House Farm
• Contributing to high flock and herd health and welfare

Peas and beans can be used in ruminant diets as a useful source of energy and protein. Peas and beans on average contain around 26% protein in the dry matter. They are both high in energy, containing 13.6 to 14 MJ/kgDM and provide an excellent source of starch too. For the purposes of this trial crimped peas and beans were purchased from another farm.   

What was done

180 ewes were selected from the flock and six groups of approximately 30 twin bearing ewes were allocated to one of two dietary treatments:

1. Standard diet - TMR based on grass silage, maize and a 50% crude protein concentrate
2. Peas and beans – TMR based on grass silage, maize and crimped peas and beans 

Three groups of 30 ewes were allocated to each treatment and were housed on opposite sides of the same shed.

The majority of the ewes and lambs were turned out to grass within 36 hours of lambing. All sheep were grazing on the same fields. The weather was challenging through lambing and early lactation with many wet and cold days and a number of lambs succumbed to joint ill. 

TMR Rations

The silage, peas and beans were analysed to form the below diets for both groups. Diets were designed to deliver the same amount of Metabolisable Energy and Metabolisable Protein.

TMR diet - Standard

TMR diet – Peas and beans

Ewes received 25g of mineral per head/day on both diets.  

Total estimated feed cost per ewe for the 7 weeks prior to lambing was £14.25 on the standard diet and £13.90 on the pea and bean ration.   

Animal performance

Lambing started on 5 March 2024. All Brix colostrum readings taken for both groups were above the recommended level of 26.

Live weight gains for all lambs reared to 10 to 13 weeks

There was a significant difference in DLWG between the treatments with lambs growing at about 40g/day faster when born to mothers that were fed peas and beans rather than the standard concentrate mix. 

Conclusions

This pilot trial has demonstrated that crimped peas and beans can be successfully used in TMR diets for pregnant ewes with an advantage to the pea and bean diet in the order of 40g DLWG/lamb per day. This amounts to additional weight of about 2.8 kgLW over 10 weeks, which at current prices (SQQ of 654.50p/kgDW 7/9/24) is worth £8.61, with these lambs also leaving the farm earlier and releasing grazing for ewes.