Understanding the genetic basis for slow plant-mediated proteolysis in festulolium hybrids

Research Parnter: Aberystwyth University (IBERS)

Project Duration: October 2010 – September 2013

Category: Beef & Sheep

PhD Student: Sally O’Donovan

Sally O'Donovan
Ruminant agriculture is responsible for considerable amounts of environmental pollution producing greenhouse gases such as methane and nitrous oxide and the release of waste nitrogen into the soil and water courses. The aim is to increase the efficiency of ruminant nutrition through developments of high quality grasses that use plant protein more effectively and reduce nitrogen losses.

The problem:
Forage from current ryegrass cultivars consumed by ruminant animals is broken- down too quickly in the rumen causing an excess of nitrogen which is excreted as harmful environmental waste. Freshly eaten forage is broken-down by rumen microbes but recent studies have shown that this process is highly inefficient due to plant-mediated “shock responses to hostile rumen conditions such as high temperatures (39°C), no oxygen, and total darkness. The consequence is an imbalance between protein availability and energy required by rumen microbes that leads to a poor protein capture by the ruminant.

Field trial of ryegrass x Mediterranean fescue hybrids
The solution:
Protein breakdown of Mediterranean fescue in the rumen has been shown to be slower than its close ryegrass relatives but little is known why this is or how this process may be reproduced. By combining ryegrass and fescue genomes I aim to slow down the rate of breakdown of forage grass protein. Mediterranean fescue is adapted naturally to high temperatures and thus it is hypothesised that this contributes to previous findings that indicate its protein breakdown to be four-times slower than ryegrass, under simulated rumen conditions. Hybrids of differing ryegrass and fescue genomic complement will be compared to optimise expression of the fescue trait whilst also providing forage that is productive, palatable, and nutritious.



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