Project Team: Aurelie Aubry, Francis Lively, Melanie Flexen and John Archer Background:  The sheep industry is a major contributor to the Northern Ireland GDP accounting for 19,511 farms, 78% of the total number of farms recorded in 2015 (DARD, 2015).  However, low profitability in sheep production enterprises is a real threat to the sustainability of this industry in NI.  The main factors that directly affect the economic and biological efficiency of sheep production are (1) feed requirements, (2) reproductive performance and (3) progeny growth rate.  Grazed grass is the cheapest form of...