Lower liveweight gains for beef finishers fed wholecrop in lieu of quality grass silage
Take Home Message: Compared with good quality grass silage, feeding lupin or vetch cereal bi-crops will increase forage intake but reduce daily liveweight gain by 26% and increase the days to slaughter
Legume/cereal wholecrop silages do not offer a suitable alternative to high quality grass silage for finishing beef cattle. “Finishing beef cattle offered legume/cereal wholecrop silage as the sole forage or in combination with grass silage had, on average, 26% lower liveweight gain relative to high quality grass silage,” said Queen’s University’s Peter Kennedy, presenting the results of a trial that compared the performance of beef finishers on different forage rations to delegate at this year’s British Society of Animal Science’s annual conference.
“In Northern Ireland, grass silage is the basal forage for beef cattle during the winter feeding period. Increasingly however, other ensiled forages are being considered due to their potentially lower cost and perceived conservation and nutritional attributes,” he said.
“Wholecrop cereals, such as wheat, have been shown to improve dry matter intake, but not animal performance and with increasing volatility in world markets creating major fluctuations in protein prices, interest has increased in home-grown protein sources.
“But limited scientific research has been undertaken on the role of legumes in combination with a cereal as a bi-crop for finishing beef cattle,” he added, explaining the rational behind his work.
His study, which set out to evaluate the effects of legume/cereal wholecrop offered either alone or in combination with grass silage on the performance of beef cattle, involved 80 continental-cross steers. These were allocated to one of 10 treatments, balanced for genotype, initial weight and farm of origin.
The five forage diets offered included solely grass silage (GS), lupins/triticale silage (L/T) and vetch/barley silage (V/B) offered either as the sole forage or in combination with GS at a ratio of 70:30, on a dry matter (DM) basis, legume/cereal wholecrop: GS.
The forages were offered ad lib once per day, following mixing in a paddle type complete diet mixer wagon, and supplemented with either 2kg or 5kg of concentrates per head per day. Daily intakes and fortnightly chemical analysis of forages and concentrates were used to calculate supplementation level of soyabean meal within treatments to stabilise protein intake.
“And we found that steers offered GS had significantly heavier final live weights compared to animals offered L/T, V/B and V/B:GS,” said Mr Kennedy.
“Steers offered GS had significantly greater carcass weights and carcass gains compared to L/T, L/T:GS, V/B and V/B:GS. And animals offered GS had a similar silage dry matter intake to L/T and V/B although significantly lower than L/T:GS and V/B:GS.”
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