Lambs grazing high sugar ryegrass (HSG) grow faster and heavier than lambs grazing a standard ryegrass (SRG), according to a two-year trial on three farms in the southern South Island.
The trial results show a consistent improvement in lamb performance when grazing a mix of AberMagic and AberDart HSG cultivars compared to lambs grazing a popular and high performing SRG cultivar.
The significance of the findings for farmers is that faster growing lambs could help to improve their financial returns.
The research was commissioned by leading meat processor and exporter Alliance Group and Germinal Seeds in partnership with Sainsbury’s supermarkets in the UK and was designed to help farmers make informed decisions on the use of high sugar ryegrasses on their farms.
The study, carried out by Dunedin-based agricultural science company AbacusBio, indicates that grazing lambs on HSG could enable farmers to bring forward a flock’s finishing date.
According to the research, lambs grazing HSG had an average increase in daily gain of 31 grams per day, which resulted in an increase of 400 grams in carcase weight at slaughter and an additional 200 grams of meat yield using Alliance Group’s VIAscan technology.
The increased growth of HSG lambs resulted in more lambs reaching target weights with 75 per cent of the HSG grazed lambs successfully finished in the 2013/14 production season compared to 62 per cent of the SRG lambs.
Murray Behrent, general manager livestock at Alliance Group, says the research provided Alliance Group suppliers with practical information about HSG and its potential for boosting on-farm production.
“The research shows that there are productivity gains from lambs grazing HSG and the resulting increase in meat yield could have significant benefits for both farmers and our customers.
“While there is a strong case for farmers in the southern region to consider using HSG on their farm, it’s important to note that the trial was an animal performance trial and was not designed to provide a comprehensive outline of plant performance.”
The trial report suggests further studies be undertaken to compare other cultivars across multiple regions to fully understand the effect of HSG on lamb performance.
Similar work supported by Sainsbury’s in the UK has shown similar results with HSG having a positive influence on growth rates.
Philip Hambling, agriculture manager at Sainsbury’s, says the results for these trials are important for farmers wanting to make an informed decision about using HSG varieties to improve performance in similar systems.
“We’ve been working closely with our sheep farmers in the UK and New Zealand for some time and we’ve long discussed the potential of high sugar grasses to help improve production and farm-gate returns. Setting up these trials was an important step to test if they can perform in New Zealand as well as UK systems.
“Earlier finishing, better yielding lambs tend to be better for returns, productivity and quality so the results suggest they can benefit our farmers and our customers.”
This also offers the potential to reduce the environmental impact of lamb production, he said.
AbacusBio research consultant Hadyn Craig agreed that the research would support farmers when making decisions on selecting cultivars for finishing lambs.
“This study indicates that HSG compared to SRG provided increased lamb growth rates which enabled a higher proportion of lambs to be finished earlier. More lambs finished earlier means feed can be utilised for other purposes, such as increased feeding of capital stock or the finishing of store animals.
“These results are a positive for HSG, however it is a comparison between HSG and a single SRG cultivar and further work would be required to understand the comparisons against other cultivars.”
The trial found the average daily weight gain of the trial’s HSG-grazed lambs was 17 percent ahead of the SRG-grazed lambs and their estimated carcase weight was 19 percent ahead at the time of processing.
David Kerr, Germinal Seeds brand manager, said the trial results showed a clear link between HSG pasture and improved livestock performance.
“Research such as this provides farmers with scientific evidence confirming a weight gain of lambs on HSG pasture in New Zealand farming conditions. It backs up the feedback from farmers saying their cattle, sheep and dairy cows perform better when grazing Aber HSG paddocks.”
Alliance Group and Germinal Seeds commissioned the study following discussion between Alliance Group and Sainsbury’s about the possible benefits of HSG to farmers supplying the retailer’s supply chain.
Pasture growth rates from mid-November to the end of April ranged from 28 to 45 kg dry matter/ha/day but there was no significant difference between the treatments and therefore the differences in lamb performance could not be attributed to differences in grass yield.
Material supplied by Alliance Group.