Processor seeks answers over lamb growth rates

A farmer hunch that shorn lambs grow faster than woolly lambs will be put to the test in a fivefarm trial by the Alliance Group.

The meat processor and exporter carried out an initial study at Mt Linton Station in Southland where shorn lambs were observed to grow marginally faster than unshorn lambs.

Some farmers believe that shearing lambs destined to be slaughtered can result in increased growth rates; however, until now there has been limited research.

Alliance Group and its research partner, AbacusBio, are testing the theory at trials to start at Mt Linton Station next week, two other farms in Southland and others in North Otago and Castlepoint in the North Island.

The extended programme will run to about April and each farm will have 400 lambs in four mobs of the same breed receiving different treatments. One mob will be shorn, another bellycrutched, another brought in but not shorn and a fourth mob will remain woolly and on pasture.

Lambs will be weighed before the trial starts and changes will be monitored every three weeks until all lambs have been processed. The study will also track local conditions such as temperature and rainfall.

The lambs’ carcass weight at the time of slaughter will be used to assess the growth rate and scans and measurements taken to assess their yield with a financial analysis completed to work out the costs and benefits of shearing lambs.

Alliance technical officer Hayden Peter said additional trials would confirm whether shorn lambs performed better after minimal gains were observed in last year’s trial in carcass weight differences.

He said the gain might have been small, but was enough to justify investing in further trials

‘‘The farmers often talk in the summer months that shorn lambs perform better than woolly lambs so we held a trial to investigate . . . Last year there was a slight advantage of shorn lambs over woolly lambs. It was minor, but we are keen to follow that with more trials.’’

Peter said the success of the trial would come down to the cost of shearing being outweighed by heavier shorn lambs receiving better prices.

He said the different trial locations would pro- vide stronger data confirming observations were correct.

‘‘Farmers often say they do better, but don’t quantify. I guess one to two kilograms of grade weights over a period of time [is the usual answer], but we need data to back up these statements and that’s why we are investing in these trials.’’

Livestock general manager Murray Behrent said the results of the research could have important implications for how suppliers managed their stock. The trials were among other research by the meat processor to help suppliers improve farm production, he said.

if anecdotal Weighty issue: Trials will determine whether shorn lambs put on more weight than woolly lambs.