The effect on lambs when docking their tails at different lengths is to be studied in research trials by Alliance Group.
Tail docking is thought to help reduce dags and fly strike, a major cost to the sheep industry.
However, there is limited objective information or research on the benefits, or otherwise, of the practice.
Now, Alliance Group, with support from the Ministry of Primary Industries' Sustainable Farming Fund, UK supermarket Sainsbury's and Beef + Lamb New Zealand, is undertaking the first research of its kind into docking in New Zealand with a three-year trial.
The first trial at the Riverton farm of Alliance Group client Euan Templeton, a member of the company's Pure South Producer Group, will examine the impact of different docking practices or no docking on lamb growth, carcase weight and yield.
The second trial at two farms in mid-Canterbury and Southland will study the effect of different tail lengths on lamb productivity, economic return and the welfare of the lamb.
The study comes as Alliance Group reminds farmers they also need to dock tails to a certain length in order to meet New Zealand's animal welfare requirements. The recommended best practice is for tails to be left long enough to cover the vulva in females and at a similar length in males.
Murray Behrent, general manager of livestock at Alliance Group, said the aim of the research was to examine the productive, economic and welfare effects on lambs by docking tails at different lengths or leaving them intact.
"The results should provide suppliers with reliable information so they can make informed decisions on the most appropriate tail docking strategy.
"The current lack of objective information leaves New Zealand farmers vulnerable to concerns from international markets on the length of the tail. International retailers are now requesting evidence-based information which can be used to assure their customers that management practices such as tail docking are justified.
"Alliance Group does not penalise its suppliers on tail lengths. This trial is all about giving farmers information so they can make an informed decision on tail length best suited to their farming practice, however all docking must meet minimum tail length requirements."
During the trials, the lambs will be weighed during the docking, weaning and slaughter process. The lambs' dags will also be scored during weaning and slaughter while fly strike will be recorded before any crutching or spray treatment.
"Welfare issues that concern consumers have the potential to become barriers in international markets so they lie at the heart of economic sustainability of sheep farming in New Zealand," said Mr Behrent.
"This project will provide suppliers with appropriate tail docking strategies by understanding current practices, determining the drivers behind docking decisions and quantifying the effects of different docking practices."
Alliance Group and its research partner AbacusBio will be working with tailing and shearing contractors as part of the trials.
As part of the research a best practice booklet on tail docking will be developed and distributed to suppliers. The initial results of the research are expected to be released in April 2013 with final results of the two trials published in March 2014.
