No silver bullet to fix foot rot

When it comes to foot rot - estimated as a $10million problem for New Zealand's sheep industry - there is no silver bullet.

But New Zealand Merino's (NZM) production science team, led by Dr Mark Ferguson, has made a major breakthrough in the FeetFirst project, providing ram breeders with a new tool to predict an animal's genetic resistance to foot rot.

It has been lauded as having the potential to lead to significant growth in fine wool production in regions previously unable to farm merino sheep.

Foot rot in sheep is a very complex disease. It is an infection that causes major changes to the hoof, resulting in lameness and loss of production.

A little more than four years ago, NZM embarked on an ambitious project to develop an estimated breeding value (EBV) for foot rot.

That work has moved through several phases to determine the best way to achieve the ultimate goal - a new way to find animals that are least likely to succumb to foot rot.

Investment by the merino industry was matched by the Ministry for Primary Industries through the Primary Growth Partnership programme.

Since the project kicked off, literally ''hundreds of thousands'' of merino feet had been looked at, Dr Ferguson said.

Drily suggesting that looking at feet had become ''quite addictive'', he said it was intriguing to see some sheep not getting foot rot and others, subjected to the same conditions, getting it quickly.

There was now a method that was working, which essentially combined genomic information with assessment of feet and predicting breeding values for foot rot.

The EBV was generated using phenotypic information collected from the fine wool central progeny test and individual studs that challenged their rams with foot rot, as well as genomic data from DNA samples.

Work was under way to improve the accuracy. The technology was still in its early days and it would take time for large numbers of foot rot-resistant rams to become widely available.

But it was now at the point where the team was confident that what it was doing would work, Dr Ferguson said.

The critical thing was there was ''not a silver bullet'' for foot rot and there never would be. If it was a single gene, then that would be perfect, but the reality was there were lots of different genes involved.

It was a slow process, but he had confidence in the pathway and the achievement made was well worth celebrating as an industry, he said.

Much investment had gone into the project, along with plenty of hard work from his team.

It had been estimated that the cost of foot rot was $10million but there was also a big opportunity cost for the economy if fine wool sheep were put into the ''crossbred zone''.

Genetics requiring fewer inputs were also going to be very important to New Zealand's farming future, he believed.

Farmer support had been ''absolutely paramount'' to the whole process right from the beginning.

Farmers had been enthusiastic and put their trust in an unknown system, backing the project without really knowing initially what the outcome was going to be, he said.

One of those farmers was Willie Jones, from Matarae, near Middlemarch, who has supplied sheep for the project.

Foot rot was ''definitely present'' on Matarae but it was something Mr Jones had been proactive about since returning to the property.

Merino ewes identified with foot rot were culled from the merino breeding flock and some natural resistance had been developed.

While there did not tend to be massive breakouts of foot rot, there were still some issues.

He agreed that one specific ''golden'' gene would have been great, but it was now essentially going to be a ''tool in the tool box'', as it was with all breeding values.

When farmers were purchasing rams, they were unlikely to focus solely on foot rot but, it gave them the ability, if they had a serious foot rot problem, to select rams that were more tolerant.

Foot rot was a ''pretty debilitating'' disease and, while it was early days, Mr Jones welcomed anything that might eventually eliminate or reduce the $10million it cost farmers.

For farmers like himself, where results had shown certain animals had some natural resistance, which led to selling more rams, then that was also positive, he said.

 

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