Deer industry action on Johne’s lauded

01-07-2009 | Not Specified

In June I had much closer contact with the deer industry than I usually do.

About 20% of my clients run deer as part of mixed species farming systems and I deal with them little differently from how I deal with sheep and cattle. Their drivers of production are clearly defined and they have some of their own animal health peculiarities. Feed is still the key to production and animal health outcomes.

A disease that has infiltrated deer herds is Johne's disease. No doubt cattle and sheep have provided the source, but the expression of the disease is quite different. Some mature deer do scour and waste away the same as sheep and cattle but an acute form takes out young deer as well. For some herds the losses have been huge and the protective effect of reducing stress that can work so well in at least sheep flocks does not appear to apply as well.

My increased interaction with the deer industry has been through that industry's attempt to manage this disease.

I have been so impressed with the resolve and commitment in that industry to manage this threat. It puts the sheep and beef industries to shame. The only equivalent programme in these industries is the current BVD control one in cattle. The deer initiative is very lateral thinking, has a global perspective and is not limited by vested interests. Funding is not a major limitation yet it is only a small industry.

Drench resistance in all of our grazing ruminants is right up there in deserving the same inputs. Yet getting industry buy in, cooperation and funding remains a major limitation to making progress. Deer are included in this shortcoming of developing a capability to manage this particular threat.

A major reason for these differing approaches is a human nature one. An immediate visible and measurable cost to production will always win in attention grabbing over one that lurks on test results. Throw in there some market access threats and the attention is all yours. The fact that only the deer industry appreciates the market implications of a disease in its livestock while exactly the same implications apply to sheep and cattle confirms the more global and market focused approach that this industry has.

Despite long periods of low profitability in deer farming this industry has maintained a very solid core of productivity, research and product development. This is only the result of personalities committed to achieving a vision. An upcoming vote for sheep and beef farmers will test their resolve to achieve a vision. Creating, presenting and personalising that vision will be a key to getting that commitment.

Johne's is blamed for most wasting sheep. For many properties this is probably so, but for a majority it is not. For North Island wasting sheep the causes are varied, with Johne's being just one likely cause. Basic defects such as poor teeth (worn or infected) or chronic lameness are still common as causes of wasting ewes that I see. Being very old is often enough to be the cause of very poor condition without any other major faults being present. Some flocks have very old ewes in them, especially when age culling is done purely on teeth wear.

Chronic lung infections and liver damage from facial eczema or liver fluke are the two very common causes of those very tail end ewes. The very strange cause that occurs on only specific properties is intestinal cancer. Why does it occur on a few properties and not most? On those properties it can be a major cause of loss.

Worms can easily be a big player but probably not as much as often blamed for. Most tail end ewe mobs are drenched excessively if high numbers of worms are present. But it is likely that the worms are there as a consequence of some other debilitating intrusion. Johne's typically does this.

The cause of wasting and dying ewes must be known before any actions can be taken to manage that loss. Just jumping in and vaccinating against Johne's in many flocks would not reduce the losses enough to justify the cost of that vaccine. Most liver-based causes can be prevented and these ought not to be present. The chronic pneumonia cause is one that the industry has failed to address. These ewes are the remnants of lamb or hogget pneumonia that plagues our sheep flocks. Losses occurring in mature sheep will be just the tip of the iceberg of the losses that will have occurred earlier. In some flocks rotten lungs are the major cause of wasting or dying ewes.

The intestinal cancer cases and the molar teeth abscessation are causes that are hard to manage because there are no specific actions that can be taken to reduce their incidence. In my experience though, these are more common in stressed flocks.

There is no question that a potent key to lifting flock performance is to minimise the number of ewes in a flock that are light. This includes those ewes classified as wasting. Tail-end drafting, diagnosing causes of wasting and implementing management programmes around these is very profitable.

One dramatic example of the success of such an approach was displayed at a recent East Coast field day. A well-managed feed programme with a focus on minimising the tail end lifted the flock lambing by 25%. It was one of the best examples that I have ever seen of appropriate feeding being used to gain maximum gain. I use the word appropriate because these ewes were at times lighter than they had been previously but were fed at the right times. This was worthy of an award.

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