Sunday, 21 June 2009

Vaccinating Sheep – An Extreme Learning Experience

On Tuesday we vaccinated our recently purchased sheep. The decision to do this was based on advice from many sources, including the vendor (who used the same product we used on the sheep in 2008), the Lachlan Livestock Health and Pest Authority veterinarian, and one of my key mentors.

While we did manage to get the job done on the day there were more ‘school of hard knocks’ learnings than we would have liked. The rest of this blog posts describes some of the main experiences.

Product Choice
The vaccine product we chose was “Cydectin Ewe Guard 6 in 1 Vaccine and Wormer for Sheep” which is manufactured by Forte Dodge Australia Pty Limited based at Baulkham Hills in the Sydney metropolitan area. The carton states “For the prevention of 5 clostridial diseases and cheesy gland, and the treatment and control of internal parasites, nasal bolt and itchmite in sheep”. Whilst this product is expensive at around $130 for a 500 ml container the fact that it provides protection against so many things SHOULD result in savings in the long term from reduced stock losses and labour in reducing the number of treatments.

The vaccinator we used was a “Quickshot™ 5 ml Vaccinator” manufactured by NJ Phillips Pty Limited of Somersby in NSW, and distributed by Pfizer Animal Health.

Preparing the Vaccinator and Feeder Tube
We followed the instructions to the ‘T’, which included sterilising the vaccinator and feeder tube by boiling in water for 20 minutes.

Coaching in Vaccinating Sheep
I had no previous experience in injecting sheep (or anything else for that matter) and so made arrangements for a neighbour to call in at 8.30ish to provide me with some coaching on vaccinating. Our sheep average around 65 kg so I set the syringe dosage to the recommended 3 ml calibration.

Mustering the Sheep
I was confident we would have no trouble getting the sheep at least into the large holding pen annexed to the sheep yards without dogs for several reasons: the yard was well grassed and had not been grazed for over 9 months meaning the sheep would enjoy moving onto fresh pasture, the sheep had not been into the area before and so would have no stress related memories, we had no trouble doing this with the wethers we had on agistment last year, we were confident of our own skills and could draw on the experience of moving the sheep a few times on the farm already. With this and the fact that we wanted to minimise the time the animals were in the yards we set off to get them in from the Front Paddock which adjoins the yards at around 8.00 am.

We had no trouble getting them into the holding yard, but it was from there a small challenge presented itself. Two obstacles became apparent: there were very tall stinging nettles in the yard AND our new chooks were in the background line of site at the entrance to the yards proper. Both presented a barrier for the sheep. We did not have them in the yards proper by the time the neighbour turned up, but with all 3 of us on the task we did achieve the objective soon enough. It was during this process that our neighbour spotted what appeared to be a small area of body fly-strike on the back of one of the sheep. On close inspection the area looked to be still active. We did not have any treatment products for fly-strike on hand.

Getting Going with the Vaccinating
Our neighbour was most helpful in trying to get the vaccinator working properly but the gun was doing two things of concern: leaking, and allowing a small quantity of air into the chamber. After completing the first pen-full in the drenching race I was sufficiently confident to ‘go it alone’ and our neighbour left and got on with the rest of his normal daily activities.

After we had done another pen of sheep we decided to take a break and have a ‘cuppa’ and to have a very close look at the vaccinator to see if I could find the cause of the air and vaccine leak. I’d tried a couple of times to tighten the fittings a few times. The cause of the problem became apparent: the tube from the vaccine container into the base of the vaccinator gun had not sealed properly due to the sterilising process softening the feeder tube. We replaced the tube and had no further problems in this respect.

The sheep with fly-strike was in the second pen of sheep we’d just finished, so we put it into the tiny yard that leads into the drafting race (with a few other sheep for company) to deal with later on.

After we’d finished another couple of pens I felt quite tired, mainly I suspect due to anxiety from doing something completely new, coupled with the physical aspects of moving along the sheep in the pen, and making sure I had them in the best position possible (for both the animals and me) to inject them under the skin at the base of the ear. In good “Aussie spirit” I decided to ‘soldier on’, rather than take a long break.

The Intense Time Kicks in
We had completed about ¾ of the sheep when I happened to notice that it was likely I might not have sufficient vaccine to finish the mob, which was puzzling as I’d calculated that there would be ample left over even allowing for wastage. It was at that point that I looked at the calibration on the vaccinator and was aghast to notice that it was set at 3.5 ml rather than 3 ml. Yes … it was obvious we would not have enough and that I’d need to go to town for more. I was angry with myself. After doing another two sheep I then knew that it was best to stop (even though I was only about half way through the pen) in the interest of my own well-being, not to mention the sheep who should not suffer due to my attitude.

What occurred next was pretty intense … and reflects poor decision making on my part during a period of high stress.

I was holding those sheep in the pen that had been vaccinated apart from the others while Jan moved sheep in the larger yards to make room for us to let those that were in the drenching race out with the others – treated and non-treated. When Jan had managed to get what I was thinking (in my confusion) were the non-treated sheep from the back of drenching race into a separate pen I then opened the gate at the front of the drenching race and started letting the sheep I thought were the treated ones in with the large lot that had been treated. Jan then (entirely appropriately) asked why I letting non-treated sheep in with the treated ones. I quickly realised my error and closed the gate, but by that time about 10 or so non-treated animals were in with the treated ones. They are impossible to distinguish.

I got my thinking a bit clearer. We were both moving a small lot (10 or so) of treated animals around to put back in with the large lot. All but one went through the gate into the next pen, but this one turned back for some reason. Finding itself isolated and (due to yard design) not being able to easily see the open gate it reacted under stress and attempted to jump the fence to get with the rest of the sheep. In the process one of its back legs got caught in the top row of the weldmesh below the pipe that runs along the top of the fence and I watched in horror as the sheep’s leg broke under the strain, with the sheep being unable to free itself. I quickly jumped to the other side of the fence and lifted the sheep back over the fence and onto the ground. It sat there totally still and in what I’d considered to be pain induced shock.

Jan and I do not want animals to suffer. I’d never heard of anyone setting broken sheep legs before. We knew the sheep was pregnant and to expect it to have to deal with a broken back leg and have, and raise, one of more lambs seemed a ‘huge expectation’. It was also not cost effective to get a veterinarian out to look at a single sheep. The decision we made was to ‘put the sheep down’ in a very quick manner, which I did out of the sight of the other sheep.

Time to Get More Chemical
After killing the injured sheep we went to town and purchased more vaccine, more spare needles and some fly treatment chemical; leaving the mob in the yard. Given we only needed to treat one sheep for fly-strike I ended up buying a can of “Extinosad – Aerosol for Wounds” which is “For the treatment and prevention of blowfly (Lucilia cuprina) strike in mulesing, marking and other wounds of sheep, including strains resistant to organophosphates. Contains antiseptic.”

Finishing the Vaccinating
After returning to the farm we finished vaccinating the rest of the mob without incident. We also caught the sheep that we thought had a small amount of fly-strike and, after removing the wool surrounding the strike area using some shears I had, we treated the area with Extinosad. We were pleased to note that the fly area did not appear to be still active.

Releasing the mob and tidying up
After the sheep were treated we released them all into the Airstrip Paddock. This paddock has not been grazed for over 9 months and so is what is describes at ‘clean’ of worms and such like.

I took the sheep carcass to the Saddle Paddock and left it on some bare ground. Whilst there may well have been other ways to use the carcass at least in this way the organic matter will be returned to the soil ‘in the circle of life’.

Events Subsequent
We’ve since learned that it is not unusual for sheep to break back legs trying to jump fences in yards AND that it is common practice to put splints on the legs, with common methods being stiff cardboard or polythene pipe held in place with string. Recovery in lambs is very rapid, and sheep suffer no long term impacts aside from the occasional limp.

We are considering contacting the manufacturers of the vaccinator and vaccine to alert them to the problem we experienced with the leakage at the base of the vaccinator due to softening of the tube during the sterilisation process.

We will also obtain a good skinning knife so that if it ever proves necessary to put a sheep down in the future we will be better able to salvage whatever is appropriate.

In Summation
Far from the best of days, however we are now much wiser. Two good points: I did manage to complete the vaccinating without injecting myself, and Jan did a marvellous job watching and remembering which sheep had been vaccinated on the odd occasion that sheep ran back and forward past me whilst I was doing the vaccinating.

1 comment:

Anonymous said...

Mate, you should have use a a modified Si ro mark to tell which had been done. Head down the local pub and have a chat with the old locals.Use a webcam and record the details for posterity and reference. Have done this with my father.Now deceased.Great way to preserve working knowledge which is both practical and beneficial to others.

Have a pleasant day.