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This article was published in 1941
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
TAKING BLOOD SAMPLES FROM CATTLE FOR COMPLEMENT FIXATION TEST FOR PLEURO PC.
By E. A. LUCAS. Stock Inspector. Maitland.
Paper read at Stock Inspectors' Conference. Sydney. June, 1941.
You have all probably bled dairy-herds, and this is comparatively a simple matter. However, some day you may get instructions, as I did, to trace the buyers of several big store cattle sales and blood test the cattle concerned as they had been in contact with pleuro. The agents were interviewed and it was found that 46 holdings were concerned and placed in quarantine by the use of Form 8 S.D. Act for 40 days in the first place, and Form 6 Stock Diseases Act for 60 days when you meet the owner. The 46 holdings had 2849 cattle running on them.
Form 9 S.D. Act was then used, ordering muster at certain times and dates and to certain yards. Form 5 would probably be more suitable, as this is mustering form. Some owners objected to the "order" wording, but as this test has aroused a great amount of antagonism amongst the cattlemen it is useless to ask them to muster, as we were definitely instructed to do the job, and that is the only way to get it done. One group decided not to muster, but, when I told them how pleased I would be if they could get away with it and advised them to show the order to their solicitor, who they had on the spot, he evidently told them to muster, because they did so.
Gear Required.-Strong head rope ¾-inch with spliced noose, half-inch rope with spliced noose for nose rope, and the same rope for neck rope with iron ring spliced in instead of noose. A "King" bleeding outfit with 2-inch needle and reemed out to take a needle with a bigger bore than usually used with this outfit. This needle must be kept very sharp. and If this size is used and kept sharp the operation is only a quick prick into the vein. The needle must be tightened into the frame with plyers. I much prefer this to the "Pound" needle which some operators use. This is a very strong thick needle about 2 inches long, but it is so thick that it is always blunt and seems difficult to sharpen. One operator who uses it says that you must shove it into the neck as if you meant to push it right through the beast, and that describes the action with this needle. By using the King outfit the job is very clean and no blood is spilt about; also it is quicker. Operators who use a needle and a bottle without the metal case to hold the bottles get blood everywhere, and you may have noticed the peculiar marks on the rubber corks. These marks are where these men hold the corks in their teeth while they grab the bottle to hold it under the stream of blood. For the actual operation you have two clean vessels with clean water in them. and a syringe to wash out the needle after each beast. If you can carry all your gear in a box and are lucky enough to be able to drive the car right to the yards, the box is very handy for a table. The cattle are now in the crush, one man ropes the beast, round the horns and ties him tight to the most convenient rail. If he is a poley beast you use a heavy halter. Another man puts the nose loop on and pulls him up tight: a third man puts the rope round the neck, and he must be smart and have the rope as far back against the shoulders as possible. The iron ring must be near the withers on the opposite side to whatever side you bleed on. He must pull the rope very tight, and if it is a few seconds before you arrive with the needle the jugular vein will stand out much better. Locate the vein with your thumb and pierce with a quick stab. As soon as the blood bottle is about one-third full withdraw the needle, cork the bottle and shake the blood out of the needle at once. dip the needle into clean water and shake again, then run more clean water through the needle with a syringe. All blood must be washed out to prevent clotting. At the next operation shake surplus water from the needle and it is ready for the next beast.
If you are using the proper needle and with smart men on the ropes it takes about three minutes a beast. We tried the "Bulldog" grips on some of the cattle, but they only seemed to tend to drive the cattle to fight against the control and they were abandoned in favour of the nose rope, which is much quicker to put on and does not hurt the beast, and saves a lot of rope, as they used to break the ropes frequently with the "Bulldog" and the station cattle would roar and fight till the "Bulldogs" were taken off. It is a fact that the beast that is fighting and heated bleeds badly. All private crushes in New South Wales are too wide and you have to bleed on whatever side you can get at the vein best, but if you can bleed on the right side and have the beast tied on the left side of the crush it seems to be the best. This job takes a lot of men: the beast has to be numbered with a firebrand on the cheek and his description taken. The taking of the descriptions is one man's job, and any particular spot or mark must be taken, as sometimes the brand may fail. The chemical branding was tried, but as it was not possible to clip the cattle with the clippers at our disposal this was not satisfactory. It may have worked all right if we had machine clippers. However, as the brands had to be legible for up to three months in some cases where reactors and suspicious reactors or anti-complimentary results occurred, it is better to brand with the firebrand and brand heavy. Especially is this the case when working with cattle that are all alike, such as Black Polls, Herefords and Devons.
In the cattle on the 46 holdings tested, reactors were found on seven holdings. In all there were 26 outbreaks of pleuro; the other 19 outbreaks occurred probably through contact with adjoining runs, and also there is considerable delay in getting the results of the test when such large numbers have to be dealt with. Cattle are bled one day and serum poured off the next day and another day to get to Glenfield, another day in advice of results, and if blood is taken on Friday it cannot go to Glenfield till Sunday. Sometimes it takes 14 days to get the results, and by that time some of the cattle are sometimes clinical cases or dead from pleuro. This unavoidable time lag is a prolific cause of spreading the disease.
Finally innoculation was decided on and 2856 cattle were innoculated as a preventive, and also on runs where the outbreaks had occurred CSIR vaccine was used with excellent results, using hypodermic syringe in the tip of the tail. If the test and innoculating is done at the same time it is essential to bleed the crush of cattle first, then wash your hands before inoculating and again before bleeding the next lot, as cases have occurred where abscesses have formed on the neck at the seat of bleeding, and it was surmised that the bleeding needle had been allowed to come in contact with the vaccine, probably from the operator's hands, with very objectionable results.
Judging by the variations in the wording of the results of the tests it must be a very difficult test to read. The reports run like this: "Negative, positive, weak positive, suspicious and tubes slow in clearing, anti-complementary," which latter means another test. Some reactor cattle were slaughtered and no visible lesions were found. This occurred in about six cases in 100 reactors. On the other hand, in one outbreak two cows died of pleuro and three others were bad clinical cases of pleura 18 days after they had given a negative reaction to this test. The test apparently at times fails to detect pleuro in its early stages. In this series of outbreaks the test was useless as a means of stopping the spread of the disease. If used simultaneously with innoculation it is useful, especially in dealing with dairy herds, but as stated above it does not always detect early cases.
The Department provided ample assistance by sending additional staff and the gear supplied was excellent. The pleuro started in the Maitland district in October, 1940, and two outbreaks have occurred in the last week of May, 1941.