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This article was published in 1956
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
PLEURO-PNEUMONIA IN CATTLE
Tail Bleeding For C.F. Test
M. R. BARRY, B.V.Sc., Inspector of Stock, Albury.
Bleeding from the tail is much simpler than from the jugular vein unless facilities are very good. The cattle usually bleed freely and the blood clots well, giving a good supply of serum.
The site of choice is on the ventral surface of the tail in the midline and about eight inches from the butt. There is a venous supply just under the skin and an artery deeper. The anatomy of the cow's tail is apparently similar to that of the horse; for which there is a drawing in Sisson (Fig. 579, page 682 in the Third Edition).
It usually is possible to feel the pulse of the middle coccygeal artery in dairy cows. A right-handed person may place the left thumb ventrally and wrap the fingers around the tail and feel with the thumb for the blood vessels midway along one of the coccygeal vertebrae. This provides a good grip of the tail and allows it to be bent so that the ventral surface is convex. The incision is made just anterior to the thumb. Sometimes the blood flows better after slackening the grip on the tail and allowing it to hang more vertically. If there is not a sufficient flow a second incision may be made.
The writer uses a bone chisel, ⅜ inch wide, bevelled both sides, of stainless steel. Having located the site of the blood vessels with the left thumb, the chisel is positioned with the cutting edge at right angles to the midline of the tail, about a quarter of an inch anterior to the thumb, and pressed hard quickly so that the chisel enters at right angles to the bone. The tail then is held loosely in the left hand and the blood flow directed into a bottle held in the right hand. While incising, the blood bottle can be held by the cork between the teeth, or by an assistant who takes the chisel.
A bucket of water, a wet cloth and a dry cloth are handy to clean up the excess blood from bottles, chisel and hands.
If the tails are dirty or daggy, a straight-edged boning knife is useful to scrape the ventral surface before bleeding. A certain amount of dust does not seem to interfere with the test as long as no water enters the blood bottle.
Except on studs or dairies there does not appear to be any need to control haemorrhage. When the tail is allowed to hang the edges of the incision come close together, and the first of these usually is clotted or only dripping before the race or crush is finished. Where control is desired a length of wet binder twine about 18 inches long can be tied tightly once around the tail anterior to the incision and tied with the first half only of a knot. The twine stays tight due to friction while wet and loosens as it dries out. The owner can pull the twine free in an hour or so, when bleeding has stopped. This is no problem on a dairy. A beef man tends to think that the amount of haemorrhage is not worth the time and trouble involved in tying on twine and handling again to pull the twine off later. Many thousands of beef cattle have been bled in Victoria without any control of haemorrhage and suffered no ill-effect.
The chisel provides a good grip even when bloody, does not blunt if it hits the bone, is easy to clean, is safe to use and is not damaged if dropped in the crush. The writer found it better than a scalpel, although such can be used equally well.
On small mobs one man can bleed, label and brand; but on large numbers it is better to have—
1 man bleeding.
1 man handing up empty bottles, labelling filled ones and recording.
1 man branding, clipping or painting the cattle.
With such a team it is possible to bleed one per minute, or better, providing the cattle can be kept up. With fire branding the irons may become too cold and slow down operations. Clipping numbers is quite quick and overcomes the problem of cold irons and bushfire risk.
The following "shorthand" system can be used:
| 1 | ⎮ |
| 2 | ⟩ |
| 3 | — |
| 4 | ∕ |
| 5 | ∖ |
| 6 | ⟨ |
| 7 | ⦢ |
| 8 | = |
| 9 | ≡ |
| 10 | × |
| 11 | ⎮⎮ |
| 12 | ⎮⟩ |
Where vaccination for P.P.C. is required at the same time as bleeding, it is better in the case of dairy cows or cows with calves at foot, to bleed from the jugular vein and vaccinate at the tail because such animals may show a big reaction to the vaccination, with sloughing of the tail; some very badly. With beef cattle, however, it has been found quite satisfactory to bleed from the tail and vaccinate simultaneously. The team is increased by one man, who vaccinates full-time.
Tail bleeding can be done in any race, yard or crush where cattle can be jammed in and their tails pulled through the rails. Dairy bulls can be bled without restraint in a yard fairly full of cows.