Day 020 - 28 Jul 94 - Page 20
1 our experience, for instance, we have found birds have not
been stunned when we have subjected them to 75 milliamps
2 per bird using a 50 herz sinosoidal AC. They have shown
immediate escape behaviour on taking them out of the water
3 bath. Yes, there is a risk. That is with a brief
application of current.
4
Q. What do you mean by "brief"?
5 A. It was less than three seconds. It was two to three
seconds, I think, if my memory serves me correctly.
6
Q. Are you of the view that currents of less than 75
7 milliamps should never be used?
A. When using a 50 herz sinosoidal AC, I am.
8
Q. Do you say that does not bear any relation to the type of
9 stunning machine?
A. I think the answer at the moment is that I do not
10 know. We are doing experiments on other waveforms at
Bristol at the moment. I cannot give you a definitive
11 answer what the minimum recommendation would be for a 500
herz DC at the moment, but we soon will be able to.
12
Q. Right. Is it not likely that a DC current is less likely
13 to induce cardiac arrest?
A. It depends on the frequency. I think frequency is
14 more important than whether it is a direct current or an
automating current, but a high frequency, such as 500
15 herz, is very unlikely to induce a cardiac arrest, even at
high current levels.
16
Q. So certainly at low current levels it is not going to?
17 A. That is correct.
18 Q. Is it not more likely that some birds are not going to be
stunned at all?
19 A. The lower the current you give a bird, the less likely
it is to stun, yes.
20
Q. This is a paper I wanted to go through. There are a
21 couple of points in it. I have actually got four copies
of this one. (Handed).
22
MR. JUSTICE BELL: I think this is a paper of yours?
23 A. Yes.
24 Q. I will put it at the back of your orange bundle in due
course. Yes.
25
MS. STEEL: On page 217 of that, in the middle of the section
26 on "Recovery experiment", it says: "The average time to
return of tension in the neck muscles tended to increase
27 with increasing stunning current. Of greater importance,
however, was the increase in the lower limit of this
28 measure with increasing current. When 45 and 60 mA were
used some birds failed to lose neck tension and based on
29 this criterion they were not stunned." Then when a higher
current was used neck tension was lost for a minimum of 52
30 seconds. Was this the study you were referring to a
little while ago?
