Day 019 - 27 Jul 94 - Page 45
1 best thing to do. You alternate between one antibiotic
and another antibiotic over periods of time such that the
2 micro-organisms do not gain resistance to one antiobiotic
when it is used over an extended period.
3
Q. Could the use of these antibiotics have any effect on
4 humans?
A. I am not competent to answer that question.
5
Q. If these antibiotics are used regularly then, can this
6 affect resistance to salmonella, for example?
A. Can I suggest you address that question to Mark
7 Pattison? He is more qualified than I am to answer that
question. He is a veterinary pathologist, a poultry
8 pathologist, as well as a poultry health expert.
9 Q. Would it not be safer to change the methods of farming and
the types of bird bred in order to cut out the risk of
10 lameness in chickens rather than relying on the heavy use
of antibiotics?
11 A. In the case of grades four and five where it is
associated with an infection, it is important to
12 understand how that infection actually takes place. The
supposition that Sun Valley have is that it occurs in the
13 hatchery. My view is that if you are taking a short term
strategy, then antibiotics is a good resolution. If you
14 are taking a longer term strategy, perhaps one should be
focusing upon hygiene within the hatchery. That applies
15 to gaits four and five, that is, severe lameness
associated with infection.
16
Now, your question or an answer to your question could
17 apply to the other grades of lameness, that is, grade 3,
for example. It is likely, but not certain yet, that this
18 could be associated with the selection pressure or absence
of selecting against leg weakness at the breeder level.
19 So it is at that sort of -- it is at grade 3 area where
improvements could be made in that capacity. Again that
20 is a long term strategy, not one that can be done
overnight.
21
Q. There are breeds available, are there not, that do not
22 suffer from these problems to such a great extent?
A. Yes. We have done some brief comparisons and there
23 are differences between breeds in terms of severity.
24 Q. Right. So something could be done on that front fairly
rapidly?
25 A. Yes, by breed substitution, that is absolutely right.
It would not cure the situation; it would not get rid of
26 it completely.
27 Q. But it would improve things?
A. Yes.
28
Q. The 93 birds that you did find had leg weaknesses -- what
29 type of leg weakness was affecting them?
A. In terms of pathology, we did not do any pathology
30 examination on those birds, so I cannot tell you in detail
what the structural problems were. We did not kill the
