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

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