A prospective longitudinal study of diseases of lambs born in December
and January and
housed through to slaughter was carried out on three flocks (A, B and C)
between 1989 and
1991. In the first year of the investigation (1989–90) three cohorts
of approximately 80 lambs
were examined in detail on a regular (weekly or fortnightly) basis. This
involved over 2000
examinations and at least one clinical abnormality was observed in each
lamb. In the second
year (1990–1) the farmers were asked to present sick lambs for
treatment on the farm. Farmers
from flocks A and B participated in this part of the study; a total of
97/1295 lambs that were slaughtered received at least one treatment.The carcases and visceral organs of lambs from each flock were observed
after slaughter.
There was no association between the abnormalities observed during
routine examination of
the cohort lambs (year 1) and those observed at post mortem meat inspection.
However, in
year 2, in lambs from flock A, there was a significant association between
lambs treated for
arthritis or pneumonia on the farm and the presence of arthritic or
pleuritic lesions,
respectively, post mortem. In both years of the study lambs which were
older when slaughtered
were significantly more likely to have pleuritic, pneumonic or arthritic
lesions at meat inspection.It was concluded that routine examination of groups of lambs is an
inefficient and possibly
ineffective method to identify lambs with lesions at slaughter. However,
lambs which have been
treated for disease, and the older lambs in a flock, had an increased
prevalence of lesions post
mortem and hence more detailed inspection of these animals would
increase the efficiency of meat inspection.
The relationship between abnormalities detected in live lambs
on farms and those detected at post mortem meat inspection