THE RELATIONSHIP BETWEEN ABNORMALITIES DETECTED IN LIVE LAMBS ON FARMS AND THOSE DETECTED AT POST-MORTEM MEAT INSPECTION

A prospective longitudinal study of diseases of lambs born in December and January and housed through to slaughter was carried out on three hocks (A, B and C) between 1989 and 1991. In the first year of the inv estigation (1989-90) three cohorts of approximately 80 lambs were exam ined in detail on a regular (weekly or fortnightly) basis. This involv ed over 2000 examinations and at least one clinical abnormality was ob served in each lamb. In the second year (1990-1) the farmers were aske d 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 la mbs that were slaughtered received at least one treatment. The carcase s and visceral organs of lambs from each flock were observed after sla ughter. There was no association between the abnormalities observed du ring routine examination of the cohort lambs (year 1) and those observ ed at post mortem meat inspection. However, in year 2, in lambs from f lock A, there was a significant association between lambs treated for arthritis or pneumonia on the farm and the presence of arthritic or pl euritic lesions, respectively, post mortem. In both years of the study lambs which were older when slaughtered were significantly more likel y to have pleuritic, pneumonic or arthritic lesions at meat inspection . It was concluded that routine examination of groups of lambs is an i nefficient and possibly ineffective method to identify lambs with lesi ons 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.