A number of significant “storm” lines have been processed in recent months. As outlined in the Pig Hunter story, a plant in the lower North Island received a line of 293 lambs, by the time processing had been completed 263 were identified with Ovis, 38 lambs were condemned on the slaughterboard and another 18 the following day during further processing. At one point during processing consideration was given to condemning the whole line!
These lambs came from a property with a number of dogs present but the dogs were on a monthly dosing programme. Given the extreme level of infection across the mob and while hunting on the farm is banned the presence of a foreign dog around the sheep yards is suspected.
In a second event four neighbouring South Island farms killing at three different processing sites within a three-week period all had storm lines processed. The lines started in March with one farm still having substantial infected lines being processed in May. Over the March to May period the four farms killed 21,494 lambs with 846 infected. Twenty lambs have been condemned.
All four farms reported being on a monthly dosing programme and no reports of stray dogs in the area. A rabbit hunting contractor had been on some farms but not all and the associated dogs were all on a monthly dosing programme.
In both situations identification of a source of infection proved difficult due to the time that can elapse before infection is found. In both cases the farms concerned appeared to be carrying out correct Ovis control with an expectation of monthly dosing across all the properties involved. However, the events above, demonstrate the impact an infected dog can have on a naive flock and the desirability of having a “zero tolerance” level to dogs being brought onto farms without evidence of treatment.