The monumental rain event that flooded large parts of central Australia tailed out over Tasmania with most sheep areas receiving between 25 and 50mm. The lower east coast received a deal more, which was a welcome relief from a desperate dry.
Mostly, the prime lambs have been doing well on irrigated crops and brassicas. As always, Merino weaners seem to struggle, and several mobs have returned high counts within 3–4 weeks of a weaning drench. Just like aeroplanes, each case is different so the suggestion is to get some advice on the best approach to reducing pasture contamination. Don’t forget the “smart graze” option: it’s not too late to prepare some autumn/winter paddocks for the weaners.
Some more on Haemonchus: since the December notes another 3 places have had clinical haemonchosus. All 4 places I’ve been involved with to date share these characteristics:
I suspect the chain of events is a build-up of contamination in the late summer and autumn when the pastures are grazed by finishing lambs. Each batch of lambs may be multiplying the worms but they are finished before they become clinical cases themselves. Ewes grazing the same paddocks in winter and spring also pick-up and multiply the worms, perhaps aided by emergence of inhibited larvae that have over-wintered in the ewes’ abomasum. This has led to enough contamination and pickup for sheep to be clinically affected by early to mid-summer. Recommendations are: