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WE have had a great start to 2023 in the King Country (for grass growth and covers at least) with some good rain in early January.
This is much needed after an extremely difficult and late growth in spring after very short covers through winter. Consequently, ewes have lambed down in poorer condition with lower pasture covers.
After ewes are weaned and shorn, this gives us the opportunity to go through and pull out any cull ewes (teeth, udders and feet, etc) and draft off any low BCS ewes for priority feeding to reach good tupping condition as soon as possible before things dry up (hopefully they don’t).
With the lighter than normal body condition comes higher worm burdens.
Seen in the diagram at right, the effects of body condition and body condition change correlates very well with worm egg output.
In general, lighter condition and more weight loss leads to higher worm contamination of pastures. Interestingly, for the greatest benefits to worm output, conditions scores of 3.5 and greater need to be achieved with minimal weight loss over their lactation.
Depending on ewe condition prior to lambing and the pasture covers, the period which ewes excrete eggs to a higher level (peri-parturient FEC rise) varies – this can be from a minimum of two weeks either side of lambing up to four-to-six weeks either side of lambing.
If the latter is the case, and this is due to poorer feed conditions and lighter BCS, then this combines to give large contamination of pasture.
Hopefully you all have the Wormwise handbook on your bedside table.
This outlines the effects of larval contamination by showing what small and moderate levels of larval ingestion has on growth rates and compares this to animals with a moderate larval challenge ingested and drenched at 21-day intervals.
This clearly shows that any level of worm larvae ingestion leads to reduced growth rates when compared to no larvae ingestion.
And, that even at a short interval of drenching at 21 days does not make up for less larval ingestion. We are aware of our challenging 2022 feed conditions leading to lighter than normal ewe condition.
This will have led to higher than normal larval contamination of pasture on lambing country and potential for more pronounced effects of the growth rate suppression from larvae ingestion.
This is compounded by the likelihood of having smaller lambs at weaning and potentially more of them post-weaning (due to killing space challenges and the effects of lighter ewes and poor early spring pasture growth). If you are worried about your ewe condition for tupping and in the future please call your vet now so they can help you develop a plan going forwards.
