Taking liver biopsies from breeding ewes is helping Welsh sheep farmers to establish the mineral status of their flocks and fine-tune rations.
Testing tissue samples from the livers of live ewes can be costly and is not commonly used in UK flocks.
The technique is however, widely used in New Zealand to monitor trace element status.
A study in Wales has looked at its usefulness in informing decision making around the nutrition of breeding ewes to provide a complete picture of flock status when used alongside blood testing and forage sampling.
Funding was provided by the European Innovation Project (see bottom of article). The project took place on 12 farms in north Wales. On each one:
- blood and tissue samples were taken from eight ewes pre tupping
- and blood samples were taken from 15 ewes pre lambing.
This monitoring, which included detailed analysis of the results and advisory reports, cost £1,299.67 (ex VAT) per flock.
Copper and selenium deficiencies
Sampling identified copper deficiencies in two flocks.
Copper is excreted through the liver and the concentration adjusts more slowly over several months than it does in blood.
Vet Joseph Angell, who was involved in the study, says liver copper concentrations allow a better understanding of historic supply, which can enable a more proactive approach to planning nutritional adjustments.
Blood sampling in another flock showed marginally low copper concentrations, but the tissue sample confirmed an above-normal concentration.
There was also a disparity with the selenium concentration in this flock – it was within the normal range in the blood sample but marginally deficient in the liver tissue.
The additional information provided by the liver tissue was therefore useful in determining the need and safety of supplementation.