Prevent disease with ewe feed
By Richard Allison
FEEDING propylene glycol to sheep in late gestation can help prevent pregnancy toxaemia and improve lamb growth rates, according to recent research.
Propylene glycol is widely used as an effective treatment against pregnancy toxaemia, twin lamb disease, says Frank Wrights ruminant specialist David Wilde. "However, it is looked upon as a treatment rather than a prevention.
"But there is on-farm evidence that feeding propylene glycol to dairy cows can help prevent ketosis, a similar metabolic disease to pregnancy toxaemia in sheep."
Nearly 55% of lamb losses are due to inadequate ewe nutrition, says Mr Wilde. During late gestation, ewe appetite is suppressed, while energy requirements increase.
In most situations, this leads to body tissue mobilisation. Pregnancy toxaemia is the result of excess mobilisation of back fat, explains Mr Wilde.
Propylene glycol supplies extra glucose to the liver, which stimulates insulin production and reduces mobilisation of body reserves. Feeding sugar supplements has little effect as they are fermented in the rumen, whereas propylene glycol feeds the liver not the rumen, he adds.
A trial at Harper Adams University College, Shrops, indicates a preventative strategy for pregnancy toxaemia can be effective. Pregnant ewes were fed propylene glycol during the last six weeks of gestation and first four weeks of lactation, says the colleges researcher David Handford.
"Results show blood glucose was increased, while levels of two indicators of body weight loss – non-esterified free fatty acids and beta hydroxybutyrate – were reduced. This indicates less body reserves were being mobilised."
Ewes were fed to their energy requirements, higher than in more extensive situations, so risks of pregnancy toxaemia were low, but there was still an effect on blood measurements. This indicates that where energy is more limiting, propylene glycol will prevent pregnancy toxaemia, believes Dr Handford.
Another trial at Coleg Gwent, Monmouthshire, showed a 27% increase in lamb growth rates, equating to 1.8kg, in their first four weeks, adds Mr Wilde. "Ewes in this trial were on amore extensive grazing system and energy was more limiting."
Daily feeding rates of propylene glycol were 50g/ewe in both trials. It was mixed with concentrate fed twice daily costing about £1.65/ewe/year, he says. *
Where energy is limiting, feeding propylene glycol will cut toxaemia risks and improve welfare, believes David Handford (inset).
• Increases glucose supply.
• Fed in late gestation.
• Prevents pregnancy toxaemia.