It can pay to absorb good sponging advice
PRODUCERS considering sponging their ewes could improve their results by heeding advice from Dr John Robinson of the Scottish Agricultural College.
• Lubricating sponges increases the chances of sheep losing them.
• All sponges should be dusted with antibiotic powder in an attempt to keep the system as bug free as possible.
• Always wash the applicator in disinfectant after each insertion.
• Make sure sponge strings are always visible.
• Take care not to force through the hymen of a gimmer.
• Most ewes come on heat 30 hours after sponge withdrawal.
Dr Robinson also points out the vagaries involved when PMSG is used in a tupping programme.
"Overstimulating the ewe can mean five or six eggs are shed ,which results in embryo mortality and only a single live lamb," he explains. "You know this has happened when the lambs birth weight is lower for its litter size than expected. The other embryos are shed from 18 to 35 days after mating.
He says you probably only need 350 international units (iu) to trigger a response, but advises against going below 300iu. "It is tricky to work out because each breed responds differently all the year round," he says.
"For example, Suffolk ewes would need 400iu each at the beginning of August, but Texels about 100iu more because they breed later in the season naturally."