46%pregnancy for direct ET
SOMERSET Cattle Breeding Centre reports an initial 46% pregnancy rate from embryo transfers using the direct transfer technique.
So reports SCBC ET vet Stewart Scott who has directly transferred quick thawed embryos into 28 dairy cows and heifers.
His results indicate that the new direct ET is successful. It involves freezing embryos in ethylene glycol for quick thawing and implanting without washing them.
Mr Scott is now attempting to reduce the concentration of ethylene glycol used for freezing to improve pregnancy rates.
Direct ET may be carried out on cows after their natural heat by trained technicians or producers. But they must be trained in direct transfer and epidural techniques. In his opinion producers aiming to implant 40 to 60 embryos a year would be suitable candidates for DIY ET.
But he claims ET pregnancy rates are dependent on good herd fertility. Aim for 50% of cows in heat 14 days after calving and a 70% pregnancy rate to first service, he advises. *