01315naa a2200181 a 450000100080000000500110000800800410001910000230006024501070008326000090019052007760019965000240097565000170099965000100101665300140102670000190104077300740105921419742024-02-01       1978    bl uuuu     u00u1 u    #d1 aMAC DONNELL, H. F.  aThe effect of progesterone impregnated sponges on fertility in anoestrous ewes.h[electronic resource]  c1978  aProgestagen impregnated sponges have been widely used for the induction and synchronization of oestrus in the ewe. We report here a study of the use of the natural hormone, progesterone, administered on sponges in order to induce oestrus in anoestrous ewes. A linear increase in fertility was observed ~hen the progesterone dose was increased from 500 to iO00 mg. A similar quantity of progesterone (250 mg) was absorbed by the ewes regardless of the dose administered in the range 500 to 1200 mg. Sixty eight per cent lambing of treated ewes was achieved using sponges impregnated with i000 mg progesterone. Optimum fertility appeared to be governed by adequate absorption of the hormone at a rapid initial rate, and this was ensured at the higher doses of progesterone.  aAnimal reproduction  aProgesterone  aSheep  aAnoestrus1 aCROWLEY, J. P.  tVeterinary Science Communicationsgv. 2, n. 2, p. 115-130, Oct. 1978.