Pulsatile release of FSH for superovulation in cattle

The studies reported here were directed towards the development of an implantable microcapsule which pulses release of follicle stimulating hormone, FSH, for application to superovulating cows. Final dose forms were administered using membrane-coated cylinders. The pulse of the FSH is achieved by membrane encapsulation of an effervescent/swelling core containing citric acid, sodium bicarbonate, glucose and FSH. Entry of water results in sufficient pressure increase (by gas generation) to rupture ( burst ) the membrane. Time to rupture is dependent upon several factors, such as membrane permeability and thickness, and core composition and loading. The final dose forms were implanted by means of a trochar. This system was tested in sheep to substantiate in vivo burst times and then tested in cows to determine efficacy. In vivo burst times in sheep varied from 8 to 96 hr, based upon maximal FSH values in blood serum, and generally paralled the planned times resulting from in vitro tests. Multiple capsules designed to release FSH as a pulse or steady state were tested on a limited number of cows plus a control (n = 10). Four of the combinations resulted in 11, 11, 14 and 16 ovulations, indicating that further development has promise of providing a one-injection system using FSH for superovulating cattle. © 1995

Capture-recapture: Before and after EURING 2000

Capture-recapture studies and analyses have become an important tool for the study of bird populations. One reason for the rapid advancement in this area has been the EURING conferences where population biologists and statisticians meet to review recent progress, identify areas that require further work, and work collaborately to solve real world problems. In this paper, we forecast the needs for future research in this area and review the recent conference to try and identify what questions are yet unsolved. This EURING conference was dedicated to Dr George Seber who was the author of a number of key papers and whose name is synonymous with 'The estimation of animal abundance and related parameter' (Seber, 1982). He has retired from working in this field.