LAUSR

A recombinant long-acting ovine follicle stimulating hormone (roFSH) has been devised and its biological effectiveness following a single dose has been assessed in several experiments under field conditions, in pasture-based beef and dairy farming in New Zealand. Owing to the molecular structure of this long-acting roFSH, which includes additional N-glycosylation sites, a single dose combined with a simple CIDR-based superovulatory regime elicits successful ovarian stimulation with averages of 11.8 corpora lutea and of 6.1 good quality embryos collected in cattle. Solid performance of this novel FSH was demonstrated in several beef and dairy breeds which included yearling heifers and mixed age cows, with embryo production results in the same range as those observed nowadays with eight doses of commercial pituitary FSH (pFSH). Viable embryos produced from these collections, when implanted either fresh or frozen and thawed, gave pregnancy rates in recipients similar to those collected from cows and heifers superstimulated with pFSH. Repeated superovulatory treatment of the same cows was not associated with a decrease in ovarian response or embryo yield. The single administration of this long-acting roFSH when combined with a modified simple superovulatory regime has the advantage of reducing animal welfare concerns, lowering labour resource requirements and giving similar results to other commercially prepared pituitary FSH extracts.