336 EFFECT OF AN INDIVIDUALLY ADAPTED SUPERSTIMULATION PROTOCOL FOR OPU IN COWS
R. De Roover A , G. Genicot A , S. Leonard A , A. Massip A and F. Dessy ACatholic University of Louvain, Louvain-la-Neuve, Belgium. email: rderoover@msn.com
Reproduction, Fertility and Development 16(2) 288-288 https://doi.org/10.1071/RDv16n1Ab336
Submitted: 1 August 2003 Accepted: 1 October 2003 Published: 2 January 2004
Abstract
The aim of this experiment was to apply an ovarian superstimulation protocol to OPU, with attention to the individual responses of each cow, and to show effects on follicle numbers and diameters. Ten non-lactating dairy cows were stimulated with pFSH and submitted to OPU-IVF 6 times at 2-week intervals. On Day 0 of each 2-week period, the dominant follicle was punctured and a progestin ear implant was inserted. Starting on Day 2, animals were treated with 6 equal doses of pFSH, administered twice daily over 3 days. On Day 7, 48 h after the last pFSH injection, follicle diameters were measured by ultrasound and animals were submitted to OPU (OPU-IVF results are not shown here). The administered dose of pFSH for the first OPU session was 30 mg per animal (stimufol, ULg-FMV, Liège, Belgium). In the following OPU sessions, pFSH doses were individually adapted to the percentage of follicles larger than 11 mm, present during the previous OPU session. If the number of follicles larger than 11 mm was between 1% and 20%, total dose remained unchanged;; if between 20% and 40%, total dose was reduced by 5 mg; and if more than 40%, total dose was reduced by 10 mg. If no follicles larger than 11 mm (0%) were present, total dose was increased by 5 mg. Only one animal received the initial pFSH dose for all 6 OPU sessions for a total of 180 mg. All other animals received more or less than 180 mg, ranging from 135 to 230 mg. For interpretation of the effects of pFSH dose on follicular diameter, data were grouped in pairs (before and after changing the dose of pFSH). This resulted in 3 groups: Fixed pFSH dose—pFSH dose was unchanged in the 2 sessions (of that pair); reduced pFSH dose—pFSH dose was reduced in the second session (of that pair); and increased pFSH dose—pFSH dose was increased in the second session (of that pair). No changes in response were found when pFSH dose remained unchanged. However, the number of small-sized follicles increased and the number of large-sized follicles decreased when dose of pFSH was reduced. The number of larger-sized follicles increased when pFSH dose was increased. The total number of follicles remained unchanged regardless of pFSH dose. Overall, the mean number of punctured follicles per session was 11.9 ± 7.7 with 16% of the follicles over 11 mm. In conclusion, subtle changes in dose of pFSH influenced follicle sizes but not follicle numbers.
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