Proposal of some alternatives to simplify a MOET programme

Abstract

The aim of this study was to propose some alternatives to simplify a sheep MOET program looking at hormonal reduction, cost-effective and less time consuming treatments. Twenty-nine animals were divided into 3 groups: natural oestrus (NT) (n=10), double cloprostenol injection (DC) by 7 days apart (n=10) and double sponge (DS) 40 mg FGA for 14 days; the sponge was replaced by a new one, maintained from day 7 to 14 (n=9) as a control group; 350 I.U. of porcine FSH per sheep was administered in eight decreasing doses twice daily starting on day 4 after onset of oestrus (day 0) in the NT group and 48 h before second cloprostenol injection or sponge removal in the DC and DS groups respectively. A single dose of 125 μg cloprostenol was injected at the same time of first FSH dose in the DS group and on day 6 after oestrus in the NT group to induce luteolysis. All ewes were naturally mated 24 h after cloprostenol injection or sponge removal. Embryos were recovered surgically by flushing at Day 7 after mating. Among all recovered embryos (NT+DC+DS) 129 were vitrified, but only 22 vitrified and 20 fresh embryos from NT group were transferred in pair into 21 synchronised natural oestrus recipients using a direct transfer technique with the help of open pulled straw (OPS). Corpora lutea (CL), embryos recovered (ER), embryos fertilized (EF) and high quality embryos (EQ₁) per ewe were analysed by ANOVA; while recovery (RR), fertility (FR), embryo quality (Q₁R) rates by Chi Square analysis; lambing rate (LR) of fresh and vitrified embryos was similarly analysed. No statistical differences were founded between NT, DC and DS groups in the number of CL/ewe (10.7±3.4, 8.8±5.9, 7.6±5.1), ER/ewe (7.2±3.9, 5.0±6.6, 4.7±4.1 ), EF/ ewe (7.2±3.9, 5.0±6.6, 3.0±3.7), EQ/ewe (6.2±3.8, 4.5±6.5, 2.6±3.6), RR% (67.2, 56.8, 62.0) and QjR% (86, 90, 88) respectively. However, statistical differences were founded on FR% (100, 100, 62) between NT, DC and DS groups respectively. LR after transfer was similar for vitrified (59%) and fresh (60%) NT embryos. Results suggest the suitability of natural oestrus and cloprostenol for simplify some steps during a MOET program in alternative to traditional protocols avoiding intravaginal sponges, reducing costs and length of treatments.