Short Communication. Embryo yield in llamas synchronized with two different intravaginal progesterone-releasing devices and superovulated with eCG
<p>The objectives of this study were to compare the effects of two intravaginal devices (ID) containing the same dose (0.5 g) of progesterone (P<sub>4</sub>) on subsequent ovarian response, embryo production and circulating P<sub>4</sub> concentration profile in llamas (<em>Lama glama</em>) treated with equine chorionic gonadotropin (eCG) for ovarian superstimulation. Female llamas were randomly assigned (n = 10 llamas per group) to one of the following groups and treated (Day 0) with an ID containing 0.5 g of vegetal P<sub>4</sub> to synchronize the emergence of a new follicular wave: i) DIB 0.5<sup>®</sup> and ii) Cronipres M15<sup>®</sup>. On Day 3 llamas were intramuscularly treated with 1000 IU of eCG. The IDs were removed on Day 7. Llamas were naturally mated (Day 9) and treated with GnRH analogue to induce ovulation. A second mating was allowed 24 h later. Embryos were collected between 7 and 8 days after the first mating. Blood samples were taken every day from Day 0 to Day 7 to measure circulating P<sub>4 </sub>concentrations. The results indicated that DIB device maintained greater plasma P<sub>4</sub> levels as compared to Cronipres until Day 2. However, the mean (± SD) number of corpora lutea and recovered embryos was not affected (<em>p </em>< 0.05) by the type of ID (5.3 ± 2.6 <em>vs</em> 4.2 ± 2.2 and 3.5 ± 2.7 <em>vs</em> 2.6 ± 3.0 for DIB and Cronipres, respectively). In conclusion, both DIB and Cronipres devices can be successfully used to synchronize the emergence of follicular wave prior to a single dose of eCG in superovulation protocol in llamas.</p>