Examinando por Autor "Ratto, Marcelo"

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Embryo transfer in camelids: Study of a reliable superovulatory treatment in llamas
(Wageningen Academic Publishers, 2006-12-01) Huanca López, Wilfredo; Ratto, Marcelo; Santiani Acosta, Alexei Vicent; Cordero, Aida; Huanca Mamani, Teodosio
South American Camelids are receiving increased interest not only in South America but also on a worldwide scale. They possess some unique features such as their fine fibre and their high adaptivity to many climatic regions across the world. Apart from the important productive aspects, their physical attractiveness also makes them popular as pet animals. However there are still many gaps in the scientific literature with regard to South American Camelids. This collection of papers brings experience of both South American and European experts together. It considers current trends in reproduction, nutrition, health, fibre morphology and genetics and discusses as new topic aspects of the potential of meat production and commercialization in South America. The particular advantages of South American Camelids for the sustainable use of fragile ecosystems with native pastures are outlined. Round tables discussions focus on the interaction between wild and domestic species, the management of alpaca populations outside of South America and health aspects under European conditions.
Ovarian response and embryo production in llamas treated with equine chorionic gonadotropin alone or with a progestin-releasing vaginal sponge at the time of follicular wave emergence
(Elsevier Inc., 2009-07-18) Huanca López, Wilfredo; Cordero, Aida; Huanca Mamani, Teodosio; Cárdenas Minaya, Oscar Efraín; Adams, Gregg Patrick; Ratto, Marcelo
The objective of the study was to compare the ovulatory response and embryo production in llamas (Lama glama) treated with a single dose of equine chorionic gonadotropin (eCG) alone or combined with intravaginal medroxyprogesterone acetate (MPA) at the time of follicular wave emergence. Llamas with a growing follicle ≥7 mm in diameter were assigned to one of the following groups: (1) Control (n = 28): Nonstimulated llamas were mated and embryos were collected 7 d after mating. (2) eCG (n = 32): Llamas were given 5 mg luteinizing hormone (LH) (Day 0) to induce ovulation, 1000 IU eCG on Day 2, a luteolytic dose of prostaglandin F2α on Day 6, mating on Day 7, and embryo collection on Day 14. (3) eCG+MPA (n = 34): Llamas were treated as those in the eCG group, but a sponge containing 60 mg MPA was placed intravaginally from Days 2 to 6. Llamas that did not respond to synchronization or superstimulation were excluded, leaving data from n = 26, 26, and 27 in the control, eCG, and eCG+MPA groups, respectively, for statistical analysis. The mean (±SD) number of follicles > 7 mm at the time of mating was greatest in the eCG group, intermediate in the eCG+MPA group, and lowest in the control group (16.6 ± 5.3, 12.9 ± 3.7, and 1.0 ± 0.0, respectively, P < 0.001). The number of corpora lutea was similar between eCG and eCG+MPA groups (10.1 ± 2.9 and 8.6 ± 3.7, respectively); both were higher (P < 0.001) than in controls (0.9 ± 0.3). The number of embryos did not differ significantly between the eCG and eCG+MPA groups (4.8 ± 2.8 and 3.5 ± 3.0, respectively), but both were higher (P < 0.001) than in the controls (0.7 ± 0.4). In conclusion, eCG, with or without MPA effectively induced a superovulatory response and multiple embryo production in llamas.