Semen from alpacas was collected by two methods: by aspiration from the female's vagina following mating and with an artificial vagina. Semen was collected, evaluated and extended with Tris buffer, and then used in artificial insemination. Altogether 160 female alpacas with proven reproductive history and five males were used. Semen was collected by vaginal aspiration from 10 females using five males as semen donors; likewise,

The present study was carried out at IVITA-Maranganí Experimental Station to evaluate the animal response to fattening in llamas of two ages submitted to different nutritional regimes in two seasons. An irrestricted randomize design with 2 x 2 x 3 factorial arrangement (two ages: 1 and 2; two seasons: rainy and dry; and three nutritional regimes: natural pasture, mixture of phalaris + clover, and mixture ofryegrass + clover) was used. A total of 60 male llamas (30 of one year and 30 of two years old) were used during a 90-day period of fattening. The stocking rate was 5, 10 and 10 animals/ha for natural pasture, phalaris + clover, and ryegrass + clover, respectively. The body weight gain was evaluated at different periods: 0-30, 31-60, 61-90, 0-60 and 0-90 days (d). Differences in body weight gain was observed in llamas of two years old (183 g/d) as compared with those of one year of age (146 g/d; P<0.05) in the period 0-30d. Body weight gain was better during the rainy (l 7lg/d) than in the dry season (136 g/d; P<0.05). The best nutritional regime was ryegrass + clover (199 g/d) and phalaris + clover (182 g/d) as compared to natural pasture (78 g/d; P<0.05). The largest body weight gain was in the period 0-60 d (178 g/d). The best economic merit were was obtained in the ryegrass + clover pasture (5.81 %) and in phalaris + clover (4.29%) in the period 0-60 d. lt is concluded that the largest body weight gain and the best economic merit were achieved in cultivated pastures.

The effect of oestradiol (E 2) during the maternal recognition of pregnancy (9-11 days after ovulation) was studied in 44 alpacas that were >20 days after delivery. The alpacas were mated with an intact male (>15 minutes) and received 500 IU of hCG to induce ovulation. The females were divided in 3 groups: Group G 1 (n=14) received 0.2 ml. i.m. of an A, D and E vitaminic complex on days 8 and 9 post-ovulation. Group G 2 (n=15) received 200 mg of E 2 and 0.2 ml i.m. of the vitamin complex (similar to G 1) on days 8 and 9 post-ovulation. Group G 3 (n=15) received 20 mg of progesterone and 0.2 ml i.m. of the same vitamin complex on day 9 post-ovulation. The females were confronted with a male to evaluate their sexual behavior (accept or denial) and then, transrectal ecography of the ovaries and uterus was conducted on days 2, 8, 13, 19, 27, 30 and 60 post-ovulation. Embryonic survival was higher in G 2 (86.7%) at day 19 in comparison to G 1 (57.1%, p<0.08), but without differences with G 3 (73.3%). Follicular dinamics in alpacas with embryonic survival was different at day 2 (p<0.1) but not on day 8 relating to those animals with embrionic mortality. The size of the corpus luteum did not have statistical differences between the three groups but was smaller in those with embryonic mortality at day 13 (10.7 ± 1.6 vs. 13.3 ± 1.5, p<0.05) which would show that the luteolisis process began at day 13 in that group. These results suggest that failure in maternal recognition of pregnancy and subsequent embryo mortality were reduced by the oestradiol, and therefore, indicating that oestradiol plays an important role in the process of maternal recognition of pregnancy in alpacas.

RESUMENEl objetivo del estudio fue evaluar el efecto de la yema de huevo fresca (YHF) y en polvo (YHP) sobre la motilidad, viabilidad, integridad funcional de la membrana plasmática (HOST) y tasa de preñez con semen fresco y refrigerado. Se colectaron 30 eyaculados de cinco alpacas mediante el método poscópula en los meses de enero a marzo. Los eyaculados fueron diluidos en Tris-glucosa y glicerol a una concentración final de 5%, y usando los dos tipos de yema de huevo a una concentración final de 20%. El semen diluido se separó en alícuotas y se mantuvo a 15 ºC por 8 h y a 5 ºC por 24 h, y se inseminaron 180 alpacas. El tipo de yema no afectó la motilidad, viabilidad y el valor HOST en los espermatozoides conservados a 15 y 5 ºC. De igual manera, los porcentajes de preñez no variaron cuando se inseminaron con semen fresco (50.0 y 46.7%), mantenido a 15 ºC (43.3 y 40%) o refrigerado a 5 ºC (33.3 y 30.0%) para YHF y YHP, respectivamente. La tasa de preñez fue mayor en hembras inseminadas con semen fresco (48.4%) y menor con semen refrigerado a 5 ºC (31.7%) (p<0.05). Los resultados sugieren que la yema de huevo en polvo puede utilizarse como substituto de yema de huevo fresco en los diluyentes de conservación y refrigeración de semen de alpacas.Palabras clave: alpaca, inseminación artificial, semen refrigerado, yema de huevo ABSTRACTThe aim of this study was to evaluate the effect of fresh (YHF) and powder (YHP) egg yolk on the motility, viability, functional integrity of the plasma membrane (HOST) and pregnancy rate after insemination using fresh and chilled semen. Thirty ejaculates of

The objetive of this research work was to study the effect of the frequency of copulation during the post-ovulatory estrous on the embryonic mortality in alpacas. Forty four female alpacas were selected having a post-partum sexual rest >20 days and bearing in the ovaries a pre-ovulatory follicle >7 mm of diameter. Animals were mated (time of coitus: >15 minutes) using a male with proven fertility and received 6 g of busereline i.m. after copula to ensure ovulation. Three experimental groups were then ramdomly organized: the first group (S 1 , n = 14) did not receive additional matings, the second gropup (S 2 , n = 15) received an additional mating on day three post-ovulation, and the third group (S 3 , n = 15) received additional matings on days three and four postovulation. Ovulation was confirmed through ultrasound images by disappearance of the pre-ovulatory follicle 42 hours post-mating and the presence of a corpus luteum on day 5 post-ovulation. In addition, the size of the corpus luteum, morfological changes of the uterine horns and presence of an embryo were recorded on days 13-14 and 19 postmating. These observations were complemented with the observation of sexual receptivity using a male on days 6, 13-14, 19 and 26 post-mating. Ovulation rate was 91%. There was a higher tendency on embryo survival at day 19 post-mating in those alpacas that received an additional mating on days 3 (S 2 = 80%) and 3 and 4 (S 3 = 85%) post-ovulation than in those animals without additional mating (S 1 = 75%). An additional study in four inducedovulated alpacas was done to detect fertilized ova at days 2, 3 and 4 post-ovulation. Recovery of the fertilized ova from oviduct was possible only until day 3 post-ovulation. Key words: alpaca, embryonic mortality, post-ovulation RESUMENEl presente trabajo tuvo como objetivo estudiar el efecto de la frecuencia copulatoria durante el celo postovulatorio sobre la mortalidad embrionaria en alpacas. Se seleccionó 44 alpacas hembras con descanso sexual postparto >20 días y con presencia de un folículo preovulatorio >7 mm de diámetro. Los animales fueron servidos con macho de fertilidad comprobada (tiempo de cópula: > 15 minutos) y se les aplicó 6 g de buserelina para asegurar la ovulación. Se formaron 3 grupos experimentales al azar: el primero (S 1 , n = 14) no recibió servicio adicional, el segundo (S 2 , n = 15) recibió un servicio adicional el día 3 postovulación, y el tercero (S 3 , n = 15) tuvo servicios adicionales los días 3 y 4 postovulación. Se confirmó la ovulación mediante observación ecográfica del ovario a través de la desaparición del folículo preovulatorio a las 42 horas postservicio (del primer