INTRODUCCIONEl ciervo rojo (Cervus elaphus) en estado salvaje es un animal poco propenso a contraer enfermedades, aunque esta situación se modifica cuando los ciervos son criados en cautiverio. En estas condiciones pueden aparecer distintas enfermedades, entre las cuales pueden citarse las deficiencias minerales.La ataxia enzoótica (AE) es una patología de los ciervos que causa parálisis lenta y progresiva en las extremidades posteriores. Es originada por una leucomielopatía del tejido nervioso, caracterizada por una desmielinización de los axones pertenecientes a la médula espinal. Dicha patología está asociada en la mayoría de los casos a una deficiencia de cobre (Cu), siendo considerado este mineral como el principal factor etiológico (Barlow y El Cu es un oligoelemento esencial para el correcto funcionamiento de numerosas enzimas involucradas, entre otras funciones en la síntesis de glóbulos rojos, matriz proteica de los huesos, cartílagos, tendones, melanina y queratina. Es además de gran importancia para el normal desarrollo del sistema nervioso (Kaneko 1989).El primer diagnóstico de esta enfermedad en la Argentina fue en el año 1995 (Campero y col 1996); sin embargo, la AE ya ha sido ampliamente descrita con anterioridad principalmente en Europa y Nueva Zelanda (Alexander y Buxton 1994).La morbilidad de la AE suele ser muy baja, usualmente menor a 1%, aunque en raras ocasiones se han observado casos de hasta el 13% (Thompson y col 1994).Si bien tiene algunas similitudes con la AE que se observa en corderos recién nacidos, la principal diferencia radica que en los ciervos rojos sólo se presenta a partir de los 9 meses de edad (Wilson y col 1979).El objetivo del presente trabajo es describir un caso de AE en ciervos rojos ocurrido en el año 2002 en un establecimiento que se dedica a la cría de esta especie en Argentina. Ataxia enzoótica en ciervo rojo (Cervus elaphus) en ArgentinaEnzootic ataxia in red deer (Cervus elaphus) in Argentina J P Soler 1 *, S B Cseh 2 1 Médico Veterinario. Actividad Privada, Argentina 2 Lic. Bioquímica. Instituto Nacional de Tecnología Agropecuaria. EEA Balcarce. SUMMARYEnzootic ataxia is a pathology that causes slow and progressive paralysis of the hind limbs in red deer and has been related to copper (Cu) deficiency. This condition is not seen until deer are about 9 months old. The objective of this paper is to describe a clinical case of enzootic ataxia in red deer kept in captivity in Argentina. The problem started with two pregnant female deer that showed hind limb weakness. One was slaughtered for necropsy. Blood and organ samples were taken, and the latter were kept in formaldehyde at 10%. A necropsy of the foetus was also carried out and a liver sample was taken. Grass and water were analyzed. Cu, Fe, Zn, Mo and SO 4 levels were measured in grass, while total salt, SO 4 , Ca, Mg, Na and Cl levels were measured in water. Disease prevalence was 0.14%. Liver Cu values were 14.6 ppm and 337 ppm DM in the female and foetus respectively. Blood Cu level in the female was 0.5 μg/...
The aims of the present study were to determine the Neospora caninum and Toxoplasma gondii seropositivity rates in farmed red deer hinds from Argentina and their relationship with reproductive losses. Over a 2-year period, 449 hinds from 4 commercial farms were serologically tested at late gestation for N. caninum and T. gondii by IFAT. During the first year, a sequential serological analysis was carried out at 3 different time points to analyze antibody dynamics from mating until the end of the gestation period. Fetal and postnatal mortality rates were estimated by 3 successive ultrasound scannings (us) annually and a breeding control carried out after the calving period. Ultrasound fetal measurements were used to estimate conception date and gestational age of abortions. The seropositivity rate for N. caninum was 25.5% (37/145) for the yearlings and 34.2% (104/304) for the adults, while for T. gondii was 64.3% (93/145) and 78.3% (238/304), respectively. Abortions detected at us1 and us2 were 13/21 (61.9%) with a range of gestational age of 30-87 days, while abortions detected at us3 were 8/21 (38.1%) with a range of gestational age of 49-209 days. The fetal mortality rate was 4% and 5.8%, while the postnatal mortality rate was 18.8% and 4.1% of 101 yearlings and 294 adult pregnant hinds, respectively. Most seropositive hinds to both protozoans showed a stable antibody titer pattern from mating to the end of gestation, and a lower proportion developed an increase in titers suggesting infection recrudescence. Seroconversion during the gestational period was demonstrated in 6 and 50 hinds for N. caninum and T. gondii, respectively. Hinds with fetal mortality were more likely to be seropositive to N. caninum (OR = 3.1) or have N. caninum titers ≥400 (OR = 27.4) than hinds that weaned a fawn. No statistical associations were detected for T. gondii seropositivity and reproductive losses. The pregnancy rate was not affected by N. caninum or T. gondii infection, while the serological evidence of N. caninum causing postnatal mortality was marginal. Based on serological evidence, N. caninum would be a potential abortigenic agent in red deer hinds.
Multiple ovulation and embryo transfer (MOET) programs for red deer (Cervus elaphus) have been established commercially over the last decade, with embryo cryopreservation being a related practice necessary to enhance the use of valuable genetic information. The aim of this work was to establish alternative methods for red deer embryo cryopreservation by using slow freezing with ethylene glycol (SF–EG) and vitrification by open pulled straw (OPS) methods. After surgical flushing of 18 superstimulated donors, 54 transferable embryos were recovered; 28 were transferred fresh to synchronized recipients and the others were cryopreserved by SF–EG (n = 11) or OPS (n = 15), respectively thawed or warmed, and transferred to recipients. Fresh embryos were maintained in Dulbecco's PBS + 20% cow serum (holding medium, HM) until transfer (maximum 3 h after collection). SF–EG cryopreserved embryos were suspended in HM + 1.78 M EG + 0.1 M sucrose + 4 mg mL−1 BSA. After a 10-min equilibration, embryos were loaded individually into 0.25-mL plastic straws and placed into a −7°C methanol bath chamber. After seeding (5 min later), the straws were cooled from −7 to −35°C at a rate of 0.5°C min. Straws were plunged into and stored in liquid nitrogen. Thawing was performed by placing the straws in a 30°C water bath for 30 s; their contents were drained into HM until transfer. Embryos were vitrified using the OPS method with minor modifications. They were first incubated in HM + 1.78 M EG + 1.3 M DMSO for 3 min and then transferred for 25 s into a vitrification solution of HM + 3.56 M EG + 2.6 M DMSO + 0.5 M sucrose. Each embryo was loaded by touching a 1-µL drop with the straw, which was immediately submerged into and stored in liquid nitrogen. Warming was done by placing the narrow end of the straws into HM + 0.25 M sucrose for 5 min. Embryos were then transferred into HM + 0.15 M sucrose for 5 min and finally to HM until transfer. Both types of cryopreserved embryos were transferred a few hours after collection, immediately after thawing or warming. Before embryo transfer, the presence of corpus luteum (CL) of recipients was confirmed by laparoscopic examination. Each embryo was surgically transferred into the apical extreme of the uterine horn ipsilateral to the CL of one recipient. Pregnancy was determined by ultrasonography 41 days after embryo transfer. The pregnancy rate between groups was compared with the chi-square test (P < 0.05). No statistical differences were found between groups (Table 1). Our results show that both vitrification and slow freezing methods with EG are suitable to cryopreserve red deer embryos. Table 1. Pregnancy rates in recipient hinds after transfer of fresh, vitrified, or frozen red deer embryos
Inconsistency of the superovulatory responses of donor hinds has been a general feature of all red deer MOET programs (Asher GW et al. 2000 Anim. Reprod. Sci. 59, 61-70). The development of the techniques has been by trial and error as there is usually a lack of basic information on which to base MOET protocols (Fennessy PF et al. 1994 Theriogenology 41, 133-138). The objective of this study was to understand follicle development during a superovulatory treatment in order to improve ovulation rates and quantity of transferable embryos produced. During the breeding season, 10 mature (3-5 years old) red deer hinds were synchronized receiving an intravaginal sponge containing 100 mg of medroxiprogesterone acetate for 13 days, with device replacement on Day 11. Four days prior to the beginning of the FSH treatment, 0.5 mg of estradiol benzoate (Syntex SA, Buenos Aires, Argentina) was given i.m. to synchronize the follicular wave. Superovulation was conducted with a total dose of 120 mg of NIH-FSH-P1 (Folltropin®-V, Bioniche Animal Health, Belleville, Ontario, Canada) given i.m. in 4 equal doses of 30 mg every 24 h, from Day 11 to 14. Forty-eight hours after sponge withdrawal, 0.84 mg of buserelin acetate (Receptal®, Intervet, Boxmeer, the Netherlands) was injected i.m. to stimulate and synchronize ovulations. Ovarian scanning was performed by transrectal ultrasonography using a multifrequency linear transducer (Tringa Linear, Esaote Pie Medical, Genoa, Italy) on Days -1, 0, 1, 2, 3, 4, 5, and 6, Day 0 being the day of sponge withdrawal. The diameters of all follicles ≥3 mm were measured and their 3-dimensional position recorded to determine growth and ovulation. The average ovulation rate was 10.8 ± 1.6. The distribution of ovulations was 9.3, 31.5, 24.1, 22.2, 9.2, and 3.7% at 24, 48, 72, 96, 120, and 144 h after sponge withdrawal, respectively. The proportion of follicles that did not ovulate during the period of this study was 16.9%. The proportion of ovulated follicles according to their diameter was 9.3, 68.5, and 22.2% for 3 mm, 4 to 5 mm, and ≥6 mm, respectively, and were during the 24- to 96-h period for the first 2 follicles categories and after 96 h for the last category. This study showed a great variability of ovulations in the superovulatory protocols routinely used in red deer donor hinds. Improvement of the hormone treatment to induce a greater degree of ovulation synchrony (within 72 h after progesterone device withdrawal) would increase the fertilization rates and the quantity of transferable embryos produced in red deer MOET programs. Table 1.Mean (±SEM) ovulation rate and number of follicles recorded at each ultrasonography day before and after sponge withdrawal
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