An experiment was designed to evaluate the effect of the length of insertion of a progesterone (P4)-releasing device on follicular and luteal characteristics and pregnancy rates to fixed-time AI (P/FTAI) in Bos indicus cows treated with oestradiol/P4-based treatments with a prolonged pro-oestrus. Multiparous Bos indicus suckled beef cows (n=659), 60-90 days postpartum, with a corpus luteum (CL) or at least one follicle ≥8mm in diameter and with a body condition score between 2 and 3.5 (1-to-5 scale) were synchronised using three treatments. On Day 0, all cows received 2mg of oestradiol benzoate (Sincrodiol, Ourofino) and an intravaginal device with 1g of P4 (Sincrogest, Ourofino). The P4 device was removed on Day 6 in cows in the J-Synch 6 group (n=195) and on Day 7 in cows in the J-Synch 7 group (n=262) and conventional group (n=202). All cows received 500μg of cloprostenol (Sincrocio, Ourofino) and 400IU of equine chorionic gonadotrophin (SincroeCG 6000UI, Ourofino) at the time of P4 device removal. Cows in the conventional treatment group also received 0.5mg of oestradiol cypionate (SincroCP, Ourofino) at the same time. In addition, all cows were tail-painted for oestrous detection (CeloTest, Biotay). Cows that had lost ≥50% of the tail paint 62-66h (J-Synch groups) or 48-52h (conventional group) after device removal were FTAI at that time. Cows not showing oestrus by 62-66h (J-Synch groups) or 48-52h (conventional group) received 10μg of GnRH (Sincroforte, Ourofino) at the same time and were FTAI 8h later. A subset of 20 cows per group was also examined using ultrasonography (Mindray DP50 Vet) every 12h from the time of device removal to determine the time of ovulation, 6 days after ovulation to determine CL diameter, and 30 days after FTAI to determine P/AI. Data were analysed using the GLM Mixed procedure (InfoStat). The results are shown in Table 1. The diameter of the dominant preovulatory follicle was larger and the interval from device removal to ovulation was longer in cows in the J-Synch groups compared with those in the conventional group (P<0.05). Furthermore, the diameter of the CL was larger and P/FTAI was higher in cows in the J-Synch 7 group compared with those in the J-Synch 6 and conventional groups. In conclusion, delaying the removal of the P4 device by 1 day (i.e. Day 7 vs. Day 6) in the J-Synch groups and prolonging the pro-oestrus period by not giving oestradiol cypionate at P4 device removal (i.e. J-Synch 7 vs. conventional) resulted in a larger preovulatory follicle and CL and higher P/FTAI in Bos indicus suckled cows. Table 1.Mean (±s.e.m.) diameter of the preovulatory follicle (P/Foll) and corpus luteum (CL), interval from progesterone (P4) device removal to ovulation, and pregnancy rates to fixed-time AI (P/FTAI) in Bos indicus suckled cows Treatment P/Foll diameter, mm CL diameter, mm Interval to ovulation, h P/FTAI,% (n) J-Synch 6 15.5±0.3a 18.7±0.8a 83.0±4.0b 41.0 (80/195)a J-Synch 7 16.4±0.2b 21.9±0.8b 86.0±3.0b 52.0 (136/262)b Conventional 13.8±0.2a 16.8±0.9a 64.0±3.0a 37.1 (75/202)a a,bDifferent superscripts denote differences between means or P/FTAI.
Los microplásticos son fragmentos plásticos de un tamaño menor a 5 mm de diámetro que actualmente son considerados contaminantes emergentes. Ante la falta de información relacionada con MPs en la zona, la presente investigación tuvo la finalidad de evaluar la abundancia y características de MPs en las playas Las Comadres, El Estero y El Uverito, distrito de Las Tablas, provincia de Los Santos. Las muestras fueron colectadas en los meses de agosto y octubre de 2022, en un transecto de 100 metros paralelos a la línea pleamar y tomando cinco muestras de arena en cada muestreo. Los MPs se contabilizaron y se clasificaron por forma y color. La abundancia se expresó en ítems/m2 y fue de 34,4, 37,2 y 9,2 ítems/m2 para Las Comadres, El Estero y El Uverito, respectivamente, encontrándose diferencias significativas entre El Uverito y el resto de las playas (p= 0,001). Goma espumosa, fragmentos y láminas fueron las formas predominantes de MPs encontrados en las playas, mientras que los MPs de color blanco fueron los más abundantes. Los resultados obtenidos evidencian contaminación por MPs en las playas del distrito de Las Tablas, lo que crea una línea base de conocimientos que ofrece información importante para que los responsables en la toma de decisiones y público en general implementen alternativas para lograr una gestión integral de desechos sólidos, en especial los de origen plástico.
An experiment was designed to evaluate the effect of the length of insertion of a progesterone (P4)-releasing device and the length of pro-oestrus on follicular and luteal characteristics and pregnancy rates to AI (P/AI) in Bos indicus heifers treated with oestradiol/P4-based treatments. Bos indicus beef heifers (n=374), 22-26 months of age, with a corpus luteum (CL) or at least one follicle ≥8mm in diameter and with a body condition score between 2.5 and 3.5 (1-to-5 scale) were synchronised using three treatments for fixed-time AI (FTAI). On Day 0, all heifers received 2mg of oestradiol benzoate (Sincrodiol, Ourofino) and an intravaginal device with 1g of P4 (Sincrogest, Ourofino). The P4 device was removed on Day 6 in heifers in the J-Synch 6 group (n=120) and on Day 7 in heifers in the J-Synch 7 group (n=105) and conventional group (n=165). All heifers received 500μg of cloprostenol (Sincrocio, Ourofino) and 300IU of equine chorionic gonadotrophin (SincroeCG 6000UI, Ourofino) at the time of P4 device removal. Furthermore, heifers in the conventional treatment group received 0.5mg of oestradiol cypionate (SincroCP, Ourofino) at the same time. In addition, all heifers were tail-painted for oestrus detection (CeloTest, Biotay). Heifers that had lost ≥50% of the tail paint by 70-74h (J-Synch groups) or 48-52h (conventional group) after device removal were FTAI at that time. Heifers not showing oestrus by 70-74h (J-Synch groups) or 48-52h (conventional group) received 10μg of gonadotrophin-releasing hormone (Sincroforte, Ourofino) at the same time and were FTAI 8h later. All heifers were also examined using ultrasonography (Mindray DP50 Vet) every 12h from the time of device removal to determine the time of ovulation, 6 days after ovulation to determine the diameter of the CL, and 28 days after FTAI for P/AI determination. Data were analysed using the MLGM procedure (InfoStat) for normal data families (follicular dynamics) and binary data family (P/AI). The results are shown in Table 1. The diameter of the dominant preovulatory follicle and the CL did not differ among groups (P>0.12). However, the interval from device removal to ovulation was longer in heifers in the J-Synch groups than in heifers in the conventional group (P<0.05). Furthermore, P/AI was not different among groups. In conclusion, although the J-Synch protocols delayed the interval from P4 device removal to ovulation, the three protocols evaluated in the present study were equally effective in Bos indicus heifers. Table 1.Mean (±s.e.m.) diameter of the preovulatory follicle (P/Foll) and corpus luteum (CL), interval from progesterone (P4) device removal to ovulation, and pregnancy rates to AI (P/AI) in Bos indicus heifers Treatment P/Foll, mm Interval to ovulation, h CL diameter, mm P/AI,% (n) J-Synch 6 10.5±0.7 101.4±2.3a 18.6±1.0 52.0 (62/120) J-Synch 7 10.6±0.7 96.0±2.2a 16.5±0.9 39.0 (41/105) Conventional 9.4±0.7 73.0±1.9b 16.8±0.9 45.0 (74/165) a,bDifferent superscripts denote differences between groups in the interval from P4 device removal to ovulation.
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