RESUMEN
This study evaluated the efficacy of the administration of different doses of equine chorionic gonadotropin (eCG; 0 IU, 200 IU, or 300 IU) at the time of the progesterone device removal in 2-year-old Nelore (Bos indicus) heifers synchronized for fixed-timed artificial insemination (FTAI). On day 0 (D0), a total of 398 heifers received 2 mg of oestradiol benzoate i.m., 0.53 mg of cloprostenol i.m., and an eight-day previously used (second use) intravaginal device containing 1 g of progesterone (P4). Eight days later (D8), simultaneous with the P4 device removal, 0.5 mg of oestradiol cypionate i.m. and 0.53 mg of cloprostenol i.m. were administered. At the same time, heifers were randomly assigned to receive one of the following treatments: G-0 IU (n = 141; no eCG treatment), G-200 IU (n = 132; treated with 200 IU of eCG), and G-300 IU (n = 125; treated with 300 IU of eCG). FTAI was performed 48 h after the P4 device removal (D10). Ultrasonographic evaluations were performed at D0, D10, and D17. Heifers were scanned to measure the size of the largest follicle (LF), the presence, number, and size of the corpus luteum (CL), and the ovulation rate. Subsequently, at D40, the heifers underwent scanning to determine the pregnancy rate and identify any twin pregnancies. Additionally, at D70, scans were performed to assess pregnancy loss (PG). Data were analysed by orthogonal contrasts [C1 (eCG effect): control x (200 IU + 300 IU) and C2 (eCG dose effect): 200 IU × 300 IU]. On D0, CL presence was similar between the groups [G-0 IU = 65.2% (92/141), G-200 IU = 55.3% (73/132), and G-300 IU = 63.2% (79/125); p = .16]. No interactions between the presence of CL on D0 and eCG treatment were found for any of the variables (p > .05). The diameter of the LF at FTAI (D10) was not influenced by eCG treatment (p = .22) or eCG dose (p = .18). However, treatment with eCG increased the diameter of the CL at D17 (G-0 IU = 15.7 ± 0.3 mmb , G-200 IU = 16.6 ± 0.2 mma , and G-300 IU = 16.6 ± 0.3 mma ; p = .001), regardless of the dose used (p = .94). The ovulation rate was higher in heifers treated with eCG [G-0 IU = 79.4%b (112/141), G-200 IU = 90.2%a (119/132), and G-300 IU = 93.6%a (117/125); p = .002], but there was no effect of eCG dose (p = .36). Pregnancy per AI (P/AI) on D40 [G-0 IU = 32.6%b (46/141), G-200 IU = 42.4%a (56/132), and G-300 IU = 42.4%a (53/125); P = 0.05] and D70 [G-0 IU = 29.1%b (41/141), G-200 IU = 40.9%a (54/132), and G-300 IU = 40.8%a (51/125); p = .02] were higher on heifers that received eCG; however, no dose effect was observed for P/AI on D40 (p = .89) nor D70 (p = .98). Pregnancy loss between D40 and D70 tended to reduce (p = .07) in eCG-treated heifers without dose effect (p = .91). Heifers with CL at D0 presented a greater follicle diameter (LF) on D10 (With CL = 11.2 ± 0.2 mm and Without CL = 10.2 ± 0.2 mm; p = .05), CL diameter on D17 (With CL = 15.8 ± 0.03 mm and Without CL = 11.8 ± 0.6 mm; p = .01), and ovulation rate [With CL = 95.5% (233/244) and Without CL = 74.7% (115/154); p = .01]. However, no difference in pregnancy rate at D40 (p = .52) and D70 (p = .84) was found. In conclusion, eCG treatment increases ovulation and pregnancy rates of heifers submitted to a FTAI protocol. Furthermore, eCG treatment increases the diameter of the CL after FTAI and reduces pregnancy losses. No dose effect was observed, suggesting Nelore (Bos indicus) heifers respond to 200 IU of eCG treatment for FTAI.
Asunto(s)
Enfermedades de los Bovinos , Enfermedades de los Caballos , Embarazo , Bovinos , Animales , Femenino , Caballos , Progesterona/farmacología , Aborto Veterinario , Ovulación , Estradiol/farmacología , Cloprostenol/farmacología , Inseminación Artificial/veterinaria , Inseminación Artificial/métodos , Sincronización del Estro/métodosRESUMEN
This study defined the normal variation range for different subsets of T-lymphocyte cells count in two different Brazilian regions. We analysed the T-lymphocytes subpopulations (CD3+, CD4+, CD8+) in blood donors of two Brazilian cities, located in North (Belem, capital state of Para, indian background) and Northeast (Salvador, capital state od Bahia, African background) regions of Brazil. Results were compared according to gender, stress level (sleep time lower than 8 hours/day), smoking, and alcohol intake. Lymphocytes subpopulations were measured by flow cytometry. Five hundred twenty-six blood donors from two Brazilians cities participated in the study: 450 samples from Bahia and 76 samples from Pará. Most (60 percent) were men, 59 percent reported alcohol intake, 12 percent were smokers, and 80 percent slept at least 8 h/day. Donors from Bahia presented with significantly higher counts for all parameters, compared with Para. Women had higher lymphocytes levels, in both states, but only CD4+ cells count was significantly higher than men's values. Smokers had higher CD4+ counts, but sleep time had effect on lymphocytes levels only for Para's donors (higher CD3+ and CD4+ counts). That state had also, a higher proportion of donors reporting sleep time <8 h/day. The values for CD3, CD4 and CD8+ cells count were significantly higher in blood donors from Bahia than among those from Pará. Female gender, alcohol intake, stress level, and smoking were associated with higher lymphocyte counts. The use of a single reference range for normal lymphocytes count is not appropriate for a country with such diversity, like Brazil is.