Is estradiol valerate an alternative to estradiol benzoate in promoting the synchronization of ovulation and timed artificial insemination in suckled Bos indicus beef cows?

The objective of the present study was to evaluate the effect of estradiol valerate administered at the beginning of the ovulation synchronization protocol on the pregnancy rate of Bos indicus cows. In the experiments, the following products from MSD, Sao Paulo, Brazil were used: estradiol valerate (EV), estradiol benzoate (EB), intravaginal progesterone device (P4), estradiol cypionate (EC), equine chorionic gonadotropin (eCG) and cloprostenol (PGF). In Experiment 1, Bos indicus cows (n=899) with a body condition score (BCS) of 2.76 ± 0.01 were included in a 3 (device) × 2 (protocol: 5 mg of EV or 2 mg of EB) factorial design. There were three types of P4 devices: a new device (New), a device previously used for 9 days (1×), and a device previously used for 18 days (2×). Nine days later (D9), the P4 device was removed, and cows received 300 IU of eCG. In addition, cows in the EB group received 1 mg of EC and 265 µg of PGF. Timed artificial insemination (TAI) was performed 48 h after P4 device removal in the EB group (TAI48) and 54 h after P4 device removal in the EV group (TAI54). In Experiment 2, Bos indicus cows (n=434) with a BCS of 2.62 ± 0.01 received a new P4 device or one previously used for 9 days and 5 mg of EV. On D9, all cows received 300 IU of eCG, and the P4 devices were removed and distributed in TAI48 and TAI54 cows. In Experiment 3, Bos indicus cows (n=429) with a BCS of 2.80 ± 0.01 were divided into the control and EV/EC groups. All cows received a P4 device. In addition, cows in the control group received 2 mg of EB, and cows in the EV/EC group received 5 mg of EV on D0. On D9, all cows received 1 mg of EC and 300 IU of eCG, and the P4 devices were removed. Cows in the control group also received 265 µg of PGF. All cows were inseminated 48 h after the removal of the P4 device. In Experiment 1, there was no effect of the interaction between protocol and P4 device on the occurrence of estrus (P=0.45) or on the pregnancy per artificial insemination ratio (P/AI; P=0.30). In addition, the occurrence of estrus and P/AI were not different between in the two estradiol groups (P=0.12 and P=0.82) and across the types of intravaginal P4 device (P=0.91 and P=0.47). In Experiment 2, the pregnancy rate was lower (tendency) in TAI48 cows (P=0.07). In Experiment 3, the estrus rate (P=0.12) and P/AI (P=0.56) were similar between the experimental groups. In summary, protocols using estradiol valerate without exogenous ovulation induction require adjustments in the timing of AI from 48 to 54 h after P4 device removal. However, a combination of estradiol valerate at the beginning of the protocol and estradiol cypionate nine days later successfully induced ovulation in Bos indicus cows inseminated 48 h after P4 device removal.

Supplementation with long-acting injectable progesterone 3 days after TAI impaired luteal function in buffaloes.

Three experiments were conducted to evaluate the effects of long-acting injectable progesterone (iP4) in buffalo cows. In Experiment 1, ovariectomized buffaloes received 300 mg (iP300) or 600 mg (iP600) of iP4, and serum P4 concentrations were evaluated. In experiment 2, three groups were compared: control or administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after timed artificial insemination (TAI). On day 16, reproductive tract was recovered for conceptus, endometrium, and corpus luteum (CL) analysis. In experiment 3, pregnancy per AI (P/TAI) and proportion of pregnancy losses were evaluated after administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after TAI in lactating buffaloes. In experiment 1, serum P4 concentrations remained over 1 ng/mL for ~ 3 days in both groups. The 300 mg dose was used in subsequent experiments. In experiment 2, CL weight and endometrial glands density were decreased, and conceptus length was increased in iP4-D3 compared to control and to iP4-D6 (P < 0.05). Transcript abundance of Prostaglandin F Receptor (FP) and ISG15 in CL and of ISG15 and MX1 in endometrium was greater in iP4-D3 when compared to control and to iP4-D6 (P < 0.05). In experiment 3, there was no difference among experimental groups for P/TAI at D30 and pregnancy losses (P > 0.1); however, iP4-D3 presented a lower P/TAI at day 60 (41.7%) when compared to control (56.8%) and iP4-D6 (57.7%; P = 0.07). In conclusion, administration iP4 at 3 days after TAI affects CL development and consequently decreases final pregnancy outcome in buffaloes.

Administration of PGF2α during the periovulatory period increased fertilization rate in superovulated buffaloes.

The aim of the present study was to determine the recovery of embryonic structures (ova/embryos) and fertilization rate in superovulated buffaloes treated with PGF2α during the periovulatory period. On day 0 (D0), buffaloes at random stages of the estrous cycle were treated with an intravaginal progesterone device (P4; 1.0 g) and estradiol benzoate (EB, 2.0 mg i.m.). From D4 to D7, all buffaloes received i.m. FSH (200 mg total) twice-daily over 4 days in decreasing doses. On D6 and D7, the animals were given PGF2α analogue (0.53 mg i.m. sodium cloprostenol) and the P4 device was removed on D7. On D8, all buffaloes received GnRH (20 µg i.m. buserelin acetate). Buffaloes were then randomly allocated to one of three groups: control (Group C, n = 18), no further treatment; PGF2α analogue injection (Group IM-PGF; n = 18), four injections (0.53 mg i.m. sodium cloprostenol) 12 h apart, from D8 to D10; PGF2α analogue osmotic pump (Group OP-PGF; n = 18), s.c. osmotic mini-pump (2.12 mg sodium cloprostenol) from D8 to D10. The study had a crossover design (three treatments x three replicates). All animals underwent timed AI, 12 and 24 h after treatment with GnRH. Embryonic structures were recovered on D14. Ovarian ultrasonography was used on D8 and D14 to record follicular superstimulation and superovulatory responses. Blood samples were obtained on Days 7, 8, 9 and 10 to measure circulating concentrations of P4, E2 and PGFM. Data were analyzed by GLIMMIX procedure of SAS®. There was no effect (P = 0.58) of treatment on the total number of embryonic structures (Group C, 2.1 ±â€¯0.8; Group IM-PGF, 2.1 ±â€¯0.6; Group OP-PGF, 1.4 ±â€¯0.4). There was also no effect (P = 0.93) of treatment on the recovery rate of embryonic structures (oocytes and embryos D14/CL D14). The fertilization rate was higher (P = 0.04) in Groups IM-PGF (84.6%) and OP-PGF (88.0%), which did not differ, than Group C (63.2%). The viable embryos rate was greater (P < 0.01) for Groups IM-PGF (82.0%) and OP-PGF (88.0%) than Group C (52.6%). There was no interaction between treatment and time and treatment effects for P4, E2 and PGFM concentrations. The findings showed that treatment with PGF2α during the periovulatory period has potential to increase fertilization rate and embryo production in superovulated buffaloes.

Immune response pattern of the popliteal lymph nodes of dogs with visceral leishmaniasis.

The present study aimed to estimate the cell response and parasite load in the popliteal lymph nodes of dogs with visceral leishmaniasis (VL), comparing these findings with the clinical staging of the disease. From the necropsy, 33 dogs were classified as symptomatic (S), asymptomatic (A), or oligosymptomatic (O). Cytology and histopathology were used to determine any presence of microscopic lesions and immunohistochemistry, for parasite load. Dog hyperimmune serum was used as the primary antibody. The inflammatory infiltrate in lymph nodes consisted of macrophages and plasmocytes. The granulomas invaded the trabecular and sinusoid regions and sometimes compressed the lymphocytes of the cortical region (atrophy) and medullary cord cells. Parasite load intensity was unrelated to the density of the macrophages infiltrating the lymph node. Significant differences in parasite load (P < 0.05) were observed between the three groups of infected dogs. Follicular hyperplasia of the cortical region occurred among A and O, while follicular atrophy predominated among S. The parasite load was the greatest among S, followed by O. It can be concluded that, regardless of clinical condition, the most evident cell response consisted of macrophages and plasmocytes. Lymphoid atrophy was observed among animals with intense granulomatous reaction and high parasite load, such as among the symptomatic dogs (P < 0.05). Likewise, the oligosymptomatic dogs also presented high density of parasites in the lymph nodes. Thus, we can confirm that dogs with clinical manifestations of VL have an immune system that is less effective for controlling infection by Leishmania chagasi, thereby favoring parasite multiplication.