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.

Prepartum and/or postpartum supplementation with monensin-molasses multinutrient blocks to optimize fertility and calf performance in primiparous beef cows.

OBJECTIVE: Pregnant Nelore heifers (n = 417) were used to evaluate the effects of supplementation with monensin-molasses multinutrient block (B) during pre and/or postpartum on reproductive and progeny performance. METHODS: Heifers were allocated in four treatments: i) CC: heifers received control supplement (C) in loose meal form (0.06% of body weight [BW] offered daily before and after parturition; n = 108); ii) CB: received C before parturition and B (0.07% of BW offered weekly after parturition; n = 117); iii) BC: received B before and C after parturition (n = 103) and iv) BB: received B before and after parturition (n = 89). During pre and postpartum periods, concentration of metabolites/hormones and cow/calf performance was evaluated over time. Cows were synchronized twice for fixed timed artificial insemination (FTAI) using an estradiol/progesterone-based protocol. Data was analyzed by orthogonal contrasts (C). RESULTS: B increased pregnancy at first FTAI (p = 0.04) and overall pregnancy rate (C1: CC vs BB+BC+CB; p = 0.05). Supplemented cows had greater body condition score (BCS) only at parturition (D0; p = 0.04) and at D40 (p = 0.02). B increased BW (p = 0.03), glucose concentrations (p = 0.01) and subcutaneous fat thickness (p = 0.03) only at D40. Concentrations of insulin were higher in supplemented cows (p = 0.008). Calves born by cows supplemented before and after parturition (C2: BB vs BC+CB) were heavier at 80 (p<0.001), 120 (p<0.001), 170 (p = 0.002) and 210 (p = 0.02) days old. CONCLUSION: Regardless of period of treatment, block supplementation increased pregnancy at first FTAI and overall pregnancy rate. Additionality, block supplementation during both pre and postpartum periods improved progeny weight until weaning. Block supplementation can be a tool to optimize fertility and calf performance in Nelore primiparous cows.

Paternal effect does not affect in vitro embryo morphokinetics but modulates molecular profile.

The use of different sires influences in vitro embryo production (IVP) outcome. Paternal effects are observed from the first cleavages until after embryonic genome activation (EGA). Little is known about the mechanisms that promote in vitro fertility differences, even less about the consequences on embryo development. Therefore, this study aimed to evaluate the paternal effect at fertilization, embryo developmental kinetics, gene expression and quality from high and low in vitro fertility bulls. A retrospective analysis for bull selection was performed using the In vitro Brazil company database from 2012 to 2015. The dataset was edited employing cleavage and blastocyst rates ranking a total of 140 bulls. Subsequently, the dataset was restricted by embryo development rate (blastocyst/cleaved rate) and ten bulls were selected as high (HF; n = 5) and low (LF; n = 5) in vitro fertility groups. IVP embryos derived from high and low fertility bulls were classified according to their stage of development (2 cells, 3-4 cells, 6 cells, 8-16 cells), at 24, 36, 48, 60, 72 hpi, respectively, to evaluate embryo kinetics. Pronuclei formation (24 hpi), cleavage rate (Day 3), development rate, and blastocyst morphology (Grade I and II - Day 7) were also assessed, as well as the abundance of 96 transcripts at 8-16 cell stage and blastocysts. There was no difference in early embryo kinetics (P > 0.05), and cleavage rate (HF = 86.7%; LF = 84.9%; P = 0.25). Nevertheless, the fertilization rate was higher on HF (72%) than LF (62%) and the polyspermy rate was lower on HF compared to LF (HF:16.2% LF:29.2%). As expected, blastocyst rate (HF = 29.4%; LF = 16.0%; P < 0.0001) and development rate (HF = 33.9% LF = 18.9%; P < 0.0001) were higher in HF than LF. At the 8-16 cell stage, 22 transcripts were differentially represented (P ≤ 0.05) between the two groups. Only PGK1 and TFAM levels were higher in HF while transcripts related to stress (6/22, ∼27%), cell proliferation (6/22, ∼27%), lipid metabolism genes (5/22, ∼23%), and other cellular functions (5/22, ∼23%) were higher on LF embryos. Blastocysts had 9 differentially represented transcripts (P ≤ 0.05); being only ACSL3 and ELOV1 higher in the HF group. Lipid metabolism genes (3/9, 33%) and other cellular functions (6/9, 67%) were higher in the LF group. In conclusion, the timing of the first cleavages is not affected by in vitro bull fertility. However, low in vitro fertility bulls presented higher polyspermy rates and produced 8-16 cells embryos with higher levels of transcripts related to apoptosis and cell damage pathways compared to high in vitro fertility ones. Evidence such as polyspermy and increase in apoptotic and oxidative stress genes at the EGA stage suggest that embryo development is impaired in the LF group leading to the reduction of blastocyst rate.

Superstimulation prior to the ovum pick-up improves the in vitro embryo production in nulliparous, primiparous and multiparous buffalo (Bubalus bubalis) donors.

The aim of this study was to evaluate the ovarian follicular population, the oocyte yield and the in vitro embryo production (IVEP) of nulliparous (NU), primiparous (PR) and multiparous (MU) buffalo donors submitted to the superstimulation with FSH prior to the ovum pick-up (OPU). A total of 54 buffalo donors (18 NU, 15 PR and 21MU) received an intravaginal progesterone device (1.0 g) plus estradiol benzoate [2.0 mg, intramuscular (im)] at random stage of the estrous cycle (Day 0) during the breeding season (autumn and winter). Buffaloes from different categories were then randomly allocated to one of two groups (Control or FSH), in a cross-over experimental design. Buffalo donors in the Control group received no further treatment, whereas buffalo donors in the FSH group received a total dosage of 200 mg im of FSH on Days 4 and 5, in four decreasing doses 12 h apart (57, 57, 43 and 43 mg). On Day 7, the progesterone device was removed and the OPU procedure was performed in both groups. The same semen was used across all replicates and donor category. Data were analyzed by the GLIMMIX procedure of SAS 9.4®. There was no interaction between FSH treatment and animal category for all analyzed variables. Furthermore, no differences between animal category (P = 0.73) and FSH treatment (P = 0.53) were observed regarding the total follicles aspirated. However, the FSH treatment increased (P < 0.001) the proportion of large (>10 mm; FSH = 16.2% and Control = 2.0%) and medium-sized follicles (6-10 mm; FSH = 36.3% and Control = 6.1%) available for the OPU procedure. The total of recovered oocytes was greater in NU than in MU, and PR were similar to NU and MU (P = 0.05). No effect of FSH treatment was observed (P = 0.85) for this variable. Buffalo donors treated with FSH had a greater viable oocytes rate (P = 0.03), blastocyst rate (P = 0.03) and embryo yield per OPU-IVEP session (P = 0.07), however, no category effects were observed for these variables. These results provided evidence that superstimulation with FSH increased the proportion of large and medium-sized follicles available for the OPU procedure. Consequently, the FSH treatment enhanced the proportion of viable oocytes for culture and resulted in greater blastocyst rates and embryo yield per OPU-IVEP session in all buffalo donors categories.

Does low-level laser therapy on degenerated ovine testes improve post-thawed sperm characteristics?

Low-level laser therapy (LLLT) can modulate redox state of the cell which could be useful to treat testicular degeneration and also prevent injuries by sperm cryopreservation. The aim of this study was to evaluate the effects of LLLT treatment on semen cryopreservation from rams submitted or not to testicular degeneration by testicular insulation. Eleven White Dorper rams were divided into four groups: animals that were not insulated (Control) and not treated (No Laser) (n = 2); animals that were not insulated and treated with LLLT (n = 3); animals that were insulated and not treated with LLLT (n = 3), and animals that were insulated and treated with LLLT (n = 3). Testicular insulation was performed using scrotal insulation bags for 72 h. LLLT treatment was 28 J/cm2 energy, 808 nm of wavelength, and 30 mW of power output, irradiated on testis for 15 days with an interval of 48 h. Three ejaculates from each ram were collected: before insulation, 23, and 59 days after insulation bag removal. Cryopreservation was performed of the third ejaculate. Sperm evaluation was performed before and after cryopreservation considering sperm motility, morphology, acrosomal and plasma membrane integrity, mitochondrial potential, and oxidative stress. As expected, cryopreservation had a negative effect on several sperm motility characteristics and sperm membranes. LLLT treatment did not improve sperm quality from rams submitted to testicular insulation. Thus, testicular insulation and cryopreservation effects on spermatozoa were not attenuated by LLLT in this study.