A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs), specifically the fertility associated antigen (FAA) and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2), act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system’s response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA) and recombinant TIMP-2 (rTIMP-2) to bovine semen before cryopreservation for use in an artificial insemination (AI) program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus) heifers were selected based on their estrus cycle, body condition score (BCS), of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal) measurements. Heifers were synchronized using estradiol benzoate (EB), Celosil® (PGF2α) (Shering-Plough) and a controlled internal drug release (CIDR) device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL) and rTIMP-2 (25 µg/mL). In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037). Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented.

The pterostilbene (PT) molecule is a phytoalexin with a reducing effect on reactive oxygen species (ROS) and with a capacity to block lipogenesis. However, the potential reducing effects of PT on equatorial lipid accumulation and ROS have not yet been elucidated for in vitro-derived bovine embryos. The present study evaluated the effects of concentrations of 3, 1, 0.33, 0.11 μM PT, and a vehicle group on the percentage of cleaved embryos, embryos with more than 6 cells, percentage of blastocyst on Day 7 and 8, percentage of transferable embryos on Day 7, the cell count and relative concentration of lipids. In the second experiment, the effects of 0.33 μM PT and a vehicle group within two different O 2 environments (5% and 20%) were evaluated for ROS generation and the percentage of Day 8 blastocysts. In the first experiment, no significant differences were found between the treatments with PT and the vehicle group (p > .05) concerning the percentage of cleaved embryos and embryos with more than 6 cells. Lipid reduction was observed in the groups treated with PT versus the vehicle group (p < .05). The vehicle group showed a higher rate of blastocyst production on Days 7 and 8 (p < .05) and an increase in the percentage of transferable embryos on Day 7 compared to the PT treatment groups (p < .05). Cell counts were not significantly different between treatments with PT and the vehicle group (p > .05). In the second experiment, the O 2 concentration did not significantly affect ROS generation (p > .05); however, the groups treated with PT (0.33 μM) had a reduction in ROS (p < .05). The O 2 concentration also did not significantly affect the rate of blastocyst production on Day 8 (p = .7696). Future research should be conducted to ascertain whether the reduction of lipids could enhance the cryopreservation and post-thaw viability of PT-treated embryos.

Like any other commercial activity, livestock and seedstock producers pursue regular industry objectives: maximize efficiency and productivity, create value and keep the company profitable. To reach these objectives, various reproductive technology tools have been developed for cattle. Artificial insemination (AI) and embryo technologies (in vivo and/or in vitro) contribute to breeding goals and increase farm productivity through the improvement of specific traits by guided mating (Lamb et al., 2016;Moore & Thatcher, 2006). Embryo technologies (superovulation and embryo collection-MOET or in vivo) and, more recently, in vitro embryo production (IVP), are mainly used to multiply high genetic merit females (Ferré et al., 2019;Galli et al., 2003). The idea/goal is to generate bulls and/or bull dams. In commercial farm operations, embryo technologies are also being applied by either implanting sexed embryos

Colour-Doppler ultrasonography (CDU) has been applied for a more detailed examination of the ovary and uterus, mainly local blood flow in ovarian follicles and the corpus luteum (CL). The main use of CDU is for the diagnosis of early pregnancy or the selection of recipients for embryo transfer in cattle; however, this tool can also be used to select oocyte donors according to blood flow to the ovary. The concept is that more blood flow in the ovary is conducive to a healthier intraovarian environment (e.g. higher progesterone levels and removal of reactive oxygen species), yielding higher quality oocytes. The objective of this research was to evaluate invitro embryo production (IVP) after selection of oocyte donors, considering ovary irrigation before ovum pickup (OPU). The research was carried out in the reproduction laboratory at the Palominos Ranch (Jalisco, México). The oocyte donors (n=15) were synchronized before each round of OPU using an intravaginal device (1.9g of progesterone) with oestradiol benzoate (2mg) and cloprostenol sodium (500µg) on Day 0, to avoid the presence of a corpus luteum and to synchronize the follicular wave. On Day 6, the intravaginal device was removed and OPU was performed. All Angus breed donors between 3 and 5 years old with a body condition score between 5–6 (scale 1–9, where 1 is extremely thin and 9 is very obese) and were evaluated with transrectal CDU (Sonoscape S2™) with a linear-array probe (7.5MHz) before the first OPU session only. The oocyte donors were classified subjectively into three categories: low blood flow (LBF, ∼30% ovarian area), median blood flow (MBF, ∼50% ovarian area), and high blood flow (HBF, ∼70% ovarian area) and were submitted to 3 cycles of IVP each (45 total cycles). Semen from a proven bull for IVF was used during all IVP cycles. All oocytes collected from each donor were used in IVF with the same semen in all IVP cycles. The total oocytes collected, and percentages of viable oocytes, cleavage, and blastocysts on Day 7 of culture were evaluated. Statistical analysis was carried out using the GLM procedure of SAS software (version 9.3; SAS Institute Inc.) to evaluate the results of LBF, MBF, and HBF (P-value=0.05). Total oocyte recovery was 11.28±1.92, 10.06±1.31, and 15.52±1.05 for HBF, MBF, and LBF, respectively, being significantly higher for LBF (P&lt;0.05). There were no differences in viable oocytes among groups. Cleavage rates were 53.04%±3.43 for HBF, 43.18%±2.34 for MBF, and 43.69%±1.89 for LBF, being significantly higher for HBF (P&lt;0.05). Percentage of blastocysts on Day 7 was 38.16%±3.80 for HBF, 30.11%±2.60 for MBF, and 17.78%±2.10 for LBF. This value tended to be significantly higher for HBF than MBF, and both were significantly superior to LBF (P&lt;0.05). In conclusion, under the conditions of this research, although LBF donors had more total recovered oocytes, blastocyst rates were increased in HBF and MBF donors. Therefore, based on the results of the present study, CDU can be a useful tool for the selection of oocyte donors.

SexedULTRA-4M™ is made using an improved method of sex-sorting sperm in a less damaging environment for better retaining sperm integrity throughout the sorting process. The objective of this research was to compare conventional (CONV) and SexedULTRA-4M™ (ULTRA-4M) semen for bovine IVP using four Angus bulls. Matured slaughterhouse oocytes (n = 4000) were divided into the CONV group and the ULTRA-4M group (2000 COCs for each semen type). The IVF process was implemented with CONV and ULTRA-4M semen from the same bull. The cleavage rates, eight cell embryos and blastocysts on day 7 of culture were evaluated for each semen type and each bull. The statistical analysis was carried out with the ANOVA procedure SAS software. The results were 54.45% ± 1.03 and 58.10% ± 1.07; 35% ± 1.57 and 39.15% ± 1.62; 22.8% ± 1.09 and 27.15% ± 1.12 for CONV and ULTRA-4M, respectively, for cleavage rate, eight cell embryos and blastocysts on day 7 for the average of all bulls, comparing only the semen type. Concerning only the semen type, ULTRA-4M was significantly superior to CONV for cleavage rates (P = 0.01) and blastocysts on day 7 (P = 0.009). There were no significant differences between the CONV and ULTRA-4M groups (P>0.05) for all variables analyzed for Bull 1 and Bull 4, however, for Bull 2 ULTRA-4M was significantly superior to CONV for cleavage rates and blastocysts on day 7 (P< 0.05). In Bull 3, ULTRA-4M was significantly higher (P< 0.05) for blastocysts on day 7 compared to CONV. In conclusion, under the conditions of this research the ULTRA-4M and CONV semen produced similar bovine IVP results overall.