Abdelghany Awad El-Shereif

This study investigated the efficacy of a modified Ovsynch (MOVS) protocol incorporating a 50% reduced dose of a gonadotropin-releasing hormone analog (GnRH_a) conjugated with chitosan nanoparticles. Thirty-two Holstein heifers under heat-stress (HS) conditions were randomly assigned to either a standard Ovsynch (SOVS) or MOVS protocol (n = 16/group). Ovarian dynamics were monitored across the protocol days (D0, D3, D7, D9, D14, and D19). Hormonal profiles, metabolic and oxidative markers, and mRNA expressions of folliculogenesis- and apoptosis-related genes were evaluated. Both protocols improved follicular recruitment (p > 0.05). However, the MOVS significantly enhanced the dominant follicle (DF) diameter on D9 (p < 0.001). On D14 and D19, CL diameters were larger in the MOVS group (p < 0.001). These findings were associated with significantly high estradiol (E₂) concentrations on D9 (p < 0.05) and progesterone (P₄) concentrations on D19 (p < 0.05). Metabolic and oxidative stress markers were increased in MOVS-treated heifers, while antioxidant markers were also improved (p < 0.05). At the molecular level, the MOVS numerically upregulated the expression of folliculogenesis-related genes (BMP15, GDF9, LHR, FSHR, and IGF-1R) and an anti-apoptotic gene (BCL2) in peripheral blood (p > 0.05). In conclusion, the MOVS protocol achieved a 50% reduction in GnRHa dose while improving ovarian, endocrine, and reproductive physiological indicators, suggesting a promising strategy for optimizing synchronization in heifers under HS conditions.

The current study was designed to investigate the effect of elevated testicular temperature caused by scrotal insulation on some hormonal profiles (testosterone T2; triiodothyronine T3; and cortisol), growth performance (body weight, femur length, and chest circumference) and thermal indices (rectal temperature RT; respiration rate RR) in 10-month-old bucks. Ten Damascus bucks were divided into an uncastrated group (control, n = 5) and a castrated group (n = 5). The testicular hyperthermia was conducted by scrotal insulation using sheep-skin pouches applied for 60 days. Blood samples were obtained biweekly for 100 days. Concentrations of T2, T3, and cortisol also RR, RT, as well as body weight, femur length, and chest circumference were measured concurrently. Results showed that the overall concentrations of T2 and cortisol were comparable between castrated and uncastrated bucks (314.26 vs. 316.22 and 40.33 vs. 39.44, respectively). However, the castrated bucks had significantly high T3 concentrations, body weight, and femur length compared to uncastrated bucks (18.14 vs. 15.82 ng/dl; 20.35 vs. 19.06 kg and 17.28 vs.16.97 cm, respectively). All T2 concentrations, body weight, femur length, and chest circumference were increased by time. Despite fluctuated T3 concentrations throughout the study period, a notable difference appeared at day 28, as the castrated bucks had a significantly higher T3 compared to uncastrated bucks. In conclusion, the physiological castration did not influence T2 and cortisol concentrations but increased T3 and enhanced growth performance. This technique may offer an alternative to physical or surgical castrations with potential benefits for animal welfare and productivity.

Objectives: This study aimed to evaluate the effectiveness of gonadotropin-releasing hormone-loaded chitosan–TPP nanoparticles (GnRH-CNPs) and prostaglandin F_2α-loaded chitosan–TPP nanoparticles (PGF_2α-CNPs) within the Ovsynch protocol for enhancing reproductive performance in heat-stressed dairy cows. Methods: Thirty-six cyclic purebred Friesian cows not detected in standing heat for more than 90 days postpartum were randomly allocated to three treatment groups. The control group (OVS, n = 12) followed the standard Ovsynch protocol with conventional doses. The ½ OVS group (n = 12) received 5 µg GnRH-CNPs on days 0 and 9, along with 250 µg PGF_2α-CNPs on day 7. While the ¼ OVS group (n = 12) was administered 2.5 µg GnRH-CNPs on days 0 and 9, with 125 µg PGF_2α-CNPs on day 7. Ovarian follicular dynamics and corpus luteum (CL) development were monitored on days 0, 4, 7, and 9 of the protocol. Serum progesterone (P₄) concentrations were measured throughout the synchronization period and on days 15 and 30 post-AI. Pregnancy was diagnosed on day 30 post-AI. Results: The ¼ OVS protocol achieved a significantly greater follicular response (p < 0.05) than other protocols. On day 4, following the first GnRH administration, the OVS group exhibited a higher number of subordinate follicles (p < 0.05) and a greater diameter of the dominant follicles (DFs), whereas the ¼ OVS group showed a greater subordinate follicle diameter (p < 0.05) and a higher number of DFs. On day 9, after PGF_2α administration, the ¼ OVS group maintained an elevated number of subordinate follicles, while larger subordinate follicle diameters were observed in the ½ OVS and OVS groups. No significant differences in DF numbers and diameters were observed among groups. P₄ concentrations remained similar across groups during treatments. Compared to control, a significantly higher value of P₄ concentration (p < 0.05) was recorded on day 15 post-AI in the ½ OVS group and on day 30 post-AI in the ¼ OVS group. These findings correlated with a higher pregnancy rate in the ¼ OVS group (65%) compared to the ½ OVS and OVS groups (40% in each). Conclusions: Nanofabrication reduced GnRH and PGF_2α dosage by 50% and 75% without impairing ovarian response and pregnancy rates. The ¼ OVS protocol notably enhanced the ovarian activity and fertility, highlighting the use of GnRH-CNPs and PGF_2α-CNPs as promising and practical approaches to enhance the fertility in dairy cattle under heat stress (HS).

Equine endometritis is one of the most common causes of reproduction failure. To achieve better treatment outcomes, different diagnostic methods should be combined. In the current study, 39 repeat breeder mares were subjected to ultrasonography examination to detect excessive accumulation of intrauterine fluids and an abnormal oedema pattern, which revealed that 61.5% of mares were positive. Combined with endometrial cytology by low-volume uterine flush, 47.7% of smears contain neutrophils (more than 2-3 per HPF X100), and microbial culture. 92.3% of mares were infected with different bacterial isolates, such as Escherichia coli, Streptococci, Staphylococcus, Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter freundii, Providencia alcalifaciens, and Proteus mirabilis. All mares were given saline solution and gravity withdrawal before being given 20 IU of oxytocin (as ecbolic agents). Mares were divided into three groups; Group one (n = 15) received an intrauterine infusion of 20 mL of freshly prepared autologous platelet-rich plasma (PRP) 6 h after breeding, Group two (n = 15) was treated with three doses of systemic Enrofloxacin 5% during the estrus period, and Group three (n = 9) received only uterine lavage and 20 IU of oxytocin. PRP and Enrofloxacin resulted in a significant (p < .05) reduction in endometrial thickness (oedema; 5.05 and 6.74 mm, respectively) and disappearance of intrauterine fluids compared to the control (10.98 mm). Furthermore, PRP (days) and Enrofloxacin (17.89 days) reduced the days to the next oestrus compared to the control (18.58 and 17.89 vs. 21.19 days, respectively). Furthermore, the pregnancy rate improved to reach 70% in the PRP group and 60% in the Enrofloxacin group, while the control remained low at 22%. In conclusion, autologous PRP can be used as a low-cost alternative therapy for modulating the inflammatory process and effectively treating mares' endometritis.