Reproduction in Domestic Animals最新文献

This experiment evaluated the effects of increasing MitoQ concentrations in semen extender on post-thaw quality of Holstein bull sperm, including motility, membrane integrity, antioxidant status and viability. Semen samples were collected, pooled and diluted with extender containing 0 (control), 5, 50, 500 and 1000 nM of MitoQ and frozen through the standard procedure. An increase in MitoQ supplementation positively influenced total and progressive motility, as well as average path velocity; however, these effects were not statistically significant until the concentration reached 50 nM. The highest MitoQ level (1000 nM) showed no difference from the control group. Supplementation of semen extender with 50 and 500 nM of MitoQ significantly increased sperm membrane integrity and mitochondrial activity. Sperm viability improved significantly in concentrations of 5, 50 and 500 nM of MitoQ compared to control, whereas 1000 nM of MitoQ did not show any difference from the control group. Moreover, MitoQ significantly reduced MDA level regardless of its concentration. The concentrations of 50 and 500 nM of MitoQ significantly reduced ROS concentration. It can be concluded that 50 and 500 nM of MitoQ in extender can improve sperm quality parameters in bull semen.

Dystocia due to developmental disorders causing foetal malformation is a significant challenge in bovine obstetrics, often resulting in severe birth complications. This narrative review provides an updated overview of the most common congenital syndromes associated with dystocia in cattle, emphasising both their clinical implications and underlying causes. Congenital disorders such as schistosoma reflexum, perosomus elumbis, arthrogryposis, hydrocephalus, anasarca and embryonic duplication are reviewed in detail, along with their impact on the course of calving. While the management of dystocia due to foetal malformations has remained relatively constant over time-mainly involving assisted delivery, foetotomy or caesarean section-our understanding of their aetiologies has advanced considerably. In addition to environmental factors, such as viral infections during gestation, genetic causes may also be implicated. Genetic aetiologies, including dominant de novo mutations and recessively inherited alleles, such as single nucleotide variants, larger structural variants or aneuploidies, have been identified as the cause of some of these congenital defects. This review provides a comprehensive resource on dystocia due to developmental disorders, offering veterinarians updated knowledge to guide clinical decision making and improve outcomes for both the dam and the calf.

Leptospirosis is a zoonotic disease caused by pathogenic bacteria of the genus Leptospira. A lesser-known form, equine genital leptospirosis (EGL), has been identified as a chronic and often silent infection involving the colonisation of the mare's genital tract. Despite its potential impact, EGL remains underdiagnosed and poorly understood, particularly in its association with reproductive inefficiency. This study showed the presence of Leptospira spp. DNA by lipL32-PCR in the genital tract of mares with a history of reproductive disturbances. Cervicovaginal mucus samples were collected from 120 adult mares exhibiting recent reproductive problems. Results showed that 30 (25%) of the mares tested positive for Leptospira DNA. Among these 30 positive cases, 23.3% had experienced abortions, 3.3% had stillbirths, 53.3% showed placental alterations, and 36.6% were subfertile. These findings suggest a possible association between EGL and reproductive disorders in mares. The high detection rate of Leptospira DNA in genital samples reinforces the need for increased awareness and improved diagnostic efforts.

Arbutin is a naturally present antioxidant derived from plants. The objective of this study was to examine the effect of arbutin on boar sperm during storage at 17°C and the underlying mechanisms. Our results showed that the addition of arbutin to extenders markedly enhanced the sperm (progressive) motility and plasma membrane and acrosomal integrity on Days 9 and 13 of preservation (p < 0.05), with the most pronounced effect of arbutin at the concentration of 100 μmol/L. The addition of 100 μmol/L arbutin also reduced the level of ROS and elevated the levels of ATP and MMP in boar sperm on Days 9 and 13 of preservation (p < 0.05). The subsequent sperm oxidative damage experiment showed that the addition of 100 μmol/L arbutin significantly alleviated the decrease in sperm (progressive) motility and in plasma membrane and acrosomal integrity caused by H₂O₂ (p < 0.05), whereas increased the T-AOC content and the activities of CAT and GPx antioxidant enzymes after 2 h of incubation at 37°C (p < 0.05). Further, the metabolomic analysis revealed that the addition of arbutin principally influenced lipid metabolism, and the Western blot analysis demonstrated that arbutin increased the sperm quality and the antioxidant capacity via the NRF2/GPX4 signalling. Together, arbutin preserves boar sperm during storage at 17°C by enhancing the antioxidant capacity via the NRF2/GPX4 signalling, laying the theoretical foundation for optimisation of the boar semen preservation diluent therefore facilitating the dissemination of superior porcine germplasm resources and improving the economic value.

Cold storage is a preferred method for short-term preservation of ram spermatozoa due to its superior fertility rates compared to cryopreservation. This study aimed to optimise the conditions for ram sperm preservation by evaluating the effects of osmolarity and egg yolk (EY) concentration in a syringe-filtered extender. In part A, semen samples were extended with solutions of varying osmolarities (330, 360, 390 and 420 mOsm/kg water). The 390 mOsm/kg solution demonstrated the best preservation of sperm viability, functional integrity and motility over 96 h of storage. In part B, different EY concentrations (10%, 15%, 20%, 25% and 30%) were assessed at the optimal osmolarity (390 mOsm/kg). A 20% EY concentration provided the most effective protection of sperm DNA, acrosome integrity and membrane functionality. Excessive EY levels (> 20%) negatively impacted sperm viability and induced higher lipid peroxidation. These findings emphasise the importance of balancing osmolarity and EY concentration for efficient cold storage of ram spermatozoa, enhancing the potential success of artificial insemination programs in sheep breeding.

This study evaluated the effect of the timing of Y-sorted sexed semen (SS) insemination after the onset of estrus on reproductive outcomes in beef heifers and examined the influence of AI sires and their sperm DNA fragmentation (%SDF) over time. Angus heifers (n = 718) from two locations were synchronised using a CIDR + Select-Synch protocol and blocked by age, body condition score, and reproductive tract score. Heifers expressing estrus were randomly assigned to AI at 12, 20, or 28 h post-estrus onset using SexedULTRA 4 M semen from one of three bulls. Post-thaw %SDF at 0, 12, and 24 h was assessed by acridine orange staining. Pregnancy per AI (P/AI) differed by timing: 12 h (45.4%), 20 h (48.1%), and 28 h (56.5%) (p < 0.05), with the 28 h group achieving significantly higher P/AI than the 12 h group. Stillbirth incidence and gender ratio (bull: heifer) did not differ significantly among groups. No overall difference in P/AI among sires was observed; however, a significant sire × time of AI interaction existed (p = 0.05), with Bull 2 showing the greatest improvement in P/AI at 28 h (up to 15.2 percentage points higher than earlier times). For Bulls 1 and 2, %SDF increased significantly from 0 to 24 h post-thaw, while Bull 3 showed no change. These findings indicate that delaying insemination to 28 h post-estrus enhances P/AI when using Y-sorted SS, potentially due to improved synchrony with ovulation and reduced exposure to sperm with increasing DNA damage.

Follicular dynamics represent the fundamental aspect of bovine reproduction, which relies on complex physiological and hormonal processes. To investigate the haemodynamics and characteristics of ovarian follicles at different stages of development in Atlas Brown cattle, 31 cycling non-lactating cows were submitted to the Ovsynch oestrous synchronisation protocol to standardise follicular development. Follicular growth and vascularisation were monitored using 2D and Doppler ultrasonography. Moreover, follicles were classified into dominant, largest subordinate and third-largest follicle. Also, 28 ovary samples were collected for histological examination focusing on the theca interna capillary density. The follicular deviation was identified between Days 1 and 3 after GnRH injection. Statistical analysis revealed that before the deviation, no differences were found between the two parameters in all types of follicles studied (p > 0.05); furthermore, after follicular deviation, the dominant follicles maintained capillary density (p < 0.05) and maintained detectable blood flow. However, the largest subordinate and third-largest follicles marked a reduction of both parameters (p < 0.05). Histological findings confirmed ultrasonographic data, demonstrating maintained angiogenesis in dominant follicles and reduced vascularisation in atretic follicles. These results demonstrate the critical role of vascularisation for follicular dominance and selection, providing helpful information for optimising reproductive management practices in cattle. Also, this study advances knowledge of bovine reproductive physiology and suggests potential improvements in synchronisation and ovulation stimulation protocols. As a result, increasing the outcome of artificial insemination and embryo transfer.

Cryopreservation of epididymal sperm is an important tool for preserving the germplasm of animals with high genetic value after death or due to clinical conditions. Nonetheless, its implementation remains challenging, as sperm are more susceptible to freezing and thawing. Osteopontin is a protein that has been linked to high fertilisation rates and antioxidant properties. The objective of this study was to evaluate the effect of adding osteopontin to the freezing extender on the post-thaw quality of bovine epididymal sperm. Sperm was collected from the epididymis cauda from 13 bovine testis-epididymal complexes from Bos indicus bulls. Each sample was supplemented with osteopontin at 0.1, 1.0 and 10 μg/mL, and a control treatment without osteopontin. The spermatozoa were extended and frozen in nitrogen vapour, then evaluated after thawing for motility, kinematics, morphology and plasma membrane integrity. Compared to the control treatment, the addition of osteopontin at 0.1, 1.0 and 10 μg/mL increased the total and progressive motility of frozen-thawed epididymal spermatozoa, with no differences among these three treatments. The use of osteopontin at 10 μg/mL increased the beat cross frequency (BCF) of spermatozoa; however, no other differences were found in the other kinematic parameters of thawed epididymal semen. An increase in the proportion of morphologically normal sperm was observed when the three concentrations of osteopontin were added to the freezing extender (0.1, 1.0 and 10 μg/mL). Similarly, all three concentrations of osteopontin improved the functional integrity of the plasma membrane of thawed epididymal sperm, regardless of the concentration used. It is concluded that adding 0.1 μM osteopontin to the freezing medium is enough to improve the quality of the frozen-thawed bovine epididymal spermatozoa, in an equivalent manner to the use of higher concentrations of this protein.

This study aimed to compare three methods used in evaluating canine sperm concentration in translucent and opaque media. These techniques were counting chamber; spectrophotometry using two commercial photometers calibrated for canine semen (Accuread and SDM1); and CASA analyzer (Hamilton Thorne IVOS II [HT-IVOS II]), for motile and non-motile spermatozoa (spz). Eight ejaculates were collected, then the sperm-rich fraction of each sample was divided into two aliquots: one was mixed with a translucent commercial buffered solution (Easy Buffer-B) and the other with an opaque egg yolk-based diluent. Each of the two aliquots was separated into five fractions evaluated respectively by the different tools. The results showed that the HT-IVOS II analyzer with immobilised spermatozoa was in good agreement with the reference method (counting chamber), whereas the Accuread photometer showed a reasonable difference, but with poor statistical agreement, while the SDM1 photometer and HT-IVOS II analyzer (with immobilised spz) were in bad agreement with the reference method in assessing translucent media-diluted canine sperm concentration. In the context of semen diluted in an opaque egg yolk-based medium, none of the studied techniques was in agreement with the reference method. The comparison between translucent media-diluted and opaque media-diluted semen revealed that except for the reference method, all evaluation techniques (SDM1, Accuread and HT-IVOS II analyzer) were unreliable (p > 0.05) in assessing sperm concentration across both situations. The authors propose to conduct further studies with an expanded sample size and to incorporate flow cytometry (FCM) into the comparative evaluation techniques.

A longer endometrial exposure to estradiol before progesterone has been shown to be beneficial in cyclic and acyclic recipient mares. Therefore, the selection of an estradiol ester that promotes longer endometrial exposure to estradiol using a single administration would be advantageous when preparing acyclic mares as embryo recipients. This study investigated plasma estradiol profiles in acyclic mares after a single administration of 17-β estradiol (17-β), estradiol benzoate (EB) and estradiol cypionate (EC), and the correlation between plasma concentrations and endometrial edema. Fifteen non-cyclic mares were divided into groups 17-β (n = 5), EB (n = 5) or EC (n = 5), receiving a single dose of 10 mg of the respective hormone. Blood sample collections and transrectal ultrasonography were performed every 6 h from hour 0 to 12, every 12 h from 12 to 48 h, and every 24 h from 48 to 120 h after hormone administration. Five of the acyclic mares were used during the breeding season as a cyclic control. Greater median concentrations were detected using EB (38.6 pg/mL; p < 0.05). For 17-β, peak concentration was observed at 6 h (29.7 pg/mL) and decreased 24 h after administration (5.9 pg/mL; p < 0.05). In the EC group, there was a modest peak starting from 12 h (11.7 pg/mL; p < 0.05), remaining relatively constant until 120 h. A more rapid increase of edema to moderate and high scores was found when using 17β estradiol, although edema scores and persistence until Day 5 were similar among the oestrogens used. A correlation between estradiol concentration and endometrial edema was only seen when using EC, and this hormone also produced the most similar concentration values to those found in natural cycling mares. Therefore, it is likely that EC would be a suitable hormone for preparing acyclic mares as embryo recipients.