Reproduction in Domestic Animals最新文献

The study aimed to evaluate the effects of GnRH given 34 h after progesterone (P4) intravaginal device (IVD) removal in a timed artificial insemination (TAI) protocol. In Experiment 1, 17 Hereford and Braford heifers (control, n = 7; GnRH34; n = 10) received 2 mg estradiol benzoate (EB) and a 1 g P4 IVD on Day 0 (D0). On D8, IVDs were removed and 150 μg d-cloprostenol (PGF) and 1 mg estradiol cypionate (EC) were administered. In the GnRH34 group, animals received 25 μg lecirelin 34 h after the IVD removal (D9). TAI was performed in both groups on D10 (48 h after IVD removal). Follicular dynamics were evaluated from D8 until ovulation; blood samples were collected 7 and 12 days after TAI. In Experiment 2, to evaluate the effect of GnRH34 on pregnancy rates (control, n = 187; GnRH34; n = 203), heifers were subjected to the TAI protocols described in Experiment 1. No significant differences were observed in preovulatory follicle (POF) diameter on D10, follicular growth and ovulation rates until 72 h and P4 concentrations on days 7 and 12 after TAI (p > 0.05). Pregnancy rates (PR) were similar between groups (Control = 50.2%; GnRH34 = 50.2%; p = 0.65). A significant effect of body weight (BW) and body condition score (BCS) on PR was observed for control (p< 0.05), but not for GnRH34. In conclusion, GnRH 34 h after the IVD removal in beef heifers previously treated with EC had no effect on luteal function and fertility.

Sperm morphology is an important marker of fertility in livestock. Since poor sperm morphology can disqualify a sire from being sold or used for breeding, it is crucial to understand the factors that influence changes in sperm morphology over time. It is often hypothesised that little variation exists in sperm morphology from ejaculate to ejaculate so long as factors such as nutrition, season, health, and thermal status remain the same. This study aimed to test this hypothesis by investigating the morphology of sperm collected from rams (Ovine aries) (n = 3) twice daily, three times per week, over an 8-week period. Sperm morphology was evaluated using an eight-category classification system. Results revealed that each ram exhibited high levels of variability, with only 10.4% of ejaculates within ±5% of their own mean percentage normal sperm (PNS). The percentage of normal sperm over the 8-week period was significantly influenced by intra-week variation, although no consistent trend was observed across the full duration of the study. Within each day, a significant decline in the percentage of normal sperm was observed when a second ejaculate was collected consecutively. This decline was primarily attributed to an increase in cytoplasmic droplets and midpiece abnormalities. These findings suggest that rams subjected to regular semen collection in a controlled environment are likely to exhibit considerable variation in the percentage of normal sperm from ejaculate to ejaculate. For artificial breeding centres and veterinarians, repeated semen collection on the same day may reduce the proportion of normal sperm. As such, assessment of each separate ejaculate for sperm morphology is recommended before pooling for processing or insemination.

The advancement of short-term storage methods for collared peccary semen targets its potential application in artificial insemination programmes and for combination with cryopreservation techniques. The objective of this study was to evaluate the performance of a transport container (Botutainer) for the preservation of collared peccary semen using commercial extenders (BTS, NUTRIXcell+ and PRIMXcell Ultra) as well as a TRIS + egg yolk extender. Ten ejaculates obtained by electroejaculation were diluted and stored at 5°C for 72 h. The cooled samples were analysed for kinetic aspects (using a computerised system), membrane functionality (hyposmotic test), membrane integrity and mitochondrial activity (fluorescent probes), morphology (Rose Bengal staining) and sperm binding capacity (to the perivitelline membrane of the egg yolk). After 72 h of storage, TRIS, NUTRIXcell and PRIMXcell preserved approximately 60% of motile sperm and 50%-65% of membrane integrity. In contrast, BTS was not effective in maintaining these parameters, preserving only ~40% and 50%, respectively (p < 0.05). All extenders preserved ~50% to 65% of mitochondrial activity and 72%-78% of normal sperm morphology up to 72 h. TRIS was the only extender that preserved ~75% of membrane functionality for 72 h. Finally, BTS exhibited a reduction in perivitelline membrane binding potential after 48 h (p < 0.05), whereas the other extenders showed results comparable to fresh semen. In summary, we demonstrate the effectiveness of the Botutainer device for preserving peccary semen at 5°C for up to 72 h using TRIS, NUTRIXcell and PRIMXcell extenders.

Various staining techniques have been used for canine sperm analysis, but direct comparisons using identical semen samples are lacking. This study aimed to assess the efficiency, time requirements and cost-effectiveness of different staining techniques: aniline blue, toluidine blue, acridine orange (AcO), chromomycin A3 (CMA3) and terminal deoxynucleotidyl transferase d-UTP nick-end labeling (TUNEL). Forty semen samples (20 fresh and 20 frozen-thawed) were used to assess chromatin condensation. Significant differences (p < 0.01) were found using two-factor repeated measures variance analysis. Aniline blue staining differed significantly (p < 0.01) from toluidine blue, AcO and CMA3 staining. A significant difference (p < 0.05) was observed between AcO and TUNEL staining for fresh sperm, with no significant differences between TUNEL and other methods. Correlations in fresh sperm samples showed r = 0.567 between AcO and aniline blue, r = 0.645 between AcO and CMA3, and correlations of 0.455 and 0.557 for aniline blue - toluidine blue and aniline blue - TUNEL, respectively. For frozen samples, significant differences were found between aniline blue and toluidine blue and AcO tests (p < 0.05), and between CMA3 and TUNEL staining (p < 0.01). Correlations in frozen samples showed r = 0.582 between AcO and aniline blue, r = 0.752 between AcO and CMA3, r = 0.698 between toluidine blue and aniline blue, and r = 0.536 between CMA3 and aniline blue. A minimal association was found between standard semen analysis and chromatin analysis. In conclusion, toluidine blue is effective for light microscopy staining, while CMA3 is recommended for fluorescence microscopy due to its simplicity, rapidity and cost-effectiveness.

Neonicotinoid insecticides (NEOs) are the most widely used pesticides in modern agriculture, and there are residues in the environment and food. Thiamethoxam (TMX) has been proven to destroy the ovarian homeostasis of mice in vivo and reduce the development of porcine oocytes in vitro. However, whether TMX can interfere with porcine oocyte maturation and its potential mechanism remains unknown. This study indicated that TMX affects the expansion of cumulus cells, destroys the balance of lipid metabolism, and damages mitochondrial function. TMX treatment decreased the expression of genes related to cumulus cell expansion, lipid synthesis and mitochondrial synthesis. Collectively, results confirm that TMX exposure can damage oocyte maturation and produce reproductive toxicity by inducing lipid metabolism and mitochondrial dysfunction in porcine.

This study aimed to determine the relationship between echogenicity and heterogeneity of ovarian structures and cyclicity status, estrus expression and pregnancy per artificial insemination (P/AI) in multiparous beef cows during timed-artificial insemination (TAI). An ultrasound ovarian examination was carried out in 406 crossbred suckled cows at progesterone (P4) insert removal on D8 of a TAI protocol and at pregnancy diagnosis 30 days after TAI. Follicular (antrum, wall and perifollicular stroma) and luteal morphometry, and echotexture and heterogeneity parameters were analysed on D8 and D30 after TAI, respectively. Follicles that did not reach divergence (< 8.5 mm) at P4 removal had higher antral echotexture and heterogeneity values (p < 0.0001) than those that surpassed divergence (> 8.5 mm). Lower follicular antrum echotexture levels at P4 removal positively correlated with subsequent estrus expression and pregnancy outcomes (p < 0.05), and negatively with follicle size (p < 0.0001). Luteal echotexture varied according to the originating follicle size (p < 0.05), with no differences between pregnant and non-pregnant cows 30 days after TAI. Cows had higher odds of estrus expression (Se, 70.61%; Sp, 61.05%; AUC 0.80; p < 0.0001) and attaining P/AI (Se, 64.52%; Sp, 61.05%; AUC 0.73; p < 0.0001) with lower follicular antrum echotexture (overall cut-off ≤ 14.25). The results show that echotexture values in antral follicles on D8 are strongly associated with pregnancy outcomes and may be useful for predicting success in TAI protocols.

Unwanted pregnancies at the slaughterhouse are a recurring problem globally, compromising ethical aspects and animal welfare, and causing production losses. This review explores contraceptive strategies for female cattle, focusing on both management practices and suppression of the estrous cycle and/or fertilisation. Contraceptive techniques such as surgical castration, emasculation of the ovaries with rubber rings, intrauterine devices (IUDs), GnRH agonist implants, and immunocastration are discussed. Surgical castration, although efficient, is an invasive procedure that compromises animal welfare. Alternative methods, such as IUDs and GnRH implants, lack commercially available products and large-scale efficacy studies. Immunocastration is easy to apply and does not require specialised equipment, but also requires further studies to evaluate its effects on animal performance. Despite the various contraceptive alternatives available, the high number of pregnant females slaughtered highlights the need for awareness among producers and technicians, as well as more in-depth studies on strategies that can promote benefits to animals and production.

This study evaluated the effect of equine chorionic gonadotropin (eCG) on ovarian vascularisation and plasma progesterone (P4) levels in Murrah buffaloes during an ovulation synchronisation protocol. Twenty buffaloes were divided into two groups: with eCG (n = 20) and without eCG (control, n = 20) in a crossover design. A 1.0 g progesterone intravaginal device (DIB) was inserted and 2 mg oestradiol benzoate was administered intramuscularly on Day 0. On Day 9, DIB was removed, PGF2α was administered to all animals and eCG was given to half. GnRH was administered on Day 11. Daily Doppler ultrasounds assessed follicular and luteal development and vascularisation from D9 to D16 and on Days 20, 24, 28 and 32. Blood samples were collected before each ultrasound to analyse plasma P4. Ovulation occurred on Day 13.42 ± 1.17 in the eCG group (19/20) and 13.53 ± 0.19 (14/20) in the control (p = 0.34). The ovulation rate was higher in the eCG group (95%) than in the control (70%). eCG increased the vascularised follicle perimeter on Days 11 (p = 0.018) and 12 (p = 0.03) and enhanced corpus luteum (CL) diameter on Day 16 (p < 0.001). A larger vascularised area was observed on Days 14-16, 20 and 24 (p < 0.05). P4 concentrations were higher in the eCG group on Days 15, 16, 20 and 24 (p < 0.05). Significant correlations were found between CL size, vascularisation and P4 concentration (r = 0.75, p < 0.001). In conclusion, eCG improves ovarian vascularisation, ovulation rates and plasma P4 levels, supporting its use to enhance reproductive performance in buffalo herds.

The present study aimed to evaluate the effect of two dilution media and five incubation times at 37°C on the kinetic and morphometric parameters of canine spermatozoa (spz) using computer-assisted sperm analysis (CASA). To do so, 14 ejaculates were collected from six dogs, and initially assessed (microscopy for motility and photometer for concentration). Each ejaculate was divided into two aliquots and diluted in two different solutions (PBS 'phosphate-buffered saline' and a commercial buffer solution 'EBB: Easy Buffer B') at a concentration of 25 million spz/mL then incubated at 37°C for five different times (T0, 10, 20, 30 and 40 min after collection) before being analysed by Hamilton-Thorne IVOS II CASA system. The analyser automatically generated two motility percentages, eight kinetic parameters and six morphometric parameters. The results showed that the sperm analysis by HT-IVOS II immediately after collection without prior incubation (T0), presented a decrease in the percentages of motility and kinetic parameters. On the other hand, incubation at 37°C for 20 min did not show any significant difference compared to T0 + 10 min. The spz retained their motility, kinetic and morphometric parameters in a similar way to the reference time (10 min). On the contrary, the incubation times T0 + 30 min and T0 + 40 min showed a highly significant difference compared to T0 and T0 + 10 min. The percentages of total and progressive motility and the kinetic parameters dropped considerably, so these times (30 and 40 min) are unsuitable for the incubation of canine spz before analysis by the HT-IVOS II system. To conclude, incubation at T0 + 20 min seems to be a good alternative to T0 + 10 min and PBS medium tends to be an acceptable substitute of EBB medium; this trend requires further exploration to be confirmed.

Cryopreservation is known to destabilise spermatozoa and is associated with deficiencies in protamine levels and increased DNA fragmentation, which can reduce fertility in various species. The objective of this study was to evaluate the impact of cryopreservation on protamine levels and DNA fragmentation in alpaca spermatozoa. A total of 108 testicles/epididymides were collected from a slaughterhouse and sperm were recovered from the cauda epididymis. Only samples meeting the criteria of > 10 g in weight, > 3 cm in length, > 30% motility, and > 50 million spermatozoa/mL were processed. Sixty samples (n = 60) were suitable for cryopreservation: 30 were used to assess protamine levels, and 30 to evaluate DNA fragmentation. Assessments were conducted both before and after cryopreservation using imaging flow cytometry. Protamine levels were assessed with chromomycin A3 (CMA3, 0.25 mg/mL), where fluorescence inversely correlates with protamination levels. The TUNEL assay was used to analyse DNA fragmentation, following fixation with 0.4% formaldehyde and permeabilisation with 0.8% Triton X-100. Results showed a significant decrease in CMA3 mean fluorescence after cryopreservation (288.19 ± 145.53 mFL vs. 68.54 ± 51.25 mFL, p < 0.05) and an increase in DNA fragmentation (2.98 ± 2.39 vs. 9.45 ± 15.43, p < 0.05). In conclusion, cryopreservation decreases CMA3 fluorescence, related to a possible increase in protamination, and increases DNA fragmentation in alpaca spermatozoa.