牦牛NGF基因克隆及其在生殖器官中的表达定位

旨在探究NGF基因的生物学特性及其在母牦牛生殖器官中的表达特性.本研究收集黄体期母牦牛的心、肝、脾、肺、肾以及胎牛期、卵泡期、黄体期、妊娠期母牦牛的卵巢、子宫和输卵管(n=3),利用RT-PCR克隆牦牛NGF基因,并对其序列进行生物信息学分析,利用RT-qPCR技术分析NGF基因的组织表达特性,利用免疫组化技术(IHC...     

雌性牦牛主要生殖器官中DBI的表达与定位分析

为加深对DBI基因功能的探究,揭示其在牦牛生殖生理过程中的作用.本试验采集健康母牦牛(3～6岁)繁殖周期不同阶段(卵泡期、黄体期和妊娠期)的卵巢、输卵管和子宫组织,共分为9组,每组设置3个生物学重复.采用实时荧光定量PCR (qRT-PCR)和蛋白免疫印迹技术(Western blotting,WB)检测牦牛DBI在繁...     

神经生长因子(NGF)在母牛性腺及性腺外生殖器官中的表达研究

本研究旨在探讨神经生长因子(nerve growth factor,NGF)在母牛卵泡期及黄体期子宫、卵巢、输卵管3种组织中的表达情况。采用FQ-PCR方法和Western blotting技术对成年母牛卵泡期及黄体期的子宫、卵巢、输卵管中的NGF mRNA和蛋白质表达进行了检测。结果表明,NGF mRNA和蛋白质在卵泡期和黄体期的子宫、卵巢、输卵管中均有表达,且卵泡期子宫中NGF mRNA表达量显著高于卵泡期卵巢和黄体期输卵管中NGF mRNA表达量(P0.05),其它组织间无显著差异。     

青年母猪不同生殖器官神经营养因子-4/5的表达研究

本研究旨在探讨神经营养因子-4/5(neuroteophin-4/5, NT-4/5)在青年母猪卵泡期与黄体期卵巢、输卵管及子宫3种生殖器官中表达情况。采用实时荧光定量RT-PCR方法与Western blotting技术对青年母猪卵泡期与黄体期卵巢、输卵管及子宫中的NT-4/5 mRNA与蛋白质表达进行检测。结果表明,NT-4/5 mRNA与蛋白质在卵泡期与黄体期卵巢、输卵管及子宫中均有表达,且卵泡期卵巢、子宫NT-4/5 mRNA表达水平均显著高于黄体期(P＜0.05),而卵泡期输卵管NT-4/5 mRNA表达水平显著低于黄体期(P＜0.05)。试验结果为进一步研究NT-4/5参与青年母猪生殖道生理功能的调节奠定基础。     

牦牛StAR基因克隆及其生物信息学与组织表达特性的研究

旨在克隆获得牦牛StAR基因编码序列（CDS）并进行生物信息学分析,探究其mRNA组织表达特性。本研究以屠宰场采集的成年母牦牛心、肝、脾、肺、肾、卵巢、输卵管、子宫组织（n=5）,不同年龄（胎牛、1岁、2岁）牦牛的卵巢（n=3）,不同发情周期（卵泡期、黄体期）的牦牛卵巢（n=3）,黄体期黄牛的卵巢（n=3）及实验室冻存的牦牛颗粒细胞为研究材料。以牦牛黄体期卵巢cDNA为模板,用逆转录PCR克隆StAR基因,并使用MEGA7.0和ExPASy-ProtParam等软件分析其生物信息学特性;采用实时荧光定量PCR技术分析牦牛StAR基因组织表达特性。结果发现,StAR基因CDS区长858 bp,编码285个氨基酸,StAR蛋白总体带正电荷,属于碱性亲水稳定蛋白,无跨膜结构及信号肽,主要存在于细胞质和线粒体; StAR基因具有较高的保守性,符合物种进化规律。牦牛StAR基因在卵巢表达水平最高（P<0.01）,且2岁时卵巢表达水平极显著高于胎牛和1岁龄（P<0.01）,黄体期卵巢表达水平极显著高于卵泡期（P<0.01）;黄体期黄牛卵巢中StAR基因的表达量极显著高于牦牛（P<0.01）;在颗粒细胞的体外培养过程中StAR基因表达量逐渐上升,在培养24 h时达到高峰（P<0.01）,随后显著降低。综上所述,StAR基因序列较为保守,在牦牛卵巢组织中表达最高,且表达水平随年龄与卵巢周期而变化,提示StAR基因可能参与牦牛卵巢及黄体功能相关的繁殖调控。     

促性腺激素受体在雌性水牛生殖器官的表达定位研究

为研究促性腺激素受体(FSHR、LHR)在广西雌性水牛生殖器官中的分布情况,运用免疫组化SABC法对处于不同发情周期(卵泡期、黄体期)成年水牛的卵巢、子宫、输卵管中FSHR、LHR分别进行染色定位。结果表明,FSHR/LHR阳性细胞在卵巢主要见于卵巢内膜细胞及卵泡颗粒细胞;子宫主要见于子宫内膜上皮细胞和腺体细胞;输卵管主要见于柱状上皮纤毛细胞。其中,随着发情周期不同,FSHR、LHR的表达量也有所差异,卵巢中卵泡期FSHR、LHR的表达量均高于黄体期;子宫中FSHR的表达量卵泡期高于黄体期,LHR的表达量黄体期高于卵泡期;而输卵管并没有显著差异。     

牦牛RBM3的基因克隆及其在不同繁殖时期卵巢、输卵管、子宫中的表达定位

旨在研究RBM3在牦牛(Bos grunniens)生殖相关调控中的作用。本研究以卵泡期、黄体期和妊娠期4~6岁健康雌性牦牛各3头为采集对象，采集其卵巢、子宫和输卵管共9组试验样品，每组设置3个生物学重复。利用基因克隆技术克隆牦牛RBM3基因并进行生物信息学分析；利用实时荧光定量PCR (quantitative real-time PCR,qRT-PCR)和蛋白免疫印迹(Western blot,WB)分别在基因层面和蛋白层面检测RBM3在牦牛子宫、卵巢和输卵管中的相对表达量；利用免疫组织化学(immunocytochemistry,IHC)方法检测RBM3蛋白在试验样品中的分布定位。牦牛RBM3基因(GenBank No.:MF142258.1)被成功克隆并预测出二、三级结构，发现其与野牦牛亲缘性最近，基因编码区第51位、98位核苷酸不同于常见哺乳动物，生物信息学分析预测其编码的蛋白质为稳定的非跨膜蛋白。RBM3蛋白在本试验9组样品的表达量有如下差异：在卵巢中，黄体期显著高于卵泡期和妊娠期(P＜0.05)；输卵管中，卵泡期显著低于黄体期和妊娠期(P＜0.05)；子宫上，卵泡期显著高于黄体期和妊娠期(P＜0.05)。免疫组织化学结果显示，RBM3在卵巢中的主要表达位置是卵泡膜、颗粒层和黄体细胞；在输卵管的表达位置是黏膜上皮；子宫上的表达主要以子宫内膜和子宫腺为主。本研究结果提示，RBM3可能参与牦牛个体发情周期和妊娠过程的调控以及妊娠识别等过程，为RBM3这一冷应激调节因子参与牦牛对高原环境的适应性生理机制方面的研究提供参考。     

Dynamics of apoptosis-related gene expression during follicular development in yak

The potential reproduction power of domestic animals is limited by a complicated follicular atresia process. P53, caspase-9 (Casp9), Bax, Bcl-2 and Fas play a crucial role in the ovarian mitochondrion-dependent apoptosis and death receptor pathway. In accordance with this study, the expression levels of Casp9, Bax, Bcl-2 and Fas were analysed in ovaries and oviducts of yak by immunohistochemistry (IHC). P53 and the above in ovarian granulosa cells (GCs) from atretic (3–6 mm) to healthy follicles (6–8 mm) and in oviducts were examined from the luteal phase to the follicular phase during the oestrous circle by Western blot (WB) and real-time PCR (RT-PCR). Results demonstrated that typical classic apoptotic factors Casp9, Bax, Bcl-2 and Fas were expressed in the cytoplasm and zonal pellucida of oocytes, primordial follicles, primary follicles, ovarian surface epithelium, ovarian GCs, granular lutein cells, surface epithelia in oviduct uterotubal junction and oviduct ampulla during the luteal phase. RT-PCR and WB revealed that P53 and Fas significantly increased in GCs of atretic follicles. P53 and Casp9 increased in oviduct epithelium during the luteal phase, but Fas was unchanged. A contrary tendency was noted in Bcl-2 and Bax expression. Overall, P53 and Fas play an essential role in inducing GC apoptosis, and Bax, Bcl-2, Casp9 and P53 are involved in oviduct epithelial regeneration in yak.     

Immunoexpression of cytokine tumour necrosis factor-α suggesting its role in formation and regression of corpus luteum in Indian buffalo

Tumour necrosis factor-α (TNF-α) is a cytokine that plays multiple important roles in corpus luteum (CL). Immunolocalization of expression of TNF-α in CL of buffalo was studied in different stages of its development and regression. Corpus luteum of healthy buffaloes (24) was collected from local slaughterhouses and categorized into early (stage I, 1–5 days, n = 6), mid (stage II, 6–11 days, n = 6), late luteal (stage III, 12–16 days, n = 6) and regressing phase (stage IV, 17–20 days, n = 6). In earliest phase of cyclic CL, per cent immunoexpression of TNF-α was significantly (p < .05) lower as compared to all phases with its expression being restricted to few developing luteal cells, usually in neutrophils. A significantly (p < .05) higher number of neutrophils with TNF-α immunoexpression were observed as compared to mid-luteal phase that indicated its role in initiation of angiogenesis at this stage. TNF-α immunoexpression almost doubled in mid-luteal phase, but the number of neutrophils exhibiting TNF-α was significantly (p < .05) lower with respect to all phases of CL. Immunoexpression percentage in late luteal phase increased sharply being significantly (p < .05) higher than earlier two phases of CL. In regressing phase, per cent immunostaining was maximum with highly significant (p < .05) difference as compared to all other stages, observed in all degrading luteal cells, abundant immune cells, that is neutrophils and macrophages which finally led to apoptosis and phagocytosis. Immunoexpression of TNF-α in early luteal phases served its role in initiation of angiogenesis, and its intense expression in regressing phase of CL suggested a shift in its role to apoptosis and structural luteal regression signifying both luteotropic and luteolytic roles in buffalo. This is probably the first study of its kind in buffaloes.     

黄体期和卵泡期小尾寒羊DIO2与DIO3组织表达

为分析DIO2和DIO3基因在小尾寒羊不同繁殖时期(黄体期和卵泡期)下丘脑-垂体-性腺轴各组织中的表达差异,阐明这2个基因在绵羊发情转换中的表达模式,实验采用实时荧光定量PCR(Real-time PCR)技术对比分析DIO2和DIO3基因在黄体期和卵泡期小尾寒羊下丘脑-垂体-性腺轴各组织中的表达差异。结果表明:DIO2和DIO3基因在下丘脑、垂体、松果体、大脑、小脑、卵巢、子宫、输卵管、肾脏、肾上腺10种组织中均表达;DIO2基因在黄体期和卵泡期的垂体组织中表达量显著高于其他组织(P<0.05),其中黄体期垂体、子宫、下丘脑、松果体、输卵管和卵巢DIO2的表达量显著高于卵泡期(P<0.05);DIO3在卵泡期松果体、下丘脑、子宫、垂体和输卵管的表达量显著高于黄体期(P<0.05)。综上,DIO2能抑制绵羊发情,而DIO3促进发情。     

牦牛FSHR基因克隆及其在生殖轴中的表达研究

本研究旨在阐明牦牛促卵泡素受体(follicle stimulating hormone receptor,FSHR)基因CDS序列及其在牦牛生殖轴中表达的特点,为探讨其在牦牛繁殖活动中的调控作用奠定基础。试验采集卵泡期的牦牛与黄牛下丘脑、脑垂体前叶、卵巢、输卵管及子宫组织,通过RT-PCR技术对牦牛FSHR基因cDNA进行扩增、克隆与序列分析;采用实时荧光定量PCR法检测FSHR基因在牦牛与黄牛中的组织表达差异。结果显示,牦牛FSHR基因编码区全长2 088bp,编码695个氨基酸,蛋白质分子式为C6378H10670N2088O2637S576,分子质量为177 263.85u,理论等电点(pI)为4.88,与黄牛、绵羊、山羊和猪氨基酸序列同源性较高(91.50%～99.38%)。FSHR蛋白为酸性不稳定疏水蛋白,存在信号肽与8个跨膜结构;二级结构由延伸链(15.54%)、α-螺旋(42.30%)、β-转角(1.44%)和无规则卷曲(40.72%)组成;系统进化树表明,牦牛与黄牛亲缘关系最近;实时荧光定量PCR结果显示,FSHR基因在黄牛、牦牛检测组织中均有表达,牦牛子宫中表达量显著或极显著高于除卵巢外的其他组织(P<0.05;P<0.01),而黄牛卵巢中表达量显著或极显著高于其他组织(P<0.05;P<0.01);黄牛卵巢中表达量极显著高于牦牛(P<0.01)。说明FSHR基因在动物进化中较为保守,其在牦牛卵巢中表达量低可能影响到牦牛繁殖机能。     

Characterization of ovarian morphology and reproductive hormones in Zhedong white geese (Anser cygnoides domesticus) during the reproductive cycle

Zhedong white goose (Anser cygnoides domesticus) is a native Chinese breed with strong broodiness and low egg production, which is related to the physiology of reproduction. However, thus far, the physiology of goose reproduction has not been well elucidated. In the present study, the ovarian morphology and reproductive hormones of Zhedong white geese were investigated during the reproductive cycle (the laying and brooding periods). The results showed that the surface of the ovary was atrophied and follicular atresia appeared to some extent in the brooding period compared with the laying period. The concentrations of follicle-stimulating hormone, progesterone and luteinizing hormone were significantly higher than those in the brooding period (p < 0.05). In contrast, the concentrations of prolactin (PRL) and anti-Müllerian hormone (AMH) in the laying period were significantly lower than those in the brooding period (p < 0.05). In addition, the mRNA expression levels of PRL, AMH, dopamine-β-hydroxylase (DβH) and cytochrome P450 side-chain cleavage enzyme (P450scc) were detected in the hypothalamus, pituitary and ovaries by using real-time polymerase chain reaction. The results showed that AMH mRNA was expressed specifically in ovary tissue. The expression levels of DβH and PRL in the brooding period was significantly higher than those in the laying period in the three tissues, especially in the early and middle stages of the brooding period. Moreover, AMH mRNA expression in the ovaries presented the same trend. In addition, P450scc mRNA was highly expressed in both the ovary and pituitary in the laying period. These results revealed the remarkable features of ovarian morphology and characterized the hormonal pattern and expression profile during the reproductive cycle, all of which contribute to understanding the differences in reproductive physiology between the laying and brooding periods in Zhedong white geese.     

牦牛Bcl-2、Bax基因克隆及其在生殖轴上的表达分析

试验旨在分析Bcl-2与Bax基因的序列特性，并分析其在母牦牛生殖轴上的表达特点，为探讨其在牦牛繁殖活动中的调控作用奠定基础。试验采集健康母牦牛与母黄牛下丘脑、垂体、卵巢、输卵管及子宫组织样品，通过RT-PCR扩增并克隆Bcl-2与Bax基因，并采用生物信息学软件进行序列分析；利用实时荧光定量PCR法检测Bcl-2与Bax基因在牦牛与黄牛不同组织中的表达差异。结果表明，牦牛Bcl-2编码区全长690 bp，编码229个氨基酸；与黄牛Bcl-2基因核苷酸序列同源性最高，为99.86%，其次是山羊、绵羊，同源性分别为98.41%、97.97%；系统进化树表明，牦牛与黄牛亲缘关系最近。牦牛Bax基因编码区全长579 bp，编码192个氨基酸，与黄牛、藏山羊和金堂黑山羊同源性较高，分别为99.83%、99.48%和99.48%，其次是绵羊、马、人，同源性分别为99.14%、95.34%、94.30%；系统进化树表明，牦牛与黄牛亲缘关系最近。Bcl-2和Bax蛋白不存在信号肽，均为酸性不稳定的疏水蛋白。Bcl-2与Bax基因在黄牛及牦牛下丘脑、垂体、卵巢、输卵管和子宫组织中均有表达，其中牦牛卵巢、子宫中Bcl-2基因表达量分别显著和极显著高于黄牛（P<0.05；P<0.01）；牦牛子宫、输卵管中Bax基因表达量显著高于黄牛（P<0.05），牦牛卵巢中Bcl-2/Bax比值极显著高于黄牛（P<0.01），子宫和垂体中显著高于黄牛（P<0.05）。表明Bcl-2与Bax在动物进化中非常保守且在繁殖活动中起重要作用，牦牛卵巢、子宫、输卵管和垂体中的高表达量可能与牦牛处于极端恶劣环境的细胞抗凋亡作用有关。     

The expression of VEGF,myoglobin and CRP2 proteins regulating endometrial remodeling in the porcine endometrial tissues during follicular and luteal phase

Endometrial remodeling is important for successful embryo development and implantation in pigs. Therefore, this study investigated change of proteins regulating endometrial remodeling on follicular and luteal phase in porcine endometrial tissues. The endometrial tissue samples were collected from porcine uterus during follicular and luteal phase, vascular endothelial growth factor (VEGF), myoglobin and cysteine‐rich protein 2 (CRP2) proteins were expressed by immnofluorescence, immunoblotting, and determined by 2‐DE and MALDI‐TOF/MS. We found that VEGF, myoglobin and CRP2 were strongly localized in endometrial tissues during luteal phase, but not follicular phase. The protein levels of VEGF, myoglobin and CRP2 in endometrial tissues were higher than luteal phase (P < 0.05). These results may provide understanding of intrauterine environment during estrous cycle in pigs, and will be used in animal reproduction for developing specific biomarkers in the future.     

民猪生殖器官PRLR基因表达发育变化

试验以民猪为试验材料,长白猪为对照组,分别在1、2.5、4、6、8月龄时进行卵巢、输卵管和子宫取样,对促乳素受体（PRLR）基因表达的发育性变化规律进行研究。结果表明,生殖器官中PRLR的表达量与生殖器官的解剖指标存在正相关。PRLR在1、2.5、4、6和8月龄的民猪和长白猪的卵巢、输卵管和子宫中均有表达。民猪和长白猪卵巢PRLR mRNA表达水平从1月龄至8月龄呈现逐渐上升趋势,在8月龄达到最高水平,民猪卵巢PRLRmRNA表达水平显著高于长白猪（P〈0.05）。民猪和长白猪输卵管PRLR mRNA表达量随月龄增加呈上升趋势,在8月龄达到最高水平,品种间差异不显著。民猪子宫PRLR mRNA表达量随月龄增加而升高,在6月龄达到最高水平,8月龄显著下降（P〈0.05）,长白猪子宫PRLR mRNA表达量随月龄增加而升高,在8月龄达到最高水平,品种间在6月龄差异显著（P〈0.05）。     

Endometrial transcript profile of progesterone‐regulated genes during early pregnancy of Water Buffalo (Bubalus bubalis)

Progesterone (P₄) plays a key role in the establishment and maintenance of pregnancy in most mammals. Unravelling the expression of progesterone‐regulated genes can expand the understanding of the embryonic mortality. Accordingly, we studied the relative mRNA expression of the P₄‐regulated genes in the buffalo. Uteri were collected from the abattoir and categorized into nonpregnant late luteal phase, stage I (28–38th days of gestation) and stage II (48–56th days of gestation) of pregnancy (n = 6/group). After extraction of total RNA from the endometrial tissues, we carried out qRT‐PCR for determining the relative mRNA expression of the P₄‐regulated genes using nonpregnant late luteal phase as calibrator group. The expression of LGALS3BP (essential for maternal recognition of pregnancy) gene was found to be significantly upregulated (p < 0.05), while MUC1 (important for embryo attachment) gene was downregulated in stage I and II of pregnancy. We observed no significant change in the expression of LGALS1, LGALS9 and CTSL genes. The SLC5A11 and SLC2A1 genes (involved in the transport of glucose to endometrium) in early pregnancy were upregulated in the pregnancy stage I (p < 0.05) relative to nonpregnant late luteal phase. The CST3 gene was significantly upregulated in pregnancy stage II (p < 0.01). These results provide molecular insights into the specific pathways involved in foeto‐maternal communication during early pregnancy in buffaloes.     

Effects of phyto‐oestrogen quercetin on productive performance,hormones, reproductive organs and apoptotic genes in laying hens

Quercetin, a polyphenolic flavonoid with diverse biological activities including anti‐inflammatory and antiviral, inhibits lipid peroxidation, prevents oxidative injury and cell death. The purpose of the research was to investigate the effect of quercetin on productive performance, reproductive organs, hormones and apoptotic genes in laying hens between 37 and 45 weeks of age, because of the structure and oestrogenic activities similar to 17β‐oestradiol. The trial was conducted using 240 Hessian laying hens (37 weeks old), housed in wire cages with two hens in each cage. These hens were randomly allotted to four treatments with six replicates, 10 hens in each replicate and fed with diets containing quercetin as 0, 0.2, 0.4 and 0.6 g/kg feed for 8 weeks. The results showed that dietary quercetin significantly increased (p < .05) the laying rate and was higher in group supplemented with 0.4 g/kg, and feed‐egg ratio was decreased (p < .05) by quercetin. Dietary quercetin has no effect (p > .05) on average egg weight and average daily feed intake. Compared with control, secretion of hormones, oestradiol (E₂)_, progesterone (P4), follicle‐stimulating hormone (FSH), luteinizing hormone (LH), insulin‐like growth factors‐1 (IGF‐1) and growth hormone (GH), was found to be significantly higher (p < .05) in quercetin‐supplemented groups. Also ovary index, uterus index and oviduct index were not significantly influenced (p > .05) by quercetin, whereas magnum index, isthmus index, magnum length, isthmus length and follicle numbers were significantly increased (p < .05) with quercetin supplementation. Additionally, expression of apoptotic genes was significantly (p < .05) up‐regulated or down‐regulated by quercetin. These results indicated that quercetin improved productive performance, and its mechanism may be due to the oestrogen‐like activities of quercetin.     

Protein and mRNA expression of follicle‐stimulating hormone receptor and luteinizing hormone receptor during the oestrus in the yak (Bos grunniens)

Follicle‐stimulating hormone (FSH) and luteinizing hormone (LH) have a central role in follicle growth, maturation and oestrus, but no clear pathway in the seasonal oestrus of yak (Bos grunniens) has been found. To better understand the role of FSH and LH in seasonal oestrus in the yak, six yaks were slaughtered while in oestrus, and the pineal gland, hypothalamus, pituitary gland, and gonads were collected. Using real‐time PCR and immunohistochemical assays, we determined the mRNA and protein expression of the FSH and LH receptors (FSHR and LHR) in these organs. The analysis showed that the FSHR mRNA expression level was higher in the pituitary gland tissue compared with LHR (p < .01) during oestrus. By contrast, there was low expression of FSHR and LHR mRNA in the pineal gland and hypothalamus. FSHR mRNA expression was higher than that of LHR (p < .05) in the ovary, whereas LHR mRNA expression was higher than that of FSHR (p < .01) in the uterus. FSHR and LHR proteins were located in the pinealocyte, synaptic ribbon and synaptic spherules of the pineal gland and that FSH and LH interact via nerve fibres. In the hypothalamus, FSHR and LHR proteins were located in the magnocellular neurons and parvocellular neurons. FSHR and LHR proteins were localized in acidophilic cells and basophilic cells in the pituitary gland, and in surface epithelium, stromal cell and gland epithelium in the uterus. In the ovary, FSHR and LHR protein were present in the ovarian follicle. Thus, we concluded that FSHR and LHR are located in the pineal gland, hypothalamus, pituitary and gonad during oestrus in the yak. However, FSHR was mainly expressed in the pituitary gland and ovaries, whereas LHR was mainly expressed in the pituitary gland and uterus.     

Application of ultrasonography in the study of the reproductive system of tropical jennies (shape Equus asinus)

The use of high-frequency (5 MHz) ultrasonography was studied in 11 jennies (7 non-pregnant and 4 pregnant) to characterize the reproductive organs and follicular activities at different stages of reproduction. The result showed close similarity with the mare. The visibility of endometrial folds increased towards ovulation. A positive correlation (p < 0.001; τ = 0.79) was found between the score of the folds and the size of the dominant follicle. The diameter of the uterus and the size of the dominant follicle were significantly correlated (p < 0.001; τ = 0.80). In pregnant jennies, an embryonic vesicle was detectable at 14 days. Follicular growth was characterized by more than one wave. The smallest ovarian follicle was 2 mm and the largest 40 mm. Depending on the reproductive stage, up to 13 follicles were detected per ovary. After monitoring 84 cycles, a mean (±SD) diameter of 34.4 ± 3.6 mm (27.5–40.2 mm) of the preovulatory follicle and 67.85% incidence of single ovulation were found. The mean (±SD) interovulatory interval was 25.7 ± 6 days. This study proved that high-frequency ultrasonography is highly effective in characterizing the reproductive organs and follicular activity of jennies and could be useful in the reproductive management of donkeys.