Characterization of physico-chemical properties of cervical mucus in relation to parity and conception rate in Murrah buffaloes

An Observation of the Microstructure of Cervical Mucus in Cows during the Proestrus, Estrus, and Metestrus Stages and the Impact on Sperm Penetration Ability

Cervical mucus not only provides energy for sperm but also forms a barrier to block sperm. This paper aims to study the microstructure of cervical mucus in dairy cows during the proestrus, estrus, and metestrus and its effect on sperm permeability. The experiment collected cervical mucus from 60 Holstein cows during these phases, then observed the different shapes of the mucus after crystallization, classified the mucus, and analyzed its proportions. Scanning electron microscopy was used to observe the ultrastructure of the cervical mucus and measure the micro-pore sizes, followed by sperm permeability tests using mucus from different estrous stages and counting the number of permeated sperm. The results indicate that cervical mucus from cows in different estrous phases includes four types (L, S, P, G), with each type constituting a different proportion. During the proestrus, the L type was significantly more prevalent than the other types (p < 0.05); during estrus, the S type was significantly more prevalent than the other types (p < 0.05); and during the metestrus, the p type was significantly more prevalent than the other types (p < 0.05). The micro-pore sizes of the same type of cervical mucus did not show significant differences across different estrous phases (p > 0.05). However, within the same estrous phase, there were significant differences in the micro-pore sizes among the four types (p < 0.05). The number of sperm that permeated the cervical mucus during estrus and metestrus was significantly higher than during the proestrus (p < 0.05). This study provides data support for the research on cervical mucus in dairy cows.

Early prediction of oestrus for herd fertility management in cattle and buffaloes - a review

Oestrus is defined as a period when a female animal exhibits characteristic sexual behaviour in the presence of a mature male. Oestrous manifestation in dairy animals is due to the oestrogen (E2) effect on the central nervous system (CNS). It is a critical issue to be considered on a priority basis. Inefficient oestrous detection reduces the fertility status of the herd. The primary and most reliable indicator of oestrus is standing to be mounted by a bull or another female herd mate, signalling receptivity and the pre-ovulatory state in dairy cattle. Oestrous detection is primarily a management challenge requiring skill and vigilance. To improve the efficiency of oestrous detection in dairy cattle, visual observation is one of the best methods if done three times a day; however, heat detection aids, if combined, give better results. However, techniques like using teaser bulls, tail painting, chin ball markers, ultrasound (USG) examination, hormonal analysis and examination of cervicovaginal mucus (CVM) improve oestrous detection efficiency. Moreover, the changes in production systems have reduced the expression of oestrous behaviour among cows, due to higher oestrogen (E2) metabolism. Therefore, automated systems, such as pedometers, accelerometers and acoustic sensors like infrared thermography (IRT) and image processing, have significantly enhanced reproductive performance by facilitating oestrous detection and optimizing insemination schedules. From this review, we would conclude that oestrous detection alone contributes considerably to the reproductive status of the herd; therefore, applying different methods of oestrous detection reduces the incidence of missed oestrus and improves the fertility status of the herd.

Comparative Proteome Profiling of Saliva Between Estrus and Non-Estrus Stages by Employing Label-Free Quantitation (LFQ) and Tandem Mass Tag (TMT)-LC-MS/MS Analysis: An Approach for Estrus Biomarker Identification in Bubalus bubalis

Accurate determination of estrus is essentially required for efficient reproduction management of farm animals. Buffalo is a shy breeder and does not manifest overt signs of estrus that make estrus detection difficult resulting in a poor conception rate. Therefore, identifying estrus biomarkers in easily accessible biofluid such as saliva is of utmost interest. In the current study, we generated saliva proteome profiles during proestrus (PE), estrus (E), metestrus (ME), and diestrus (DE) stages of the buffalo estrous cycle using both label-free quantitation (LFQ) and labeled (TMT) quantitation and mass spectrometry analysis. A total of 520 proteins were identified as DEPs in LFQ; among these, 59 and four proteins were upregulated (FC ≥ 1.5) and downregulated (FC ≤ 0.5) during E vs. PE, ME, and DE comparisons, respectively. Similarly, TMT-LC-MS/MS analysis identified 369 DEPs; among these, 74 and 73 proteins were upregulated and downregulated during E vs. PE, ME, and DE stages, respectively. Functional annotations of GO terms showed enrichment of glycolysis, pyruvate metabolism, endopeptidase inhibitor activity, salivary secretion, innate immune response, calcium ion binding, oocyte meiosis, and estrogen signaling. Over-expression of SERPINB1, HSPA1A, VMO1, SDF4, LCN1, OBP, and ENO3 proteins during estrus was further confirmed by Western blotting. This is the first comprehensive report on differential proteome analysis of buffalo saliva between estrus and non-estrus stages. This study generated an important panel of candidate proteins that may be considered buffalo estrus biomarkers which can be applied in the development of a diagnostic kit for estrus detection in buffalo.

Assessment of different diagnostic methods for the identification of subclinical endometritis in dairy cows with pathological puerperium and their reliability to conceive

The aim of study was to evaluate different methods for subclinical endometritis (SCE) diagnoses and their accuracy to predict pregnancy. The study was performed on 51 postpartum cross breed dairy cows with pathological puerperium. Artificial insemination (AI) was done in spontaneous estrus. Endometrium samples were taken by cytotape (CT), cervical mucus (CM) samples by Metricheck and smears for crystallization degree were obtained at AI day. Blood serum samples for progesterone (P4) concentration determination were taken at AI day and 17 days later. Cows were examined by ultrasound 35 days after AI to confirm pregnancy. Percent (%) of polymorphnuclear leukocytes (PMNs) taken by CT were expressed by ROC curve (with cut-off point set at 1%). Out of the total of 51 cows involved in the study, 13.73% true positive and 41.17% true negative cows were found (54.90%). The content of CM sampled with Metricheck was altered in 11 cows (21.57%), and one of them was pregnant (1.96%). An average macroscopic CM value for pregnant cows was 0.06±0.24 vs. 0.39±0.79 for non-pregnant (p<0.05). An average value of CM crystallization in pregnant cows was 2.50±1.04 vs. 1.85±1.15 in non-pregnant (p<0.05). P4 concentration was not statistically different at AI day, but was statistically significantly higher 17 days later in pregnant cows (p = 0.002). CT alterations may be a reliable diagnostic tool for SCE diagnosis, while macroscopic CM alterations may be used for CE detection. P4 determination is beneficial in pregnancy diagnosis while CM crystallization degree is helpful in determination of best time for AI.

Urinary Cell-Free miR-99a-5p as a Potential Biomarker for Estrus Detection in Buffalo

Accurate estrus detection method is the need of the hour to improve reproductive efficiency of buffaloes in dairy industry, as the currently available estrus detection methods/tools lack high sensitivity and specificity. Recently, circulating miRNAs have been shown as non-invasive biomarkers by various studies. Hence, in order to evaluate their potential as estrus biomarkers, the objective of this study was to identify and compare the levels of 10 hormone-responsive miRNAs in the urine collected at proestrus (PE), estrus (E), and diestrus (DE) phases of buffaloes (n = 3) pertaining to a discovery sample. Among 10 urinary miRNAs, the levels of bta-mir-99a-5p (E/PE 0.5-fold, P < 0.05; DE/PE 1.9-fold), bta-miR-125b (E/PE 0.5-fold; DE/PE 0.7-fold), bta-mir-145 (E/PE 1.5-fold; DE/PE 0.7-fold), bta-mir-210 (E/PE 1.2-fold, DE/PE 0.7-fold), mir-21 (E/PE 1.5-fold, DE/PE 2-fold), and bta-mir-191 (E/PE 1.3-fold; DE/PE 0.8-fold) were found to be altered during different phases of buffalo estrous cycle. In contrast, bta-mir-126-3p, bta-let-7f, bta-mir-16b, and bta-mir-378 were undetected in buffalo urine. Furthermore, a validation study in an independent group of 25 buffalo heifers showed the increased levels of urinary bta-mir-99a-5p during the DE (3.92-fold; P < 0.0001) phase as compared to the E phase. Receiver operating characteristic curve analyses also revealed the ability of urinary miR-99a-5p in distinguishing the E from the DE phase (area under the curve of 0.6464; P < 0.08). In silico analysis further showed an enrichment of miR-99a-5p putative targets in various ovarian signaling pathways, including androgen/estrogen/progesterone biosynthesis and apoptosis signaling, implicating the role of miR-99a-5p in ovarian physiology. In conclusion, significantly lower levels of bta-mir-99a-5p at the E phase than the DE phase in buffalo urine indicate its biomarker potential, which needs to be further explored in a large cohort in the future studies.

Examination of oestrus-dependent alterations of bovine cervico-vaginal mucus glycosylation for potential as optimum fertilisation indicators

Oestrus is the period in the sexual cycle of female mammals where they become most receptive to mating and are most fertile. Efficient detection of oestrus is a key component in successful reproductive livestock management programmes. Oestrus detection in cattle is most often performed by visual observation, such as mounting behaviour and standing heat, to facilitate more successful prediction of optimal time points for artificial insemination. This time-consuming method requires a skilled, diligent observer. Biological measurements using easily accessible biomolecules in the cervico-vaginal mucus could provide an alternative strategy to physical methods of oestrus detection, providing an inexpensive means of rapidly and accurately assessing the onset of oestrus. In this study, glycosylation changes in cervico-vaginal mucus from three heifers following oestrus induction were investigated as a proof of concept to assess whether potential glycosylation-based trends could be useful for oestrus stage indication. Mucus collected at different time points following oestrus induction was immobilised in a microarray format and its glycosylation interrogated with a panel of fluorescently labelled lectins, carbohydrate-binding proteins with different specificities. Individual animal-specific glycosylation patterns were observed, however each pattern followed a similar trend around oestrus. This unique oestrus-associated glycosylation was identified by a combination of relative binding of the lectins SNA-I and WFA for each animal. This alteration in cervico-vaginal mucus glycosylation could potentially be exploited in future to more accurately identify optimal fertilisation intervention points compared to visual signs. More effective oestrus biomarkers will lead to more successful livestock reproductive programmes, decreasing costs and animal stress.

A combinatorial model for effective estrus detection in Murrah buffalo

BACKGROUND

Buffaloes are silent heat animals and lacunae in their estrus detection results a substantial economic loss in developing countries. Many advanced tools to aid heat detection have been developed but are neither affordable nor easily interpretable by marginal farmers.

AIM

The present investigation was made to develop a cost-effective estrus detection model by combining several known estrus predicting parameters.

MATERIALS AND METHODS

Various signs of estrus were classified under major parameters such as visual, cow behavioral, bull behavioral, biochemical, and gyneco-clinical. Expression of those parameters was observed in buffaloes, and the percentage of positive estrus detection was calculated for each combination of estrus prediction parameters.

RESULTS

The present result concludes that the model comprises of five parameters group with several signals with twenty-six different combinations. It was observed that the expression of individual combinations and their corresponding estrus detection efficiency varies significantly, i.e., detection efficiency rises as the number of combination increases.

CONCLUSION

Combination of three parameters would provide an estrus detection efficiency >70% and suggested for an easy estrus detection. This would be a cost-effective model for farmers and benefits in enhancing buffalo population/reproduction.

Efficiency of uterine fluid cytology in the diagnosis of subclinical endometritis in the water buffalo (Bubalus bubalis)

This study compared endometrial cytology vis-a-vis uterine fluid cytology for assessment of uterine health in clinically normal and subclinical endometritis (SE)-affected buffaloes. Uterine fluid samples and endometrial samples were collected from the buffaloes (n = 38) at oestrus using blue sheath and cytobrush, respectively. The smears were stained with Field stain for 3 minutes, and a minimum of 400 cells were counted in each smear for determination of the percentage of polymorphonuclear (PMN) leucocyte. The incidence of subclinical endometritis, based on the cytobrush cytology, was 23.08%. The correlation between cytobrush cytology with uterine fluid cytology was positive and significant (r = .37; p = .02). The ratio of PMN leucocyte in cytobrush cytology to uterine fluid cytology was 1:2.4. ROC analysis revealed that the threshold value of 6.16% PMN leucocyte in uterine fluid cytology showed a diagnostic sensitivity and specificity of 100% in differentiating normal from SE-affected buffaloes. In conclusion, collection of uterine fluid was easier compared to collection of endometrial samples using cytobrush and the percentage of PMN leucocyte in uterine fluid cytology can be used as a tool for diagnosis of subclinical endometritis in buffaloes.