Demographic drivers of reproductive failure in a threatened bird: Insights from a decade of data.

Hatching failure affects up to 77% of eggs laid by threatened bird species, yet the true prevalence and drivers of egg fertilization failure versus embryo mortality as underlying mechanisms of hatching failure are unknown. Here, using ten years of data comprising 4,371 eggs laid by a population of a threatened bird, the hihi (Notiomystis cincta), we investigate the relative importance of infertility and embryo death as drivers of hatching failure and explore population-level factors associated with them. We show that of the 1,438 eggs that failed to hatch (33% of laid eggs) between 2010 and 2020, 83% failed due to embryo mortality, with the majority failing in the early stages of embryonic development. In the most comprehensive estimates of infertility rates in a wild bird population to date, we find that fertilization failure accounts for around 17% of hatching failure overall and is more prevalent in years where the population is smaller and more male biased. Male embryos are more likely to die during early development than females, but we find no overall effect of sex on the successful development of embryos. Offspring fathered by within-pair males have significantly higher inbreeding levels than extra-pair offspring; however, we find no effect of inbreeding nor extra-pair paternity on embryo mortality. Accurately distinguishing between infertility and embryo mortality in this study provides unique insight into the underlying causes of reproductive failure over a long-term scale and reveals the complex risks of small population sizes to the reproduction of threatened species.

Expression pattern of germ cell markers in cryptorchid stallion testes.

Cryptorchidism affects spermatogenesis and testis development, often resulting in stallion subfertility/infertility. This study aims to identify the specific germ cells impacted by cryptorchism in stallions. In a previous study, we found that PGP9.5 and VASA are molecular markers expressed in different germ cells within stallions. Herein, we assessed the heat stress-induced response of spermatogonial stem cells (SSCs) in the seminiferous tubules (ST) of cryptorchid stallion testes (CST) and normal stallion testes (NST). This goal was accomplished by comparing PGP9.5 and VASA expression patterns through reverse transcription quantitative PCR and immunofluorescence assays. We also compared the cross-sectional ST area between groups. Six post-pubertal Thoroughbred unilateral cryptorchid stallions were used. The relative abundance of the mRNA transcripts of PGP9.5 and VASA was significantly upregulated in the NST group than in the CST group. Additionally, the cross-sectional ST area and localization of PGP9.5 and VASA in germ cells were significantly higher in the NST group than in the CST group. Regarding Leydig cells, PGP9.5 staining was observed in both groups. Spermatogonia, primary spermatocytes and secondary spermatocytes were immunostained with VASA in the NST group, while immunostaining was only observed in spermatogonia in the CST group. These results indicate long-term exposure to heat stress conditions, such as cryptorchidism, directly impacts germ cell proliferation and differentiation, leading to impaired spermatogenesis and compromised fertility in stallions.

Development of alternative diagnosis of HH1, HH3, HH5 and HCD fertility haplotypes and subfertility syndrome in cattle.

The increasing prevalence of hereditary anomalies in Holstein cattle populations presents a pressing issue, leading to concerns such as embryonic mortality and the birth of non-viable offspring. This study addresses the urgency of managing harmful genetic mutations in Holstein cattle by developing alternative diagnostic methods. The research aims to devise effective means to diagnose fertility haplotypes HH1, HH3, HH5, HCD and BY and subfertility syndrome in cattle. To achieve this goal, a range of molecular genetic techniques were employed, including Tetra-Primer ARMS-PCR methods, PCR-RFLP analysis and allele-specific PCR. These methods facilitated the identification of heterozygous carriers of various fertility haplotypes and subfertility syndrome in Holstein cows and servicing bulls. The study reveals the prevalence of these genetic defects within the Republic of Kazakhstan's cattle population. HH1, HH3, HH5, HCD and BY fertility haplotypes were found to have occurrence rates ranging from 1.4% to 16.6%, with subfertility syndrome detected in 4.5% of Simmental bulls. The practical significance of this research lies in its contribution to genetic monitoring and management strategies for Holstein cattle populations. By introducing affordable, rapid and accurate diagnostic methods, such as the T-ARMS-PCR, the study provides a valuable tool for controlling and mitigating the spread of harmful genetic mutations, ultimately improving the overall genetic health and productivity of Holstein cattle in the region. This research addresses a critical need in the cattle breeding industry and underscores the importance of genetic monitoring to ensure the long-term viability and sustainability of Holstein cattle populations.

Causes of pregnancy arrest in the canine species.

In the canine species, early pregnancy arrest before 30-40 days of pregnancy will induce intra-uterine embryonic or foetal resorption, with very few clinical signs. If no genital examination by ultrasound is performed at that time, it will often remain unnoticed and the bitch will be qualified as infertile. It is only when pregnancy stops at a later stage, mostly after 40 days, that clinical signs will be seen. Expulsion of aborted foetuses or placentas may be observed, although the dam frequently eats the expelled tissues. Intra-uterine mummification may also occur. This article reviews the causes of pregnancy termination in the bitch, both at the embryonic and the foetal stages, reported in the literature. Canine brucellosis is by far the most important disease concerned in this aspect. There is an important current concern about this disease, due to the fact that several outbreaks have been observed recently in Europe, and that it is a very contagious disease; it may be an underestimated zoonosis. Other bacterial causes of pregnancy arrest are sporadic. There is, however, a growing attention towards the microbiological content of raw food diets which are more and more popular among dog breeders and may-if badly prepared-contain abortifacient bacteria such as Campylobacter jejuni or Listeria monocytogenes. The abortifacient role of endogenous vaginal bacteria and mycoplasms remains unclear and may be related to an imbalanced vaginal flora with subsequent ascending bacterial contamination of the uterus. The role of Canine Herpesvirus on abortion is controversial and probably not frequent. Other viruses have been shown experimentally to induce abortion but their natural occurrence in this respect remains unknown. The same applies to the parasite Neospora caninum which is suspected, but not proven, potentially to induce pregnancy arrest in bitches. Among non-infectious causes, uterine pathology such as cystic endometrial hyperplasia (CEH) or sub-clinical post-mating endometritis which can cause infertility and may also induce embryonic resorption. The role of luteal insufficiency in pregnancy arrest is probably overestimated.

Reviving rare chicken breeds using genetically engineered sterility in surrogate host birds.

In macrolecithal species, cryopreservation of the oocyte and zygote is not possible due to the large size and quantity of lipid deposited within the egg. For birds, this signifies that cryopreserving and regenerating a species from frozen cellular material are currently technically unfeasible. Diploid primordial germ cells (PGCs) are a potential means to freeze down the entire genome and reconstitute an avian species from frozen material. Here, we examine the use of genetically engineered (GE) sterile female layer chicken as surrogate hosts for the transplantation of cryopreserved avian PGCs from rare heritage breeds of chicken. We first amplified PGC numbers in culture before cryopreservation and subsequent transplantation into host GE embryos. We found that all hatched offspring from the chimera GE hens were derived from the donor rare heritage breed broiler PGCs, and using cryopreserved semen, we were able to produce pure offspring. Measurement of the mutation rate of PGCs in culture revealed that 2.7 × 10-10 de novo single-nucleotide variants (SNVs) were generated per cell division, which is comparable with other stem cell lineages. We also found that endogenous avian leukosis virus (ALV) retroviral insertions were not mobilized during in vitro propagation. Taken together, these results show that mutation rates are no higher than normal stem cells, essential if we are to conserve avian breeds. Thus, GE sterile avian surrogate hosts provide a viable platform to conserve and regenerate avian species using cryopreserved PGCs.

Targeted sequencing reveals candidate causal variants for dairy bull subfertility.

Bull fertility is a key factor for successful reproductive performance in dairy cattle. Since the semen from a single bull can be used to inseminate hundreds of cows, one subfertile bull could have a major impact on herd reproductive efficiency. We have previously identified five genomic regions, located on BTA8 (72.2 Mb), BTA9 (43.7 Mb), BTA13 (60.2 Mb), BTA17 (63.3 Mb), and BTA27 (34.7 Mb), that show large dominance effects on bull fertility. Each of these regions explained about 5-8% of the observed differences in sire conception rate between Holstein bulls. Here, we aimed to identify candidate causal variants responsible for this variation using targeted sequencing (10 Mb per region). For each genomic region, two DNA pools were constructed from n ≈ 20 high-fertility and n ≈ 20 low-fertility Holstein bulls. The DNA-sequencing analysis included reads quality control (using FastQC), genome alignment (using BWA and ARS-UCD1.2), variant calling (using GATK) and variant annotation (using Ensembl). The sequencing depth per pool varied from 39× to 51×. We identified a set of nonsense mutations, missense mutations, and frameshift variants carried by low-fertility bulls. Notably, some of these variants were classified as strong candidate causal variants, i.e., mutations with deleterious effects located on genes exclusively/highly expressed in testis. Genes affected by these candidate causal variants include AK9, TTLL9, TCHP, and FOXN4. These results could aid in the development of novel genomic tools that allow early detection and culling of subfertile bull calves.

Andrological and cytogenetic investigations of an infertile Przewalski's stallion.

The case of an 8-year-old, sexually active but infertile Przewalski's stallion (Equus ferus przewalskii) was studied. Besides the infertility, the stallion also showed permanent problems with its body condition, being obviously weaker than all the other group members. The horse was kept in a separate place for two years with 12 mares in its harem group (six mares had foals earlier); however, none of the mares covered got pregnant. Andrological and cytogenetic investigations revealed underdeveloped testes, arrested spermatogenesis, azoospermia, and XY/XXY/X0 mosaicism. We classify the case as a mosaic Klinefelter syndrome, the first reported case in Przewalski's horse.

Two Novel Cases of Autosomal Translocations in the Horse: Warmblood Family Segregating t(4;30) and a Cloned Arabian with a de novo t(12;25).

We report 2 novel autosomal translocations in the horse. In Case 1, a breeding stallion with a balanced t(4p;30) had produced normal foals and those with congenital abnormalities. Of his 9 phenotypically normal offspring, 4 had normal karyotypes, 4 had balanced t(4p;30), and 1 carried an unbalanced translocation with tertiary trisomy of 4p. We argue that unbalanced forms of t(4p;30) are more tolerated and result in viable congenital abnormalities, without causing embryonic death like all other known equine autosomal translocations. In Case 2, two stallions produced by somatic cell nuclear transfer from the same donor were karyotyped because of fertility issues. A balanced translocation t(12q;25) was found in one, but not in the other clone. The findings underscore the importance of routine cytogenetic screening of breeding animals and animals produced by assisted reproductive technologies. These cases will contribute to molecular studies of translocation breakpoints and their genetic consequences in the horse.

Socio-economic impacts of brucellosis on livestock production and reproduction performance in Koibatek and Marigat regions, Baringo County, Kenya.

BACKGROUND: Brucellosis in Africa is caused by Brucella species transmitted through contaminated or contacts with infected animals or their carcasses. The disease reduces livestock production and reproduction performance evident by frequent episodes of abortion, still births, swollen testes, weak calves/lambs and swollen joints. However, the socio-economic impacts of these brucellosis-associated symptoms on milk, fat, meat and blood production, infertility, sale value, dowry and costs of treatment has not been evaluated extensively in developing countries. In Baringo County, Kenya, there is a continuous movement of cattle as a result of trade and grazing, which predisposes many herds to brucellosis infection. The objective of this study was to investigate the socio-economic impacts of Brucella infection on production systems for sheep, goats, cattle and camels and explore the impact of brucellosis on livestock production and reproduction performance among livestock keeping communities in Baringo County, Kenya. The study adopted a cross-sectional survey using quantitative data collection methods. RESULTS: Results demonstrated an impact on milk production in suspected brucellosis cases resulting from abortions (OR = 0.151, P < 0.0001) and swollen joints (OR = 2.881, P < 0.0001). In terms of infertility, abortion as a symptom of brucellosis (OR = 0.440, P = 0.002), still birth (OR = 0.628, P = 0.042), and weak calf or lamb (OR = 0.525, P = 0.005) had an impact on infertility. In terms of sale value, abortion (OR = 0.385, P = 0.008), weak calf/lamb (OR = 2.963, P = 0.013) had an impact on sale value. Other analyses demonstrated that for dowry, swollen testes (OR = 5.351, P = 0.032), weak calf and lambs (OR = 0.364, P = 0.019) had a likelihood of reduction of dowry value. Finally, in terms of cost of treatment, abortion (OR = 0.449, P = 0.001), still births (OR = 0.208, P = 0.015), swollen testes (OR = 0.78, P = 0.014), weak calf/lambs (OR = 0.178, P = 0.007) and swollen joints (OR = 0.217, P = 0.003) significantly increased the costs of treatments. There was no impact on fat and meat and blood production. CONCLUSION: Even though there was a huge socio-economic impact on milk production, infertility, sale value, and dowry, it was the costs of treatment that was significantly impacted on all symptoms associated with brucellosis on this community. A 'One Health' approach in tackling the brucellosis menace as a holistic approach is recommended for both humans and their livestock.

Effect of treatment of phantom cows with a progesterone-based synchrony programme.

Aim: To determine the effect of a progesterone-based synchrony programme on the daily hazard of conception and the probability of being pregnant at the end of the seasonal mating period in cows not observed in oestrus within 35-49 days of insemination and that were diagnosed non-pregnant (phantom cows) on seasonally calving New Zealand dairy farms. Secondary aims were to determine the prevalence of phantom cows and estimate the proportion of phantom cows with a functional corpus luteum (CL) at enrolment. Methods: Phantom cows from 14 New Zealand commercial dairy farms were enrolled in a randomised, controlled trial. Cows that were artificially inseminated ≤14 days after mating start date and were not subsequently detected in oestrus, were presented for pregnancy diagnosis approximately 49 days after mating start date. Non-pregnant cows were diagnosed as phantom cows and randomly allocated to treatment and control groups. A milk sample was collected for progesterone assay to determine the presence of a functional CL. Treatment consisted of an injection of buserelin and insertion of an intravaginal device containing progesterone on Day 0, injections of dinoprost and equine chorionic gonadotrophin, and removal of the intravaginal device on Day 7, injection of buserelin on Day 9, and fixed time artificial insemination on Day 10. Treatment group cows were then mixed with bulls for the remainder of the seasonal mating period. Cows allocated to the control group were mated naturally by bulls. Statistical models were constructed to determine the effect of treatment on the daily hazard of conception and the probability of being pregnant at the end of the seasonal mating period. Results: A total of 378/4,214 (9.0%) cows presented for pregnancy diagnosis were diagnosed as phantom cows. A functional CL was diagnosed in 257/362 (71.0%) phantom cows. Median predicted enrolment to conception intervals were 33 (95% CI = 30-45) and 30 (95% CI = 28-33) days, for cows in the control and treatment groups, respectively. The odds of being pregnant at the end of mating were 1.70 (95% CI = 1.34-2.17) times greater for treated phantom cows than untreated phantom cows. Estimated marginal mean proportion pregnant at mating end date were 59.5 (95% CI = 47.9-70.1)% and 71.5 (95% CI = 62.6-79.0)% for control and treatment group cows, respectively. Conclusions: Treatment with a progesterone-based synchrony programme significantly increased the probability of phantom cows being pregnant at the end of the seasonal mating period.

Genetics of Equine Reproductive Diseases.

Reproductive disorders are genetically heterogeneous and complex; available genetic tests are limited to chromosome analysis and 1 susceptibility gene. Cytogenetic analysis should be the first test to confirm or rule out chromosomal aberrations. No causative genes/mutations are known. The only available genetic test for stallion subfertility is based on a susceptibility gene FKBP6. The ongoing progress in equine genomics will improve the status of genetic testing. However, because subfertile phenotypes do not facilitate collection of large numbers of samples or pedigrees, and clinical causes of many cases remain unknown, further progress requires constructive cross-talk between geneticists, clinicians, breeders, and owners.

Management strategies, reproductive performance and causes of infertility in sheep flocks in the central region of Saudi Arabia.

The objectives of this study were to identify the management strategies, reproductive characteristics, and causes of the infertility in sheep flocks in the central region of Saudi Arabia. Reproductive data were collected from 43 Awassi flocks containing 12,012 heads and 16 Najdi flocks having 2867 heads. Reproductive tracts of females culled from breeding from these flocks (Awassi, n = 127; Najdi, n = 32) were collected from slaughterhouses to detect the common pathological lesions. The results showed that most flocks contained large number of animals housed mainly in shelters and involved small number of workers. Few managers had high school education and very few farms relied on breeding records, regular veterinary visits, and the use of modern reproductive techniques. Sheep flocks with large number of animals; low-educated and less-experienced managers showed higher stillbirth rate than other flocks (P = 0.02). Sheep housed in shelter demonstrated greater lambing rate than sheep managed between grazing and shelter systems (P = 0.03). Ewes bred seasonally had greater lambing rate than those bred all year (P = 0.03). Non-functioning ovaries, pyometra, and ovarian-bursal adhesion were the common findings in the culled barren ewes. In conclusion, reproductive efficiency of sheep in the central area of Saudi Arabia could be improved by reforming some management approaches, justifying workers/animals ratio, instructing sheep breeders, and controlling genital diseases.

UNILATERAL SINGLE VAGINAL ECTOPIC URETER WITH IPSILATERAL HYPOPLASTIC AND DEGENERATED KIDNEY ASSOCIATED WITH INFERTILITY IN IBERIAN IBEX (CAPRA PYRENAICA) DOES.

This article describes the urinogenital condition of three female Iberian ibexes (Capra pyrenaica-one infertile 3-yr-old adult and two prepubertal animals aged 1 (PP1) and 2 (PP2) yr, respectively, all raised in captivity. All showed constant urinal dribbling, leading to ulcerative dermatitis in the vulvar area. Housed in a stable with other females, the adult did not become pregnant after male contact in either of two consecutive mating seasons. Vaginoscopy and laparoscopic exploration performed on the prepubertal females revealed abnormalities of the vagina and urinary bladder. Ultrasound examination revealed atrophy of the left kidney in the adult female and PP1, and of the right kidney in PP2, with degeneration of the renal pelvis. A paraovarian cyst with hydrosalpinx was also detected in the left oviduct of the adult female. Postmortem analysis of the adult and PP2, which shared a mother, confirmed an extramural single ectopic ureter with vaginal insertion associated with atrophy of the ipsilateral kidney. Though PP1 was officially unrelated to the latter animals, all three might have had a common ancestor in their lineages.

Novel method for mass producing genetically sterile fish from surrogate broodstock via spermatogonial transplantation†.

A stable system for producing sterile domesticated fish is required to prevent genetic contamination to native populations caused by aquaculture escapees. The objective of this study was to develop a system to mass produce stock for aquaculture that is genetically sterile by surrogate broodstock via spermatogonial transplantation (SGTP). We previously discovered that female medaka carrying mutations on the follicle-stimulating hormone receptor (fshr) gene become sterile. In this study, we demonstrated that sterile hybrid recipient females that received spermatogonia isolated from sex-reversed XX males (fshr (-/-)) recovered their fertility and produced only donor-derived fshr (-) X eggs. Natural mating between these females and fshr (-/-) sex-reversed XX males successfully produced large numbers of sterile fshr (-/-) female offspring. In conclusion, we established a new strategy for efficient mass production of sterile fish. This system can be applied to any aquaculture species for which SGTP and methods for producing sterile recipients can be established.

Autogenous transfer of intracytoplasmic sperm injection-produced equine embryos into the uterus of the oocyte donor during the same oestrous cycle.

The clinical use of intracytoplasmic sperm injection (ICSI) in horses usually involves the transfer of embryos into recipient mares, resulting in substantial cost increases. This is essential when subfertile mares are oocyte donors; but some donors are fertile, with ICSI compensating for limited or poor-quality spermatozoa. Fertile oocyte donors could carry pregnancies, eliminating the need for a recipient. We assessed the potential of using oocyte donors as recipients for their own ICSI-produced embryos during the same cycle. Donors in oestrus and with large dominant follicles were administered ovulation-inducing compounds to cause follicle and oocyte maturation. Maturing oocytes were collected, cultured and fertilised using ICSI. At 6 or 7 days after ICSI, developing blastocysts were transferred into respective donors' uteri, and pregnancy rates were determined. Twenty follicles were aspirated from nine mares and 12 oocytes were collected. After ICSI, 10 of the 12 oocytes (83%) cleaved, and eight (67% of injected oocytes) developed into blastocysts for transfer. Five pregnancies resulted from the eight transferred embryos (pregnancy rate 62% per embryo and 42% per sperm-injected oocyte). Following this synchronisation regime, ICSI-produced embryos can be transferred into oocyte donors' uteri during the same cycle, allowing donors to carry pregnancies after assisted fertilisation.

Depletion of endogenous germ cells in striped catfish Pangasianodon hypophthalmus (Sauvage, 1878) by heat-chemical treatments.

Germ cell (GC) transplantation (GCT) is a proven powerful reproductive technique to enhance the production efficiency of domesticated animals and aid to the recovery of endangered germ lines. In mammals, several methods have been adopted for the eradication of GCs such as treatment with cytotoxic drugs, irradiation, cold ischaemia and hyperthermic treatment. Some of these methods have also been tried in fishes, and conditions for sterilization of gonads have been established. Here, we report the production of GC-depleted male striped catfish Pangasianodon hypophthalmus in 12 weeks by the combination of heat and chemical treatments. The cytotoxic drug busulphan (40 mg/kg) was intraperitoneally injected into the animals at 2-week intervals (six doses in total) and maintained in water at 38°C between weeks 1 and 12. The effectiveness of the treatment was assessed using gonadal index and histology. At the end of 12 weeks, very severe gonadal degeneration was observed in fish treated with the heat-chemical combination, and 100% of sampled fish (n = 5) were found devoid of endogenous GCs. On contrary, high temperature alone caused minor gonadal degeneration. Results obtained in this study suggest that endogenous GCs of large-bodied fish such as P. hypophthalmus can also be sterilized by heat and chemical treatments within a considerably short period.

Is sperm cryopreservation in absence of permeable cryoprotectants suitable for subfertile donkeys?

Sperm from fertile donkeys have been successfully frozen in absence of permeable cryoprotectants. The aim of this study was to determine whether this cryopreservation method is suitable for subfertile donkeys in comparison to conventional sperm freezing with glycerol. Ejaculates were collected from four Andalusian Donkeys: three fertile and one subfertile. Semen was frozen with an extender containing glycerol (GLY), or adding instead sucrose 0.25 molar and 1% bovine serum albumin (SUC) as non-permeable cryoprotectants. After thawing, samples were assessed for total (TM, %) and progressive (PM, %) sperm motility by CASA, plasma membrane integrity (PMI, %) by epifluorescence microscopy and DNA integrity (DFI, %) by SCSA. Results (mean ± SD) were compared between extenders in fertile and subfertile donkeys using the Student's t test. No differences between GLY and SUC treatments were found in the fertile group for the sperm parameters assessed. In subfertile donkey ejaculates, GLY resulted in significantly higher values than SUC for TM (25.5 ± 3.1 vs. 19.6 ± 1.9) and PM (13.3 ± 5.1 vs. 4.0 ± 1.2), respectively. In conclusion, considering all the sperm parameters assessed, sperm freezing in absence of permeable cryoprotectants may not be still an option for cryopreservation of subfertile donkey sperm.

A new molecular screening tool for the detection of chromosomal abnormalities in donkeys.

Chromosomal abnormalities are a major cause of infertility and reproductive problems in equids. Nowadays, their detection is rising due to the use of new diagnostic tools based on molecular markers instead of karyotyping. Reports of this kind of genetic aberrations in domestic donkeys (Equus asinus) are extremely scarce, despite their importance in human activities. In the present study, we analysed the implementation of a short-tandem-repeat (STR)-based molecular method initially developed for horses, as a diagnostic tool to detect chromosomal abnormalities in donkeys. The frequency of five X-linked (LEX003, LEX026, TKY38, TKY270 and UCEDQ502) and one Y-linked (ECAYM2) molecular markers and one Y-linked gene (sex-determining region Y, SRY) was characterized in 121 donkeys from two diverse breeds, the Spanish Andalusian and the African Moroccan breeds. The molecular panel showed 100% sensitivity and 99.67% specificity in detecting 10 different chromosomal abnormalities in the species. In conclusion, this methodology is a valid, rapid and low-cost tool for the detection and characterization of chromosomal abnormalities in domestic donkeys.

Coxiella burnetii in Infertile Dairy Cattle With Chronic Endometritis.

Coxiella burnetii is an obligate intracellular pathogen and the cause of Q fever in many animal species and humans. Several studies have reported the association between C. burnetii and abortion, premature delivery, stillbirth, and weak offspring. However, no solid evidence indicates that C. burnetii causes endometritis, subfertility, and retained fetal membranes. For this study, histopathological and PCR evaluation were performed on 40 uterine biopsies from dairy cattle with poor fertility. Uterine swabs were concurrently tested with microbiology assays. The endometrial biopsies of 30 cows did not have any significant lesions, and no pathogens were identified by aerobic bacterial culture and PCR. Ten cows were PCR-positive for C. burnetii and negative for other pathogens by aerobic bacterial culture and PCR. These 10 cases revealed a mild to severe chronic endometritis admixed with perivascular and periglandular fibrosis. Immunohistochemical evaluation of C. burnetii PCR-positive biopsies identified, for the first time, the presence of intralesional and intracytoplasmic C. burnetii in macrophages in the endometrium of cattle.

Homology between cattle bull sperm and bacterial antigenic proteins viz a viz possible role in immunological infertility.

This study was carried out to investigate the possible presence of identical sperm and bacterial antigens which may cause similar antisperm antibody production leading to lower fertility. Cross-reactive antigens of cattle bull spermatozoa and different bacteria including Escherichia coli (E. coli), Bacillus sp., and Staphylococcus sp. were characterized by immunoblotting and mass fingerprinting. Significant cross-reactivity was obtained for 75, 72, 44, 40, 33, 30, 25, 18, 14 kDa proteins with purified IgG of calves, heifers and cows between spermatozoa and the studied bacteria. Significantly (p < 0.05) matched cross-reactive 40/33/30 kDa sperm, 33 kDa Staphylococcus sp/Bacillus sp and 40/25 kDa E. coli proteins were analyzed. Mass fingerprinting of 40/33/30 kDa (spermatozoa); 40/25 kDa (E. coli) and 33 kDa (Bacillus/Staphylococcus) proteins revealed their matching with vitellogenin-1-like/mitochondrial malate dehydrogenase 2, NAD/acrosin-binding protein isoform XI; outer membrane insertion signal domain/spore coat protein and glyceraldehyde-3-phosphate dehydrogenase, respectively. Acrosin-binding protein isoform X1 and mitochondrial malate dehydrogenase 2, NAD contributes to the capacitation of spermatozoa. Spore coat protein; glyceraldehyde-3-phosphate dehydrogenase of E. coli; Bacillus/Staphylococcus are 37.6% and 39.01% identical to acrosin-binding protein isoform X1; mitochondrial malate dehydrogenase 2, NAD of cattle bull spermatozoa. It can be interpreted from these observations that cross-reacting antibodies developed against 33/30 kDa sperm proteins and 25, 33 kDa bacterial proteins in cows may affect the functional activity of spermatozoa leading to delayed fertility in heifers and cows.