Detection of Tritrichomonas Foetus by Polymerase Chain Reaction in Cultured Isolates, Cervicovaginal Mucus, and Formalin-Fixed Tissues from iNfected Heifers and Fetuses

A rapid, reliable polymerase chain reaction (PCR) assay, originally developed for definitive laboratory identification of the bovine venereal pathogen Tritrichomonas foetus from cultures of male reproductive tract fluids, was used for testing the following: 1) cultured, geographically disparate trichomonad isolates, 2) formalin-fixed tissues from infected heifers and naturally infected fetuses, and 3) cervicovaginal mucus (CVM) from experimentally infected females. In 12 of 12 Western Hemisphere isolates of pathogenic T. foetus (isolated from outbreaks of clinical trichomoniasis or from screening surveys) and in 1 of 1 American Type Culture Collection strain of Tritrichomonas suis, PCR yielded a positive result, i.e., a 347—base pair amplicon in the 5.8S ribosomal RNA and internal transcribed spacer (5.8S—ITS) region of the genome, whereas cultures of Trichomonas vaginalis and Trichomonas gallinae did not produce a PCR product. The PCR assay was also positive in formalin-fixed, paraffin-embedded endometrial samples from 4 of 4 experimentally infected heifers, as well as in archived tissues from 2 of 2 T. foetus—infected aborted bovine fetuses that were submitted to the diagnostic laboratory from a natural outbreak. It was negative in fixed, embedded uterine tissues of 2 of 2 uninfected virgin heifers used as negative controls and in archived fixed gut tissue of a T. gallinae—infected pigeon. In another experiment, CVM aspirated from 4 of 4 experimentally infected heifers in the fifth or sixth postinfection week yielded a positive PCR product of the expected size, whereas CVM from 2 of 2 controls were PCR negative. Pending validation in larger clinical studies, the PCR assay for the 5.8S—ITS coding region of the T. foetus genome offers the prospect of definitive identification of this agent directly from CVM or from formalin-fixed tissues or when false-positive culture results are suspected.

Survival of bovine embryos stored at 4 degrees C

These experiments were designed to test the efficacy of storing bovine embryos at 4 degrees C. Of particular interest were the age of embryo at which maximum post-storage survival could be achieved and longevity at 4 degrees C. A greater proportion of day 8 blastocysts developed in vitro at 37 degrees C following refrigeration for 48 hr than did embryos collected 2, 4 or 6 days after estrus (P<0.01). Survival of blastocysts stored at 4 degrees C for 48 hr was similar to that of nonstored blastocysts. In a subsequent experiment, day 8 blastocysts were recovered nonsurgically and assigned to one of the following treatments: (a) immediate transfer; (b) culture at 37 degrees C; or (c) storage at 4 degrees C for 1, 2, 3 or 5 days. Post-storage viability was assessed by either development in culture at 37 degrees C or embryo survival following nonsurgical transfer to synchronized recipients. In vitro survival of nonstored embryos and embryos stored 1 day did not differ. Survival decreased after storage for 2 days (P<0.10) or longer (P<0.05). Similar results were observed for survival after transfer, but embryo viability decreased even more rapidly with increasing duration of storage. In vitro survival was approximately 50% for blastocysts stored for 3 and 5 days, but few pregnancies resulted from transfer of embryos stored for these periods. In another experiment survival after transfer of blastocysts stored at 4 degrees C for up to 2 days was similar to that of nonstored blastocysts.

A pregnant mouse model for bovine Tritrichomonas foetus infection

The economically important effects of Tritrichomonas foetus infection in cattle are abortion and infertility, yet there has not been an animal model to examine the parasite-host interactions during gestation. In this study, 5- and 7- to 8-week-old BALB/cAnNCr, BALB/cJ, and SCID/NCr mice on a BALB/c background were intravaginally infected with T. foetus. All BALB/cAnNCr and BALB/cJ mice, and 89% of SCID/NCr mice sustained infections for 13 weeks, if inoculated before 5 weeks of age. Infection rates were lower in all mouse strains inoculated at 7 weeks of age, although BALB/cAnNCr mice were significantly more susceptible than BALB/cJ or SCID/NCr mice. Vaginal bacterial flora did not account for the variation in mouse-strain susceptibility, although coagulase-negative staphylococci in vaginal flora were associated with failure of T. foetus to infect. As with infected cattle, T. foetus-specific vaginal immunoglobulin (Ig) G and IgA antibodies were elevated after infection. The number and viability of day-10 fetuses were reduced in mice infected at 5 weeks of age and bred 12 weeks after infection. Lesions in pregnant and nonpregnant infected mice, including suppurative and eosinophilic vaginitis; cervicitis; endometritis with distension of the uterine lumen; endometrial ulceration; and glandular ectasia, with neutrophils in the glandular lumen and loss of gland epithelium, were similar to those in cattle. The decidua and placenta were multifocally necrotic. Immunohistochemistry demonstrated trichomonads in vaginal folds and uterine glands, and adjacent to fetal tissues. In summary, experimentally infected BALB/cAnNCr mice showed many pathologic similarities to cattle and may serve as a model to study host-trichomonad interactions.

Sensitivity and specificity of culture and PCR of smegma samples of bulls experimentally infected with Tritrichomonas foetus

The sensitivity (Se) and specificity (Sp) of different testing schemes were estimated for detecting Tritrichomonas foetus (T. foetus) in smegma samples from experimentally infected bulls. Culture and polymerase chain reaction (PCR) on smegma samples were evaluated alone and in parallel testing. Mature dairy bulls (n=79) were intrapreputially inoculated with T. foetus (n=19); Campylobacter (C.) fetus venerealis (n=13); both T. foetus and C. fetus venerealis (n=11); Tetratrichomonas spp. (n=9); C. fetus fetus (n=8); or were not inoculated (n=19). For each bull, smegma samples were collected for 6 week post-inoculation and tested for T. foetus by In Pouch TF culture and PCR. Most T. foetus-inoculated bulls became infected, according to culture (86.7%), PCR (90.0%), and both tests together (93.3%). In T. foetus-inoculated bulls, both tests combined in parallel on a single sample had a Se (78.3%) and Sp (98.5%) similar to two cultures (Se 76.0%, Sp 98.5%) or two PCR (Se 78.0%, Sp 96.7%) sampled on consecutive weeks. The PCR on three consecutive weekly samples (Se 85.0%, Sp 95.4%) and both tests applied in parallel on three consecutive weekly samples (Se 87.5%, Sp 95.6%) were similar to the current gold-standard of six weekly cultures (Se 86.7% and Sp 97.5%). Both tests used in parallel six times had the highest Se (93.3%), with similar Sp (92.5%). Tetratrichomonas spp. were only sporadically detected by culture or PCR. In conclusion, we have proposed alternative strategies for T. foetus diagnostics (for the AI industry), including a combination of tests and repeat testing strategies that may reduce time and cost for bull surveillance.

Selected diseases and conditions associated with bovine conceptus loss in the first trimester

The outcomes of insults to the bovine conceptus depend on the predilection of the insulting agent for the gravid reproductive tract, the virulence of the insult, and the developmental maturity/immune competence of the conceptus at the time of the insult. Agents that are lethal at one time during gestation may be harmless at another, or may have completely different effects (some not so harmless) at different gestational ages. This review discusses some of the known physical-mechanical, physiological, and infectious causes of first trimester bovine conceptus losses, including three infectious agents that have been the subject of recent studies for their potential to transmit disease via embryo transfer.

Birth of large calves that developed from in vitro-derived bovine embryos

High birth weights were observed in calves that developed from bovine embryos produced by in vitro maturation (IVM) and in vitro fertilization (IVF) procedures. After IVM and IVF, embryos were either co-cultured in vitro with oviductal epithelial cells or transferred into the sheep oviduct for development to the blastocyst stage. Blastocysts were transferred to the reproductive tracts of recipient heifers and cows for development to term. Birth weights and gestation periods were compared between calves that developed from in vitro-derived embryos and calves born after artificial insemination (AI) of cows in the herd from which recipient females were selected. Gestation periods were not different among the groups (P > 0.05), but calves that developed from IVM/IVF-derived embryos co-cultured in vitro were larger at birth than calves born from IVM/IVF-derived embryos that developed into blastocysts in the sheep oviduct and calves born from AI (P < 0.001). Dystocia and calf mortality were associated with large calf size at birth. These data were collected from an experiment designed for other purposes, and confounding variables and small sample size could have influenced the observed differences in birth weights. Nevertheless, the extreme birth weights of some calves suggest that abnormal prenatal growth occurs in some IVM/IVF-derived bovine embryos and that conditions for co-culture to the blastocyst stage may exacerbate the problem.

Importation of in vitro-produced Bubalus bubalis embryos from Italy into the United States: a case report

On December 19, 2005, 14 in vitro-fertilized water buffalo (Bubalus bubalis) embryos, which had been cryopreserved by vitrification, were thawed and transferred into B. bubalis recipients in California. The embryos had been produced in Italy, following transvaginal oocyte pickup (TVOPU), with subsequent in vitro maturation, insemination, and culture. This case study relates our experience in meeting the regulatory criteria, established by the Animal Import/Export Office of the USDA-Animal and Plant Health Inspection Service (USDA-APHIS), in order to successfully import these embryos into the USA.

Evaluation of factors that affect embryonic loss in dairy cattle

OBJECTIVE

To identify potential risk factors for embryonic loss before 35 to 42 days of gestation in dairy cattle.

DESIGN

Prospective observational study.

ANIMALS

381 cows.

PROCEDURE

Body condition score was determined at the time of artificial insemination (AI; day 0) and on days 20, 23, and 27 and between days 35 and 41; serum progesterone concentration was measured on days 0; 20 or 21; and 23, 24, or 25. Cows were excluded from analyses if day 0 serum progesterone concentration was > or = 1.0 ng/mL and classified as pregnant on day 23 if serum progesterone was > 1.5 ng/mL on day 20 or 21 and day 23, 24, or 25. Cows were examined via transrectal ultrasonography on day 27 or 28 and rectally palpated for pregnancy on days 35 to 41.

RESULTS

39% of cows that were pregnant on day 23 lost their embryo by day 27, and 18% of cows that were pregnant on day 27 or 28 were not pregnant on days 35 to 41. Breeding a pregnant cow posed the greatest risk for embryonic loss at both time periods. Mean serum progesterone concentrations on day 21 or 22 and day 23, 24, or 25 were lowest for cows that lost an embryo between days 24 and 28. Cows with a linear somatic cell count score > 4.5 before AI were twice as likely to lose the embryo by 35 to 41 days, compared with cows with a score < 4.5.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that embryonic loss could be reduced by more accurate estrus detection, reducing mastitis, and strategies to improve progesterone concentration after breeding.

An improved molecular assay for Tritrichomonas foetus

Tritrichomonas foetus (T. foetus) is the causative agent of bovine trichomonosis, a sexually transmitted disease leading to abortion (from 1 to 8 months gestation), infertility, and occasional pyometra. The annual losses to the U.S. beef industry are estimated to be in the hundreds of millions of dollars. Currently, the "gold standard" diagnostic test for trichomonosis in most countries is the cultivation of live organisms from reproductive secretions. The cultured organisms can then be followed by PCR assays with primers that amplify T. foetus to the exclusion of all other trichomonad species. Thus, negative results present as null data, indistinguishable from failed PCR amplification during T. foetus specific amplification. Our newly developed assay improves previously developed PCR based techniques by using diagnostic size variants from within the internal transcribed spacer 1 (ITS1) region that is between the 18S rRNA and 5.8S rRNA subunits. This new PCR assay amplifies trichomonad DNA from a variety of genera and positively identifies the causative agent in the bovine trichomonad infection. This approach eliminates false negatives found in some current assays as well as identifying the causative agent of trichomonad infection. Additionally, our assay incorporates a fluorescently labeled primer enabling high sensitivity and rapid assessment of the specific trichomonad species. Moreover, electrophoretic separation of amplified samples can be outsourced, thus eliminating the need for diagnostic laboratories to purchase expensive analysis equipment.

Hot Topic: Using a Stearoyl-CoA Desaturase Transgene to Alter Milk Fatty Acid Composition

Stearoyl-CoA desaturase enzyme converts specific medium- and long-chain saturated fatty acids to their monounsaturated form. Transgenic goats expressing a bovine beta-lactoglobulin promoter-rat stearoyl-CoA desaturase cDNA construct in mammary gland epithelial cells were produced by pronuclear microinjection. The fatty acid composition of milk from 4 female transgenic founders was analyzed on d 7, 14, and 30 of their first lactation. In 2 animals, the expression of the transgene changed the overall fatty acid composition of the resulting milk fat to a less saturated and more monounsaturated fatty acid profile at d 7 of lactation; however, this effect diminished by d 30. In addition, one animal had an increased proportion of the rumen-derived monounsaturated fatty acid C18:1 trans11 converted by stearoyl-CoA desaturase to the conjugated linoleic acid isomer C18:2 cis9 trans11. Milk that has higher proportions of monounsaturated fatty acids and conjugated linoleic acid may have benefits for human cardiovascular health.

Development of a simulation model to evaluate the effect of vaccination against Tritrichomonas foetus on reproductive efficiency in beef herds

OBJECTIVE

To develop a model to evaluate the effect of vaccination against Tritrichomonas foetus on reproductive efficiency in beef herds.

SAMPLE POPULATION

A beef herd of 300 cows and 12 bulls (8 bulls < or = 3 years old and 4 bulls > 3 years old).

PROCEDURE

The model was developed by use of data for various risk factors and vaccine efficacy. The reference herd was considered to be one in which T. foetus had been diagnosed and bulls were tested for T. foetus before the breeding season. Five thousand iterations were run for each of 13 simulations, with each simulation representing a separate combination of risk factors.

RESULTS

In all simulations, vaccination resulted in significantly higher calving incidence than nonvaccination. Shared grazing was found to be the most significant risk factor for a decrease in calving incidence attributable to T. foetus infection, followed in importance by lack of testing before the breeding season and a higher proportion of old bulls. Combinations of risk factors contributed to a loss of income of up to 22%, some of which could be blunted by vaccination.

CONCLUSIONS AND CLINICAL RELEVANCE

Highest calving incidence is achieved when all bulls are tested for T. foetus before the breeding season and all bulls with positive culture results are culled. Avoiding all risk factors is better than vaccinating, but when this is not feasible for a given herd, the results of this simulation indicate that proper vaccination can decrease economic losses attributable to abortions caused by T. foetus.

Effect of post-insemination supplementation with PRID on pregnancy in repeat-breeder Holstein cows

Embryonic mortality contributes to repeat-breeding in dairy cows; luteal insufficiency is a known cause of embryonic mortality. The objective of this study was to assess the efficacy of supplementation with exogenous progesterone for 14 days on pregnancy maintenance in inseminated repeat-breeder dairy cows. On Day 5 after insemination, treated cows ( n=143 ) received a modified PRID (i.e. without estradiol capsule), which was removed on Day 19. Control cows ( n=148 ) did not receive any treatment. Overall there was no effect of PRID supplementation on pregnancy rates. However, when the study population was stratified by parity and stage of lactation, PRID supplementation significantly improved pregnancy rate in first and second parity late lactation cows (risk ratio = 3.26; 95% CI 1.22, 8.69). Pregnancy rates did not differ between PRID-treated cows with ( n=81 ) and without vaginitis. Control cows tended ( P=0.077 ) to have a higher proportion of abortions than PRID-treated cows (7/50 versus 2/51, respectively). In conclusion, young late lactation repeat-breeder cows benefited from progesterone supplementation, in terms of maintaining pregnancy until traditional time of pregnancy diagnosis.

Attempts to enhance production of porcine chimeras from embryonic germ cells and preimplantation embryos

Porcine embryonic germ (EG) cells share common features with porcine embryonic stem (ES) cells, including morphology, alkaline phosphatase activity and capacity for in vitro differentiation. Porcine EG cells are also capable of in vivo development by producing chimeras after blastocyst injection; however, the proportion of injected embryos that yield a chimera and the proportion of cells contributed by the cultured cells in each chimera are too low for practical use in genetic manipulation. Moreover, somatic, but not germ-line chimerism, has been reported from blastocyst injection using porcine ES or EG cells. To test whether efficiency of chimera production from blastocyst injection can be improved upon by changing the host embryo, we used as host embryos four groups according to developmental stage or length in culture: fresh 4-cell and 8-cell stage embryos subsequently cultured into blastocysts, fresh morulae, fresh blastocysts, and cultured blastocysts. Injection and embryo transfer of fresh and cultured blastocysts produced similar percentages of live piglets (17% versus 19%). Four piglets were judged to have a small degree of pigmentation chimerism, but microsatellite analysis failed to confirm chimerism in these or other piglets. Polymerase chain reaction analysis for detection of the porcine SRY gene in female piglets born from embryos injected with male EG cells identified six chimeras, at least one, but not more than two, from each treatment. Chimerism was confirmed in two putative pigmentation chimeras and in four piglets without overt signs of chimerism. The low percentage of injected embryos that yielded a chimera and the small contribution by EG cells to development of each confirmed chimera indicated that procedural changes in how EG cells were combined with host embryos were unsuccessful in increasing the likelihood that porcine EG cells will participate in embryonic development. Alternatively, our results suggested that improvements are needed in EG cell isolation and culture procedures to ensure in vitro maintenance of EG cell developmental capacity.

Increased efficiency of transgenic livestock production

Production of transgenic livestock by pronuclear microinjection of DNA into fertilized zygotes suffers from the compounded inefficiencies of low embryo survival and low integration frequencies of the injected DNA into the genome. These inefficiencies are one of the major obstacles to the large-scale use of pronuclear microinjection techniques in livestock. We investigated exploiting the properties of recombinase proteins that allow them to bind DNA to generate transgenic animals via pronuclear microinjection. In theory, the use of recombinase proteins has the potential to generate transgenic animals with targeted changes, but in practice we found that the use of RecA recombinase-coated DNA increases the efficiency of transgenic livestock production. The use of RecA protein resulted in a significant increase in both embryo survival rates and transgene integration frequencies. Embryo survival rates were doubled in goats, and transgene integration was 11-fold higher in goats and three-fold higher in pigs when RecA protein-coated DNA was used compared with conventional DNA constructs without RecA protein coating. However, a large number of the transgenic founders generated with RecA protein-coated DNA were mosaic. The RecA protein coating of DNA is straightforward and can be applied to any species and any existing microinjection apparatus. These findings represent significant improvements on standard pronuclear microinjection methods by enabling the more efficient production of transgenic livestock.

Two-step (culture and PCR) diagnostic approach for differentiation of non-T. foetus trichomonads from genitalia of virgin beef bulls in Argentina

Preputial fluids from 567 virgin Angus and Hereford bulls, 1-2 years old, were inoculated into Sutherland medium, and approximately 8.4% produced cultures with a protozoan suggestive of Tritrichomonas foetus. Under brightfield microscopy, large numbers of single-celled motile organisms with multiple anterior flagellae, a posterior flagellum, axostyle, and a visible undulating membrane were detectable. Motility was jerky and rolling, as described for T. foetus. Air-dried smears of cultures stained with Giemsa or Diff-Quick + iodine revealed an organism similar to T. foetus, although somewhat more rounded. Several organisms appeared to have four anterior flagellae. Scanning electron microscopy (5000x) of representative samples revealed four anterior flagellae on most organisms, and an axostyle that was consistently longer than that seen in T. foetus. Using pan-trichomonal primers and T. foetus-specific primers in a polymerase chain reaction (PCR) assay, amplification products of 372bp were detected in all virgin bull isolates, but only with the pan-trichomonal primers. Positive control isolates of T. foetus yielded amplification products of the expected size (372 and 347bp) with the two sets of primers, respectively. We conclude that these protozoa are not T. foetus, and note the similarity of these findings with those reported earlier in North American beef cattle. Because in several countries there is no legal treatment for bovine trichomonosis, veterinarians recommend slaughter of bulls with positive preputial cultures. The existence of easily mis-identified non-T. foetus trichomonads in the bovine prepuce suggests that the current "gold standard" diagnostic test (culture of preputial scrapings or washings) should be augmented with a more specific confirming test, such as the PCR employed in this study.

Comparison of the 5.8S rRNA gene and internal transcribed spacer regions of trichomonadid protozoa recovered from the bovine preputial cavity

Sequence analysis of the 5.8S rRNA gene and the internal transcribed spacer regions (ITSRs) was used to compare trichomonadid protozoa (n = 39) of varying morphologies isolated from the bovine preputial cavity. A multiple sequence alignment was performed with bovine isolate sequences and other trichomonadid protozoa sequences available in GenBank. As a group, Tritrichomonasfoetus isolates (n = 7) had nearly complete homology. A similarity matrix showed low homology between the T. foetus isolates and other trichomonads recovered from cattle (<70%). Two clusters of trichomonads other than T. foetus were identified. Eighteen isolates comprised 1 group. These isolates shared >99% homology among themselves and with Pentatrichomonas hominis. The other non-T. foetus cluster (n = 14) did not exhibit a high degree of homology (<87%) with other bovine isolates or any of the trichomonad sequences available in GenBank. The sequence homology among isolates in that cluster was >99%, except for 1 isolate that varied from the others in both ITSRs (approximately 2% dissimilarity). Sequence analysis of the 5.8S rRNA gene and ITSRs was useful for comparing trichomonadid protozoa isolated from the bovine preputial cavity and demonstrated that 2 distinct types of trichomonads constituted the non-T. foetus isolates recovered from the bovine preputial cavity.

Experimental transmission of epizootic bovine abortion (foothill abortion)

Advances in defining the biology of epizootic bovine abortion (EBA), including identification of the etiologic agent, have been hampered by the inability to reproduce the disease with confidence. Experimental reproduction of EBA, by feeding the tick vector Ornithodoros coriaceus on susceptible pregnant heifers, is not reliable. The primary objectives of this study were to identify specific tissue(s) obtained from EBA-infected fetuses that could transmit the disease, and then utilize such an infectious challenge system to better define the pathogen, host immunity and geographic distribution of the agent. Described here is the ability to routinely reproduce EBA following inoculation of cryopreserved suspensions of homogenized thymus into susceptible pregnant heifers. This challenge system permitted experiments demonstrating the agent was non-filterable, inactivated upon sonication and susceptible to antibiotics. These findings suggest a prokaryotic microbe and represent a major advance in EBA research. Additional experiments demonstrated that inoculation of the cryopreserved EBA-infectious tissue into heifers, prior to breeding, conferred immunity. Furthermore, such immunized heifers were resistant to challenge with heterologous sources of infectious tissue, suggesting monovalent vaccine development might be feasible. Lastly, challenge studies employing animals from Central Nevada, an area considered free of EBA, demonstrated partial immunity, suggesting the pathogen, and possibly the disease, enjoy a broader distribution than previously thought.

Immunity to bovine reproductive infections

Protective immune responses in the genital tract are robust, as shown by convalescent and vaccine-induced immunity. Systemic immunity is crucial for systemic infections that result in reproductive failure (such as brucellosis, leptospirosis, and the systemic forms of C. fetus and H. somnus infection). Although IgA responses can protect against sexually transmitted or venereal infections, systemically induced IgG antibody responses also protect. IgA responses can be induced by immunization of the genital tract, where inductive sites develop after antigenic stimulation. The common mucosal immune system can also be used to induce a genital IgA response, as shown by intranasal vaccination. Lastly, it is necessary to determine which antigens of each infectious agent are protective and which types of immune responses protect best.

Immunological and biochemical analysis of glycosylated surface antigens and lipophosphoglycan of Tritrichomonas foetus

Immunoaffinity-purified TF1.17 adhesin antigen was compared biochemically and antigenically to Tritrichomonas foetus (TF) lipophosphoglycan (LPG) and a soluble glycosylated antigen (SGA) released from T. foetus and implicated in pathogenesis and immunity. The monoclonal antibodies (Mabs TF1.15 and TF1.17) specific for a glycosylated TF1.17 antigen were previously shown to prevent adhesion of the T. foetus parasites to bovine vaginal epithelial cells and to mediate killing by bovine complement. SGA was isolated from T. foetus-conditioned buffer and purified by octyl-Sepharose hydrophobic column chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of SGA showed a major SGA1 component (approximately 190 kDa) and a minor SGA2 component (50-70 kDa), which migrated close to TF-LPG and TF1.17. The carbohydrate and lipid compositional analyses of affinity-purified TF1.17 and SGA2 by high-performance liquid chromatography (HPLC) and gas-liquid chromatography revealed the presence of monosaccharides and fatty acids as found in TF-LPG. All antigens contained terminal fucose as determined by alpha-fucosidase digestion followed by HPLC. ELISA and western blots were used to further characterize these glycosylated antigens and to analyze their relationships. The Mabs TF1.15 and TF1.17 reacted very strongly to TF-LPG and SGA2. as well as TF1.17 antigen, indicating that these molecules share common epitopes. These Mabs did not react with the SGA1 component either in ELISA and western blot analyses. Also, the monosaccharide composition of SGA1 was very different from the other three antigen, suggesting SGA1 was different from LPG, SGA2 and TF1.17. Although LPG reacted with Mabs to native TF1.17 antigen, LPG did not induce an immune response in cattle with the same route and adjuvant used to produce strong antibody responses to the native antigen. The latter response suggests that the tightly bound peptide present in the immunoaffinity-purified antigen is necessary for induction of a response to (an) epitope(s) in TF-LPG and TF1.17. Furthermore, vaginal fluid from T. foetus-infected heifers and serum from a cow with a T. foetus-associated pyometra recognized both TF1.17 and TF-LPG in western blots. These results suggest that T. foetus LPG and SGA2 are related to TF1.17 antigen, which was previously shown to play an important role in the pathogenesis and host response in bovine trichomoniasis.

Reproductive effects of estradiol cypionate in postparturient dairy cows

OBJECTIVE

To determine the effects of estradiol cypionate (ECP) on measures of reproductive efficiency in postparturient dairy cows.

DESIGN

Randomized clinical trial.

ANIMALS

273 cows in a single herd in California.

PROCEDURE

Twenty-four hours after parturition, 122 cows were treated with ECP (4 mg, IM); the remaining 151 cows were untreated controls. Percentages of cattle with abnormal findings during uterine palpation 27 to 40 days after parturition were compared between groups, along with days to first artificial insemination (AI), percentages of cows that were not pregnant after the first AI, and days to pregnancy.

RESULTS

Treatment with ECP did not have a significant effect on whether results of uterine palpation 27 to 40 days after parturition were abnormal, days to first AI, or odds that a cow would be pregnant after the first AI. Treatment with ECP appeared to have a negative effect on days to pregnancy (hazard ratio, 0.72)

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that prophylactic administration of ECP during the early postparturient period in dairy cows did not have measurable beneficial effects on reproductive efficiency.

Bovine trichomoniasis as a model for development of vaccines against sexually-transmitted disease

PROBLEM

Human sexually transmitted diseases (STDs) are widespread but effective vaccines are rare. Experimental and commercially available vaccines for bovine trichomoniasis have been well studied. Principles for immune protection of the female genital tract derived from studies of bovine trichomoniasis may be generally applicable to human trichomoniasis and other STDs.

METHOD OF STUDY

A bovine model of trichomoniasis has been developed for study of mechanisms of immunoprophylaxis.

RESULTS

Both systemic and local immunization with an immunoaffinity purified antigen cleared the genital tract of trichomonads significantly earlier than non-immunized controls. Predominantly IgA responses or predominantly IgG responses in uterine and vaginal secretions were essentially equally protective. Uterine and vaginal IgA responses could be induced by systemic priming and local boosting via either the vaginal or nasal mucosa. In either case, lymphoid aggregates were formed in the uterine and vaginal mucosa which were not present in the genital mucosa of naïve animals.

CONCLUSIONS

Systemic immunization or systemic priming with local boosting protects against bovine trichomoniasis via IgG or IgA antibodies (respectively) to a major surface antigen of trichomonads. Immunization of the genital mucosa results in formation of inductive sites for a local IgA response.

Fetal leukocyte trafficking as a stimulus for the production of maternal antibodies in the goat

The production of antibodies during pregnancy or after parturition is a natural occurrence in many mammalian species. Fetal cells have been detected in the peripheral blood of women and mice and are thought to be the immune stimulus for antibody production. The aim of this study was to investigate if the production of maternal anti-fetal antibodies during ruminant pregnancy is the result of fetal leukocyte trafficking across the placenta. Maternal pregnancy serum was collected from 94 does whose fetuses received sheep hematopoietic stem cells via in utero transplantation at 49 to 62 d of gestation. Serum samples were collected before surgery and at weekly intervals throughout gestation. A lymphocyte microcytotoxicity assay was used to screen the serum samples from does that carried chimeric fetuses to term (n = 75). Of these 75 does, 28 parous does had presurgery serum that contained alloreactive antibodies. Nine of the 75 does had nonreactive presurgery serum, but they produced alloreactive antibody titers during gestation. Xenoreactive antibodies were detected in the pregnancy sera from 2 of the 75 does tested. Hemolytic assays confirmed the species-specificity of the xenoreactive serum from these 2 does. In view of the fact that hematopoietic cells were the only source of anti-sheep antibody stimulation in this model, we propose that fetal leukocyte trafficking does take place across the caprine placenta.

Evidence against humoral immune attack as the cause of sheep-goat interspecies and hybrid pregnancy failure in the DOE

The failure of interspecies and hybrid pregnancies between the domestic sheep (Ovis aries) and goat (Capra hircus) is not completely understood. The sheep-goat hematopoietic chimera is a unique model for studying the role of the maternal immune response in failure of interspecies and hybrid pregnancies between these species. Hematopoietic chimeras were created by in utero transplantation of sheep fetal liver cells into goat fetuses. The resulting chimeric females were recipients of sheep demi-embryos genetically identical to their sheep cells and/or were bred to a ram to create a hybrid pregnancy. Pregnancy sera were analyzed for the presence of anti-species antibodies (Ab) using a lymphocyte microcytotoxicity assay. None of the concepti survived to term. Gross and histological evaluations of two interspecies sheep concepti revealed abnormal placentome formation. The humoral immune response of several hematopoietic chimeras to the challenging concepti differed from control animals. We observed delayed onset of Ab production, low and absent titers, and persistent Ab titers with delayed fetal death. Ultrasonography typically revealed normal fetal development associated with high volumes of placental fluids and retarded placentome development. We conclude that fetal death was associated with abnormal placental development that was not the result of maternal humoral immune attack.

Degradation of bovine complement C3 by trichomonad extracellular proteinase

Bovine trichomoniasis is a local infection of the reproductive tract making interaction with mucosal host defenses crucial. Since the parasite is susceptible to killing by bovine complement, we investigated the role of the third component of complement (C3) in host parasite interactions. Bovine C3 was purified by anionic and cationic exchange chromatography. The purified protein was characterized by immunoreactivity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and peptide sequencing of the amino terminus of the beta chain. When purified bovine C3 was incubated for varying time periods with trichomonad extracellular proteinases, SDS-PAGE gels revealed digestion of the alpha chain to small fragments. Such degradation in vivo would prevent formation of C3b and completion of the complement cascade, resulting in evasion of killing. To evaluate the relevance of this data, we determined whether C3 was present in bovine genital secretions. With a quantitative ELISA assay, C3 could be demonstrated in both uterine and vaginal washes. To our knowledge, this is the first demonstration of bovine C3 in genital secretions. The C3 concentration increased significantly in vaginal secretions by 8 and 10 weeks in heifers infected with Tritrichomonas foetus. An increase was also seen in uterine secretions of infected heifers, but sample numbers were insufficient for statistical analysis. Transcription of the major extracellular cysteine proteinase (TFCP8) was demonstrated in T. foetus cells from uterine secretions of infected heifers by RT-PCR and Southern blotting. The results indicate that C3 may be important in genital defense and that trichomonad extracellular proteinases may play a role in evasion of complement-mediated killing.

Hematopoietic Stem Cell Transplantation in Utero Produces Sheep–Goat Chimeras

Both allogeneic and xenogeneic hematopoietic chimera models have been developed, including fetal sheep models that demonstrated high levels of stable, multilineage engraftment created by in utero hematopoietic stem cell transplantation. The aim of this study was to test the efficacy of in utero transplantation to create xenogeneic sheep-goat hematopoietic chimeras. Fetal liver cells and T-cell-depleted adult bone marrow were tested as sources of hematopoietic stem cells. Donor cells were injected intraperitoneally into 130 recipient fetuses between 49 and 62 days of gestation. Groups 1 and 2 received crude fetal liver cell preparations. Group 3 received fetal liver cells that were incubated overnight in a phytohemagglutinin-stimulated lymphocyte-conditioned medium (PHA-LCM). In Group 4, hematopoietic stem cells were concentrated by using additional density separations. Group 5 fetal recipients received low-density, T-cell-depleted adult bone marrow cells. In Group 1, fetuses were accessed via hysterotomy. Hematopoietic stem cells were injected into Groups 2, 3, 4, and 5 without cutting through the uterine wall. Fetal survival in the five groups ranged from 56 to 100%. The percentage of chimeras from injected fetuses ranged from 43 to 92% by FACS and PCR analyses; however, levels of chimerism were low (<1%). The highest rates of chimerism were found among recipients of low-density fetal liver cells. Despite the pre-immunocompetent status of the fetal recipients and the genetic similarities between sheep and goats, high levels of engraftment were not observed. The consistently low levels of chimerism observed in this study, as well as the poor results recently reported by others using these procedures, indicate that significant barriers exist to transplanting hematopoietic stem cells in utero.

Refinement of the pressure assay for milk urea nitrogen

We report improvements in the application of a pressure-based assay for urea. The assay involved the enzymatic hydrolysis of urea and subsequent measurement of CO2 partial pressure. Effects of the preservative bronopol on the assay and their implications for laboratory applications are discussed. A method of remediating these effects with cysteine is described. A method is also described wherein these additives can be used to prepare standards of known urea concentration in milk. The improved assay can be used to measure urea N in unadulterated milk or in bronopol preserved milk with an accuracy of +/-0.7 mg/dl (0.25 mM) in the range from 0 to 30 mg/dl (0 to 10.7 mM).

Demonstration of Tritrichomonas foetus in the external genitalia and of specific antibodies in preputial secretions of naturally infected bulls

Portions of penis and prepuce were collected from 24 bulls with current or recent Tritrichomonas foetus infection. Epididymides were collected from seven of the bulls, and seminal vesicles and prostate were collected from four. Following immunohistochemical staining with two monoclonal antibodies (34.7C4.4 and TF1.15) prepared against T. foetus surface antigens, trichomonads were identified in sections from 15 of the bulls. Organisms were most often located in penile crypts in the midshaft and caudal regions and less often in preputial crypts. Trichomonads were not observed in sections from other genitalia or in subepithelial tissue. T. foetus antigen, however, was present in the cytoplasm of some epithelial cells and the cytoplasm of some mononuclear cells in subepithelial lymphoid aggregates and follicles. Preputial smegma was collected from 16 T. foetus-infected bulls and from 16 control bulls with negative T. foetus cultures. Preputial antibody levels to TF1.17, a surface antigen of T. foetus, were determined by an enzyme-linked immunosorbent assay. Preputial secretions from infected bulls contained specific antibody of each isotype and subisotype tested. IgG1 responses were the greatest, IgM and IgA responses were approximately equal, and IgG2 responses were low. Each isotype and subisotype response in infected bulls was significantly greater than that in the controls. These results confirm previous speculation concerning anatomical sites of infection and suggest that parasite antigen can be taken up and processed locally, resulting in deposition of specific IgG1, IgG2, IgA, and IgM antibodies in the preputial cavity.

Establishment of pluripotent cell lines from porcine preimplantation embryos

Embryonic stem (ES) cells are pluripotent cells isolated from in vitro culture of preimplantation embryos. Experiments were undertaken to identify preimplantation embryonic stages and culture conditions under which pluripotent, porcine embryo-derived cell lines could be isolated. Cell lines were established from in vitro culture of intact, porcine early hatched blastocysts and isolated inner cell masses (ICM) from intermediate and late hatched blastocysts on feeder layers prepared from permanent mouse embryonic fibroblasts (STO). The cells of these porcine embryo-derived cell lines had a morphology similar to that of murine ES cells, but colony morphology was more epithelial-like. The cell lines retained a normal diploid karyotype, consistently expressed alkaline phosphatase activity, and survived cryopreservation. When subjected to in vitro differentiation, either spontaneous or induced, the embryo-derived cell lines differentiated extensively into a wide range of cell types representing the 3 embryonic germ layers. In vivo pluripotency of the cells was demonstrated by birth of a chimeric piglet, documented by pigmentation and DNA markers, and the ability to direct the development of nuclear-transfer embryos to the blastocyst stage. Such pluripotent embryo-derived cells provide a potential route for porcine genetic manipulation.

Progestin implants can rescue demi-embryo pregnancies in goats: a case study

Survival after transfer of demi-embryos (i.e., half-embryos produced by embryo splitting) to recipients usually is lower than survival after transfer of intact embryos. Reduced survival after demi-embryo transfer could be due to loss of viability after splitting, failure of a viable demi-embryo to prevent corpus luteum (CL) regression in the recipient female, or a combination of factors. From a retrospective analysis of pregnancy and embryo survival rates after demi-embryo transfer in sheep and goats, we report the rescue of caprine demi-embryo pregnancies in which CL regression occurred at the end of diestrus despite the presence of a viable conceptus in the uterus with progestin implants. Day 5 or 6 morulae and blastocysts were flushed from superovulated ewes and does and split into demi-embryos of approximately equal halves. Demi-embryos were either transferred fresh to synchronized recipients of the homologous species or frozen in liquid nitrogen. Approximately half of the recipient does and ewes were treated with norgestomet implants on Day 10 of the embryo transfer cycle and again 2 wk later. Serum collected on Day 25 from recipients with implants was assayed for progesterone to determine if a CL of pregnancy had been maintained. Pregnancy was diagnosed by ultrasonography on Day 35 of gestation. Corpus luteum regression occurred despite the presence of a viable conceptus in the uterus in 6 of 55 progestin-treated caprine demi-embryo recipients and in 0 of 66 ovine demi-embryo recipients. Five of the caprine pregnancies were maintained to term with norgestomet implants and produced 5 live kids. The sixth fetus, which was carried by a progestin implant-treated 8-mo-old doeling, died at approximately 50 d of gestation. These results suggest that, at least in goats, some demi-embryos may provide inadequate signaling for maternal recognition of pregnancy, and such pregnancies can be rescued with progestin treatment to the doe.

Rapid enzyme immunoassay for measurement of bovine progesterone

Reproductive management is a primary financial concern of the dairy industry with missed estrus detection one of the major causes of lost income. A rapid enzyme immunoassay (EIA) was developed for on-line measurement of progesterone in bovine milk with a biosensor for detection of estrus. The EIA was developed using covalent binding microtiter wells, monoclonal antibody, horseradish peroxidase, and 3,3',5,5'-tetramethylbenzidine (TMB). The EIA took 8 min and had a dynamic response for progesterone in buffer and milk between 0.2 and 20 ng/ml.

Comparison of diagnostic methods for detection of active infection with Tritrichomonas foetus in beef heifers

OBJECTIVE

To compare sensitivity of a generic trypticase-yeast extract-maltose (TYM) medium versus a commercial nutrient medium in the diagnosis of Tritrichomonas foetus infection in heifers and to assess sensitivity when incubation of samples inoculated into commercial medium pouches is delayed overnight.

DESIGN

Prospective study.

ANIMALS

30 virgin beef heifers.

PROCEDURES

20 heifers vaccinated with a trichomonad antigen and 10 unvaccinated control heifers were exposed at synchronized estrus by intravaginal instillation of 10(6) T foetus organisms. Cervicovaginal mucus samples were collected every other week for 10 weeks from controls and once (10 weeks after exposure) from vaccinated heifers. Samples were inoculated into both media and immediately incubated at 37 C (98.6 F). A duplicate inoculation from controls was made into commercial medium, and the pouch was shipped overnight to a diagnostic laboratory without prior incubation.

RESULTS

For 40 of 50 samples from control heifers, there was agreement on diagnoses between media. There was agreement on a positive diagnosis for 3 of 20 samples from vaccinated heifers and on a negative diagnosis for 15 of these 20 samples. For samples shipped overnight before incubation, there were 10% fewer positive diagnoses, compared with samples incubated immediately in commercial medium and 10% more positive diagnoses, compared with samples immediately incubated in TYM.

CLINICAL IMPLICATIONS

Use of the commercial medium is a more sensitive indicator of current infection in heifers than use of generic TYM medium. In herds where infection prevalence is high, this method is likely to identify more infected females, an important consideration when control programs include culling of infected cows.

Female reproductive tract immunity in bovine trichomoniasis

PROBLEM

Mechanisms of protective immunity in the female reproductive tract are poorly understood. For sexually transmitted diseases, bovine trichomoniasis is a useful model because it resembles human trichomoniasis to some extent, and antibodies play an important role in protection against these extracellular parasites. Protective efficacy was compared in animals with genital responses of predominantly immunoglobulin G (IgG) or predominantly IgA antibodies to a purified surface antigen of Tritrichomonas foetus.

METHOD OF STUDY

Immunization of mice by various routes with immunoaffinity-purified T. foetus surface antigen (TF1.17) or killed cells was used to define the best routes and antigen combinations to give predominantly IgG or IgA antibodies to TF1.17 antigens in genital secretions. Cattle were then immunized either subcutaneously (SC) two times with TF1.17 antigen and once SC with killed T. foetus or twice SC with TF1.17 antigen and once intravaginally with killed T. foetus. All immunizations were in Quil A adjuvant. Controls were not immunized. Animals were challenged intravaginally with 10(6) T. foetus 3 weeks after the third immunization. Vaginal mucus was collected weekly for culture and antibody assays. Serum was collected weekly, and uterine secretions were collected at 10 weeks post-challenge. Tissues were fixed at 10 weeks also.

RESULTS

Murine studies showed systemic priming with vaginal boosting gave the highest genital IgA responses. In cattle, systemic immunization (group S) induced high IgG1 antibody levels in vaginal secretions. Systemic priming with vaginal boosting (group S/V) primed for an anamnestic vaginal IgA response after challenge with T. foetus. Cattle with predominantly IgG or predominantly IgA responses in vaginal secretions either did not become infected or cleared infection faster than controls. Uterine IgA responses at 10 weeks were highest in the vaginally boosted group, but other responses were not different from the controls at this time point. Microscopic examination of genital tissues showed subepithelial infiltration of mononuclear cells in all groups. Lymphoid aggregates or nodules were detected in vaginal sections in cattle of groups S/V and C as well as in uterine sections of all animals in all three groups.

CONCLUSIONS

Both IgG and IgA antibodies to T. foetus superficial antigen were associated with protection. The timing of the response was related to the time of clearance. Lymphoid organization in the vagina and uterine tissues suggested development of mucosal inductive sites.

Isolation of pluripotent stem cells from cultured porcine primordial germ cells

Embryonic germ (EG) cells are undifferentiated stem cells isolated from cultured primordial germ cells (PGC). To date, EG cells have been isolated only in the mouse. Murine EG cells share several characteristics with embryonic stem (ES) cells, including morphology, pluripotency, and the capacity for germline transmission. We report here the isolation of porcine EG cells. PGC collected from Day 24 or 25 porcine embryos were cultured on mitotically inactivated murine fibroblasts. Four EG cell lines were isolated from repeated subculture of porcine PGC. Porcine EG cells morphologically resembled murine ES cells and consistently expressed alkaline phosphatase activity. These cell lines maintained a normal diploid karyotype and survived after cryopreservation. Porcine EG cells were capable of differentiating into a wide range of cell types in culture, including endodermal, trophoblast-like, epithelial-like, fibroblast-like, and neuron-like cells. In suspension culture, porcine EG cells formed embryoid bodies. When injected into host blastocysts, the EG cells were able to differentiate and contribute to tissues of a chimeric piglet. Both in vitro and in vivo evidence demonstrates that the isolated EG cells were pluripotent. These cells are potentially useful for genetic manipulation in pigs.

Pathogenesis, diagnosis, and management of trichomoniasis in cattle

Trichomoniasis is a disease of the pregnancy, but apparently not of either the cow or the bull, except in the case of postcoital pyometra. Its self-limiting nature in the cow and chronic nature in the bull mean that a positive diagnosis for the herd can more easily be obtained from bulls than from cows. Incubation of preputial scrapings or washings (or pyometritic fluid, if available) in a selective growth medium such as the InPouch system is the diagnostic method of choice. The diagnosis is based on identification of the morphology and characteristic rolling motility of the trichomonad. "High tech" molecular approaches may eventually offer greater diagnostic sensitivity than can culture methods, but currently they are no more accurate. In addition, serologic screening of the female herd (but interestingly, not the bulls) may become possible and may allow the practitioner to at least determine whether exposure has occurred in an unvaccinated herd. Control in an infected herd involves no pharmacologic treatment but rather culling of infected bulls, retention of younger, culture-negative bulls, and segregation of the female herd by reproductive status.

Development of bovine and porcine embryonic teratomas in athymic mice

Inner cell masses (ICM) and embryonic discs from bovine and porcine blastocysts of various ages were transplanted under the kidney capsule of athymic (nude) mice to evaluate growth of teratocarcinomas containing both differentiated tissues and undifferentiated stem cells. Inner cell masses were isolated immunosurgically from Day 8, Day 9 and Day 10 porcine blastocysts and from Day 8, Day 10 and Day 12 bovine blastocysts. Embryonic discs were mechanically dissected from Day 11 and Day 12 porcine embryos and from Day 14 bovine embryos. Day 6 egg cylinders were dissected from BALB/C embryos and from hybrid embryos of a cross between BALB/C and an outbred strain of mouse. Two to four ICM, embryonic discs or egg cylinders were transplanted under the kidney capsule of each athymic host. After 8 weeks, graft hosts were killed and their tumors removed, fixed and prepared for histological and immunohistochemical examination. Embryonic teratomas developed at high frequency from murine egg cylinders and from Day 11 and Day 12 porcine and Day 14 bovine embryos. Tumors were observed only infrequently from younger bovine and porcine blastocysts. Murine embryonic tumors were composed of numerous differentiated cell types of ectodermal, mesodermal and endodermal origins, but representation of the three embryonic germ layers was somewhat more restricted in bovine and porcine embryonic tumors. No undifferentiated stem cells were detected in tumors of any of the three species. These results demonstrate that teratomas will develop from bovine and porcine embryos when grafted to an immunocompromised host, but the presence of undifferentiated teratocarcinoma stem cells from these species has yet to be achieved.

Immune and inflammatory responses to reproductive tract infection with Tritrichomonas foetus in immunized and control heifers

Histopathologic changes and local antibody responses were studied in immunized and control heifers after intravaginal challenge with 10(6) Tritrichomonas foetus. Animals were given 3 intramuscular inoculations of immunoaffinity-purified superficial antigen, TF 1.17, in 2 different adjuvant combinations (incomplete Freund's adjuvant or dextran sulfate plus IFA-8 animals each) or adjuvant alone at 3-wk intervals and were challenged with T. foetus 2 wk later. Histologically, a nonsuppurative endometritis with nodular lymphoid aggregates in the stratum spongiosum was present in 9 of 24 heifers. Twice as many control heifers as immunized had moderate to severe endometritis at 10 wk and the rate of clearance of the organism was significantly faster in immunized than in control heifers. Furthermore, time of clearance was statistically correlated with severity of endometritis at 10 wk postinfection, when necropsies were done (P < 0.02). Because 9-10 wk postinfection is thought to be the critical period for determining fetal loss associated with endometritis, this correlation with early clearance is important to protection against disease. In heifers with moderate to severe infiltration of mononuclear cells in the endometrium, lymphoid nodules and some secondary follicles were detected. In the subgroup of 12 animals from which uterine secretions were collected. IgA antibody responses to antigen were detected by 6 wk in infected animals with increases in mean responses at 8 and 10 wk, but not in uninfected animals. A rationale is presented for consideration of the lymphoid nodules as a possible inductive site for this local antibody response to T. foetus.

Development of a simple, rapid sandwich enzyme immunoassay for the measurement of serum rat LH

The present study describes the development and validation of a rapid, sensitive, specific and precise enzyme immunoassay (EIA) sandwich suitable for measuring luteinizing hormone (LH) in rat serum. Ninety-six well polystyrene microtiter plates were coated with 100 microliters (250 ng/ml) of a well-characterized monoclonal antibody (518B7, Roser, UC Davis) generated against bovine LH. A polyclonal antiserum raised in rabbits against ovine FSH (G4-215B, Papkoff) was conjugated to sodium periodate-activated horseradish peroxidase (HRP), and used as the second antibody of the sandwich assay. This anti-ovine FSH antiserum cross-reacted more than 200% with rat LH. Standards (r-LH-RP-3, NIADDK, range 0 pg/well to 2.5 ng/well or 100 microliters) diluted in a 3(N-Morpholino) propane sulfonic acid (MOPS) buffer, or serum, were incubated with the solid phase antibody for 2 hours. Plates were washed and the anti-oFSH:HRP (100 microliters) in MOPS buffer was added and incubated a further 2 hours before a second wash and the addition of the substrate (TMB, 3,3',5,5'-tetramethylbenzidine dihydrochloride and H2O2). The least detectable concentration of LH was 16.1 +/- 1.42 pg/ml. The recovery of known concentrations of LH added to several samples was 93.5 +/- 1.70%. Mean intra-assay and inter-assay coefficients of variation (%) were less than 10% (n = 20). The anti-FSH:HRP showed less than 8.0% cross reactivity with rFSH in this LH EIA system. The correlation coefficient (r) of samples analyzed by EIA in parallel with RIA was r = 0.90 (p < 0.001, n = 26). Results showed levels between 105.21 and 633.87 pg/ml. This new LH EIA sandwich offers a stable, rapid, and improved EIA system for the measurement of serum LH concentrations of this species over previously reported methods.

Bovine vaginal antibody responses to immunoaffinity-purified surface antigen of Tritrichomonas foetus

Bovine trichomoniasis is a prevalent sexually transmitted disease of cattle caused by the protozoan Tritrichomonas foetus. Currently, diagnosis is most often made by culture. In order to provide a faster immunodiagnostic approach, a specific enzyme-linked immunosorbent assay (ELISA) was investigated. A protective surface antigen (TF1.17 antigen) of T. foetus was immunoaffinity purified and used in an ELISA to detect antibodies in vaginal mucus from heifers inoculated with T. foetus. In preliminary studies, antibodies of the immunoglobulin A (IgA) isotype were detected in mucus from all experimentally infected heifers which were tested at 6 weeks postinoculation, whereas IgG1 and IgG2 were not. In addition, IgA responses detected in postinoculation samples were all greater than those detected in preinoculation samples, unlike those detected by a whole-cell antigen ELISA. For these two reasons, IgA antibodies appeared to be useful diagnostically. Further investigation of IgA antibodies used vaginal mucus collected weekly from heifers inoculated intravaginally with 10(2), 10(4), or 10(6) T. foetus organisms. Heifers with positive cultures for T. foetus had similar IgA responses to TF1.17 antigen over the 10 weeks of infection regardless of the initial inoculum dose. This indicates that if the dose is sufficient to establish infection, the magnitude and duration of the immune response are no longer dependent on dose. All of the infected animals receiving all dosages responded with high absorbance values in the IgA anti-TF1.17 antigen ELISA by 6 weeks postinoculation, and all absorbance values remained high at 10 weeks. To determine the duration of the IgA response, four other heifers inoculated with 7 x 10(6) T. foetus organisms were studied through 24 weeks postinoculation. IgA antibody responses to TF1.17 antigen were still high at 24 weeks, even though some heifers cleared the infection several weeks earlier. These results indicate that experimentally infected heifers produced detectable long-lasting IgA responses to TF1.17 antigen in vaginal mucus, which may be useful in a herd test for the diagnosis of bovine trichomoniasis.

Delivery of a live calf after in vitro maturation and fertilization of oocytes obtained from ovaries removed from a moribund cow

An aged Holstein cow of high genetic merit and economic value was determined to have a squamous cell carcinoma of the tarsus. Treatment was unsuccessful, as was an attempt at superovulation and embryo collection; thus, the owner elected euthanasia. On day 17 of the estrous cycle, the ovaries were removed via laparotomy and the cow was immediately euthanatized. Oocytes were aspirated from ovarian follicles and subjected to in vitro maturation and fertilization procedures. Seven morulae that developed in culture were transferred nonsurgically to 3 recipient females, resulting in birth of a full-term healthy male calf. In vitro maturation and fertilization procedures can be used to obtain offspring from valuable, terminally ill cows for which conventional embryo collection techniques have proven unsuccessful.

Comparison of sampling and culture methods for the diagnosis of Tritrichomonas foetus infection in bulls

Sampling methods for preputial secretions and culture methods for Tritrichomonas foetus were compared in a two-by-two factorial experiment. Fourteen bulls were confirmed as infected by repeated weekly sampling and culture on Diamond's medium over the course of 10 months. In a six-week test of alternative methods of diagnosis, the bulls were randomly assigned to have their preputial contents sampled weekly either by washing or by scraping of the preputial membrane. The samples were cultured on Claussen's medium and in InPouch packets at 37 degrees C in air for seven days. The results were compared by McNemar's chi 2 test for symmetry. Washing yielded 69 positive cultures from 84 samples whereas scraping yielded 65 from 83. These differences were not statistically significant. InPouch culture detected 73 of 83 samples from positive bulls, whereas Claussen's medium detected 61 of 83. The difference in sensitivity between the two culture methods was highly significant (P = 0.0027), with the InPouch method 'missing' two positive samples that were detected by Claussen's medium and Claussen's medium missing 14 positive samples that were detected by InPouch culture.

Experimental reproduction of bovine fetal Neospora infection and death with a bovine Neospora isolate

Studies were conducted to determine the pathogenic potential of the recently isolated bovine Neospora protozoa (BPA-1) for the bovine fetus. Cows chosen for study had Neospora titers < 160 using an indirect immunofluorescent antibody (IFA) test. Four experimental groups were studied. In group 1, 2 fetuses were inoculated in utero at 118 days gestation with culture-derived Neospora tachyzoites. A pregnant control cow was housed in the same pen, observed daily and screened serologically for evidence of exposure to Neospora. In group 2, 2 cows were infected with Neospora tachyzoites at 138 or 161 days gestation, and 1 control cow was given uninfected cell culture suspension simultaneously at 154 days gestation. Groups 3 (85 days gestation) and 4 (120 days gestation) each consisted of 2 cows infected with Neospora tachyzoites and 1 control cow given uninfected material at the same stage of gestation. Dead fetuses were surgically removed from the infected cows in group 1 on postinfection day (PID) 17. The histopathology was compatible with protozoal fetal infection, and protozoa were identified by immunohistochemistry. Viable fetuses were removed surgically from cows in group 2 on PID 28-30. The histopathology was compatible with protozoal fetal infection, protozoa were identified by immunoperoxidase techniques, and Neospora tachyzoites were reisolated in vitro from tissues of the 2 infected fetuses. In groups 3 and 4, the control fetus and 1 infected fetus were removed surgically between PID 26 and PID 33. The remaining infected cows were observed until fetal death or abortion occurred.(ABSTRACT TRUNCATED AT 250 WORDS)