Abstract. Parasite-specific antibody responses were detected using an indirect fluorescent antibody (IFA) test in cattle that were naturally or experimentally infected with Neospora parasites. The test was developed using Neospora tachyzoites isolated from an aborted bovine fetus and grown in bovine cell cultures (isolate BPA1). In all cases, infections were confirmed by the identification of Neospora tachyzoites and/or bradyzoite cysts in fetal or calf tissues using an immunoperoxidase test procedure. Fifty-five naturally infected cows that aborted Neospora-infected fetuses had titers of 320-5,120 at the time of abortion. The titer of 6 cows that were serologically monitored over a prolonged period decreased to 160-640 within 150 days after they aborted infected fetuses. Two of the cows showed an increase in their Neospora titers during their subsequent pregnancy, and they gave birth to congenitally infected calves that had precolostral titers of 10,240-20,480. Postcolostral titers of these calves and of 4 other calves with congenital Neospora infections were all 25,120, whereas calves with no detectable parasites had titers ≤ 160. Two pregnant heifers that were experimentally infected with the BPA1 isolate at approximately 120 days gestation seroconverted to Neospora antigens within 9 days and developed peak titers of 5,120 and 20,480 within 32 days of infection. The fetus taken by caesarian section 32 days postinfection from 1 heifer and the full-term calf born to the other had Neospora titers of 640 and 10,240, respectively. Nine cows that aborted uninfected fetuses and 61 adult cattle maintained under pasture or feedlot conditions, where risk of exposure to Neospora was considered to be low, had titers ≤ 320. Some of the feedlot cattle tested had serologic reactivity that was restricted to antigens at the apical end of both Neospora and Toxoplasma gondii tachyzoites. This type of reactivity, which may result from serologic cross-reactivity between conserved apical complex antigens of closely related sporozoan parasites, differed from the whole parasite fluorescence that was observed with sera from Neospora-infected animals. The significance of these results and the potential application of the IFA test for the diagnosis of Neospora infections in cattle are discussed.

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The potential for applying biotechnology to benefit animal agriculture and food production has long been speculated. The addition of human milk components with intrinsic antimicrobial activity and positive charge to livestock milk by genetic engineering has the potential to benefit animal health, as well as food safety and production. We generated one line of transgenic goats as a model for the dairy cow designed to express human lysozyme in the mammary gland. Here we report the characterization of the milk from 5 transgenic females of this line expressing human lysozyme in their milk at 270 microg/mL or 68% of the level found in human milk. Milk from transgenic animals had a lower somatic cell count, but the overall component composition of the milk and milk production were not different from controls. Milk from transgenic animals had a shorter rennet clotting time and increased curd strength. Milk of such nature may be of benefit to the producer by influencing udder health and milk processing.

Abstract. 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 protozoa1 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 protozoa1 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. In group 3, the fetus that was surgically removed from 1 infected cow had no pathologic abnormalities, and parasites were not found (PID 26). The second fetus in group 3 died in utero, and expulsion of a mummified fetus was induced on PID 67. Brain histopathology was compatible with protozoa1 infection, and parasites were identified by immunoperoxidase techniques. The fetus that was surgically removed (PID 32) from 1 infected cow in group 4 had lesions compatible with protozoa1 infection, and Neospora tachyzoites were reisolated in vitro from fetal tissues. The second infected cow in group 4 produced a full-term live calf that had a precolostral Neospora titer of 20,480. Clinically, this calf had depressed conscious proprioception in all limbs. Very mild lesions were found in the central nervous system, but protozoa were not found in the tissues. The results demonstrate that the bovine Neospora protozoa can be transplacentally transmitted, resulting in fetal infection and death, and mimics the naturally occurring fetal disease.

Scrapie eradication efforts cost 18 million dollars annually in the United States and rely heavily upon PRNP genotyping of sheep. Genetic resistance might reduce goat scrapie and limit the risk of goats serving as a scrapie reservoir, so PRNP coding sequences were examined from 446 goats of 10 breeds, 8 of which had not been previously examined at PRNP . The 10 observed alleles were all related to one of two central haplotypes by a single amino acid substitution. At least five of these alleles (M142, R143, S146, H154, and K222) have been associated with increased incubation time or decreased odds of scrapie. To the best of our knowledge, neither S146 nor K222 has been found in any goats with scrapie, though further evaluation will be required to demonstrate true resistance. S146 was more common, present in several breeds at widely varying frequencies, while K222 was observed only in two dairy breeds at low frequency. Overall, this study provides frequency data on PRNP alleles in US goats, shows the pattern of relationships between haplotypes, and demonstrates segregation of multiple scrapieassociated alleles in several breeds not examined before at PRNP .