Ten multiparous sows were inoculated between 46 and 50 days of gestation with a fetal swine isolate of encephalomyocarditis virus (EMCV) to investigate the ability of the virus to cause transplacental infection and fetal death. Four sows (group 1) were inoculated IM with EMCV MN-25 that had been passaged 4 times on baby hamster kidney-21 line cell monolayers. Two sows were euthanatized at postinoculation (PI) day 23, and the other 2 sows at PI day 44. An additional 6 sows (group 2) were inoculated IM with the same virus that had been passaged 5 additional times in pigs. Two sows were euthanatized at 14 days, and the remaining 4 sows at PI day 28. Clinical signs were not observed in any of the sows, whereas all sows seroconverted to EMCV. In group 1, only 2 of 50 fetuses were mummified. Virus was not recovered, although EMCV antibodies were detected in the 2 mummified fetuses. In group 2, the 2 sows that were euthanatized at PI day 14 had 26 normal fetuses and there was no evidence of fetal infection. However, in the 4 sows euthanatized at PI day 28, 20 of 48 fetuses were mummified, hemorrhagic, or edematous. Encephalomyocarditis virus was recovered from 21 of 48 fetuses. Transplacental infection and fetal deaths in pregnant sows was achieved following infection with EMCV passaged in pigs.

Pregnant sows, immune against pseudorabies after vaccination, were inoculated at 70 days of gestation either with autologous blood mononuclear cells that had been infected in vitro with pseudorabies virus (PRV) or with cell-free PRV. The infected cells or cell-free PRV were inoculated surgically into the arteria uterina. Eight sows (A to H) had been vaccinated with an inactivated vaccine. The titer of seroneutralizing antibodies in their serum varied between 12 and 48. Five sows (A to E) were inoculated with autologous mononuclear cells, infected either with a Belgian PRV field strain or with the Northern Ireland PRV strain NIA. These 5 sows aborted their fetuses: 2 of them (B and C) 3 days after inoculation, and the other 3 (A, D, and E) 10, 11, and 12 days after inoculation, respectively. Sows F, G, and H were inoculated with a cell-free PRV field strain. They farrowed healthy Utters after normal gestation. Neutralizing antibodies were absent against PRV in the sera of the newborn pigs, which were obtained prior to the uptake of colostrum. The 23 fetuses that were aborted in sows B and C 3 days after the inoculation were homogeneous in appearance and size. Foci of necrosis were not detected in the liver. Viral antigens were located by immunofluorescence in individual cells in lungs, liver, and spleen of 15 fetuses. Virus was isolated from the liver, lungs, or body fluids of 12 fetuses. The 39 fetuses that were aborted in sows A, D, and E between 10 and 12 days after inoculation were of 2 types: 17 were mummified and 22 were normal-appearing. Foci of necrosis were found in the liver of all mummified fetuses and 13 of the normal-appearing fetuses. In fetuses with foci of necrosis in the liver, viral antigens were located in groups of cells in the liver, lungs, and spleen. Virus was isolated from 16 normal-appearing fetuses and from 11 mummified fetuses. Pseudorabies virus was isolated from vaginal excretions of sows A and D until 1 and 2 days after abortion, respectively, and of sows B and C until 4 and 5 days after abortion, respectively. Virus was not isolated from sow E. It was concluded that PRV can reach the uterine and fetal tissues, via infected mononuclear cells, in the presence of circulating antibodies induced on vaccination. This cell-associated spread led to abortion. Cell-free virus did not induce abortion under similar circumstances.

Five studies were performed to determine factors affecting progesterone concentration in skim milk. Results of the first study indicated that progesterone concentration was higher in skim milk of samples kept 16 hours in an ice bath (0 C) than of those left at room temperature (21 C). In the second study, this temperature effect was found to be reversible, with skim milk progesterone concentration increasing when whole milk samples were cooled prior to centrifugation. In the third study, [3H]-labeled progesterone was used to determine the relationship between fat content of foremilk (the first milk obtained from the teats), midmilk (milk obtained through milking), and strippings (milk obtained immediately after milking machines have been removed) samples and temperature (4 C and 21 C) on the percentage of progesterone in the skim milk fraction. The relationship between percentage of butterfat and percentage of progesterone in skim milk was linear when the log of these variables was used for calculations. In the fourth study, assayable progesterone in the skim milk fraction of foremilk, midmilk, and strippings was affected by temperature. In the fifth study, a multiple-regression procedure was used to determine the amount of variation in percentage of radioactive progesterone in the skim milk fraction. Independent variables (whole milk butterfat and temperature of incubation [1, 3, 13, 22, 37, and 50 C]) and the natural log of each variable, were entered into a stepwise multiple-regression analysis. The log of the temperature and percentage of butterfat of whole milk at the time of centrifugation accounted for 89.2% (r2 = 0.892) of the variation in the log of the progesterone concentration in the skim milk fractions. The equation describing this relationship was: log percentage of progesterone in the skim milk fraction = 4.046 - 0.144 X (log of temperature of whole milk sample) - 0.688 X (log percentage of butterfat in whole milk sample). The loss of progesterone from skim milk fractions of warm whole milk samples is possibly a physical phenomenon dependent on the temperature of the sample and its percentage of butterfat. A nomograph was created to allow others to use these variables in making adjustments in progesterone concentrations.

The purpose of this study was to experimentally reproduce swine infertility and respiratory syndrome (SIRS). Six multiparous sows were intranasally inoculated at 93 days of gestation with lung homogenates from clinically affected pigs, and 3 additional sows were similarly inoculated with a virus isolated in cell culture from the lung homogenate (SIRS virus, isolate ATCC VR-2332). Inoculated sows developed transient anorexia, farrowed up to 7 days prematurely, and delivered a mean of 5.8 live pigs and 6.0 dead fetuses/litter. Clinical signs of disease were not observed in 3 sham-inoculated control sows that delivered a mean of 12.7 live pigs and 0.3 stillborn fetuses/litter. The sirs virus was isolated from 50 of 76 live-born and stillborn fetuses from the 9 infected fitters. Virus was not isolated from 26 autolyzed fetuses or 15 control pigs. Six of 9 inoculated sows developed neutralizing antibodies to SIRS virus. The reproductive effects found in these experiments were identical to those found in field cases. On the basis of our findings, virus isolate ATCC VR-2332 causes the reproductive failure associated with SIRS.

Immunogenicity of the lipid A component of Haemophilus somnus lipooligosaccharide in cattle and mice was examined after purification, detoxification, and covalent conjugation to a protein carrier. After 2 inoculations, a substantial antibody response was induced in most cattle to lipid A and the protein carrier. To determine whether antibodies to lipid A would be protective, 5 X 10(7) colony-forming units of H somnus strain 649 were administered IV to endotoxin-responsive (C3H/HEN) mice. In one study, 8 of 13 C3H/HEN mice aborted when inoculated. In contrast, abortion did not result when mice were inoculated with the same dose of an isolate of H somnus normally found in the prepuce or with the rough mutant Escherichia coli J5. In addition, endotoxin-nonresponsive (C3H/HeJ) mice were significantly (P = 0.03) more resistant to abortion by strain 649 than were C3H/HeN mice, but inoculated C3H/HeN mice were only slightly more resistant to H somnus abortion, compared with control mice. Although a large antibody response to lipid A was detected, there was no significant difference in the immunized group between mice that aborted and mice that delivered normally. Thus, lipooligosaccharide and other properties of virulent H somnus strains may contribute to abortion in mice.

To test the efficacy of a polyvalent Tritrichomonas foetus vaccine, 130 nulliparous heifers were randomly assigned to either receive the test T. foetus vaccine or to serve as nonvaccinated controls. The polyvalent test vaccine consisted of a Campylobacter fetus/Leptospira canicola-grippotyphosa-hardjo-icterohaemorrhagiae-pamona bacterine containing 5 X 10(7) killed T. foetus/dose. The polyvalent control vaccine consisted of the aforementioned formulation without T. foetus. Heifers were administered 2 doses of control or experimental vaccine at 3-week intervals. Heifers were bred to T. foetus-infected bulls and their conception and pregnancy rates were determined throughout gestation. In addition, serum samples were analyzed to determine induced concentrations of antitrichomonal antibodies and vaginal secretions were sampled to determine T. foetus infection rates in control and vaccinated animals. One week after each of the 15-day breeding periods, 60% (6 of 10) of tested vaccinates and 80% (8 of 10) of tested control animals were T. foetus culture-positive. The mean duration of infection of vaccinates was 3.8 weeks (+/- 7.5 days), compared with 5.4 weeks (+/- 7.5 days) of infection for control heifers. All vaccinates developed increased immunofluorescence and serum neutralizing antibody titers following the first immunization, and had additional increases of at least fourfold in response to the second injection. In contrast, no consistent increase in immunofluorescence or serum neutralizing antibodies was observed in control animals. Conception rates were 89.2% for vaccinates and 85.9% for control animals 30 days after breeding and 80 to 90% of these remained pregnant 60 days after breeding. However, within the next 4 months, the pregnancy rate of control heifers decreased to 30% for those that had conceived. During the same 4-month period, more than 60% of vaccinated heifers remained pregnant. Significantly, 62.5% of heifers vaccinated against T. foetus produced calves, whereas only 31.5% of control heifers produced calves. These findings indicate that the polyvalent test vaccine induced an immune response that was effective in lowering the rate of T. foetus infection, decreasing the duration of infection, and reducing losses in calf production attributable to early fetal death and abortion caused by T. foetus infection.

Administration of progesterone in poly(d-,l-lactide) microspheres was used to maintain pregnancy in mares after luteolysis was induced by treatment with pros F2 alpha at day 14 of pregnancy. Mares were given vehicle only (control, n = 6) or 0.75 g (n = 7), 1.5 g (n = 8), or 2.25 g (n = 5) of microencapsulated progesterone at days 12 and 22 of pregnancy. Serum progesterone concentrations were determined daily, and pregnancy was evaluated by transrectal ultrasonography on alternate days. Significantly (P < 0.05) more mares given 1.5 or 2.25 g of progesterone (6 of 8 and 4 of 5 mares, respectively), but not those given 0.75 g (3 of 7 mares), maintained pregnancy through day 32, compared with control mares (O of 6). Progesterone concentrations decreased significantly (P < 0.025) in all groups after administration of prostaglandin F2 alpha at day 14, and significant (P < 0.05) effects of time and treatment on progesterone concentrations were found between days 12 and 22, and 22 and 32. Although treatment with 1.5-g and 2.25-g doses of microencapsulated progesterone improved maintenance of pregnancy, compared with that of vehicle-treated controls, administration of 2.25 g of microencapsulated progesterone appeared to be most efficacious in maintenance of pregnancy during the study interval.

Chorioallantoic membranae (CAM) explants were used to determine the in vitro growth and cytotoxic potential of 3 strains of Brucella abortus. Bovine CAM explants were inoculated with 2 X 10(7) colony-forming units of the pathonic strain 2308, attenuated strain 19, or the rough strain RB51 of B abortus. After inoculation, the explants were harvested and examined at 2 or 4 hours, 12 or 14 hours, and 24 or 26 hours of incubation. Bacterial growth associated with each explant was determined by counting colony-forming units. The degree of cellular damage in each explant associated with bacterial growth or bacterial toxins were evaluated by morphometric analysis after trypan blue staining. Significant differences were not detected in the numbers of bacteria of any strain of B abortus in the CAM explants at comparable time intervals. The rate of growth of the bacteria in CAM explants was higher between 2 and 12 hours after inoculation than between 12 and 24 hours after inoculation. Cytotoxic effects associated with strain 2308 were significantly (P < 0.05) greater than that caused by other strains. Cytotoxic effects associated with strain 19 and rough strain RB51 were similar, and both were significantly (P < 0.05) greater than the phosphate buffer solution control. Chorioallantoic membrane explants inoculated with a filtrate of heat-killed strain 2308 induced minimal cellular damage, compared with that caused by the viable bacteria. These results indicated that the number of B abortus in trophoblasts was independent of the degree of cellular damage.

The purpose of the study reported here was to get detailed information about the normal size and texture of the liver in sheep by means of ultrasonographic examinations. Structure, location, and shape of the liver, gallbladder, portal vein, and caudal vena cava were examined ultrasonographically in 100 sheep. Furthermore, 10 sheep were scanned 10 times within 2 weeks to determine reproducibility of findings. Examinations were performed on the right side of the abdomen in the seventh through twelfth intercostal spaces. In each intercostal space, the dimensions of the liver, and, if visible, the location and diameter of the caudal vena cava and portal vein were determined. The angle of the liver, and location and size of the gallbladder also were determined. Ultrasonographic measurements of liver size and location in healthy sheep can be used as references for changes in liver size attributable to illness.

Equine alpha1-acid glycoprotein (alpha-1AG) was isolated from equine serum by successive ammonium precipitation, anion- and cation-exchange chromatographies, and gel filtration. Purified equine alpha-1AG had a molecular weight of 46,000 +/- 1,000, and contained 31.4% carbohydrate. Gel isoelectric focusing revealed an isoelectric point range of 2.8 to 3.7. With immunoelectrophoresis, it was found that alpha-1AG migrated to the alpha-1-globulin region. Single radial immunodiffusion was used for quantitative measurement of alpha-1AG in equine serum. In clinically normal foals, serum alpha-1AG was undetectable (less than or equal to 20 micrograms/ml) in less than or equal to 7-day-old foals, but was detected by 14 days. The alpha-1AG concentration (mean +/- SD) increased to reach mean adult values of 99.23 +/- 26.90 micrograms/ml by 1 year of age. The alpha-1AG concentration in pregnant mares decreased at 2 to 3 months before parturition, then gradually increased until 1 day after parturition, when a brief decrease was observed. The concentration increased again at 2 weeks after foaling, then a decrease was observed, after which the alpha-1AG concentration increased again by 2 to 4 months after parturition. The concentration of serum alpha-1AG quickly rose to peak values 2 to 3 days after castration and jejunojejunostomy in adult horses, returning to baseline values by 14 to 28 clays after surgery. The alpha-1AG was concluded to be an acutephase reactive protein in horses.