Passive immune haemolysis -- a class specific antibody assay for use in the pig.

An antibody assay is described based on the principle of complement mediated lysis of sheep red blood cells labelled with antigen. The technique provides a sensitive class specific assay enabling antibody in all three major immunoglobulin classes to be quantitated independently. The assay may be performed in tubes allowing precise measurement of antibody concentration, or in microtitre plates which provides a rapid estimation of antibody titre.

Immunohistochemical studies of the local immune system in the reproductive tract of the sow.

Tissues from the reproductive tract of sexually mature female pigs were examined histologically using antisera to porcine IgG, IgA and IgM coupled to horseradish peroxidase. Plasma cells synthesising all three immunoglobulins were found in all regions of the tract, with IgA-producing cells as the predominant type. Larger numbers of plasma cells were found in the lower region of the tract and the number of plasma cells was raised during oestrous. Intercellular staining of immunoglobulins was also observed and was also under hormonal influence. The results indicate the presence of a local mucosal immune system in the female reproductive tract of the pig.

Quantitation and origin of immunoglobulins A, G and M in the secretions and fluids of the reproductive tract of the sow.

Immunoglobulin quantitation of fluids obtained from several regions of the female reproductive tract indicated the presence of IgG, IgA and IgM. IgG was almost invariably present in greatest amounts and IgM always made the smallest contribution. Although much of this immunoglobulin was derived from serum, evidence of the molecular size of IgA, the IgA and IgG ratios and that obtained from experiments involving the injection into sows of 125I-labelled immunoglobulin indicated that local synthesis within the tract also occurred.

The immune response of the pig following oral immunisation with soluble protein.

The immune response of pigs fed 200 mg per day of dinitrophenylated bovine gamma globulin has been evaluated in terms of the antibody and lymphocyte responses and of the induction of tolerance and immune exclusion. Although dosing for ten days resulted in a small IgA response as indicated by splenic plaque forming cells, serum antibody could only be detected when dosing was continued for 42 days. secretory antibody was detected at any time. Antigen feeding for two weeks rendered the animals hyporesponsive to subsequent parenteral antigenic challenge but had little effect upon their ability to exclude an oral dose of antigen from the circulation.

A study of cells in the mammary secretions of sows.

The morphology and some of the in vitro functional properties of the cells in the mammary secretions of sows have been examined. A mean cell yield of 1 x 10(7) cells/ml was obtained from sow colostrum but during the first week post-partum the yield decreased approximately 10 fold. The polymorphonuclear leucocyte was the predominant cell type in colostrum and milk and was associated with varying proportions of lymphocytes, macrophages and epithelial cells. The phagocytes of sow milk ingested heat-killed yeast, although the phagocytic index for milk macrophages was low compared with autologous neutrophils and alveolar macrophages. Milk whey provided an effective opsonising medium for yeast ingestion. Intra-mammary immunisation of sows with ovalbumin induced antigen-reactive lymphocytes in both peripheral blood and milk.

Evaluation of the morantel sustained release bolus in cows and calves.

The efficacy of the morantel sustained release bolus (MSRB) in controlling gastrointestinal parasitism in beef cattle was assessed during the 1982 spring-autumn grazing season. Forty-eight cows and their calves were allotted to three equal groups. One group (T-1) served as a nonmedicated control group. One MSRB was administered to each calf of the T-2 group, and to each cow and calf of the T-3 group at the beginning of the study. The efficacy of the bolus was assessed by comparison of weight gain performance and parasitological data (fecal worm egg counts, herbage larval counts, worm counts from tracer and principal trial calves, and plasma pepsinogen level determinations). Though not statistically significant, treated calves from Group T-2 had a numerical mean weight gain advantage of 2.6 kg, and those from Group T-3 of 4.7 kg, over control calves. Average daily gains (ADG) for the three groups of calves were 0.69, 0.72, and 0.73 kg, respectively. Untreated cows from Group T-2 and treated cows from Group T-3 outperformed the control cows by 12.3 and 7.5 kg, respectively. Fecal worm egg counts from both groups of treated calves were significantly (P less than 0.01) lower than counts from control calves during the entire 169-day trial; notably, egg counts were reduced by 99% 28 days after MSRB administration to both groups of calves. There were no significant differences in the number of eggs counted from the three groups of cows, probably because of the very low numbers of eggs encountered. Mean total worm burdens of principal calves (six per group) necropsied at trial termination indicated a 91% (P less than 0.01) reduction in Group T-2 and an 87% reduction (P less than 0.01) in Group T-3. Worm-free tracer calves were introduced onto pastures every 28 days to monitor availability of infective larvae. The mean number of worms recovered at necropsy from tracer calves that grazed with control cattle increased as the season progressed. However, the numbers of parasites recovered each month from mid-August through mid-October from tracers that grazed pastures with treated cattle were lower (P less than 0.05) than those levels displayed at trial initiation. In addition, the mean numbers of worms from treated group tracers were lower than from the controls for each necropsy period.(ABSTRACT TRUNCATED AT 400 WORDS)

Field efficacy of a morantel sustained release bolus for control of gastrointestinal nematodes in yearling steers.

The efficacy of a morantel sustained release bolus (MSRB) for control of gastrointestinal nematodes in yearling steers was evaluated over a 6-month grazing period commencing on 26 March 1982. Three groups of 15 steers were allotted to the following treatments: Group 1 -- one MSRB at start of trial; Group 2 -- one therapeutic dose of thiabendazole at start of trial; Group 3 -- untreated control. The treatment groups were grazed separately. Parasite egg counts (EPG), herbage larval counts, pepsinogen levels and weight gains were monitored. Every other month, sets of 2 parasite-free tracer calves were placed in the pasture grazed by each treatment group and allowed to graze for 3 weeks before being subsequently necropsied for worm counts. At the end of the trial, 6 animals from each group were also necropsied for worm counts. The MSRB treatment resulted in significantly lower egg counts, fewer infective larvae on pasture, lower pepsinogen levels and lower worm burdens in tracer calves than was the case for the untreated group, but generally the levels were not significantly different from those associated with the thiabendazole treatment. The mean weight gain for the MSRB treated steers showed a significant advantage (70.9 lb) over the untreated animals, but was not significantly different from those which received thiabendazole. Total worm counts at the end of the trial were not different from any treatment group.

Efficacy of morantel sustained release bolus against gastrointestinal nematodes in first season grazing Holstein calves.

The efficacy of the morantel sustained release bolus (MSRB) in reducing gastrointestinal parasitism in first season grazing calves was evaluated during the summer--autumn grazing seasons of 1982 and 1983 in western Oregon. Each of 38 calves (1982) and 40 calves (1983) were randomly assigned to either control or treatment groups which were given MSRB on the day of turnout onto pasture. Mean worm burdens from tracer calves grazed with treated animals in 1982 and 1983 showed overall reductions of 86.4% (P greater than 0.05) and 84.3% (P less than 0.01), respectively, compared to tracers grazed with controls. Ostertagia ostertagi, Cooperia oncophora and Nematodirus helvetianus were the primary nematodes collected at necropsy. Twelve full-season 1982 tracer animals (6 treated and 6 control) indicated an 88.1% (P less than 0.05) overall reduction in mean worm burdens. Mean fecal worm egg per gram (EPG) counts of treated animals reflected a reduction of 69% (P less than 0.05) in 1982 and 90% (P less than 0.05) in 1983. Autumn inhibition of O. ostertagi was observed. In the 1982 trial the control animals showed a slight mean weight gain advantage over the treated group from Day 84 until Day 160 (trial termination) when the mean difference was 7.9 kg. The final mean weight gain advantage of treated animals in 1983 was 13.5 kg (P less than 0.05). These trials demonstrated that the MSRB was an effective anthelmintic for reducing gastrointestinal parasitism in grazing calves and for decreasing pasture larval contamination.

Dosage response evaluation of luprostiol administered to pregnant sows.

Two trials were completed to investigate the effects of luprostiol in swine. The first trial was to evaluate parturition induced by various dosages of luprostiol compared with those of lutalyse or vehicle. Sows were assigned by random allotment to one of the following treatments on Day 112 of gestation: Group A, control (0 mg luprostiol); Group B (1.88 mg luprostiol); Group C (3.75 mg luprostiol); Group D (7.5 mg luprostiol); Group E (15 mg luprostiol); Group F (10 mg lutalyse). All prostaglandin-treated groups farrowed earlier than the controls (P<0.05), with Groups D (26.3 h), E (31.0 h) and F (25.8 h) having the shortest treatment-to-first-pig intervals, and Groups A (76.0 h), B (54.4 h) and C (40.0 h) having the longest intervals. Luprostiol-treated sows had the shortest farrowing time (P<0.05; range = 3.2 to 3.9 h). Significant differences were found for the time (min) between births: Group A (32.1), Group B (28.4), Group F (35.5) took longer than Group C (20.2), Group D (21.0) and Group E (21.6). In a second trial, 20 crossbred pregnant sows received either vehicle or luprostiol (7.5 mg) on Day 112 of gestation. Progesterone concentrations declined rapidly (P<0.05) in luprotiol treated females but were unchanged in control females during the 24-h collection period. The results of these trials show 7.5 mg luprostiol to be the most effective dose for inducing farrowing.

Reproductive characteristics of cyclic beef heifers treated with the prostaglandin analog luprostiol.

One hundred and twenty crossbred Angus heifers, after exhibiting a 17- to 23-d estrous cycle, were placed into six groups of 20 heifers each and administered 2 ml i.m. propylene glycol containing either 0 (controls), 3.75, 7.5, 15.0 or 30.0 mg of luprostiol, or saline containing 0.5 mg cloprostenol (Groups 1 through 6, respectively). Heifers were observed for estrus every 6 h and all treatments were given 6.5 to 8.0 d after heifers were observed in standing estrus. Blood samples were collected after treatments from 10 heifers in each groups. Blood serum was assayed for progesterone. The synchronization period was considered to be 120 h after administration of luprostiol or cloprostenol. There were 0, 16, 17, 18, 20 and 18 heifers observed in estrus during the synchronization period in Groups 1 through 6, respectively. Progesterone concentrations in blood serum dropped below 1 ng/ml in 0, 8, 9, 10, 10 and 10 of the heifers from which blood samples had been taken in the six groups. All heifers observed in estrus were artificially inseminated. During the synchronization period, 0, 12, 14, 15, 16 and 10 heifers conceived in Groups 1 through 6, respectively. The interval from injection to estrus for the 89 heifers that exhibited estrus in the synchronization period averaged 49.0 h and was not different among the luprostiol and cloprostenol treated groups. Control heifers returned to estrus an average of 13.2 d after the treatment. The number of heifers that conceived at first insemination, regardless of when estrus occurred, was 16, 15, 16, 16, 16 and 12, and the total number that conceived at the first and second inseminations was 18, 18, 17, 19, 19 and 16 for Groups 1 through 6, respectively. Based on serum progesterone concentration and/or interval from treatment to estrus, 15 and 30 mg of luprostiol effectively regressed corpora lutea (100%) when administered between 6.5 and 8.0 d after estrus, and the estrous response and conception rate for these two groups equalled or exceeded that of the control and cloprostenol groups.

Synchronization of estrus after treatment with Luprostiol in beef cows and in beef and dairy heifers.

Four trials were conducted to study synchronous estrous response in beef cows and in beef and dairy heifers to Luprostiol (13, thia-PG-F(2)alpha analog) in comparison with other prostaglandin products. In Trial 1, 60 virgin beef heifers were observed for estrus for 5 d and artificially inseminated. Heifers not observed in estrus within 5 d were randomly assigned to receive 15 mg Luprostiol or 25 mg Lutalyse. In Trial 2, 75 multiparous, lactating beef cows were randomly assigned to receive either 15 mg Luprostiol, 25 mg Lutalyse or 500 mcg Estrumate. All cows received a second injection of the respective treatment 11 d later. In Trial 3, 96 multiparous, lactating beef cows were randomly assigned to receive 15 mg Luprostiol or 25 mg Lutalyse. All cows received a second injection of the respective treatment 11 d later. In Trial 4, virgin dairy heifers were palpated per rectum. Seventy-seven heifers with a palpable corpus luteum (CL) were randomly assigned to receive 15 mg Luprostiol or 500 mcg Estrumate. In all trials animals were artificially inseminated 12 h following observed estrus. Estrous response during the 5-d synchronized period was 44% for Luprostiol and 42% for Lutalyse treated heifers in Trial 1. It was 52, 56 and 60%, respectively, for Luprostiol, Lutalyse and Estrumate treated cows in Trial 2; 23% for Luprostiol and 19% for Lutalyse treated cows in Trial 3; and 68% for Luprostiol and 70% for Estrumate treated heifers in Trial 4. Treatment with Luprostiol results in a similar synchronous estrous response as with the other prostaglandin products used in these studies.

Endocrine, estrous and pregnancy response to varying dosages of Luprostiol in beef cows.

Multiparous lactating beef cows were observed for estrus and randomly assigned to one of four Luprostiol (13, thia-PG-F(2)alpha analog) treatment groups receiving 3.8 (LI), 7.5 (LII), 15 (LIII) or 30 (LIV) mg Luprostiol, respectively, or to an untreated control group (C), or to a positive control group (E) receiving 500 mcg Estrumate. Cows received their respective treatments in a single dosage on Day 7, 8 or 9 of the estrous cycle (estrus = Day 0) and were artificially inseminated 12 h following the subsequent estrus. Blood samples were collected from all groups immediately prior to treatment and at 12-h intervals to 48 h post treatment and analyzed for progesterone (P(4)). Blood samples were collected at 3-h intervals from 24 to 72 h post treatment for animals in Group LIII and for 48 h (or observed estrus) starting on Day 19 of the estrous cycle for animals in Group C. These samples were analyzed for estradiol-17beta(E(2)), follicle stimulating hormone (FSH) and luteinizing hormone (LH). Treatment with Luprostiol at doses >/= 7.5 mg resulted in a synchronous estrous response during the first 5 d post treatment in 75 to 95% of cows treated. Luteal function, as evaluated by systemic P(4) concentration, paralleled results observed for estrous response. Treatment with a 15 or 30 mg dose of Luprostiol resulted in greater overall pregnancy rate at synchronized estrus. No biologically significant differences were found in blood levels of E(2), FSH or LH around the time of estrus between cows in Groups C and LIII. Results from these studies indicate treatment with Luprostiol at doses >/= 7.5 mg resulted in a synchronous estrus during the first 5 d after treatment. Pregnancy rates and endocrine changes were similar to those observed in control and Estrumate-treated cows.

The influence of route of vaccination on the systemic and local immune response in the pig.

The influence of the route of vaccination on the systemic and local immune response has been studied in the sow with ferritin antigen using three methods of vaccination: 1. intramuscular with Freund's complete adjuvant (FCA); 2. intramammary without FCA; 3. intramammary with FCA. Intramammary vaccination was found to be superior to intramuscular vaccination in producing both a local and systemic response. Folowing stimulation by either route, antibody activity was found in all immunoglobulin classes, the major amount of antibody activity in a body fluid correlating with the major immunoglobulin class in that fluid. Antibody production was increased in all immunoglobulin classes by using FCA. Vaccination of one gland resulted in antibody activity in the secretions of the other mammary glands.

Influence of diet on postweaning malabsorption and diarrhoea in the pig.

Five-day-old pigs challenged with 10(3) pathogenic Escherichia coli (nalidixic acid resistant) showed no clinical signs of disease until subsequently weaned at three weeks. Dietary manipulation was shown to influence xylose malabsorption, diarrhoea and bacterial proliferation after weaning. Brief, but not continuous, contact with the diet before weaning markedly increased the severity of subsequent disease after weaning. Immunogenicity of the weaning diet was critical for the development of the disease. Two diets, identical except that in one the protein source (casein) had previously been enzymatically hydrolysed, were compared. Pigs fed the predigested diet showed no clinical signs of post weaning diarrhoea whereas those fed the untreated casein all developed diarrhoea.

An immunohistological study of feline glomerulonephritis using the peroxidase-antiperoxidase method.

Twenty-two cases of feline glomerulonephritis were investigated for the presence of immune complexes within the glomerulus using the peroxidase-antiperoxidase (PAP) method. This method was used with formalin-fixed paraffin-wax embedded tissues which were pretreated with trypsin and with frozen sections of kidney tissue. Of a total of 25 kidney specimens examined (two cats had repeated biopsies) the composition of the deposits was 23/25 IgG, 17/25 C3, 11/25 IgM and 2/25 IgA. Serial studies of two cats showed a progression of the disease from initial nephrotic syndrome to chronic renal failure. With the more severe form of the disease there was a tendency for the deposition of complement and more than one class of immunoglobulin within the glomeruli.

Responses of cats to nasal vaccination with a live, modified feline herpesvirus type 1.

Intranasal vaccination with a cold-adapted strain of feline herpesvirus type 1 (FHV-1) two days before challenge gave partial protection, and four days before challenge gave complete protection, against feline viral rhinotracheitis. Protection at this time appeared to be specific since vaccination with FHV-1 did not affect the disease caused by the unrelated feline calicivirus. The time course of onset of protection also confirmed that the protective mechanism was likely to be specific. However, six days after vaccination only low levels of FHV-specific IgA and IgM antibody and of interferon were found in serum and nasal washings. In lymphocyte transformation assays neither peripheral blood lymphocytes nor tonsil lymphocytes gave a significant proliferative response in the presence of FHV antigen. Pathogenesis experiments demonstrated that the tonsil and nasal turbinates were the most important sites of virulent FHV-1 replication. Vaccination significantly reduced levels of infectious virus found in both sites. The results provide evidence that no one mechanism is responsible for protection following vaccination but local specific responses are more likely to be involved.

Response of cattle upon reexposure to Anaplasma marginale after elimination of chronic carrier infections.

Sixteen cattle serotest-negative for anaplasmosis with either no previous exposure (2 animals) or cleared 8 months earlier of their carrier state by chemotherapy (14 animals) were each exposed to Anaplasma marginale. Anaplasma serotest titers were determined by complement-fixation and rapid card agglutination tests conducted during a 63-day trial period. Serologic reactions indicated that all cattle (both groups) were converted to seropositive by the 21st day after exposure. Fluctuations in PCV were seen in the 2 groups between days 21 and 35. However, parasitemia levels were detectable only in the 2 previously unexposed control cattle. Three splenectomized calves, given 10 ml of blood from 3 of the former carrier cattle 14 days after the latter were reexposed, developed severe clinical and hematologic signs of anaplasmosis and seroconverted from negative to positive on both serologic tests. The need to acquire a better understanding of immunity in anaplasmosis is discussed.

Elimination of naturally acquired chronic Anaplasma marginale infections with a long-acting oxytetracycline injectable.

Four injections of a long-acting oxytetracycline (20 mg/kg) were administered at 3-day intervals to 14 naturally infected anaplasmosis carrier cattle. Individual anaplasma serology titers were evaluated, using complement-fixation and rapid card-agglutination tests at frequent intervals during a 180-day posttreatment period. Serologic results indicated fluctuating complement-fixation titers during the trial period. However, at trial termination, 12 of 14 animals were negative by complement-fixation testing and all animals were card-test negative. Eight splenectomized calves given 10 ml of blood from the medicated cows at their posttreatment day 150 failed to manifest any clinical, hematologic, or serologic signs of anaplasmosis during 56 days. Susceptibility to anaplasmosis challenge exposure was demonstrated by positive clinical and serotest reactions when 3 of the recipient calves were inoculated with blood from a parasitemic carrier calf.

Efficacy of a morantel sustained-release bolus for the control of gastrointestinal nematodes in Florida dairy heifers.

The effectiveness of a morantel sustained-release bolus (MSRB) in controlling gastrointestinal nematode infections was determined in 70 Holstein heifer calves with no prior grazing experience. Calves were allotted to 2 treatment groups and were maintained in Florida during the grazing season on divided pastures of equal area. One MSRB was administered to each calf in 1 group at the time of turnout onto spring pasture, whereas calves in the other group remained as nonmedicated controls. By the end of the grazing season, treatment resulted in significantly (P less than 0.05) lower worm burdens and significantly improved weight gains. The MSRB-treated calves were able to reach breeding weight 2 to 4 weeks earlier than did nonmedicated calves.

Autumn acquisition of nematodes by calves given a morantel sustained-release bolus the preceding spring.

Reinfection with nematodes late in the grazing season was assessed in calves treated the preceding spring with a morantel sustained-release bolus (MSRB). During an initial 155-day grazing period, MSRB-treated calves (n = 15) grazed a pasture used the preceding year for identically treated calves (MSRB pasture). Control calves (n = 15) were not given anthelmintic treatment in the spring and grazed heavily contaminated herbage for the initial 155-day period (control pasture). At the end of the initial grazing period, 3 calves from each group were killed for parasite recovery and counting, with control calves found to harbor 9.2 times more nematodes, compared with the MSRB-treated calves. Nematode counts from tracers killed periodically during the initial grazing period were of similar proportions, reflecting the much greater nematode exposure experienced by the control calves, compared with the MSRB-treated calves. At the end of the initial grazing period, 10 calves (5/group) were placed on a common, contaminated pasture after all were treated twice with fenbendazole (10 mg/kg of body weight, 7 days apart) while on concrete. The second grazing period was for 29 days, followed by a 3-day confinement on concrete. Then, the calves were killed and necropsied. During the 29-day grazing period, the MSRB-treated calves maintained their weight advantage over the control calves, and significant differences in nematode egg counts were not found between the 2 groups of calves. At necropsy, the MSRB-treated calves harbored 27.9% fewer nematodes than did the controls, indicating that prior therapeutic and prophylactic anthelmintic activities of the MSRB did not predispose the animals to enhanced acquisition of nematodes after MSRB protection.