Effects of supplemental protein type on productivity of primiparous beef cows.

Effects of supplemental degradable (DIP) and undegradable (UIP) intake protein on forage intake, BW change, body condition score (BCS), postpartum interval to first estrus, conception rate, milk production and composition, serum metabolites and metabolic hormones, and calf gain were determined using 36 primiparous Gelbvieh x Angus rotationally crossed beef cows. On d 3 postpartum, cows (average initial BW = 495 +/- 10 kg and BCS = 5.5 +/- 0.1) were randomly assigned to one of three dietary supplements (12 cows/treatment). Date of parturition was evenly distributed across treatment (average span of calving date among treatments = 2.4 +/- 2.5 d). Individually fed (d 3 through 120 postpartum) dietary supplements were 0.82 kg of corn and 0.23 kg of soybean meal per day (DIP), the DIP + 0.12 kg of blood meal and 0.13 kg of corn gluten meal per day (DIP + UIP), and 0.82 kg of corn, 0.07 kg of blood meal, and 0.08 kg of corn gluten meal per day in an isonitrogenous replacement of soybean meal (UIP IsoN). Cows had ad libitum access to native grass hay (8.5% CP) and trace-mineralized salt. Total OM intake was greater (P = 0.06) for DIP + UIP than UIP IsoN cows. At 30 d postpartum, DIP + UIP cows produced more milk than UIP IsoN, with DIP being intermediate; however, at 60 d postpartum, DIP + UIP and DIP cows were not different, but both had greater milk production than UIP IsoN (treatment x day interaction; P = 0.08). A treatment x day interaction (P = 0.06) for BCS resulted from DIP + UIP cows having the greatest BCS at 60, 90, and 120 d d postpartum and DIP having greater BCS than UIP IsoN cows only on d 60 postpartum. Serum insulin concentrations were highest (treatment x day interaction; P = 0.09) for DIP + UIP cows at 30 d postpartum but did not differ among treatment thereafter. Serum insulin-like growth factor-binding protein (IGFBP)-2 (34 kDa) and -3 (40 and 44 kDa) were greatest (P < 0.0003) for DIP cows. Serum urea-N concentrations were greater (P < 0.01) in DIP + UIP cows than in either DIP or UIP IsoN cows. However, postpartum interval to first estrus, conception rate, and calf weaning weights were unaffected (P = 0.35, 0.42, and 0.64, respectively) by treatment. Although UIP in addition to or in replacement of DIP affected milk production and blood metabolites, the productivity of these primiparous beef cows was not altered. Thus, the type of supplemental protein does not seem to influence productivity of primiparous beef cows in production systems with conditions similar to our experimental conditions.

Prevalence and epidemiology of trichostrongylids in Wyoming cattle with consideration of the inhibited development of Ostertagia ostertagi.

During 1988, monthly collections of abomasa and the cranial portion of the small intestine of 208 native Wyoming cattle were examined for adult and larval helminth parasites. Egg counts were performed on colonic faecal specimens. The animals ranged from 7 months to 8 years of age and were sampled at slaughter houses or diagnostic laboratories from five different counties in the State. Most of the cattle had ranged for a long time on non-irrigated, high altitude grass plains from about 1250 to 2500 m above sea level. All animals examined were found infected. Nematode genera (and number of species) found included Ostertagia (4), Trichostrongylus (2), Haemonchus (1), Cooperia (4) and Nematodirus (2). One trematode, Fasciola hepatica, and a cestode, Moniezia benedeni, also were found. Trichostrongylus axei, Trichostrongylus longispicularis and Cooperia lyrata were found for the first time in Wyoming, Ostertagia circumcincta was found for the first time in cattle in Wyoming, and Haemonchus placei, tentatively identified in a previous survey, was definitively confirmed. Predominant species (and prevalence) were Ostertagia ostertagi (98%), Cooperia oncophora (60.6%), Ostertagia bisonis (41.8%), Cooperia bisonis (33.6%) and T. Axei (27.9%). One or more of the four species of Ostertagia were found in all animals. Inhibited O. ostertagi and O. bisonis larvae predominated from November to April and reached a peak in January to comprise 88% of the total nematode burden for that month. The adult population of abomasal nematodes peaked in April and predominated thereafter until October. Haemonchus placei also spent the autumn-winter period in an inhibited state of development. Faecal egg counts were lowest during winter months, when the highest number of worms were present as L4 larvae, as determined by luminal and mucosal counts. Nematode populations in the small intestine peaked in June and persisted until November. The results of this study showed the magnitude and species composition of nematode parasitism in cattle raised on high altitude grass plains, underscored the inaccuracy of faecal egg counts as an indicator of worm burden during fall and winter seasons, and provided information on which anthelmintic treatment timing would be most efficacious.

Laboratory findings associated with abomasal ulcers/tympany in range calves.

The etiology of abomasal ulcers/tympany was investigated in 48 animals from 36 ranches in Wyoming and Nebraska. Results indicate that subclinical trace mineral deficiencies of copper and/or selenium exist in the range cattle in west central Nebraska and Wyoming. Etiological agents most frequently incriminated by bacteriologic cultures and/or histopathic examination were Clostridium perfringens and Campylobacter species. Histopathologic evaluation of abomasums revealed 31 of 38 cases contained abundant gram-positive bacteria associated with the damaged abomasal mucosa. Campylobacter-like organisms were demonstrated in 9 of 38 cases using the modified Dieterle stain. Clostridium perfringens was isolated in 14 of 38 cases, and Campylobacter jejuni was recovered from 5 of 38 cases.

Adjuvant activity of water-insoluble surfactants.

A series of cationic amine and diamine surfactants, nonionic surfactants, and traditional vaccine adjuvants were compared for capacity to induce serum IgG antibody. With one exception, none of the aliphatic primary, secondary, tertiary or quaternary amines or diamines exhibited adjuvant activity beyond that of the dilute hexadecane emulsion vehicle nor was a structure-activity relationship determined. Avridine, a lipoidal diamine, potentiated the antibody response, but not the level of some nonionic surfactant adjuvants or Freund's adjuvants. Among the nonionic surfactants, T1501 tetronic block copolymer, trehalose dimycolate, sorbitan trioleate, and glycerol trioleate were equivalent (P greater than 0.05) to Freund's complete adjuvant in their capacity to stimulate antibody. The latter two surfactants have not been reported previously. The results suggest that certain nonionic surfactants in dilute oil-in-water emulsions are effective replacements for Freund's adjuvants. Such adjuvant emulsions are easily prepared, easily injected and do not produce the grossly adverse reaction observed with Freund-type water-in-oil emulsions.

Opposing effects of the interferon inducer, avridine: enhancement or suppression of tumor growth depending on treatment regimen.

Tumor growth and regression was studied in C57BL/6J mice injected with Moloney sarcoma virus (MSV) and treated with the interferon (IFN)-inducing drug, avridine. Avridine decreased the persistence of tumors when given one or five days after virus, but shortened the prepatent period and increased persistence if given one day prior to virus. Additional studies were undertaken to study the role that serum interferon and natural killer (NK) cell activity might have in this phenomenon. Interferon levels were greatly enhanced (over that induced by virus alone or avridine alone) when avridine was given one day after, but not one day before, virus. Six days after viral infection, interferon titers had returned to near zero but could be boosted by injecting avridine at day 5. Multiple injections of avridine before and after virus resulted in refractoriness to interferon induction and tumor persistence. NK activity was greatly increased by virus at two days post-infection, and avridine given one day after infection significantly enhanced cytotoxicity of these splenic cells against tumor cells. By six days after infection, NK activity had returned to normal but could be increased by avridine given at five days post-infection. It appeared that high levels of interferon induced by avridine given at one or five days after infection increased NK activity and may have been responsible for enhanced regression. Pre-treatment by avridine had little effect on interferon levels over that induced by virus alone, but that did not explain the enhancement of tumor growth since NK activity was increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Stable oil-in-water emulsions: preparation and use as vaccine vehicles for lipophilic adjuvants.

Many of the most potent immunoadjuvants for inclusion in vaccines are extremely hydrophobic surfactants. Lipophilic vehicles are needed as carriers for these water-insoluble adjuvants and to provide the hydrophilic-hydrophobic interfacial surface at which they act. We used emulsifiers comprised of fatty acid esters of polyoxyethylene sorbitan (Tweens) or sorbitan (Spans) to prepare oil-in-water (O/W) emulsions of hexadecane. Emulsion stability could be predicted from a ratio of spectrophotometric absorbance readings at 800 and 400 nm but not from published hydrophilelipophile balance (HLB) values. Emulsions that were stable even after heating or freezing resulted when equal volumes of hexadecane and a 70:30 blend of Tween 80/Span 80(T80/S80) were mixed and then diluted with normal saline solution to the desired hexadecane concentration. This blend of monooleate esters has an HLB value of 11.8. Other Tween-Span formulations were mixed to yield emulsifiers with the same HLB value, but only those that contained either T80 or S80 were effective stabilizers. Instability resulted when both esters were derived from saturated fatty acids. Addition of bovine serum albumin (BSA) antigen to the oil phase of 5% hexadecane emulsions tended to destabilize the emulsions, especially at higher protein concentrations. The surface active adjuvant, hexadecylamine, increased emulsion stability. Highest antibody responses in mice were seen when BSA was added to the internal phase of emulsions, i.e., the oil phase of O/W emulsions and the aqueous phase of W/O (Freund's) emulsions. Addition of the hydrophilic T80 to the aqueous phase of O/W emulsions was detrimental to antibody production. In general, stability, oil concentration, and T80/S80 concentration of emulsions had little effect on IgG levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dexamethasone on babesiasis in hamsters.

Three subcutaneous injections of 0.20 mg of dexamethasone/kg of body weight caused a substantial increase in Babesia microti-parasitized RBC of hamsters, indicating that this was a useful method for revealing the presence of latent infections. A relative neutrophilia, lymphocytopenia, and eosinopenia were also seen in the long-term B microti-infected carrier hamsters after 0.20 mg or 0.02 mg of dexamethasone/kg. Noninfected hamsters treated with dexamethasone had a neutrophilic leukocytosis and a transient lymphocytopenia. Spleen to body weight ratios of noninfected hamsters decreased significantly (P less than 0.02) after 4 injections with either dosage level. These ratios did not significantly (P greater than 0.05) decrease in dexamethasone-treated infected hamsters.

Immune responses of calves antigenically stimulated and challenge exposed with Anaplasma marginale during tick infestation or treatment with dexamethasone.

Similar anamnestic antibody responses to a 2nd injection of a Anaplasma marginale vaccinal antigen were observed in calves infested with the tick Dermacentor albipictus and in tick-free calves. When challenge exposure of these calves to virulent A marginale was done, infestation with the tick Boophilus microplus increased anemia (P less than 0.01), but did not suppress antibody production to A marginale or increase parasitemia. None of the vaccinated calves, regardless of infestation, experienced clinical anaplasmosis. Mitogenic responses of lymphocytes from infested animals were unaltered by either infestation. Tick infestations did not cause immune suppression in the calves, whereas use of dexamethasone resulted in a significantly lower antibody response (P less than 0.05) after a 2nd injection of vaccinal antigen. After challenge with virulent A marginale, dexamethasone-treated calves showed more pronounced parasitemia (P less than 0.01) and anemia (P less than 0.01) than did control calves. Anaplasmosis did not prevent the calves from developing resistance to reinfestation, which was accompanied by immediate, but not delayed, hypersensitivity reactions against homologous tick extracts. Dermacentor albipictus did not seem to share common antigenic determinants with B microplus, since extracts from the latter did not elicit immediate hypersensitivity responses in calves sensitive to D albipictus extracts. Calves were somewhat resistant to reinfestation as evidenced by reduced numbers of adult fed ticks, decreased weights of ticks after feeding, and smaller egg masses.

Delayed-type skin hypersensitivity and in vitro lymphocyte immunostimulation responses of swine following inoculation with Mycobacterium avium cell walls and a mycobacterial immunopotentiating glycolipid.

Miniature swine (n = 5 per group) were inoculated intradermally with mineral oil-in-water emulsions containing either 150 micrograms of mycobacterial immunopotentiating glycolipid P3 (EP3), 150 micrograms of lyophilized Mycobacterium avium (serotype 8) cell walls (E-MaCW), or 150 micrograms P3 and 150 micrograms M. avium cell walls (EP3-MaCW). Swine vaccinated with E-MaCW and EP3-MaCW developed antigen-sensitive lymphocytes detectable with delayed-type hypersensitivity (DTH) skin tests and lymphocyte transformation assays. Swine injected with EP3 were not sensitized. In general EP3-MaCW evoked a more pronounced in vivo DTH tuberculin skin test and in vitro lymphocyte transformation responses than E-MaCW. Time-course studies indicated a more persistent response in swine injected with EP3-MaCW than in those given E-MaCW. Commercial type Yorkshire swine (n = 5) inoculated intradermally with EP3-MaCW developed cell-mediated immune (CMI) responses to avian tuberculin detectable in vivo with delayed-type skin hypersensitivity and in vitro with lymphocyte immunostimulation responses.

Comparative efficacy of an experimental S45/20 bacterin and a reduced dose of strain 19 vaccine against bovine brucellosis.

Yearling beef heifers were vaccinated with 2 doses of an experimental Brucella abortus S45/20 bacterin or a reduced dose of strain 19 (S19) vaccine, or were used as nonvaccinated controls. None of the vaccinated heifers was positive by the acidified plate, Rivanol, complement-fixation, or card tests 5 months after inoculation. Sixteen of 21 heifers given S45/20 bacterin with trehalose dimycolate adjuvant had delayed hypersensitivity when skin was tested 7 months after initial vaccination, whereas none of the S19 vaccinates or controls was reactive. After natural breeding, pregnant heifers were challenge exposed at 3.5 to 5 months of gestation with 2.5 X 10(7) viable B abortus S2308 organisms in the conjunctival sac. Abortions occurred as follows: 16/19 (84.2%) of heifers given S45/20 bacterin, 6/12 (50.0%) of heifers vaccinated with S19, and 17/18 (94.4%) of the nonvaccinated controls. Of the 10 heifers that calved normally, only 3 (1 in each group) were seropositive. A correlation was not seen between skin hypersensitivity and acquired resistance. Possible reasons for the poor protection with a reduced dose of S19 vaccine and the failure of S45/20 bacterin to enhance cellular resistance are discussed.

Scanning electron microscopy of in vitro serum-mediated destruction of juvenile Fasciola hepatica.

The tegumental surface of immature Fasciola hepatica was damaged when incubated in vitro with serum collected from an experimentally infected calf. Degeneration of the tegumental surface was observed by scanning electron microscopy (SEM) at 4 hr. after incubation. Decomposition was observed 8 to 12 hr after incubation and complete destruction of the tegument occurred by 16 hr. The flukes became inactive after 8 to 12 hr of incubation. None of the above findings were observed for the tegument of flukes incubated in tissue culture media or in media containing normal calf serum and the trematodes remained motile throughout the incubation period. Latex particles were used as an immunological marker for SEM studies to determine if gamma globulin could be responsible for the observed changes and, if so, the site of antibody attachment. The coated latex particles covered the entire surface of flukes recovered from mice 5 days after infection with metacercariae. In contrast, latex particles coated with either normal gamma globulin or gamma globulin from serum of the experimentally infected calf that had been adsorbed with disrupted adult flukes were not attached to the surface of the flukes. Absorption of the serum with disrupted, adult flukes decreased the concentrations of immunoglobulins (Ig)G1 and G2 whereas IgA and IgM were apparently not affected.

Brucella abortus vaccines: comparison of protection provided by immunopotentiated 45/20 bacterins and live strain 19 vaccine in guinea pigs.

Guinea pigs were subcutaneously inoculated with 300 microgram of Brucella abortus strain 45/20 killed cells combined in 1% oil emulsion with trehalose dimycolate (TDM), muramyl dipeptide (MDP), or a combination of the 2 immunopotentiators. Protection, as determined by splenic infections in the guinea pigs after challenge exposure, was compared with that induced by strain 19 vaccine. With few exceptions, protection induced by bacterins containing 50 to 1,000 microgram of TDM or TDM-MDP/dose was comparable with that of strain 19 vaccine (P greater than 0.05). Bacterins that contained MDP as an adjuvant were inferior to those with TDM regardless of the excipient or method of preparation. There was no further enhancement of immunogenicity by the addition of MDP to bacterins that already contained TDM. Mineral oil could not be replaced by a metabolizable excipient in bacterins potentiated with TDM.

Effects of maternal nutritional restriction and cold stress on young calves: absorption of colostral immunoglobulins.

Fifty-seven newborn calves delivered from heifers fed rations either adequate or restricted in protein or metabolizable energy were housed in cold (1 C) or normothermic (21 C) environmental chambers for 3 days to determine the effects of maternal nutritional stress and cold exposure on ability of the animals to absorb colostral immunoglobulins (Ig). In general, the serum Ig concentrations in the newborn calves from dams fed rations restricted in protein or metabolizable energy and the concentrations in sera of the respective calves from dams fed adequate protein or metabolizable energy were similar throughout the 3-day period of observation. Likewise, the serum Ig concentrations in the cold-exposed calves were similar to those in the calves kept at normothermic temperature. An exponential increase in mean serum concentrations of IgM, IgG1, and IgG2 occurred between 3 and 6 hours of age; the values continued to increase, but at a slower rate after 6 hours and reached a peak by 12 hours of age. Then, IgM and IgG2 decreased until 48 hours, after which time they increased, but IgG1 varied only slightly from the peak at 12 hours and then increased. With one exception, data indicated that neither the maternal dietary restrictions or the cold exposure imposed on the calves caused significant (P greater than 0.05) differences in absorption of colostral Ig when compared with that of the respective calves from dams fed adequate diet or the calves kept at normothermic temperature.

Antibody and delayed hypersensitivity responses of neonatal calves delivered from protein-restricted dams.

The effects of moderate maternal protein restriction on in vivo humoral and cell-mediated immune responses of bovine neonates were studied. Hereford heifers were fed protein-adequate or protein-restricted rations for the last 150 days of gestation and for 6 months after parturition. At birth, all calves from these heifers were allowed to remain with their dams and were inoculated with tetanus toxoid (TT) and an emulsion of tuberculoproteins and trehalose dimycolate (cord factor) of Mycobacterium bovis. One month later, blood samples were collected from all calves, and sera were examined for antibodies to TT. The calves were given a 2nd inoculation of TT, and anamnestic antibody responses were measured 7 days later. Differences in primary or secondary antibody responses were not observed between principal and control groups of calves. Also, differences in tuberculin reactivity were not observed in calves from cows fed protein-adequate or protein-restricted diets.

Immunoglobulin levels in serum and colostral whey or protein-metabolisable energy restricted beef cows.

Aberdeen Angus cows were fed adequate diets or diets restricted in protein and, or metabolisable energy for the last 156 days of gestation to determine effects of nutritional restriction on concentrations of immunoglobulins in serum and colostral whey. There were no significant interactions between the effects of low protein and metabolisable energy on immunoglobulin concentrations. Thus, observed differences in immunoglobulin concentrations between the restricted and adequate dietary groups were attributed to the main effects of treatment. Low protein or metabolisable energy had little overall effect on serum IgM concentrations although levels began to decrease sooner in gestation in restricted animals than in those fed adequate diets. Concentrations of IgG1 in serum of all animals were similar and a precipitous decrease in concentration was noted at about 240 days of gestation and this decrease continued until parturition. Serum IgG2 concentrations increased in all animals as parturition approached. Immunoglobulin concentrations in colostral whey were either similar to or tended to be slightly higher in dietary restricted animals than in animals fed adequate diets although the differences were not significant.