Serum hormone and metabolite concentrations in fasted young bulls and steers.

The effect of dietary energy restriction on serum insulin, insulin-like growth factor I (IGF-I), growth hormone, (GH), cortisol, plasma urea nitrogen (PUN) and nonesterified fatty acid (NEFA) concentrations was examined. Angus bulls and steers (10 mo) were allotted to two groups of 12 animals and assigned a treatment order. In a switchback design, animals in order 1 were fed a high grain diet, then fasted, while order 2 animals were fasted, and then fed. Animals were allowed 60 hr to acclimate between treatments. Serum and plasma were obtained at 20 min intervals and 60 min, respectively, for 6 hr after feeding and for the last 6 hr of a 30 hr fast. Serum was assayed for insulin, IGF-I, GH, and cortisol (total and free). Plasma was assayed for PUN and NEFA. Mean insulin (ng/ml) differed between fed (.95 +/- .08) and fasted (.26 +/- .08) animals (P less than 01). Both mean total and free cortisol (ng/ml) were lower in fed (11.48 +/- .99) (1.06 +/- .12) than in fasted (17.10 +/- .93) (1.62 +/- .12) animals, respectively (P less than .01). Animals in order 1 differed in mean IGF-I (ng/ml) between fed (199.0 +/- 8.0) and fasted (116.5 +/- 7.2) treatments (P less than .01). Mean IGF-I for animals in order 2 was 146.7 +/- 7.2 in fed and 213.9 +/- 7.2 in fasted animals (P less than .01). Mean GH did not differ between treatments. Mean PUN and NEFA were higher in fasted than in fed animals (P less than .01). Except for % free cortisol (P less than .05), the hormones did not differ between bulls and steers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Avian leucocyte common antigens: molecular weight determination and flow cytometric analysis using new monoclonal antibodies.

New leucocyte common antigens expressed on all the normal chicken leucocytes have been characterized using two monoclonal antibodies designated as K-11 and K-55. These monoclonal antibodies stained virtually 100% of the leucocytes derived from various lymphoid organs including the spleen, thymus, bursa of Fabricius, caecal tonsil and peripheral blood, as well as a monocytic cell line (MC29), a B cell line (LSCC-RP9), and a T cell line (CU12). However, they did not stain mature erythrocytes, intestinal epithelial cells, or chicken embryonic fibroblasts. The two monoclonal antibodies showed different staining patterns and detected non-overlapping epitopes on MC29 cells in two color immunofluorescence analysis. Western blot analysis under non-reducing conditions showed that the monoclonal antibody K-11 recognized three splenic leucocyte proteins with molecular weights of 92, 42 and 41 kDa, whereas the monoclonal antibody K-55 recognized two proteins with molecular weights of 97 and 42 kDa. The data indicate that the monoclonal antibodies K-11 and K-55 recognize novel leucocyte-common antigens which have lower molecular weights than the previously reported leucocyte-common antigen family.     

HPLC purification of recombinant NcGRA6 antigen improves enzyme-linked immunosorbent assay for serodiagnosis of bovine neosporosis

The gene for a dense granule protein (NcGRA6) of Neospora caninum was expressed in Escherichia coli as a His-tag fusion protein and purified by NiNTA affinity chromatography. In a preliminary study, high binding of antibodies from N. caninum-negative cows was observed in enzyme-linked immunosorbent assay (ELISA) using NiNTA-purified NcGRA6. Analysis of NiNTA eluates revealed a significant number of E. coli proteins that co-purified with recombinant NcGRA6. In an attempt to improve the relative sensitivity and specificity of the NcGRA6-based ELISA, the rNcGRA6 eluates were subjected to a secondary purification using reverse phase-high performance liquid chromatography (RP-HPLC). Analysis of RP-HPLC eluates by SDS-PAGE/silver staining revealed the purification of recombinant NcGRA6 from contaminating E. coli proteins. ELISAs using the RP-HPLC purified NcGRA6 (dELISA) or singly purified NcGRA6 (sELISA) for identifying seropositive and seronegative cows in a beef herd experiencing an epidemic outbreak of neosporosis were compared to standard assays based on native tachyzoite protein-immunofluorescence antibody test, immunoblot assay, and ISCOM-ELISA. The relative sensitivity, specificity, and kappa value of the NcGRA6d-ELISA were greatly improved over the NcGRA6s-ELISA when compared to the three native antigen immunoassays. These results indicate that removal of contaminating E. coli proteins improves the performance of recombinant NcGRA6 ELISA in diagnosing bovine neosporosis, and may have applicability to the use of recombinant proteins in diagnosing other infectious agents.     

Echinococcus granulosus in wildlife in and around the Kosciuszko National Park, south-eastern Australia

OBJECTIVE: To investigate the distribution of Echinococcus granulosus in wild dogs and foxes and hydatidosis in wildlife coexisting with foxes and wild dogs in and around Kosciuszko National Park. DESIGN: Prospective and ad hoc surveys by necropsy of definitive and intermediate hosts. PROCEDURE: Wild dogs and foxes were trapped at one location in the Kosciuszko National Park and at 7 locations around the periphery of the Park. Feral pigs, macropodid marsupials, wombats, and feral goats were collected at some of the same locations. The animals were humanely killed, their small intestines removed in the field, the contents collected, preserved and examined microscopically. All internal organs of intermediate hosts were examined for hydatid cysts. Unidentified lesions were examined histologically. RESULTS: Echinococcus granulosus tapeworms were found in wild dogs from all locations. Prevalence ranged up to 100% with worm burdens up to 300,000 worms. Prevalence in foxes ranged up to 50% in animals recovered from 5 locations. The worm burdens were usually less than 50 E. granulosus per fox. Hydatid cysts were found in all macropodid species. Prevalence (69%) and cyst fertility (100%) were highest in swamp wallabies (Wallabia bicolour). Prevalence of cysts in feral pigs ranged up to 49%. Less than 22% of the cysts were fertile. No cysts were found in any of the wombats or feral goats. CONCLUSION: Echinococcus granulosus occurs commonly in wildlife in and around the Kosciuszko National Park. High numbers of fertile cysts in swamp wallabies, a favoured dietary item for wild dogs in this region, suggests swamp wallabies are pivotal in maintaining transmission. Physical contact with wild dogs and foxes or accidental contact with wild canid faeces is a public health risk.     

Frictional properties of cattle hooves and their conformation after trimming

The conformation of the hooves of nine heifers obtained from an abattoir was measured and their coefficient of static friction (mu) was determined for movement in forward, backward and sideways directions. The hooves were trimmed by the Dutch method and their conformation and p were measured again. Trimming increased mu, and decreased the length of the digit and the angle between it and the floor. The value of mu was considerably greater for movement in a forward or backwards direction than sideways. The relationship between the value of mu for sideways movement and hoof conformation was examined by using 52 lower limbs from a variety of cattle breeds. Although mu was greater for Belgian blue than other cattle breeds, there were no relationships between mu and hoof conformation, including a measure of the roughness of the sole.     

Genetic correlations for daily gain between ram and ewe lambs fed in feedlot conditions and ram lambs fed in Pinpointer units

When performance is recorded in automated facilities that measure feed intake of individual lambs that are penned in a group, such as Pinpointer units, a legitimate question is the degree to which daily gain is genetically correlated with daily gain achieved under feedlot conditions. Lambs were from a composite population (1/2 Columbia, 1/4 Suffolk, and 1/4 Hampshire germplasm) and of the F2 or more advanced generations. Data were daily gains of 1,101 rams (PR) fed in Pinpointer units (11 to 17 wk of age) and 2,021 rams (FR) and 3,513 ewes (FE) fed under feedlot conditions (9- or 10-wk period starting at 9 wk of age). The FR and FE lambs were born from 1983 through 1995, whereas the PR lambs were born from 1986 through 1995. Measurements of daily gain in PR, FR, and FE lambs were considered to represent three correlated traits. Unadjusted means were .411, .406, and .326 kg/d for PR, FR, and FE, respectively. Random effects in the model were animal direct genetic, maternal genetic, and maternal permanent environmental. Fixed effects were associated with age of dam (1 to 6 yr), type of rearing (1 to 4), and contemporary group (test date). Variances due to maternal genetic effects with single-trait analyses were near zero, so those effects were eliminated from the three-trait analysis although a random uncorrelated effect due to dam was included in the model. Estimates of heritability were .22, .14, and .23 for PR, FR, and FE, respectively, with fractions of variance due to dam effects ranging from .02 to .05. Estimates of genetic correlations were .86 for PR with FR, .83 for PR with FE, and 1.00 for FR with FE. Estimated phenotypic variances were similar for PR and FR, but one-third less for FE. The similarity of heritability estimates and estimates of genetic correlations all exceeding .83 suggest that daily gain of rams fed in Pinpointer units will reflect genetic expression for daily gain in both ram and ewe lambs fed under feedlot conditions.     

Serological investigation of an outbreak of Neospora caninum-associated abortion in a dairy herd in southeastern United States

An outbreak of Neospora caninum-associated abortion occurred in a South Carolina dairy wherein greater than 10% of the herd aborted over a 4-month period. Of the total number of cows at mid-late gestation, nearly 40% (28/71) aborted while the remaining 60% (43/71) gave birth to normal calves. Immunohistochemical examination of brain tissue from a subset of aborted fetuses confirmed N. caninum as the causative agent of abortion in these animals. A variety of serological assays, including indirect fluorescence antibody test (IFAT), recombinant enzyme-linked immunosorbent assay (rELISA), ISCOM-ELISA, avidity ELISA, and Neospora agglutination test (NAT), were used to evaluate sera collected during the outbreak from 240 cows for antibodies to N. caninum. IFAT and ISCOM-ELISA testing showed that nearly 80% of the dairy cows had antibodies to N. caninum. NAT and rELISA had similar levels of seropositivity relative to IFAT and ISCOM-ELISA, but the percentage of positive sera was dependent on the cut-off value chosen. As indicated by kappa coefficient statistical analysis, ISCOM-ELISA and IFAT exhibited the highest level of agreement in identifying N. caninum-positive and -negative cows. A decrease in the percentage of seropositive cows as determined by ISCOM-ELISA and IFAT with increasing cow age was noted. However, no significant difference was observed between cow age and abortion status. In addition to these tests, an avidity ELISA was performed on all sera with high (> or =0.4) ISCOM-ELISA readings. Avidity index (AI) increased with time post-abortion suggesting that most abortions were due to recent N. caninum infection. Of the cows at risk for abortion, the mean serological AI of aborting cows was significantly lower (P<0.05) than mean serological AI of non-aborting cows.     

Effect of propionate level in a volatile fatty acid salt mixture fed to lambs on weight gain, body composition and plasma metabolites

Chopped hay supplemented with a volatile fatty acid salt mixture at 20% of metabolizable energy (ME) was fed to 30 Suffolk X Corriedale lambs (mean wt 29.6 kg) to determine the effects of dietary propionate on weight gain, body composition and plasma metabolites. Propionate accounted for 0, 25, 50, 75 or 100% of the salt mixture energy, and acetate accounted for the remainder. Each diet was fed at two levels of daily intake (158.7 and 130.6 kcal ME/W.75). Lambs on the high level of intake lost more (P less than .05) energy in feces, lost less (P less than .05) energy in CH4 and had carcasses with more (P less than .10) water and fat than lambs on the low intake level. Percentage of propionate in the salt mixture had no effect on ME or body composition of lambs. Increasing the percentage of propionate in the salt mixture increased plasma propionate in blood samples taken at 1 and 2 h after feeding (linear, P less than .05). Empty body weight gain per megacalorie of ME above maintenance increased as the percentage of propionate in the salt mixture increased, but not until propionate reached 75% of the salt mixture (linear, P less than .05; cubic, P less than .05). These results show that propionate in the blood has a positive, but nonlinear, effect on weight gain, even when energy intake is held constant.