Passage of I131-Albumin and I125-Gamma Globulin Into the Small Intestine of Calves

Intestinal transfer of I¹³¹-albumin and I¹²⁵-gamma globulin was studied in 5 calves fitted with re-entrant intestinal loops. The passage of the two proteins across the intestinal wall proved highly variable (cf. Table II). However, the transfer of I¹³¹-albumin and I¹²⁵-gamma globulin was of the same order of magnitude, which is taken as evideńce of similar transfer mechanisms of albumin and gamma globulin, in spite of different molecular weights. Instillations of hypertonic magnesium sulphate solution and of intestinal digesta were followed by increased transfer rates. It appears, therefore, that the passage of digesta will influence the transfer of proteins along the gut. It is emphasized that quantitation of the transfer as related to total catabolism of plasma proteins is subject to considerable inaccuracy.     

Causes of culling and death in sows.

Over a 4-year period, the annual number of culled sows in 9 Danish herds averaged 54.8 per cent of the year-sows and the number of culled sows in per cent of total number of farrowings averaged 25.8 (Table I). -- The culling rate varied considerably from herd to herd within the same year and from year to year (Tables I and II); however, the average annual culling rate for all the herds only presented small variations (Table II). The average number of litters reared per sow before culling was 3.6. The culling rate was higher in pedigree herds than in commercial herds, and it was highest in the small pedigree herds (Table III). The hygiene level in the herds and the introduction of new female breeding stock did not influence the culling rate (Table IV). A proportionally lower percentage of the sows was culled in herds where the dry and pregnant sows were housed in stalls and/or were tethered, as compared to herds where these sows were housed in pens (Table V). -- The culling rate in the age groups of sows with less than 8 farrowings remained at approximately the same level (Table VI). The main reason for culling was infertility problems, which were recorded in 41.4 per cent of the culled sows, while 16.7 per cent of the sows were culled because their litters were poor and/or small (Table VII). The mortality rate among the culled sows was 11.9 (Table VII), and the main causes of death were chronic pyogenic infections, which occurred in 25.5 per cent of the fatal cases (Table VIII). Certain aspects concerning the recording and calculation of culling rates in the different herds are discussed and it is emphasized that the culling rate per se may not have any direct relationship to the productivity in the herd.     

Evaluation of antibovine IgG subclass specific antisera from guinea pigs and goats

A technique for producing specific antibovine IgG2 antibodies is described. The method relies on the abrogation of the class-specific antibody response of guinea pigs to bovine IgG1 by intravenous injection of goat serum immediately before immunisation in the foot pads with bovine IgG2 in adjuvant. Of the 10 resulting antisera, six were judged monospecific for IgG2 by immunoelectrophoresis but, of these, two antisera gave a very faint line in gel diffusion using IgG1 as the antigen. Radial immunodiffusion studies indicated that the strength of the antisera, using IgG2 as the antigen, was similar to antisera of guinea pigs not injected with goat serum before absorption with bovine IgG1. For guinea pigs injected with goat serum, using bovine IgG1 as an immunogen did not result in the production of subclass specific antisera, rather, the specificities were similar to those of animals not receiving goat serum. This data is compared to absorption studies of goat antibovine IgG1 and IgG2 antisera. The relationships of goat and bovine IgG subclasses are discussed.     

Ontogeny of T cells in the pig fetus

Mononuclear cells isolated from thymus, spleen and cord blood of pig fetuses ranging in age from 48 to 112 days were examined for the presence of sheep red blood cell rosette-forming cells (SRBC-RFC). After an initial increase from 77 % (mean) at 48 days of gestation to 88 % at 60 days, the proportion of SRBC-RFC in thymus remained constant throughout the gestational period. In spleen and cord blood, the proportion of SRBC-RFC increased with age, from occasional rosette-forming cells at 48 days of gestation to 21 % and 30 %, respectively, at 112 days. The demonstrated development of SRBC-RFC in the thymus, spleen and cord blood is considered to reflect the ontogeny of T cells in these fetal pig tissues.     

Glutathione Peroxidase Activity and Erythrocyte Lipid Peroxidation as Indices of Selenium and Vitamin E Status in Young Pigs

A randomized, blocked 2³ factorial experiment was conducted with 48 pigs from sows fed a diet low in selenium and vitamin E. From 3 to 12 weeks of age the piglets were kept in single pens and fed a basic diet consisting mostly of barley, dried skim milk, soybean meal and dried yeast, and containing 55 µg selenium and 3 mg vitamin E per kg. The treatment factors — i.e. feed supplements — were 2 levels of Se (nil, 60 µg/kg), 2 levels of vitamin E (nil, 50 mg/kg), and 2 levels of the feed antioxidant ethoxyquin (nil, 150 mg/kg). Blood samples, collected at termination of the experiment, were examined for glutathione peroxidase activity (GSH-Px) and resistance against erythrocyte lipid peroxidation (ELP) to evaluate Se and vitamin E status, respectively. Analysis of variance showed the GSH-Px activity to be litter-dependent (P < 0.001) and influenced by selenium supplementation (P < 0.001) but not by the other supplements or by interactions between supplements. Resistance against ELP was influenced only by vitamin E supplementation (P < 0.001). GSH-Px and ELP thus seem to be valuable and simple methods for evaluating, respectively, Se status and vitamin E status in growing pigs.     

The application of the soluble antigen fluorescent antibody test for the diagnosis of avian influenza.

The application of the soluble antigen fluorescent test as a tool for serological investigation of influenza type A infection in wild birds was studied. The soluble antigen fluorescent antibody test is basically an indirect fluorescent antibody test except that an artificial matrix of cellulose acetate discs is used as a substrate for antigen and the test results are scanned and recorded by a fluorometer. THe influenza type A soluble antigen fluorescent antibody was obtained from concentrated and detergent disrupted virus particles, absorbed onto cellulose acetate discs. Anti-influenza sera were prepared in pheasants and ducks to A/turkey/Ontario/6118/67 and in pigeons to A/turkey/Ontario/6213/68. The antigen-antibody complex was detected by specific staining with monovalent or polyvalent fluorescein isothiocyanate conjugated rabbit anti-avian immunoglobulins. The soluble antigen fluorescent antibody test is a sensitive technique for the detection of specific influenza A antibodies in several avian species, and could be adapted for use in large scale surveys.     

Etiologic studies on late-term swine abortions

One hundred thirty-eight swine abortions were studied in detail in an effort to identify an etiologic agent. A viral agent was implicated in 7 cases. Bacteria were isolated in less than half of the examined cases: however, in 61% of the cases, motile, filamentous organisms were observed in tissues and fluids. Although swine sera from farms experiencing reproductive problems had a high reactor rate to Leptospira bratislava antigen, electron microscopy of the observed organism revealed a wall-free prokaryote morphologically typical of the class Mollicutes.     

An evaluation of bias in estimated breeding values for weaning weight in Angus beef cattle field records. III. Estimates of bias due to nonrandom mating

Field records from 15 herds involved in the Angus Herd Improvement Records program of the American Angus Association indicated that positive assortative mating for weaning weight estimated breeding value (EBV) was being practiced. For each dam, a separate EBV was calculated from information on each progeny with all other progeny data deleted. Individual, paternal and maternal half-sib data available in all years were included in each calculation and thus, were held constant. Bias in cow EBV caused by nonrandom mating was measured as the pooled within dam regression of dam EBV on progeny's sire EBV deviated from the contemporary site average EBV. Across herds, the average estimated bias associated with positive assortative mating ranged from .05 to .08 ratio units.     

Suckling behavior of calves with dams varying in milk production

Two experiments were performed to test the hypothesis that suckling behavior of calves with similar growth potential varies depending on cows' level of estimated milk production and stage of lactation. Eleven mature cows, which varied in estimated 205-d milk production (996 to 2354 kg/205 d), nursing heifer calves of similar growth potential were used in Exp. 1. Suckling behavior of calves was observed for two 24-h periods at three stages of lactation (average of 52, 104 and 167 d postpartum). Suckling frequency (suckling bouts/24 h) declined as milk production increased at 52 d of lactation (-.00382 bouts/kg milk) but was unrelated to milk production at later stages. Duration of suckling (minutes/suckling bout) increased with estimated level of milk production at all stages of lactation (means = .001556 min/kg milk). Total time suckling tended to increase as estimated level of milk production decreased at 52 d of lactation, but this component of suckling behavior was unaffected by milk level at later stages. Suckling frequency declined from 8.6 bouts/24 h at 52 d of lactation to 4.5 bouts/24 h at 167 d of lactation when averaged across all cows. Total minutes nursed/24 h declined in a similar manner (64 min/24 h to 44 min/24 h) between 52 and 167 d of lactation. Duration of each suckling bout did not change with stage. In the second experiment the relationship of suckling behavior to estimated milk production was evaluated at four early stages (average of 17, 38, 59 and 80 d postpartum) of lactation using 20 mature cows.(ABSTRACT TRUNCATED AT 250 WORDS)