Reproductive performance in a diallel cross among lines of mice selected for litter size and body weight

Genetic factors affecting female reproductive performance in lines of mice with a known history of selection were estimated from a 5 X 5 diallel cross. Lines were selected as follows: large litter size at birth (L+); large 6-wk body weight (W+); an index for large litter size and small 6-wk body weight (L+W-); the complementary index (L-W+) and randomly (K). Partitioning of direct and correlated responses for litter size, 6-wk body weight and related traits into average direct genetic (li) and average maternal genetic (mi) effects indicated that the magnitude of differences in li exceeded those in mi. Lines having positive responses in li were W+ greater than L+ greater than L-W+ for dam body weight, L+ greater than L+W- greater than W+ for litter size and L+ greater than (W+, L+W-) for litter birth weight, whereas L-W+ responded negatively for litter size. A positive association was found between mi for litter size and dam body weight, W+ and L-W+ being high and L+ and L+W- low for both traits. Female infertility and time from male exposure to parturition had relatively small correlated responses. Line rankings in general combining ability (gi) and net line effects were similar for the respective traits. Depending upon the line and trait involved, the relative contribution of average direct genetic and line direct heterotic (hi) effects to general combining ability [gi = (1/2) li + hi] varied. Line heterosis refers to average heterosis in crosses involving that line. Direct heterosis ( hij ) for each trait differed considerably among crosses. The three crosses showing the highest hij for litter size at birth, W+ X L-W+ (1.78), L+ X W+ (1.28) and L-W+ X L+W- (1.22), possibly had loci contributing directional dominance to litter size with frequencies of parental lines deviating in opposite directions relative to mean gene frequency. The correlation between absolute difference in parental line means and hij for litter size was not significant, suggesting that the magnitudes of absolute differences in parental means were not reliable predictors of divergence in gene frequency. Crossbred performance increased linearly with midparent values for litter size at birth (b = .88 +/- .09, R2 = .92) and dam parturition body weight (b = 1.13 +/- .04, R2 = .99), the latter trait showing an increase (P less than .01) in heterosis as midparent values increased.     

Determination of the antigenic relationships within the Massachusetts (M41) type of infectious bronchitis virus using the hemagglutination-inhibition test

The antigenic relationships, antigenic spectrum, and immunogenicity of seven IBV-Massachusetts-41 isolates were investigated using the hemagglutination-inhibition (HI) test. HI titers equal to 32 are considered suspicious, titers lower than 32 are considered negative, and titers higher than 32 are considered positive immune responses to infectious bronchitis virus (IBV). Some isolates of Massachusetts-41 ( M41 ) were capable of inducing large quantities of antibodies in chickens following inoculation and demonstrated a wider antigenic spectrum than others. Variations in antigenic spectrum observed within M41 isolates in this study are in agreement with previous reports. This variation is of importance in selecting a proper vaccine strain for a successful immunization program for IBV.     

An epornitic of avian pox in a research aviary

An outbreak of avian pox in a bird research colony was reported. Although 10 species of passerine birds were housed within the facility, clinical signs and mortality were restricted to canaries and house sparrows. Post-mortem lesions initially occurred in the upper and lower respiratory tracts and were characterized by proliferative rhinitis, proliferative bronchopneumonia, and proliferative airsacculitis, and diphtheritic lesions occurring in the esophagus were characterized by proliferative granulomatous esophagitis. Cutaneous lesions occurred subsequently in some birds, and a diagnosis was made by histopathology, electron microscopy, and virus isolation. The occurrence of diphtheritic lesions in pox infections of wild birds has been rare, and a sparrow showed an unusual combination of both diphtheritic and acute systemic lesions previously undescribed.     

Pitfalls in immunofluorescence testing in dermatology. III. Pemphigus-like antibodies in the horse and direct immunofluorescence testing in equine dermatophilosis

Indirect immunofluorescence testing for pemphigus-like antibodies was performed on 79 horses: 28 horses with various nonpemphigus dermatologic diseases, 21 horses with various nondermatologic diseases, and 30 normal horses. Pemphigus-like antibodies were detected in 6 horses: 3 normal horses with titers of 1:40, 2 horses with dermatophilosis at titers of 1:10 and 1:80, and 1 horse with lymphosarcoma at a titer of 1:320. It was concluded that equine pemphigus-like antibodies are a potential source of misinterpretation and misdiagnosis in indirect immunofluorescence testing. Direct immunofluorescence testing for whole immunoglobulin, IgG, IgM, and IgA was performed on skin lesions from 2 horses with dermatophilosis. Diffuse intercellular deposition of whole immunoglobulin and IgG was found in both horses. It was concluded that equine dermatophilosis is a potential source of misinterpretation and misdiagnosis in direct immunofluorescence testing.     

Antimicrobial residues in milk. Comparison of different agar diffusion methods

Different agar diffusion methods were compared in order to find a sensitive method for the detection of various antimicrobial residues in milk. A total of 588 producer milk samples were analyzed using subsets of the most sensitive methods.With the IDF method, 2 positive cases (0.34 %) appeared among the producer milk samples, with the Thermocult method 13 positive cases (2.21 %) and with the Test agar pH 8 method with trimethoprim and glucose 4 positive cases (0.68 %). A combination of the IDF method and the Test agar pH 8 method resulted in 6 positive cases (1.02 %) and a combination of the Thermocult method and the Test agar pH 8 method in 17 positive cases (2.89 %). With penicillinase 41 % of the positive cases were identified as β-lactam antibiotics and with p-aminobenzoic acid 18 % of the positive cases were identified as sulphonamides. 41 % of the positive cases remained unexplained.The best combination for the detection of antimicrobial agents in milk seems to be that of the Thermocult method and the Test agar pH 8 method with trimethoprim and glucose.     

Idiopathic skeletal muscle necrosis in bluegills

Skeletal muscle degeneration and necrosis in a wild population of bluegills (Lepomis macrochirus) were investigated. Hemorrhage and large areas of muscle necrosis were evident at necropsy. Histologically, muscle fibers were granular, vacuolated, and fragmented. Ultrastructural alterations included mitochondrial swelling, clumping and loss of actin and myosin fibrils, swelling of T tubules, and loss of continuity of the sarcolemma. An etiologic agent was not identified.     

Measurement of plasma antithrombin III activity in healthy horses

A fluorometric assay was used to determine plasma antithrombin III (AT III) activities in 15 healthy adult horses. Nearly all plasma samples had an initial value of greater than 100% thrombin inhibited, so a 1:1 dilution of the prepared samples was performed. Following dilution, the mean value of the animals was 59.17 +/- 7.4% thrombin inhibited. Mares had significantly greater AT III activity than did geldings (P less than 0.01). The results of this study indicate the horse has more AT III activity than did other domestic species in which AT III activity has been reported.     

Use of Isobutyl-Cyanoacrylate Adhesive in Osteosynthesis A Preliminary Study

Isobutyl 2-cyanoacrylate was used to reattach partial-thickness cortical bone fragments from the femur in rabbits. Stability, apposition, callus formation, and inflammation around the fragments were evaluated at 2, 4, 8, and 12 weeks.
All glued bone fragments were stable, compared with 85% of controls. Good apposition was achieved in 95% of the glued bone fragments, compared with 19% of the controls. Analysis of the mean scores for callus formation revealed a significant difference only in the 8 week survival group.
Bony union was noted in 20 of 21 of the glued fragments. No evidence of inflammation was seen around the glue, and viable bone was seen adjacent to the adhesive in many sections. In control legs, 13 fragments had healed by osseous union, two by fibrous union, and in six the chip had resorbed.     

Nutritional effects on the growth and fatness of broilers

1. Broiler chickens given diets high in protein, or choice-fed on a high protein balancer, had much lower abdominal fat contents than those reported in many recent experiments. The values for males were 10.8 g/kg liveweight at 56 d at 2.43 kg liveweight in one experiment in Scotland and 16.0 g/kg liveweight at 42 d at 1.93 kg liveweight in another in South Africa. For females the values were 18.8 g/kg liveweight at 56 d at 2.15 kg liveweight in Scotland and 15.7 g/kg liveweight at 42 d at 1.60 kg in South Africa. 2. The content of abdominal fat was, in general, increased by reducing the protein content of the diet or by dilution of the food with oil or starch. It was, in general, reduced by diluting the food with dietary fibre which also reduced liveweight gain. 3. The results are consistent with the idea that chickens attempt to control their food intake so that they achieve a particular fatness. This level of fatness differs between the sexes and between degrees of maturity.     

The use of monoclonal antibodies in an enzyme immunospot assay to detect isotype-specific antibody-secreting cells in pigs and chickens

Monoclonal antibodies directed against porcine immunoglobulin isotypes G, G1, G2, M, and A and against chicken immunoglobulin isotopes G, M, and A were tested in an antigen-specific spot-forming cell (SFC) assay based on the principle of the enzyme immunoassay. The SFC assay was used to quantitate ovalbumin (OA)-specific antibody-secreting cells (ASC) in pigs that had been primed and boosted with OA. The SFC assay was also used to quantitate trinitrophenyl (TNP)-specific ASC in chickens that had been primed with TNP-conjugated keyhole lympet haemocyanin (TNP-KLH). Although, the classical plaque-forming cell (PFC) assay cannot reliably detect isotope-specific ASC in pigs and chickens, it can detect these cells in mice. Therefore, we compared the OA- and TNP-specific SFC assays with PFC assays that were specific for these antigens in mice. The study demonstrated that the SFC assay is superior to the PFC assay in detecting both OA-specific ASC and TNP-specific ASC. The frequencies of OA-specific and TNP-specific SFC detected in mice were of the same order of magnitude as those detected in pigs and chickens. We concluded that the SFC assay is the better method for quantitating ASC in pigs, chickens, and probably all domestic animals for which isotype-specific monoclonal antibodies are available.