Increased litter size in Rambouillet sheep: I. Estimation of genetic parameters.

The variance and covariance components needed to estimate heritabilities of and genetic correlations among litter size, ovulation rate, scrotal circumference, and BW in a flock of Rambouillet sheep were estimated using REML via an expectation-maximization type algorithm. The heritability estimates from univariate analyses were .14, .21, .25, .36, and .15 for litter size, ovulation rate, scrotal circumference, 180-d BW of females, and 180-d BW of males, respectively, and average heritability estimates from bivariate analyses were .19, .20, .20, .34, and .10 for litter size, ovulation rate, scrotal circumference, 180-d BW of females, and 180-d BW of males, respectively. The genetic correlation between litter size and ovulation rate was near unity. Body weight in ewes had a moderate genetic correlation with both litter size (.22) and ovulation rate (.20) and a low residual correlation with both litter size (.03) and ovulation rate (.09). The genetic correlation between BW in rams and scrotal circumference was 0, whereas the residual correlation was .71. The genetic correlations of scrotal circumference with litter size and ovulation rate were -.25 and +.20, respectively.     

Frequency of urinary tract infection in catheterized dogs and comparison of bacterial culture and susceptibility testing results for catheterized and noncatheterized dogs with urinary tract infections

OBJECTIVE: To determine frequency of urinary tract infections (UTIs) in catheterized dogs that had intervertebral disk disease (IVDD) or disease other than IVDD and compare bacterial culture and susceptibility testing results for catheterized and noncatheterized dogs with UTIs. DESIGN: Retrospective cohort study. ANIMALS: 147 catheterized dogs (105 with IVDD and 42 with other diseases) and 99 noncatheterized dogs with UTIs. PROCEDURES: Medical records were reviewed for signalment, history, clinical problem, duration of urinary tract catheterization, administration of drugs, and urine bacterial culture and susceptibility testing results. RESULTS: Forty-two percent (44/105) of dogs with IVDD and 55% (23/42) of dogs with other diseases had UTIs; this difference was not significant. For catheterized dogs, the odds of UTI were increased by 20% for each year increase in age, 27% for each day increase in duration of catheterization, and 454% with antimicrobial administration. Escherichia coli and Proteus spp were more frequently isolated from noncatheterized dogs, whereas Enterobacter spp and Staphylococcus spp were more frequently isolated from catheterized dogs. There was no significant difference in frequency of 1, 2, or 3 isolates between groups. Proportions of antimicrobials to which the most frequently isolated bacteria were resistant were not significantly different between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that urinary tract catheterization is a reasonable alternative for management of dogs with urinary bladder dysfunction, but that duration of catheterization should be minimized and indiscriminate antimicrobial administration to dogs with indwelling urinary catheters should be avoided.     

Physicochemical characteristics of onion (Allium cepa L.) tissues

The structure and mechanical properties of onions are important factors affecting their textural quality. The onion bulb consists of several layers of pigmented, papery scales surrounding fleshy storage scales that comprise an upper epidermis, an intermediate parenchyma tissue, and a lower epidermis. The purpose of this study was to examine the chemical composition of cell walls from the papery scales and outer fleshy scales of onion (Allium cepa L. cv. Sturon) in relation to their mechanical properties. Cell-wall material (CWM) was prepared from the component tissues and analyzed for its carbohydrate and phenolic composition. The CWMs were rich in uronic acid and glucose, with smaller quantities of arabinose, galactose, and xylose. In the fleshy scales, the lower epidermis contained relatively more galactose-rich pectic polysaccharides, whereas the upper epidermis and the papery scales contained virtually no galactose. Analysis of mechanical properties showed that the order of strength of the tissues was papery scales > fleshy scales, which were in the order lower epidermis > upper epidermis > intermediate parenchyma. The upper epidermis of fleshy scales was stronger in the vertical than the horizontal direction, and both orientations showed negligible notch sensitivity. Cyclohexane-trans-1,2-diaminetetraacetate-induced vortex-induced cell separation of the intermediate layer of fleshy scales indicated that calcium cross-linking may play an important role in cell-cell adhesion. A small but significant amount of ferulic acid was found in the walls, predominantly in the thick cuticle of the lower epidermis of fleshy scales. Alkali-labile wall-bound flavonoids were also detected.     

Tall fescue forage mass in a grass-legume mixture: predicted efficiency of indirect selection

High fertilizer prices and improved environmental stewardship have increased interest in grass-legume mixed pastures. It has been hypothesized, but not validated, that the ecological combining ability between grasses and legumes can be improved by breeding specifically for mixture performance. This experiment examined the predicted efficiency of selection in a grass monoculture environment to indirectly improve tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) forage mass in a grass-legume mixture. Heritability, genetic and rank correlations, and selection efficiencies were estimated for forage mass in a tall fescue half-sib population grown as spaced-plants overseeded with either turf-type tall fescue (monoculture) or alfalfa (mixture). Heritability for tall fescue forage mass in monoculture ranged from 0.32 to 0.70 and were always similar or greater than those in mixture (range 0.27–0.55) for four successive harvests and annual total. Genetic correlations between monoculture and mixture tall fescue forage mass varied with values of 0.48, 0.92, ?0.31, 0.70, and 0.25 in June, July, August, October, and annual total, respectively. Indirect selection efficiencies exceeded or approached direct selection for mixtures only in July and October (1.29, and 0.73, respectively). Whereas, indirect selection efficiencies were low in June, August, and annual forage mass (0.58, ?0.31, and 0.28, respectively). Moreover, low Spearman’s rank correlations (?0.03 to 0.35) indicated differing half-sib family performance between the monoculture and mixture environments. Results indicate that direct selection should be used to improve tall fescue forage mass in a grass-legume mixture, and support the hypothesis of increasing ecological combining ability by breeding for mixtures per se.     

Failure of viral protein 3 of infectious bursal disease virus produced in prokaryotic and eukaryotic expression systems to protect chickens against the disease

In recent years, infectious bursal disease virus (IBDV) has become a serious economic problem as a result of the emergence of new and very virulent strains. Most of the antibodies produced against IBDV are for the structural proteins viral protein (VP) 2 (VP2) and VP3. The purpose of this study was to test the potential of recombinant VP3 to induce protective antibodies. The gene for VP3 was isolated from a virulent strain of the virus and cloned into prokaryotic (Escherichia coli) and eukaryotic (baculovirus) expression systems. The protein expressed by both systems was of the expected size (32 kD) and was detected by anti-IBDV antibodies. Following partial purification, the polypeptides were injected into intact birds and induced the production of high levels of anti-IBDV antibodies, as detected by immunoblot and enzyme-linked immunosorbent assay tests. These antibodies did not prevent changes in the bursa and mortality when birds were challenged with a virulent IBDV strain after vaccination with the recombinant VP3. The results show that VP3 polypeptide cannot be used as a subunit vaccine against IBDV and raise questions concerning the nature of the neutralizing epitope on this structural protein.     

Phenotype and function of murine discrete Peyer's patch macrophage derived - dendritic cells

The phenotype and function of peritoneal cavity macrophage-derived dendritic cells (PEC-DC) was previously reported. In this study we have gone further in using our established culture system to generated discrete Peyer's patch dendritic cells (DPP-DC) from murine discrete Peyer's patch macrophages (DPP-M?), following stimulation with granulocyte macrophage colony stimulating factor (GM-CSF) plus interleukin 4 (IL-4) for 7 days. DPP-M? from murine small intestines were obtained by mechanical disruption of discrete Peyer's patches (DPP), followed by metrizamide density gradient centrifugation to remove Peyer's patch resident DC and debri, after which an overnight adherent step in tissue culture medium was carried out for macrophage enrichment. Characterization of the generated DPP-DC was carried out using well-established criteria of morphology, expression of membrane antigens and capacity for antigen presentation. Dendritic cells expressed DEC-205, F4/80 and CD34 at high levels, but exhibited very low CD11c levels. They were shown to present soluble protein antigen to CD3(+) spleen T cells. A comparison of the surface antigen expression in the progenitor DPP-M? population and the generated DPP-DC showed a significant decrease in MHC class II levels and a marked down regulation of the co-stimulatory molecule CD86 (B7-2). High expression of the haemopoietic progenitor marker CD34 indicates that the generated DC, possess a haemopoietic rather than myeloid origin. Taken together, these results may provide a better understanding of the complex network regulating mucosal immune responses.     

Effect of fenoldopam on renal function after nephrotomy in normal dogs

OBJECTIVE: To evaluate effects of fenoldopam on renal function in normal dogs subjected to bisection nephrotomy. In addition, effects of bisection nephrotomy on renal function in normal dogs were evaluated. STUDY DESIGN: Controlled, randomized, blinded experiment. SAMPLE POPULATION: Sixteen mixed-breed adult dogs. METHODS: Dogs were paired for sex, body weight, and approximate age and assigned to 1 of 2 groups: fenoldopam (F) or placebo (P). Baseline glomerular filtration rate (GFR) based on quantitative renal scintigraphy using (99m)Tc-DTPA, blood urea nitrogen (BUN), serum creatinine (SCr), urinalysis, and urine culture were performed before surgery. Left nephrotomy was performed via median celiotomy. Group F dogs were administered intravenous (IV) fenoldopam (0.1 microg/kg/min) for 90 minutes, whereas group P dogs were administered an equivalent volume of saline (0.9 % NaCl) solution for 90 minutes. Temperature, heart rate, respiration, direct arterial blood pressure, and urine volume were recorded during anesthesia. Renal function was assessed by measuring SCr, BUN, and GFR at 1, 21, and 42 days after surgery. RESULTS: There was no significant difference between groups in measured physiologic variables. No significant difference in GFR, BUN, or SCr between groups or between operated or control kidneys was detected. CONCLUSIONS: Bisection nephrotomy in normal dogs with renal arterial occlusion of 15 minutes and using a simple continuous capsular closure does not adversely affect renal function. CLINICAL RELEVANCE: Bisection nephrotomy, as described in this study, does not decrease renal function; perioperative administration of renoprotective agents is not necessary in normal dogs.     

A role for balance of interferon-gamma and interleukin-4 production in protective immunity against Neospora caninum infection

A suitable balance in the production of Th1/Th2-type cytokines has a crucial role in the control of microbial infections. We investigated cytokine production patterns and effects during Neospora caninum infection, based on two mouse models and an in vitro system. In the acute infection of N. caninum, BALB/c-background IFN-gamma-deficient mice that were sensitive to the N. caninum infection showed high levels of IL-10 production, whereas significant levels of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production were observed in resistant wild type mice. BALB/c mice vaccinated with recombinant vaccinia virus expressing N. caninum surface protein NcSRS2 resisted parasite spread throughout the body, low levels of IFN-gamma production and high levels of IL-4 production were observed compared to unvaccinated animals. The treatment of N. caninum-infected cells with IFN-gamma or IL-10 decreased the host-cell viability in an in vitro system using mouse macrophage J774A.1 cells. On the other hand, IL-4, but not IL-10 administration, increased the viability of N. caninum-infected and IFN-gamma-treated cells. In the light of the balance of Th1/Th2-type cytokine production, an IFN-gamma/IL-4 balance may have a crucial role for the control of cellular responses against the parasite invasion.     

Volatile fatty acid metabolism by epithelial cells isolated from different areas of the ewe rumen

Cells were harvested from four rumen locations in four 2- to 3-yr-old ewes fed fescue hay to determine whether cell origin has an effect on cellular VFA metabolism. Tissue (approximately 150 cm2) was excised from the anterior cranial pillar, ventral sac floor, caudal pillar surface, and dorsal sac ceiling. Cells were isolated using serial tryptic digestion. One milliliter of isolate was incubated for 2 h in 6 mL of medium containing 25 mM propionate and 10 mM butyrate. Incubations were terminated at 0, 30, 60, 90, and 120 min and analyzed for beta-hydroxybutyrate, acetoacetate, lactate, and pyruvate. Cell yield was 22, 22, 24, and 14 (+/- 6) x 106 cells/mL, and viability was 92, 92, 94, and 87% for anterior cranial pillar, ventral sac floor, caudal pillar surface, and dorsal sac ceiling, respectively. All metabolite concentrations and ratios of redox pairs increased throughout the incubations, indicating continuous cellular activity. Final 2-h concentrations (nmol/10(6) cells) were 123, 113, 163, and 158 (+/- 35) for beta-hydroxybutyrate; 38, 42, 24, and 45 (+/- 10) for acetoacetate; 25.3, 20.6, 10.1, and 20.4 (+/- 5.6) for lactate; and 2.54, 0.98, 1.06, and 1.31 (+/- 0.61) for pyruvate in the anterior cranial pillar, ventral sac floor, caudal pillar surface and dorsal sac ceiling incubations, respectively. Origin of rumen tissue had no significant effect on metabolite production, indicating that cellular location is not a critical factor that affects rate of rumen epithelial cell VFA metabolism under these specific in vitro conditions.     

Retroperitoneal hemangiosarcoma causing chronic hindlimb lameness in a dog.

The clinical, radiographic, ultrasonographic, computed tomographic, surgical and histopathological findings in a Boxer dog with retroperitoneal hemangiosarcoma are described in this study. A seven-year-old, male, castrated Boxer dog was referred for evaluation of chronic hindlimb lameness. The physical examination revealed muscle atrophy and sciatic nerve deficits. Radiography and ultrasonography revealed a caudodorsal abdominal mass. Computed tomography revealed that the mass involved the left margin of the L7 vertebra, lumbosacral canal, and lumbosacral plexus. At surgery, a large retroperitoneal haematoma was removed. Histopathology of amorphous tissue found near the haematoma was consistent with haemangiosarcoma. The owner declined any further treatment. Ten weeks after discharge, the dog was euthanatized due to collapse and haemo-abdomen.