Systemic salmonellosis in mature beef cows

Systemic infection of mature beef cows with Salmonella typhimurium resulted in death of cows, abortions, and premature births. Salmonella typhimurium was isolated from the kidney, liver, and spleen of cows but not from an aborted fetus. Diarrhea was not a prominent clinical feature of the epizootic. The source of the salmonella was not determined.     

Economic Evaluation of Different Stocking Densities for Various Sized in Texas

There has been a trend toward intensification of shrimp farming in the U.S. FiCteen simulated farms were used to evaluate economies of scale and to compare three Penaeus vannclmei commercial production strategies: semi-intensive, intensive, and very-intensive. Large economies of scale were associated with each production strategy. Over the range of farm sizes considered, investment cost per hectare decreased approximately 50% and production cost decreased approximately 25%. Farms' returns were measured with Internal Rate of Return (IRR). When investment was greater than $0.75 million, the intensive strategy provided slightly better returns to the investor than semi-intensive or very-intensive strategies. At investment levels less than $0.75 million, the semi-intensive strategy provided the highest IRR.     

Effect of porcine parvovirus vaccination on the development of PMWS in segregated early weaned pigs coinfected with type 2 porcine circovirus and porcine parvovirus

The objectives of this study were to determine if coinfection of segregated early weaned (SEW) pigs with porcine circovirus type 2 (PCV2) and porcine parvovirus (PPV) induces an increase in the incidence of post-weaning multisystemic wasting syndrome (PMWS) compared to singular PCV2 infection, and to determine if vaccination against PPV protects pigs against PMWS associated with PCV2/PPV coinfection in SEW pigs. Seventy, 3-week-old, SEW pigs were randomly assigned to one of the five groups. Pigs in group 1 (n = 14) served as the negative controls, group 2 pigs (n = 14) were inoculated with PCV2, group 3 pigs (n = 12) were inoculated with PPV, groups 4 (n = 16) and 5 (n = 14) pigs were inoculated with both PCV2 and PPV. Pigs in groups 1-3 and 5 were vaccinated with two doses of a killed parvovirus-leptospira-erysipelothrix (PLE) vaccine prior to inoculation. The PCV2/PPV-coinfected pigs (groups 4 and 5) had significantly (P < 0.05) higher and more persistent fevers than the singular PCV2-infected pigs. One pig in each of the coinfected groups developed clinical disease (fever, respiratory disease, jaundice, weight loss) consistent with PMWS. Lymphoid depletion was significantly (P < 0.05) more severe in the dually-infected pigs at 42 days post-inoculation (DPI). Vaccinated, coinfected pigs (group 5) remained viremic significantly (P < 0.05) longer and had higher copy numbers of genomic PCV2 DNA in sera at 28, 35, and 42 DPI compared to the unvaccinated coinfected pigs (group 4). PPV-viremia was detected only in the unvaccinated group 4 pigs. PLE-vaccination prevented PPV-viremia but did not prevent clinical PMWS or reduce the severity of lymphoid depletion in PCV2/PPV-coinfected pigs. Evidence of increased incidence of clinical PMWS due to vaccination was not observed in this model.     

Extensive lesions of monkeypox in a prairie dog (Cynomys sp)

Monkeypox with extensive lesions was diagnosed in a prairie dog that was involved in a recent human outbreak of monkeypox in the Midwestern United States. Gross lesions included oral ulcers, pulmonary consolidation, enlarged cervical and thoracic lymph nodes, and multifocal, small, white umbilicated plaques in the gastrointestinal wall. Microscopic lesions were extensive in the lungs and consisted of fibrinonecrotic bronchopneumonia with vasculitis and poorly defined eosinophilic intracytoplasmic inclusion bodies in cells thought to be alveolar epithelial cells, histiocytes, and fibroblasts. Multifocal necrotizing lesions, often accompanied by myxedema, were also present in most of the other examined organs. Aggregates of pox viral particles were observed within lesions by transmission electron microscopy. Monkeypox virus infection was confirmed by real-time polymerase chain reaction and virus culture at the Centers for Disease Control and Prevention. This report highlights the difficulties of rapid diagnosis of exotic or emerging diseases and further substantiates the prairie dog as an animal model of monkeypox.     

The Effects of Mustard Protein Concentrate on Nutrient Digestibility and Performance of Broiler Chickens

This experiment was conducted to determine the effects of feeding mustard protein concentrate on nutrient digestibility and the performance of broiler chickens.A total of 180,day-old,male broiler chickens,weighing an average of 52.8 ± 0.6 g,were randomly assigned to one of six dietary treatments in a randomized block design.The control diet was based on wheat and soybean meal and contained 15% canola meal.The experimental diets contained 3%,6%,9%,12% or 15% mustard protein concentrate added at the expense of canola meal.The digestibility of crude protein and energy declined linearly(P0.01)with increasing levels of mustard protein concentrate.In addition,weight gain and feed intake were linearly(P0.01)reduced as the level of mustard protein concentrate in the diet increased.Feed conversion was also negatively affected(P0.01)by mustard protein concentrate while mortality did not differ among treatments.The results of the present experiment provide a strong indication that there is a factor or factors present in mustard protein concentrate which negatively affects broiler performance.The process through which the protein in mustard seed is concentrated from mustard meal may concentrate some of the anti-nutritional factors found in mustard.Previous research has reported an increase in the concentration of phenolic compounds in protein isolates from mustard and this may be the cause of the reduction in performance as the level of mustard protein concentrate in the diet increased.Further research should be conducted to test this hypothesis.     

Use of a Mycoplasma hyopneumoniae nested polymerase chain reaction test to determine the optimal sampling sites in swine.

A number of polymerase chain reaction (PCR)-based diagnostic tests have been developed for Mycoplasma hyopneumoniae, including one from this research group. This report presents further development, optimization, and standardization of a nested PCR test. Detection sensitivity was 1 fg of M. hyopneumoniae chromosomal DNA (approximately 1 organism). This exceeded the sensitivity of or compared favorably with other published PCR tests. Polymerase chain reaction primers to porcine beta2-microglobulin were included as internal controls for amplifiable chromosomal DNA from porcine samples. To standardize the test, a number of samples from experimentally infected pigs, including nasal, tonsil, tracheobronchial swabs, lung tissue, bronchial alveolar lavage (BAL) fluid, and tracheobronchial brush samples, were examined by PCR. Samples obtained from BAL fluid and tracheobronchial sites were most predictive of infection, whereas nasal swabs and lung tissue were not reliable indicators of experimentally induced infection. In conclusion, the nested PCR developed for this study was found to be a highly sensitive and specific diagnostic tool for M. hyopneumoniae, but the enhanced sensitivity may be unnecessary if the proper sites are sampled.     

Effect of predigestion factors on the apparent digestibility of protein for swine determined by the Mobile Nylon Bag Technique

Five Yorkshire x Lacombe barrows (45 kg initial wt) fitted with duodenal cannulas approximately 10 cm from the pyloric sphincter were used to determine the influence of the pH of the predigestion solution (pH 1.0, 1.5, 2.0 or 2.5), pepsin activity (189 vs 377 IU/liter) and duration of predigestion (0, 1.5, 2.5 or 4.0 h) on the apparent digestibility of the protein in soybean meal (SBM), meal and bone meal (MBM) or canola meal (CM) determined with the Mobile Nylon Bag Technique (MNBT). An additional six barrows were used to determine protein digestibility by conventional methods. Protein digestibilities determined using conventional digestibility techniques were 93.1 +/- .7, 79.1 +/- 1.8 and 79.3 +/- 1.4% for the SBM, MBM and CM diets, respectively. Protein digestibilities determined with the MNBT were highest at pH 2.0 for all three protein sources. Increasing pepsin activity from 189 to 377 IU/liter resulted in a slight increase in the digestibility of SBM and CM, but not of MBM. The absence of predigestion (0 h) resulted in a dramatic reduction in protein digestibility; predigestion times of 1.5 or 2.5 h usually resulted in lower protein digestibilities than did a predigestion time of 4.0 h. The closest agreement between results obtained by the MNBT and conventional digestibility studies occurred with a pH of 2.0, a predigestion time of 4.0 h and a pepsin activity of 377 IU/liter.