Efficacy of combined chemotherapy against gastrointestinal nematodes and Fasciola hepatica in cattle

Direct blood smear examination (using 0.05 ml of whole blood) detected 168 (80.9%) of 204 microfilaremic canine blood samples as determined by the modified Knott test for microfilariae (mff) of Dirofilaria immitis (using 1 ml of whole blood). Direct smear examination detected all of 134 microfilaremias greater than 50 mff ml(-1), but only 31 of 70 (44.3%) microfilaremias having less than 50 mff ml(-1). In a separate retrospective query of a database of 963 dogs with necropsy-confirmed heartworm infections, 834 (86.6%) were positive by the DiroCHEK heartworm antigen test, and 504 (52.3%) were microfilaremic by the modified Knott test. Only 2 (0.4%) of the microfilaremic dogs were DiroCHEK negative and another 18 (3.6%) were very weak positives. Although these microfilaremic dogs were not tested by direct smear, only one of the two DiroCHEK-negative and six of 18 weakly DiroCHEK-positive dogs had microfilaremias so low that a direct smear may have given a false negative result. Significant adverse reactions to either diethylcarbamazine or the macrolide endectocides have not been reported for microfilaremias less than 500 mff ml(-1), thus substitution of the direct smear for a concentration test for mff, such as the modified Knott test or membrane filtration, does not appear to increase the risk of an unexpected adverse reaction to heartworm prophylactic drugs. Such a substitution results in only a very slight decrease (on the order of 0.1%) in the overall sensitivity of heartworm screening, provided a test for mff is run concurrently with an antigen test. If a test for mff is the only screening test used, then substitution of a direct smear for a concentration test may decrease the sensitivity of heartworm screening by nearly 20%, depending on the prevalence of low level microfilaremias in the population of dogs tested.     

Characterization of staphylococci associated with clinical and subclinical bovine mastitis

Attempts were made to identify 900 species of staphylococci or micrococci recovered from samples of bovine milk examined for mastitis pathogens. The presence and identity of haemolysins was recorded together with results of disc diffusion antibiotic sensitivity tests. The occurrence of clinical mastitis was also noted and somatic cell counts (SCC) were performed on milk samples which were normal in appearance. Eight hundred and thirty-one coagulase positive staphylococci were obtained, of which 810 were S. aureus and 21 were S. intermedius. Of 65 coagulase negative staphylococci the species of 19 could not be determined by the identification systems used. The remainder were identified as S. hyicus sub sp. hyicus (1), S. hyicus sub sp. chromogenes (19), S. haemolyticus (17), S. hominis (3), S. epidermidis (4), S. capitis (1) and either S. hominis or S. warneri (1). Four other isolates could not clearly be assigned to the genus Staphylococcus or Micrococcus and were designated irregular strains. No micrococci were identified. The presence of alpha, beta, or delta haemolysins occurring singly or in various combinations was identified in 98.3% of coagulase positive staphylococci and in 60% of coagulase negative staphylococci. Epsilon haemolysin was detected in 47.6% of the coagulase negative staphylococci and in 9.5% of S. intermedius. All staphylococci were sensitive to tetracycline (30 microg), novobiocin (1.6 microg), nafcillin (30 microg), methicillin (10 microg) and cephalothin (30 microg) and variable numbers of each species were sensitive to penicillin (2 iu) and streptomycin (10 microg). One non-identified species of coagulase negative staphylococcus was sensitive to erythromycin (0.4 microg) the remaining staphylococci were resistant. Each of the four irregular strains was sensitive to erythromycin and novobiocin. Clinical mastitis was associated with 30.6% of coagulase positive staphylococci, 15.3% of coagulase negative staphylococci, and two of the four irregular strains (50%). Subclinical mastitis as determined by SCC of 500 x 10(3) or greater was associated with 92.7% of coagulase positive and 37.5% of coagulase negative staphylococci.     

Effects of Compound Plant Nutrients on Rumen Fermentation Parameters,Rumen Microbiota and Fatty Acid Composition of Longissimus dorsi Muscle in Finishing Small Tail Han Sheep北大核心CSCD

This study was conducted to investigate the effects of compound p1ant nutrients (CPN) on rumen fermentation parameters, rumen microbiota and fatty acid composition of longissimus dorsi musc1e in finishing sma11 tai1 Han sheep. Sixteen 4-month-o1d finishing sma11 tai1 Han sheep with an initia1 body weight (BW) of (24.18±0.31) kg were random1y divided into two groups, name1y, with 8 rep1icates per group and 1 sheep per rep1icate. The sheep in the contro1 group were fed a basa1 diet, whereas the sheep of the contro1 group (CPN group) was fed the basa1 diet supp1ementation with 3‰ CPN. The experiment 1asted for 97 days after 7 days adaption. The resu1ts showed as fo11ows: compared with the contro1 group, 1) adding CPN decreased the concentration of ammonia nitrogen (NH3-N) (P<0.05); 2) CPN supp1ementation affected beta diversity of rumen microbiota; 3) the re1ative abundance of Acidobacteriota, Erysipe1otrichaceae_UCG-002, Lactobacillus, and Megasphaera were enhanced by adding CPN (P<0.05), whereas, the re1ative abundance of Bacteroidetes and Prevotella was 1ower (P<0.05); 4) the supp1ementation of CPN had no significant effect on fatty acid composition of longissimus dorsi musc1e of fattening sma11-tai1ed Han sheep (P>0.05); 5) the contents of tota1 MUFA, C18:1n9c, C14:1, C16:1, C18:2n6c, C18:3n3 and n-3PUFA in the longissimus dorsi musc1e were corre1ated with the re1ative abundance of Megasphaera, Erysipe1otrichaceae_UCG-002, Succiniclasticum and Ruminococcus (P<0.05). In conc1usion, CPN can regu1ate the rumen microbiota structure and reduce the rumen NH3-N concentration of fattening sma11-tai1ed Han sheep. In production practice, CPN can be used as a rumen eco1ogica1 regu1ator. © 2023 Authors. All rights reserved.     

Feed additives in whole milk fattening. Effect on production and health of fattening calves

In two fattening trials, each time 64 male calves of Simmental x Red Holstein cross breeds were used to investigate the influence of different commercial feed additives containing at the same time antimicrobial agents, minerals and vitamins on growth performance, feed intake, feed conversion and health condition. Calves whose milk diets were supplemented had, depending on products used, higher growth rates (9 to 28%) and better feed conversion rates (2 to 12%) compared to control calves which were fed only whole milk. This improved performance is primarily due to higher feed intakes. It is questionable how much the minerals and vitamins in addition to antimicrobial agents contributed to the improvement. The additional mineral supply caused after 8 weeks a statistically significant higher haemoglobin content, serum magnesium and glutathione peroxidase activity in erythrocytes compared to the exclusive whole milk feeding. Calves which were fed no additives refused feed intake more often as a result of disease incidence and required veterinary treatment more frequently.     

Immunohistochemical evaluation of a malignant phecochromocytoma in a wolfdog

A malignant pheochromocytoma with multiple metastases was diagnosed in a 7-year-old male wolfdog that resulted from a cross between an eastern timber wolf (Canis lupus lycaon) and an Alaskan malamute. A yellowish white neoplastic mass approximately 10 cm diameter was found in the right adrenal gland. The neoplasm penetrated through the wall of the caudal vena cava. A diagnosis of pheochromocytoma was established by histopathologic and immunohistochemical procedures. Immunohistochemically, the neoplastic cells expressed chromogranin A, substance P, synaptophysin, Leu-7, protein gene product 9.5, methionine-enkephalin, S100 protein, and galanin. Multiple metastatic tumors were found in the kidneys, spleen, lungs, heart, and liver.     

Two new variants of the Rhodococcus equi virulence plasmid, 90 kb type III and type IV, recovered from a foal in Japan

Calves were vaccinated orally, subcutaneously or intraperitoneally with a smooth, plasmid-cured strain of Salmonella enterica serovar typhimurium, strain 81. Oral vaccination was not effective, as only 1/5 calves survived challenge with virulent S. typhimurium. Strain 81 was attenuated for calves, as only a slight rise in rectal temperatures was detected after vaccination. The organism was excreted by some calves in the faeces, but no signs of diarrhoea were observed after vaccination. After parenteral vaccination, strain 81 was able to reach the intestines, gastric associated lymphoid tissues and other internal lymphoid tissues and remained viable for up to 14 days in the bovine host. After oral challenge with a virulent strain, 9/10 vaccinated calves survived challenge as opposed to 4/10 control calves (p<0.5). Diarrhoea was present in all calves of the control groups, but in only 4/10 of the vaccinated calves. The clinical reactions of the vaccinated calves were milder than in the control calves, as the rises in rectal temperatures were lower, diarrhoea was less severe, and the challenge strain was present in fewer organs from vaccinated calves than control calves. This study showed that parenterally administered Salmonella vaccines can induce both mucosal and systemic immunity, and it is postulated that this capability of strain 81 is related to its colonisation of lymphoid tissues and other systemic and intestinal tissues. This study confirmed that plasmid-cured strains were attenuated in the bovine host and conferred significant protection after parenteral vaccination, but not oral vaccination.     

A survey of canine echinococcosis in Gobi Altai Province of Mongolia by coproantigen detection

Few studies have been carried out for the prevalence of canine echinococcosis in Mongolia. This study was designed to elucidate a preliminary information of the prevalence from feces collected in the field. Sixty-seven fecal samples from dogs and 2 red foxes in Altai town were collected and examined for Echinococcus coproantigen and eggs. Coproantigen detection was performed by a sandwich ELISA using a monoclonal antibody EmA9 raised against Echinococcus multilocularis somatic antigen. Of the dog samples examined, 17 (25.4%) were positive by the ELISA. One out of two foxes was positive, too. Taeniid egg-positive feces were recognized in 12 dog feces. Only 6 samples were both coproantigen and egg positive. Eggs of Ancylostoma sp., Trichuris sp.; and Capillaria sp.; were also registered.     

Survey of internal parasites in Western Australian pig herds. 1. Prevalence

Between September 1982 and March 1984, 101 Western Australian piggeries with 15 or more sows were surveyed to determine the prevalence of internal parasites and examine the relationship between parasitism and management practices. Faecal samples were collected from 20 pigs in 4 age groups in randomly selected piggeries, and examined for the presence of eggs of helminth parasites and protozoan cysts. Evidence of nematode parasites was found in 79% of piggeries. Sows were more commonly affected than other classes of pigs with worm eggs being found in 68% of herds. Oesophagostomum spp was the most prevalent worm species, being found in pigs from 65% of piggeries and in sows in 60% of herds. Ascaris suum was the most common species of worm found in growing pigs. There was no evidence of infection with either Metastrongylus spp or Strongyloides spp in any of the herds sampled. Oocysts of coccidia were found in pigs from 56% of piggeries and Balantidium coli cysts were detected in pigs from 42% of piggeries sampled.