Evaluation of a Killed Vaccine Against Porcine Pleuropneumonia Due to Haemophilus pleuropneumoniae

A bacterin containing serotypes 1 and 5 of Haemophilus pleuropneumoniae was developed for the prevention and the control of porcine pleuropneumonia. It was injected intramuscularly into three groups of ten piglets, the first group with one dose, the second one with two doses and the third one with three doses at two-week intervals. Another group of ten piglets did not receive the vaccine. All the piglets were then challenged by an aerosol of mixed suspensions of H. pleuropneumoniae serotypes 1 and 5. Two and three injections of vaccine completely prevented mortality, whereas half of the control piglets and of those receiving only one dose of vaccine died. All surviving piglets, both control and vaccinated, had severe signs of respiratory disease for at least 36 hours after exposure to challenge. Moreover, vaccination did not induce the production of antibodies at high titers. Local reactions were not noted after vaccination and at postmortem; ten weeks after the challenge, there were no signs of abscess formation or induration.     

Escherichia coli strains isolated from diarrheic piglets in the Province of Quebec.

During 1972 to 1974, 112 Escherichia coli strains isolated from diarrheic piglets were recieved from different parts of the Province of Quebec, Canada. Fifty-six strains elicited a positive gut loop response in three week old piglets and were then considered as Moon's class 1 enteropathogens, while four of the 56 remaining strains reacted only in ten day old piglets and were classified as class 2 enteropathogens. Forty-eight strains produced both a heat-labile and a heat-stable enterotoxin, while 12 isolates which included the four class 2 enteropathogens produced only a heat-stable enterotoxin. Fifty-one enterotoxigenic strains could be serogrouped using OK antisera against E. coli strains commonly associated with colibacillosis in piglets. The most common serogroups encountered were O157: K "V17"; 88a,c, O149:K91; 88a.c. O157:K"V1c, O149:K91; 88a.c, O157:K"V17"; 88 a,c or a,b and O45:K"E5"; 88a,c. No significant difference was observed in the fermentation patterns, antibiotic susceptibility, colicin production, production of a filterable hemolysin and transferable tetracycline resistance between the enterotoxigenic and the nonenterotoxigenic strains.     

Storage performance of clementines treated with hot water,sodium carbonate and sodium bicarbonate dips

Summary

The potential of using hot water (2.5 min at 45°C), 2% sodium carbonate or 2% sodium bicarbonate solutions alone or combined with hot water, for control of Penicillium digitatum (green mould) was investigated on commecially ripe clementines. The effect of such treatments on the post-harvest storage life of clementines was determined during two months analysing weight loss, increase in rind deformation and internal maturity. Carbonate and bicarbonate solutions effectively control green mould during storage but hot water does not. Compared with the control and hot-water treated fruits, clementines treated with carbonate and, to a lesser extend with bicarbonate, showed higher weight loss and lower firmness during storage. In contrast, lower increase in ripening index was found when the fruits were treated with carbonate or bicarbonate. Fruits treated with hot water alone or combined with carbonate exhibited no change in ripening during the first month of storage. Rinsing the fruit significantly reduces weight and firmness loss in the fruits treated with carbonate and bicarbonate, but did not change the ripening index. The primary finding of this work was that carbonate and bicarbonate treatments might significantly increase the loss in weight and firmness during storage. Rinsing the fruit immediately after treatment appeared to be a simple solution to avoid these losses in quality.     

Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract

OBJECTIVE: To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE). ANIMALS: 22 healthy 5- to 15-year-old horses. PROCEDURES: Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection. RESULTS: Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.     

Milk yield, age at first calving, and the risk of BSE: an analysis at the farm level in France

The epidemic of bovine spongiform encephalopathy (BSE) in France, as in the UK, has affected dairy cattle much more than beef cattle. However, the intensification of dairy herd management as a risk factor for BSE has not to date been analyzed. For this purpose, two databases were merged: the French Milk Records database, and the French BSE database, which can be considered as being devoid of notification bias since July 2001, when systematic tests were implemented. Only pure Holstein herds were considered, which represent the vast majority of total and BSE-affected dairy herds in France. A case-control study was designed so that 20 control herds were matched to each case herd according to the location of the farm and the year of birth of the index case. Three thousand and forty five farms were included, among which 145 with a BSE case notified between July 2001 and July 2003, and 2900 controls. With respect to the risk of BSE, odds ratios for each class of milk yield and age at first calving were estimated by using conditional logistic regression models with appropriate adjustments to herd size. The two main results were the following: firstly, whereas most Holstein herds, with average production between 7000 and 10,000kg, had nearly the same BSE risk, a small category of very intensive herds, with annual milk yields above 10,000kg, were significantly more at risk than the other herds. Secondly, a very early first calving (under 26 months of age) was found to be at risk for BSE as compared to other categories, independently of the milk yield. These results are discussed in the light of the known age-dependent susceptibility to BSE.