Trypanosoma evansi infection in buffaloes in north-east Thailand. I. Field investigations

Clinical, parasitological and serological findings of Trypanosoma evansi infections in buffaloes (Bubalis bubalis) from north-eastern Thailand are reported. The overall infection rate was found to be around 20% with a distinct peak of acute infections during the rainy season. The disease is aggravated by normally well tolerated concomitant infections such as liver fluke infestations and by other stress factors.     

Toxicological effects of gamma-irradiated sewage solids fed as seven percent of diet to sheep for four years

Breeding ewes in drylot were fed pelleted complete diets with 3% cottonseed meal (CSM) or 7% dried, gamma-irradiated sewage solids (DGSS) for 4 yr. Cytochrome P-450 (P-450) content and enzyme activities for xenobiotics biotransformations were assayed in livers after 2 yr and in livers, kidneys and ileal tissue after 4 yr. Dietary DGSS caused no increase in P-450 and few changes in activities of oxidative, hydrolative and conjugative biotransformational enzymes. Consumption of DGSS for 4 yr caused slight enlargement of spleens (1.1-fold, P less than .10) and ovaries (1.3-fold, P less than .10), but no change in size of livers, kidneys, hearts, adrenals and thyroids (P greater than .10), nor liver vitamin A levels (P greater than .10). Of 22 refractory lipophilic residues assayed in abdominal adipose tissue, few were detected and of those detected DGSS caused none to exceed normal levels. Dietary DGSS increased (P less than .01) Fe in livers 1.5-fold and in spleens 5.6-fold, and increased Cu in livers 1.3-fold (P less than .01) and in kidneys 1.2-fold (P less than .05). Dietary DGSS increased Cd levels in livers (P less than .01) but not in kidneys or spleens (P greater than .10); yet all Cd levels were within ranges for livestock fed conventional feed. Dietary DGSS caused no increase (P greater than .10) in levels of Ag, Ca, Cr, Hg, K, Mg, Mn, Na, Ni, P, Pb or Zn in livers, kidneys or spleens. There were no histopathological lesions of toxicosis except mild hemosiderosis of spleens. Consumption of a diet with 7% DGSS throughout 4 yr caused no hazardous accumulation of toxic elements and little, if any, evidence of toxicosis.     

Idiopathic megaesophagus in a calf: clinical and pathologic features

A 4-month-old female Gelbvieh calf regurgitated 3 to 9 minutes after eating hay but not after eating grain or drinking water. A fiberoptic endoscopic examination and positive-contrast radiography revealed megaesophagus. The calf was euthanatized, and necropsy revealed a dilated esophagus (12 cm long) proximal to the thoracic inlet. Histologically, the major portion of the muscular layers of the esophagus was replaced by fat cells.     

Immune responsiveness and lymphoreticular morphology in cattle fed hypo- and hyperalimentative diets

Immune responses and lymphoreticular morphology were studied in 3 groups of yearling Hereford steers fed hypoalimentative, maintenance and hyperalimentative diets for 142 days. Significant decreases in plasma protein levels and circulating lymphocyte levels occurred in low energy intake steers. Percent circulating lymphocytes bearing surface immunoglobulins and serum levels of IgG and IgM did not vary significantly within or between groups. Antibody responses to Brucella abortus bacterin inoculated on day 63 were similar in all 3 groups. Antibody responses to chicken erythrocytes inoculated on day 88 were significantly lower in hypoalimentated steers. Differences between groups in lymphocyte blastogenic responses to phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) were not significant. Hyperalimentated steers had significantly depressed PWM responses compared to a baseline value established for that group. In addition, hypoalimentated steers tended to have elevated responses to PHA, although differences were not significant. There were no significant differences between groups in dermal hypersensitivity responses to tuberculin following sensitization with viable Bacillus Calmette-Guerin (BCG). The thymuses of hypoalimentated steers were markedly atrophied but lymph nodes and splenic white pulp were normal. Thymus, lymph nodes and spleen were normal in hyperalimentated steers.     

Reaction cements as materials for the sustained release of trace elements into the digestive tract of cattle and sheep. II. Release of cobalt and selenium

Acid-base reaction cements, containing salts of copper, cobalt and selenium, were placed in the reticulum of sheep and cattle, and the rate of release of cobalt and selenium from them was measured. The rate of release of cobalt decreased with time but was sufficient to provide adequate supplementation for at least 6 months. After an initial rate of release of 4 mg Se/day for 1-2 weeks, the mean subsequent rate of release of selenium over a period of 4 months was 0.1 mg Se/day (identical to 5 micrograms Se/day/cm2 surface area). Field trials in lambs and growing steers showed that the cement increased the selenium concentration of their blood throughout a summer grazing period.