William B. Buck

Herd health status of animals exposed to polybrominated biphenyls (PBB).

The health status of 16 herds of dairly cattle exposed to low levels of polybrominated bipenyl (PBB) was compared with that of 15 control herds. Milk production of the contaminated herds was not significantly changed in 1972, 1973, and 1974 and was not significantly different from that of control herds in the same years. Mortality of adult cows and calves, the percentages of cows culled from the herds because of old age and low production, disease, or sterility, and the general health conditions were similar in the two groups. Serum concentrations of calcium, glucose, and cholesterol in contaminated herds were significantly different from those of the control herds, but the relationship to PBB exposure needs further investigation.

Dieldrin exposure and vigilance behavior in sheep

Sheep exposed to a daily oral dose of 20 mg dieldrin per kg body weight exhibited a large decrement in the performance of a vigilance task. Three of four sheep recovered their preexposure response levels within 10 days following the termination of exposure. Reexposure of these three animals to 5 mg dieldrin per kg body weight also resulted in a response decrement.

Epidemiology of Lead Poisoning in Cattle– A Five-Year Study in Iowa

AbstractLead poisoning has been increasingly recognized as a significant and major cause of bovine poisoning in Iowa during recent years [3, 4]. Data from the Iowa Veterinary Diagnostic Laboratory for the years 1965 through 1971 indicate an increasing number of lead poisoning cases in cattle, with 1970 as the peak year. From January, 1967, through June 30, 1971, 80 episodes of bovine lead poisoning have been confirmed by the Veterinary Diagnostic Laboratory. Of this number, 28 were recognized in 1970 alone. Lead poisoning is the single most common toxicosis in cattle in Iowa. In order to further delineate the incidence, clinical severity, sources, seasonal occurrence, and chemical results of affected and non-affected animals, this study was undertaken.

Effects of Low Level Lead ingestion in Sheep

AbstractLead intoxication is common among young urban dogs. The age, seasonal, and slum occurrence is similar to that in children. The clinical signs, radiographic, hematologic, and urinary changes, and the tissue lesions are also comparable to those in children. Because of these similarities, the study of accidental and experimental lead poisoning in dogs may be of considerable comparative interest. It is suggested that the study of known or suspected toxicologic diseases and the blood or tissue accumulation of various toxicants in urban pets, especially dogs and cats, might be of considerable value in determining the hazards of environmental lead and other toxins for urban man.

Development of behavioral tests for the assessment of neurologic effects of lead in sheep.

Reports of neurologic impairment of children following recovery from acute lead encephalopathy have raised questions concerning the effects of chronic low-level lead exposure on the central nervous system. Behavioral toxicologic techniques have been employed to assess the effects of lead on the central nervous system in sheep. Mature sheep receiving daily doses of 100 mg lead/kg showed a significant decrease in performance on an auditory signal detection task. Daily oral doses of 120 and 230 mg lead/sheep for 27 weeks did not alter the performance of mature sheep on a fixed-interval schedule of reinforcement behavioral task. Prenatal exposure to maternal blood lead levels of 16 or 34 μg/100 ml during gestation and postnatal daily ingestion of 16, 8, 4, or 2 mg lead/kg did not alter performance of lambs on a closed-field maze task. Slowed learning was demonstrated in lambs prenatally exposed to maternal blood lead levels of 34 μg/100 ml during gestation when tested on nonspatial, two-choice visual discrimination problems at 10–15 months of age.

EFFECT OF DIELDRIN EXPOSURE ON DETOUR BEHAVIOR IN SHEEP

Two experiments were conducted to investigate the effect of a chlorinated hydrocarbon insecticide (dieldrin) on detour behavior in sheep. The visibility of the goal object and its distance behind the barrier were also studied. Dieldrin exposure did not significantly affect detour behavior. The distance of the goal object from the barrier, and the visibility of the goal object produced no reliable differences.