Grazing animals

Strategies to reduce risk of pathogen transfer from animal grazing phases prior to planting of crops... 

In this way, Crosby demonstrates that environments and societies create one another, or more abstractly, they are mutually produced. The success of grasses depends on the success of the human settlement efforts that surround them, and vice versa. While these introduced Old World grasses benefited from European behaviors (grazing, and so forth), so too, settlers catered to the needs of the grasses, by planting and weeding, and animal grazing as they went. 

Hypercalcaemia and soft-tissue calcification have been found in animals grazing on plants such as Cestrum diumum and Solanum malacoxylon, and attributed to the presence of a l,25-(OH)2D3-glycoside.453 The calcinogenic plant Trisetum flavescens causes severe calcification on ingestion, but the vitamin D3 species responsible has not been identified 454... 

Copper deficiency occurs in domestic animals grazing on pasture that is low in copper. Remedial measures include the application of fertilizers containing added copper or the use of suitable salt licks. However, human diets are apparently sufficiently diverse that copper deficiency is not likely in man. Instead, there is the risk that the use of copper cooking utensils and water pipes might lead to an excessive uptake. In conditions where body copper levels are undesirably high it may be necessary to restrict the uptake of copper. Because of the insolubility of copper sulphide, potassium sulphide is sometimes taken orally to render dietary copper unavailable. 

The level of cadmium in animal tissues other than offal is usually low, average concentrations being less than 0.05 mg/kg. Individual samples of kidneys may contain levels higher than 0.5 mg/kg. Animals grazing on land contaminated with cadmium will often have meat with normal levels of cadmium, while the level in offal would usually be significantly higher.16... 

The mechanism by which an animal can become poisoned in many instances is completely different from that by which humans are affected. As in humans, inhalation is an important route of entry in acute air-pollution exposures such as the Meuse Valley and Donora incidents (see the paragraph on humans below). However, probably the most common exposure for herbivorous animals grazing within a zone of pollution will be the ingestion of feed contaminated by air pollutants. In this case, inhalation is of secondary importance. 

Swainsonine also induces high mountain disease, when the animals graze at high elevation, associated with congestive right-sided heart failure [157]. 

In sheep and cattle, a condition known as heart disease occurs when these animals graze on plants containing abnormally high amounts of molybdenum. Dietary levels of 10 ppm molybdenum and higher can cause teart disease. Symptoms that may occur within 24 h include weakness and diarrhea. Longer exposure can lead to decoloration of hair, skeletal deformities, sterility due to damage to testicular interstitial cells, poor conception and deficient lactation. 

The investigations of Wilson (1973) led to similar conclusions. After a 7-year application of 2,4,5-T at abnormal rates (1000 kg active ingredient/ha) no TCDD was found either in the soil or in the animals grazing in the treated area. 

Acid soils generally provide sufficient micronutrients, occasionally even toxic amounts, to plants or to animals grazing on those plants. Because of the small quantities of micronutrients required for plant growth, adequate amounts can be taken up from small portions of the root zone, if such regions are sufficiently acidic. In basic soils the acidity from fertilizers or from small quantities of elemental sulfur or sulfuric acid added to a portion of the root zone may provide adequate micronutrients to plants. 

Poisoning in livestock has been recorded on many occasions, and is due to animals grazing in meadows where G. autumnale grows. It is most likely to occur in spring and autumn. Cases due to inclusion of the plant in hay are also known. Horses and cattle are the animals most commonly affected (108-110). 

Selenium substitutes for sulfur in amino acids to form seleno-cysteine, cystine, and methionine. The selenium-containing antioxidant glutathione peroxidase is biologically important, and selenium is a necessary trace nutrient in warm-blooded animals. Grazing animals develop a form of muscular dystrophy and other disorders when grazing in areas in which the selenium has been depleted with selenium-depleted diets, people develop... 

Siderocapsa ganic slimes with loss in carrying capacity. Entrainment of algae. Animals graze any slime or deposit... 

Although a low dietary intake of Mo can result in Mo deficiency in some animals (Scott, 1972), the main problem faced by animals grazing pastures and forage is consumption of excessive amounts of Mo (Kubota and Allaway, 1972 Suttle, 1975). Excessive intake of Mo will induce Cu deficiency in ruminants (Suttle, 1975). Although herbage Mo concentra-... 

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