Strategies for the prevention and control of natural intoxication by photosensitizing plants in cattle

The study was conducted at the Livestock Production Enterprise Bacuranao, of the Habana del Este municipality (La Habana province, Cuba), in order to establish a strategy for the prevention and control of natural intoxications by photosensitizing plants in cattle. For such purpose, a presumptive diagnosis on photosensitization was carried out, through the floristic inventory of the plants present in grazing and with the use of the clinical method. Diverse plants which cause hepatogenous photosensitization in the animals were identified, with Ageratum houstonianum Mill., Lantana camara L., Crotalaria retusa L. Crotalaria incana L. and Crotalaria spectabilis Roth standing out. The density of cattle per quadrant, the areas with higher incidence of this type of plants and the animals with dermatitis were determined through the Epidemiological Surveillance System (SIVE), by quadrants and grids. In the evaluation of the relative risk (RR) with and without the presence of the sun and with regards to the green forage intake, it was found that the animals exposed to sunlight and those that consumed forage had 1,85 and 3,17 times more incidence, respectively, of clinical signs associated to the hepatogenous photodynamic dermatitis, with higher levels for the ones that ingested the toxic plant A. houstonianum Mill along with the forage. From these results a plan of general and specific measures was elaborated for the control of toxicosis in the areas contaminated with these plants. It is concluded that the use of SIVE, the botanical census, the support treatments to animals with severe symptoms and the management and feeding measures can improve the efficacy in the control of toxicosis and, in turn, the protection of the animals at risk.