Impact des carences en oligoéléments sur la reproduction et la productivité des bovins (diagnostiques et traitements)

Abstract

For obvious economic reasons, the study of severe enzootic diseases involving trace elements was approached many years ago by countries where mortality was high. It later became apparent that the deep deficiencies were only in extreme cases of much more widespread and difficult to detect subdeficiencies. In 1958, a map of trace element deficiencies was presented in the United States where these authors indicate certain areas where animals cannot survive without mineral supplementation. These studies show the soil-plant-animal relationships in different biogeochemical provinces. Deficiencies in cattle at slaughter due to poor forage for copper, selenium and cobalt have been reported and confirmed in most countries. This deficiency is strongly associated with the intensification of growth in calves. Forage intensification can decrease the trace element content of forages. It is likely that animal subcarriers are likely to be revealed with increasing frequency. It is therefore necessary to survey practising veterinarians and farmers. The results of these surveys should be confirmed by analysing the fodder first, which can be accused of trace element deficiencies. The diagnosis of the latter is difficult because the symptoms are not always specific; they are not all found together in the same patient and their frequency of appearance may vary. The objectives of this study are to specify and estimate the different trace element deficiencies in cattle; to indicate the symptomatology of these deficiencies; and to establish a diagnosis in the face of a drop in productivity or the appearance of various pathologies within a farm. The analyses carried out thereafter in the laboratory will help to identify the deficiencies or subdeficiencies, making it possible to estimate their importance and severity, thus providing the veterinary practitioner with a basis of memoranda for the clinical diagnosis, enabling him to advise the farmer on the implementation of supplements and to set up a rational prophylaxis strategy enabling him to remedy these deficiencies in order to avoid any drop in the reproductive performance and production of the animals, and to limit to the greatest extent possible, the risks of economic losses.