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Master thesis

Evaluation du risque de contamination par le chlordécone via l'ingestion de sol par des bovins Créoles au pâturage, étude de deux facteurs de variation : offre fourragère et humidité du sol

Abstract : Chlordecone (CLD) is a phytosanitary product widely used in banana plantations between 1972 and 1993 to control the banana weevil Cosmopolites sordidus. Banned in France in 1993, its presence in the Caribbean biotopes was highlighted in 1999 following the discovery of high concentrations in drinking water. In 2005, AFSSA published its report on the status of food contamination by the CLD. The massive use of pesticides in the French West Indies has resulted in long-term soil pollution. Soil is the main route of contamination and transfer of pollutants to animal products. Several studies have shown that livestock can be exposed to a risk of intentional or unintentional ingestion of a significant amount of soil. The tethered rearing widely practiced in Guadeloupe, prone to influence this ingestion of soil. Thus, it appears necessary to quantify the amount of ingested soil by the Creole bulls at tethering under different soil humidity conditions and grazing conditions. Twelve Creole bulls were conducted in an individual grazing system to the tether with a daily grazing area. The experimental design consisted of a cross-over with three different daily herbage allowances (BAS, 100g DM / kg BW / d, HAUT, 150g DM / kg BW / d, ADLIB, 300g DM / kg BW / d) crossed with two levels of soil humidity (SEC, lent conditions, matrix potential> 40, HUM, Caribbean winter conditions, matrix potential <19). The specific individual grazing area is calculated daily according to the quantity of grass offered and the available biomass. The allocated area is modulated by the chain length. The three offers proposed resulted in a different daily grazing area (P <0,001) (BAS: 23,28 m2, HAUT: 34,51 m2 and AD LIB: 69,16 m2). These different surfaces involved different levels of dry matter intake with a significantly lower ingestion (P <0,05) for the BAS modality (BAS: 1,59 kg DM / animal / d, HAUT: 2,09 kg DM / animal / j and AD LIB: 2,33 kg DM / animal / day). The organic matter digestibility is also significantly lower for the BAS modality (BAS: 0,67, HAUT: 0,73 and AD LIB: 0,73). The daily intake of soil per animal was measured by the titanium content of the faeces, with titanium being a soil marker ingested due to its high concentration ratio in soil vs grass. The BAS offer induced a higher grazing pressure and resulted in a significantly higher proportion of soil intake than for AD LIB (BAS 1,34%, HIGH 1,12% and AD LIB 0,70 %). The amounts of soil ingested in the BAS and HIGH modalities are significantly higher than those of the AD LIB modality (BAS: 21,04 g / 100 kg BW, HIGH: 20,07 g / 100 kg BW and AD LIB: 14,17 g / 100 kg BW). Indeed, the BAS and HAUT modalities cause higher grazing pressures than for the AD LIB modality and therefore a higher risk of soil ingestion.
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https://hal.inrae.fr/hal-02791408
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Submitted on : Friday, June 5, 2020 - 7:41:25 AM
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  • HAL Id : hal-02791408, version 1
  • PRODINRA : 415644

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Alexandre Tricheur. Evaluation du risque de contamination par le chlordécone via l'ingestion de sol par des bovins Créoles au pâturage, étude de deux facteurs de variation : offre fourragère et humidité du sol. Sciences du Vivant [q-bio]. 2017. ⟨hal-02791408⟩

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