## 1 Introduction  
The haematological profile is a collection of certain parameters obtained from the analysis of whole blood [1]. The evaluation of haematological indices allows us to understand the health status of the animal and evaluate the presence of pathological states [2; 3; 4; 5]. Among the haematological parameters, the most used are haematocrit, haemoglobin, circulating erythrocyte, and leukocyte counts. However, the interpretation of haematological parameters in animals can be complex, and the benchmarks are very broad; indeed, haematological indices are influenced by various factors, including breed, age, reproductive status, season, and environmental factors [6; 7; 8]. When analysing these values, it must be understood that they can also be affected by sample collection and preparation, transport time, and the instrument used for the analysis [9; 10; 11]. Noteworthy, the complete haematological profile also makes it possible to assess environmental pollution. For this reason, there are numerous model organisms, including plants, amphibians, and fish, that are used for analysing the haematological profile for different purposes [12; 13; 14; 15]. Moreover, animals, particularly grazers, including large and small ruminants and horses, are considered good indicators of environmental pollution. As a matter of fact, these animals inhabit the same space as humans and are exposed to the same pollutants through the ingestion of polluted vegetation, small amounts of soil, and drinking water [16]. Given the significance of environmental pollution, the evaluation of the presence of compounds in the environment is of paramount importance, and, in this regard, the investigation of compounds' presence in certain biological indicators represents a valuable tool to assess animal exposition to pollutants. Among pollutants, xenobiotics, divided into natural and synthetic, are chemical compounds which are considered foreign to living beings exposure to these substances can be through the skin, the respiratory and digestive systems [17]. Blood cells are constantly exposed to various xenobiotics and metabolites, and thus, these cells can be considered a useful target for pollution exposition. It has been previously demonstrated that these compounds cause a breakdown in the integrity and metabolism of the entire blood cell population [18; 19]. The effects of xenobiotics on red blood cells are many; for example, they cause the programmed death of these cells, known as cryptosis [20]. Erythptosis is often linked to an increase in osmotic fragility, and precisely because of this, the major signals are cell contraction and loss of membrane symmetry. This is important because osmotic fragility can be used as a biomarker of oxidative damage following exposure to xenobiotics [21]. Additionally, it will be possible to observe the translocation on the erythrocyte surface of certain membrane proteins, including phosphatidylinositol serine. Furthermore, cryptosis is indicated by increased cytosolic calcium, ROS activity, oxidative stress, and energy depletion [22; 23; 24]. It has been demonstrated that xenobiotics can induce substantial direct or indirect damage to the cytoskeleton and alter cell metabolism [25]. Horses and cattle, which are grazers like sheep and goats, were identified for this study. The interest in studying the exposition of horses and cattle instead of sheep and goats is because they are exposed to significant amounts of substances and different pollutants by ingesting vegetation, soil, and water. For this reason, they can be considered detectors of environmental pollution. Blood samples from these two species were exposed to two compounds, Quaternium-15 and Thiacloprid, selected based on their concentrations in the environment and their effects on organisms. Specifically, Quaternium-15 is a preservative used for cosmetics such as shampoos, creams and lotions, disinfectants, and laundry soaps.