Agricultural Science Volume 2, Issue 1 (2014), 37-47 ISSN 2291-4471 E-ISSN 2291-448X Published by Science and Education Centre of North America ~ 37 ~ Haematological Parameters and Factors Affecting Their Values NseAbasi N. Etim 1 *, Mary E. Williams 1 , Uduak Akpabio 2 , and Edem E. A. Offiong 1 1 Department of Animal Science, Akwa Ibom State University, Obio Akpa Campus, Akwa Ibom State, Nigeria 2 Department of Veterinary Public Health and Preventive Medicine, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria *Correspondence: NseAbasi N. Etim, Department of Animal Science, Akwa Ibom State University, Obio Akpa Campus, Akwa Ibom State, Nigeria. E-mail: etimbobo@yahoo.com DOI: 10.12735/as.v2i1p37 Abstract This article presents an overview of haematological parameters and factors affecting their values. Blood act as a pathological reflector of the status of the exposed animals to toxicants and other conditions. The examination of blood provides the opportunity to clinically investigate the presence of metabolites and other constituents in the body of animals and it plays a vital role in the physiological, nutritional and pathological status of an animal. Blood constituents change in relation to the physiological status of an animal. These changes are important in assessing the response of farm animals to various physiological situations. These changes are often caused by several factors; some of which are genetic and others, non-genetic. Age, sex, breed and management systems are among the factors that influence blood-based parameters of farm animals. It is important to establish baseline indices for these parameters on the basis of these factors and determine the effects of these factors on these indices. Keywords: haematology, parameters, factors, values 1. Introduction Haematology refers to the study of the numbers and morphology of the cellular elements of the blood – the red cells (erythrocytes), white cells (leucocytes), and the platelets (thrombocytes) and the use of these results in the diagnosis and monitoring of disease (Merck Manual, 2012). Haemtological studies are useful in the diagnosis of many diseases as well as investigation of the extent of damage to blood (Onyeyili, Egwu, Jibike, Pepple, & Ohaegbulam, 1992; Togun et al., 2007). Haematological studies are of ecological and physiological interest in helping to understand the relationship of blood characteristics to the environment (Ovuru & Ekweozor, 2004) and so could be useful in the selection of animals that are genetically resistant to certain diseases and environmental conditions (Mmereole, 2008; Isaac, Abah, Akpan, & Ekaette, 2013). Haematological parameters are good indicators of the physiological status of animals (Khan & Zafar, 2005). Haematological parameters are those parameters that are related to the blood and blood forming organs (Waugh, Grant, & Ross, 2001; Bamishaiye, Muhammad, & Bamishaiye, 2009). Blood act as a pathological reflector of the status of exposed animals to toxicant and other conditions (Olafedehan et al., 2010). As reported by Isaac et al. (2013) animals with good blood composition are likely to show good performance. Laboratory tests on the blood are vital tools that help detect