Haematological profiles of pigs of different age in relation to the presence or absence of porcine reproductive and respiratory virus, porcine circovirus type 2 and hepatitis E virus

Abstract

This study was aimed to assessing haematological parameters in pigs of different age categories from six farms differing in the presence or absence of selected pathogens. The following categories were included: 5 age groups of growers, fatteners and breeding sows. Individual blood samples for determining complete blood count and white blood cell differential count were taken. Group samples of oral fluid and faeces were collected from each farm and tested for detection of Porcine Reproductive and Respiratory Virus (PRRSV), Porcine Circovirus Type 2 (PCV2), and Hepatitis E Virus (HEV) using PCR, RT-PCR, and qRT-PCR protocols. On farms free of PRRSV, PCV2 and HEV, the age of pigs had significant effect on: white blood cell count (WBC), haemoglobin concentration (Hb), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration, platelet count (PLT), percentage of neutrophils, lymphocytes and eosinophils and absolute numbers of neutrophils, lymphocytes, monocytes, basophils and ‘large unstained cells’ (LUCs). On positive farms all observed blood parameters except the percentage of LUCs were significantly affected by the age. The percentages of lymphocytes, mean corpuscular volume (MCV) and haematocrit were significantly lowered by PRRSV, while WBC, PLT, percentage and absolute numbers of neutrophils, basophils and LUCs were increased. Nine-week-old pigs with PCV2 had significantly lower red blood cell count, PLT, percentage and absolute numbers of monocytes and LUCs, and significantly higher MCV, MCH, percentage of neutrophils and percentage and absolute number of eosinophils than 9-week-old pigs with PCV2 and HEV. Age-related changes in haematological parameters occurred in PCR negative and positive farms.HIGHLIGHTS Age-related changes in haematological parameters were present in PCR negative farms and in PCR positive farms in relation to selected pathogens. Values for several haematological parameters in 9-week-old pigs with a monoinfection differed significantly from those in pigs of the same age with two viral infections. To interpret results of haematological analyses correctly, it is important to consider the haematological analyser used, the pig age and, health history, and clinical data.

Keywords

• haematological parameters
• hepatitis e virus
• porcine circovirus type 2
• porcine reproductive and respiratory virus