author(s)
Nanda Kumar Roy, Girin Kalita, L Hmar, Ranjana Goswami, Tridip Kumar Rajkhowa, Kalyan Sarma and Dibyajyoti Talukdar

abstract
A study was carried out to know the causes and season wise mortality of Large White Yorkshire pigs (LWY) of Instructional livestock farm Complex, College of Veterinary Sciences and Animal Husbandry, CAU, Selesih, Aizawl, Mizoram. A total of 114 post mortem were performed in Department of Veterinary Pathology of the college from August 2012 to February 2018. The morality pattern was recorded from weaning to adults. The causes of mortality were categorized as per the age group i.e. 0-42 days and above 42 days. Season wise mortality were also recorded. Mortality survey revealed that young piglets (0-42days) showed high mortality 63%) than above 42 days age group (37%). The causes of mortality of pigs (0-42days) were enteritis (37.50%), pneumonia (36.11%), pneumonia with enteritis (6.94%), Classical swine fever (4.16%) and 1.38% of other causes i.e. diarrhea, liver abscess, general poor health with debility, hypovolemic shock, spleen rupture, fibrinous polyserositis, trauma, liver rupture, and physical wound. In other age groups (above 42days) the causes of mortality were pneumonia (41.86%), enteritis (27.90%), CSF (9.30%) and 2.32% other causes i.e. general poor health with debility, peritonitis, cardiac failure with shock and parasitic infestation. The study revealed the highest mortality rate in winter (47.36%) followed by summer (27.19%) and monsoon (25.43%). It may be concluded that the major causes of mortality in both the groups were enteritis and pneumonia in the winter season.