Materials and methods
Study area: Nigeria is located in West Africa, bordered by the Benin Republic to the west, the Niger Republic to the north, Cameroun to the east, and the Atlantic Ocean to the south. The country is divided into 36 States and the Federal Capital Territory (FCT) Abuja. The 36 States are further divided into Local government areas (LGA) with a total of 774 LGAs. Pigs are reared in 30 States of the country. Nigeria has two seasonal periods, the rainy season which is from April to October, and the dry season from November to March. The common breeds of pigs in Nigeria are the Iberian type Nigerian Indigenous Pig (NIP) which is usually black or pied, others are exotic breeds including, Large White, Landrace, Duroc, Hampshire, and their crossbreeds (Fadiga et al, 2013).
Selection and description of live pig markets: Organized LPMs are common in northern parts of Nigeria, while in the southern part of Nigeria, pigs are sold live at farm gates or as processed pork at stores. Due to limited information on the LPM operation in Nigeria, selection of LPM sites were done purposively based on information from pig farmers, easy access, literature search, logistics, visit to LPM, the network of distribution, security challenges, and the number of live pigs traded at markets visited. Hence, four (4) live pig markets were purposefully selected, all located in Northern Nigeria namely: Katsit pig market (also called Kafanchan pig market) in Zagon Kataf LGA of Kaduna State, Pandam pig market in Qua Pan LGA, and Dawaki pig market in Kanke LGA both located in Plateau State and Numan pig market in Numan LGA of Adamawa State (Fig 1). Katsit pig market is located on latitude N 90. 34255 and Longitude E 80.164936 at the outskirts of Kafanchan, Kaduna State. It is the largest LPM in Nigeria, Table 1), it is once a week market with trading activities taking place on Thursdays only. Located within the premises of the Katsit pig market is a slaughter slab where pigs bought within the market are slaughtered and sold to traders and the surrounding communities. The second market is Pandam pig market located on latitude N90.52519 and longitude É80.50510, it is also a once in week market with sales of pigs taking place on Mondays (Table 1). There is a slaughter point 500m to the market. The third market is Dawaki pig market, which is located on latitude N9.2625956 ° and longitude E 9.3401578 °. Apart from pigs, other animals sold at the Dawaki pig market including sheep, goats, chickens, and dogs. The Dawaki pig market holds weekly on Thursdays. The slaughter point at Dawaki pig market is located directly behind the perimeter fence of the market with an access point for free movement of butchers and traders. The fourth market is the Numan Pig market located in Numan LGA of Adamawa State, the market holds on Tuesdays with GPS co-ordinates N 090.27440’ E12 .002043’