Effects of Method of Killing on Decomposition of Pig (Sus scrofa L.) Carrions in Benin, Nigeria
EKRAKENE, T. and lLOBA, B.N.
Department of Basic Sciences, Benson Idahosa University, Benin City, Nigeria.
Nig . J. Entomol. 33: 1-6 (2017)
ABSTRACT: The decomposition of 48 pig (Susscrofa L.) carrions (mean weight=22.30±1.20 Kg) was monitored in the wet season (June – October) and dry season (November – March) from June 2006 to March 2008 in Benin City. The pigs had been killed by slaughtering, oxygen-deprivation or poisoning with aluminum phosphide (Phostoxin) or monocrotophos (Monocrown). The stages and duration of decomposition of the carrions as well as mass maggot production and density were recorded. In both seasons, decomposition progressed through four distinct stages, namely, fresh, bloated, wet and dry decay but duration of decomposition was shorter in the dry than in the wet season. Decomposition duration varied with method of killing, being in the range of 32 – 41 days for slaughtered, 32 – 41 days for oxygen-deprived, 49 – 53 days for aluminum phosphide- poisoned, and 64 -75 days for monocrotophos-poisoned pigs. Over the active decomposition period, monocrotophos-poisoned pigs produced no maggot mass; maggot densities (cumulative numberlcarrion) in slaughtered- and oxygen deprived pigs were statistically comparable but each differed significantly from the values for poisoned pigs. Irrespective of the method of killing the pig and the season, the species of dipteran flies involved in decomposition were similar. It was concluded that method of killing exerted influence on rate of carrion decomposition through effect on mass maggot production and density as well as the elevated carrion temperature that resulted.
Keywords: Pig carrions; Maggot, Decomposition rate; Killing method.