COW DUNG

Cow dung can be defined as the undigested residue of consumed food material being excreted by herbivorous species. Being a mixture of faeces and urine in the ratio of 3:1, it mainly consists of lignin, cellulose and hemicelluloses. It also contains 24 different minerals like nitrogen, potassium, along with trace amount of sulphur, iron, magnesium, copper, cobalt and manganese. The indigenous Indian cow also contain higher amount of calcium, phosphorus, zinc and copper than the cross-breed cow (Garg and Mudgal 2007; Randhawa and Kullar 2011). Cow dung harbours a rich microbial diversity, containing different species of bacteria (Bacillus spp., Corynebacterium spp. and Lactobacillus spp.), protozoa and yeast (Saccharomyces and Candida) (Nene 1999; Randhawa and Kullar 2011). Sawant et al. (2007) have isolated many different bacterial genera such as Citrobacter koseri, Enterobacter aerogenes, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Kluyvera spp., Morgarella morganii, Pasteurella spp., Providencia alcaligenes, Providencia stuartii and Pseudomonas spp. from cow dung.

In India, 69.9 % population resides in rural areas (The Hindu 2011), where cow (Bos indicus) is major cattle and generates 9–15 kg dung/day (Werner et al. 1989; Brown 2003). Waste is generally meant for discarding because it may act as a source of pollution (Pongrácz and Pohjola 2004). However, if it is used in some other process such as feedstock it may be considered as co-product (Brown 2003). People in Indian villages use cow dung for cooking purpose by direct burning. It is also used in plastering of walls and floor in rural houses for providing insulation during winter and summer. Application of smoke generated from the burnt cow dung as mosquito repellent and subsequent ash as cleaning agent for kitchen utensils is an age old practice. Accordingly, different usage of cow dung by village peoples reflect the native knowledge associated with it. It also depict that cow plays an important role in village economy and has high socio-economic value (Dhama et al. 2005a).

Cow dung in India is also used as a co-product in agriculture, such as manure, biofertiliser, biopesticides, pestrepellent and as a source of energy (Dhama et al. 2005a). As per ayurveda, it can also act as a purifier for all the wastes in the nature (Randhwa and Khullar 2011). Therefore in India, Cow (B. indicus) is not only just milk-producing animal but also truly considered as Gomata (mother of all) and Kamdhenu (Dhama et al. 2005a; Jarald et al. 2008). Detailed study of cow dung is gaining interest around the world and few attempts have been made for utilising its potential in the field of energy production, pharmaceutical products. The review intends to highlight the possible applications of cow dung particularly in the area ranging from energy, agriculture and environment to medicine for human welfare