International audience | In Burkina Faso, rural livestock farmers in arid and semi-arid areas rely heavily on woody plant resources such as Acacia nilotica and Acacia raddiana to satisfy the needs of small ruminant rearing. The assessment of the availability and the use of these two species are therefore essential to better manage them sustainably for their preservation. The survey carried out in the area showed that the questioned farmers exploited the leaves and pods of the two Acacia for the needs of the ruminants. 100% of the farmers exploit A. raddiana only for the feeding of small ruminants. However, A. nilotica was exploited for animal feed and health. The most commonly reported treatments are Foot and Mouth Disease (98.7%) followed by diarrhea (73.7%) and foot wounds (51.2%). In order to compare the results of the survey, a botanical inventory was carried out in the area and the results showed that A. raddiana is more available compared to A. nilotica. Also, other local species such as Faidherbia albida, Acacia senegal, Balanites aegyptiaca and Acacia siberiana are also exploited for the needs of small ruminant rearing in the study area. The most important constraints were excessive cutting, drought and overexploitation that negatively impact their survival. Data on these constraints provide the basis for a campaign to raise awareness among herders' communities to preserve these plants to sustainably improve the productivity of small ruminants and consequently farmer’s income.

An experiment was conducted to study the effect of supplementing plant metabolites like tannin and saponin through Acacia nilotica plant extract on methane mitigation and rumen fermentation characteristics for dairy cattle by in vitro gas production technique (IVGPT) in forage based diet. A highly significant (P<0.01) reduction of methane was observed in Acacia nilotica plant extract supplemented groups than their respective controls. The significant (P<0.05) reduction of methane (ml) per 100 mg of truly digested substrate was found in 0.75 ml of Acacia nilotica extract supplemented group than other treatment groups after eliminating the errorinduced by the extractant. The rumen fermentation characteristics viz. ammonia nitrogen, in vitro true dry matter digestibility (IVTDMD), bacterial and protozoal population was significantly decreased in 0.75 ml and 1.0 ml Acacia nilotica plant extract added groups. The total volatile fatty acids (TVFA) and propionic acid were significantly (P<0.05) increased and acetic acid and acetate to propionate (A/P) ratio were significantly (P<0.05) decreased in 0.75 ml and 1.0 ml Acacia nilotica plant extract added groups than their respective control groups. It was concluded that the methane (ml) per 100 mg of truly digested substrate was significantly decreased at the inclusion level of 3.09 % of tannin and 2.34 % saponin through Acacia nilotica plant extract supplemented group than control.