Potential of using invasive Petiveria alliacea for feeding goats in total mixed rations

Abstract

Petiveria alliacea is a perennial herb invasively spreading in Kandy and Mathale districts and has already become a troublesome weed in the farmlands. The present study assessed the biological value of tannins in P. alliacea and its potential to include in total mixed rations (TMR) for feeding goats. Panicum maximum was used as a control plant. Both P. alliacea and P. maximum at the boot stage were harvested from the Peradeniya University Experimental Station field in Dodangolla, dried, ground, and analyzed for proximate composition. Further, the in vitro organic matter digestibility (in vitro OMD), metabolizable energy (in vitro ME) and biological effect of tannins were determined using in vitro gas fermentation assay. Two isonitrogenous (16.4 and 16.8% CP) and isoenergic (7.44 and 7.25 ME MJ/kg DM) total mixed rations (TMR) were formulated using different levels of P. alliacea, P. maximum and coconut meal (0:46:54 and 35:33:32, respectively). Using Sannan male goats (13-month, 23.7 ± 1.19 kg), a feeding experiment consisting of two weeks of adaptation period followed by one week of collection period was conducted according to a Latin Square Design (n = 6). The crude protein (CP) content of P. alliacea (15.33 ± 0.32%) was greater (p < 0.05) compared to P. maximum (7.61 ± 0.11%). Despite the significant (p < 0.05) effect on the biological value of tannins, P. alliacea had significantly greater in vitro OMD and in vitro ME compared to P. maximum (p < 0.05). The use of P. alliacea in TMR formulation did not influence the feed intake, in vivo dry matter digestibility and in vivo OMD. Petiveria alliacea herb is a protein and energy-rich, more digestible forage than P. maximum and can be included at 35% in TMR formulation for feeding goats. The ration with P. alliacea can be cheaper as it replaced 22% coconut meal (54 vs 32%) of the ration.