Empirical verification of local knowledge in the description of nutritive value of forages in mixed farming systems of Turiani, Morogoro, Tanzania.

Abstract

Studies were conducted in the mixed farming system of Turiani division, Morogoro, Tanzania in order to find out how local knowledge (LK) characterizes different types of forages, feeding and production responses of crossbred cattle as well as to understand how nutritive value of forages defined by LK compares with formal scientific knowledge. Participatory rural appraisals (PRA), cross-sectional and longitudinal surveys and controlled animal experiments were undertaken. The crosssectional survey covered 125 households. In the longitudinal survey, 30 respondents months. Feed preference experiments were carried out with four intact male crossbred calves whereby green grasses wire provided either singly [Panicum maximum. purputtum cochinchineusis} or in combinations of two forages in equal proportions [P. maximum + P. trichocladum; P. maximum + R. cc mchinensis; P. trichocladum + R. cochinchineusis and P. purpureum + P. trichocladum} for four consecutive days. Calves were simultaneously observed while each animal was feeding on one of the four treatments in sequential periods of 15 minutes each in four random orders (1, 2, 3 and 4) every test-day. Amounts of herbage eaten and numbers of prehension bites were recorded. The bite rate, bite mass and intake rate were calculated. In another experiment, five bull calves were allocated to each of the four treatments; [P. ratio) (plus concentrate supplement); P. maximum (without supplement) and P. maximum + P. trichocladum (in 5:1 ratio) (without supplement)] in a completely maximum (plus concentrate supplement); P. maximum + P. trichocladum (in 5:1 were individually interviewed for four consecutive times within intervals of two Panicum trichocladum, Penniwtum and Rottboelia randomised design. Dry matter intake (DMI) and growth performance of calves similar to those used in the preference study were determined including economic analysis of the above practices. The surveys revealed that criteria for forage quality include preference by animals, high milk yield, fast stomach fill, availability, absence of feeding disorders, high milk quality, health condition of animals and convenience in cut and carry. Logistic regression analysis showed that forage preference by cattle ranked (in descending order) Digitaria spp, P. purpureum, T. laxum, P. reference grass forage. However, P. purpureum and T. laxum ranked first and second respectively for criteria of high milk yield, fast stomach fill, improving health condition and convenience at harvesting whereas M. pruriens was the species most preferred by cattle followed by V. pubescens, 1. aquatica and C. africana when the legumes and forbs were compared against M. atropurpureum. The intake rate of P. purpureum of 15.72gDM/min, bite rate of 5.31bites/min and bite mass of 3.1 Ig/bite respectively was significantly higher f < 0 05) than that of other single grass species tested. Total DMI of P. trichocladum + R. cochinchinensis and P. purpureum + P. higher than that of P. maximum + P. trichocladum and P. maximum + R. cochinchinensis respectively. Supplementation increased total DMI of grass forages regardless of whether they were mixed or not. It is concluded that LK and formal scientific knowledge of forage quality description have social, economic and biological justifications that may be similar or different. However, more studies are needed in LK and complementary knowledge systems for sustainable utilization of feeds and other resources abundant in smallholder settings. trichocladum, Cynodon spp and R. cochinchinensis with P. maximum serving as a trichocladum of 224.54g/15min and 232.52g/15min were significantly (P < 0.05) higher than that of P. maximum + P. trichocladum and P. maximum + R. cochinchinensis respectively. Supplementation increased total DMI of grass forages regardless of whether they were mixed or not. It is concluded that LK and formal scientific knowledge of forage quality description have social, economic and biological justifications that may be similar or different. However, more studies are needed in LK and complementary knowledge systems for sustainable utilization of feeds and other resources abundant in smallholder settings.