Trop Anim Health Prod DOI 10.1007/s11250-015-0839-y
REGULAR ARTICLES
Nutritional values of available ruminant feed resources in smallholder dairy farms in Rwanda Mupenzi Mutimura 1,2 & Cyprian Ebong 2 & Idupulapati Madhusudana Rao 3 & Ignatius Verla Nsahlai 1
Received: 9 January 2015 / Accepted: 20 April 2015 # Springer Science+Business Media Dordrecht 2015
Abstract Smallholder dairy farmers in Rwanda use diversity of resources to cope with endemic feed shortages. However, there is inadequate real farm data to support farmer decisions on choices of options. The main objective of this study was to evaluate nutritional quality of feed types that farmers use in different agro-ecological zones of Rwanda. Samples of feed types were collected from 90 randomly selected households in the low- and mid-high-altitude zones of Rwanda and analysed for proximate composition, contents of metabolisable energy (ME), organic matter digestibility (OMD) and neutral detergent fibre digestibility (NDFd). Rumen fermentation characteristics and efficiency of energy utilisation were examined by determining partitioning factor (PF). Results showed that only five out of 24 feed types were common in both districts. Chemical composition, OMD, ME, NDFd and PF of these feed types differed significantly (P2000 m), adequate rainfall (1800 mm) zone and with acidic kaolinite soils which are prone to aluminium toxicity. Samples were collected from 90 randomly selected households in four sectors (sub-district) in Bugesera and Nyamagabe districts. In each sector, five households per cell (local government administration under a sector) in three randomly selected cells per sector provided samples.
Sampling, sample handling and laboratory analysis Samples from each household and feed type were divided into two parts. One part was dried at 60 °C for 48 h and milled to pass through a 1-mm screen for subsequent laboratory analyses. The other part was dried at 105 °C for determination of DM (AOAC 1990; method ID 9420.5), OM (AOAC 1990; method ID 9420.5), CP (AOAC 2006; method ID 984.13) and NDF (Van Soest et al. 1991). Using in vitro gas technique organic matter digestibility (OMD), metabolisable energy (ME) and partitioning factor (PF) were determined. Samples (≈200 mg) were accurately weighed and transferred into airtight graduated gas syringes (100 mL) for anaerobic fermentation (39±1 °C; 24 h) in an oven. The media was a mixture of 1:2 of inoculum source and buffer solutions (v/v) made from solutions A, B and C (Osuji et al. 1993). The inoculum sources were rumen fluids from two surgically prepared steers according to ethical practice. These animals were fed on grass hay (Brachiaria hybrid cv. Mulato II). The inoculum preparation procedure was done according to Osuji et al. (1993) as modified by Mutimura et al. (2013b). Gas readings were recorded at 0, 1, 3, 5, 7, 9, 12, 16, 20 and 24 after inoculation. Syringes were removed at 24 h of incubation. OMD and ME were calculated according to Menke et al. (1979)—Eqs. (1) and (2). OMD ðg=kg DMÞ ¼ 148:8 þ 8:89G24 þ 4:5CP þ 0:651XA
ð1Þ
Where G24 is the gas volume at 24 h after inoculation and XA is the ash content (g/100 g). ME ðM J=kg DMÞ ¼ 2:2 þ 0:136G24 þ 0:057CP þ 0:0029CP2 ð2Þ
1000xðND Ffeed ‐ ND Fres Þ ND Ffeed
ð3Þ
Where NDFfeed NDF in feed; NDFres was NDF in residues after refluxing in neutral detergent solution. PF was calculated based on equation by Blümmel and Becker (1997)—Eq. (4). P F ðmg=mL of gas volumeÞ ¼ TOMD=IVGP
ð4Þ
Where TOMD is true organic matter digestibility and IVGP is in vitro gas production. Data analysis Cross comparison of forage species distribution was computed using chi-square for frequency procedure of SAS system 9.3 (2010). Chemical composition, OMD, ME and PF of feed resources were examined using Mixed Model of SAS system 9.3 (2010).
Results Only five of 24 feed types were common across districts. In Bugesera (low altitude) more than 90 % of farmers used crop residues and herbage opportunistically collected from roadsides and marshland. In Nyamagabe (mid-altitude) 19 % of the dairy farmers relied on crop residues. The majority for households (63 %) depended on pastures from edges of cultivated land; roadside and marshlands. Napier grass was found in less than 20 % of the dairy households (Table 1). Chemical composition of feed resources Chemical composition of feed resources is shown in Table 2. Feed types differed significantly in DM content (P
REGULAR ARTICLES
Nutritional values of available ruminant feed resources in smallholder dairy farms in Rwanda Mupenzi Mutimura 1,2 & Cyprian Ebong 2 & Idupulapati Madhusudana Rao 3 & Ignatius Verla Nsahlai 1
Received: 9 January 2015 / Accepted: 20 April 2015 # Springer Science+Business Media Dordrecht 2015
Abstract Smallholder dairy farmers in Rwanda use diversity of resources to cope with endemic feed shortages. However, there is inadequate real farm data to support farmer decisions on choices of options. The main objective of this study was to evaluate nutritional quality of feed types that farmers use in different agro-ecological zones of Rwanda. Samples of feed types were collected from 90 randomly selected households in the low- and mid-high-altitude zones of Rwanda and analysed for proximate composition, contents of metabolisable energy (ME), organic matter digestibility (OMD) and neutral detergent fibre digestibility (NDFd). Rumen fermentation characteristics and efficiency of energy utilisation were examined by determining partitioning factor (PF). Results showed that only five out of 24 feed types were common in both districts. Chemical composition, OMD, ME, NDFd and PF of these feed types differed significantly (P2000 m), adequate rainfall (1800 mm) zone and with acidic kaolinite soils which are prone to aluminium toxicity. Samples were collected from 90 randomly selected households in four sectors (sub-district) in Bugesera and Nyamagabe districts. In each sector, five households per cell (local government administration under a sector) in three randomly selected cells per sector provided samples.
Sampling, sample handling and laboratory analysis Samples from each household and feed type were divided into two parts. One part was dried at 60 °C for 48 h and milled to pass through a 1-mm screen for subsequent laboratory analyses. The other part was dried at 105 °C for determination of DM (AOAC 1990; method ID 9420.5), OM (AOAC 1990; method ID 9420.5), CP (AOAC 2006; method ID 984.13) and NDF (Van Soest et al. 1991). Using in vitro gas technique organic matter digestibility (OMD), metabolisable energy (ME) and partitioning factor (PF) were determined. Samples (≈200 mg) were accurately weighed and transferred into airtight graduated gas syringes (100 mL) for anaerobic fermentation (39±1 °C; 24 h) in an oven. The media was a mixture of 1:2 of inoculum source and buffer solutions (v/v) made from solutions A, B and C (Osuji et al. 1993). The inoculum sources were rumen fluids from two surgically prepared steers according to ethical practice. These animals were fed on grass hay (Brachiaria hybrid cv. Mulato II). The inoculum preparation procedure was done according to Osuji et al. (1993) as modified by Mutimura et al. (2013b). Gas readings were recorded at 0, 1, 3, 5, 7, 9, 12, 16, 20 and 24 after inoculation. Syringes were removed at 24 h of incubation. OMD and ME were calculated according to Menke et al. (1979)—Eqs. (1) and (2). OMD ðg=kg DMÞ ¼ 148:8 þ 8:89G24 þ 4:5CP þ 0:651XA
ð1Þ
Where G24 is the gas volume at 24 h after inoculation and XA is the ash content (g/100 g). ME ðM J=kg DMÞ ¼ 2:2 þ 0:136G24 þ 0:057CP þ 0:0029CP2 ð2Þ
1000xðND Ffeed ‐ ND Fres Þ ND Ffeed
ð3Þ
Where NDFfeed NDF in feed; NDFres was NDF in residues after refluxing in neutral detergent solution. PF was calculated based on equation by Blümmel and Becker (1997)—Eq. (4). P F ðmg=mL of gas volumeÞ ¼ TOMD=IVGP
ð4Þ
Where TOMD is true organic matter digestibility and IVGP is in vitro gas production. Data analysis Cross comparison of forage species distribution was computed using chi-square for frequency procedure of SAS system 9.3 (2010). Chemical composition, OMD, ME and PF of feed resources were examined using Mixed Model of SAS system 9.3 (2010).
Results Only five of 24 feed types were common across districts. In Bugesera (low altitude) more than 90 % of farmers used crop residues and herbage opportunistically collected from roadsides and marshland. In Nyamagabe (mid-altitude) 19 % of the dairy farmers relied on crop residues. The majority for households (63 %) depended on pastures from edges of cultivated land; roadside and marshlands. Napier grass was found in less than 20 % of the dairy households (Table 1). Chemical composition of feed resources Chemical composition of feed resources is shown in Table 2. Feed types differed significantly in DM content (P
