Data variables in 'SSA Feeds'

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Data sources

The information on nutritional data of livestock feeds made available through 'SSA Feeds' was generated at the Animal Nutrition/Analytical Services Laboratories of the International Livestock Research Institute (formerly the International Livestock Centre for Africa) in Addis Ababa, Ethiopia. The laboratory analyses were performed as described by Osuji et al. (1993) and Ogubai and Sereke (1997). The initial dataset used is the one published by Anindo et al. (1994); however, this was modified extensively to exclude duplicate entries and extreme cases of outliers and the nutritive values obtained here may therefore differ substantially from that publication.

At the time of most recent updating, the scientific names in ‘SSA Feeds’ were checked against the taxonomy used by the U.S. National Plant Germplasm System taxonomic database:

This taxonomic database is frequently updated and users are advised to check there for alternative names and synonyms if a particular species is not found in ‘SSA Feeds’.


Data variables

'SSA Feeds' provides data on the following nutritional variables:

Variable Variable name Unit Method
DM Dry matter % Dried basis 105ºC ,12 hours overnight
OM Organic matter % of DM 500ºC, 12 hours overnight
ADF Acid detergent fiber % of DM van Soest and Robertson (1985)
NDF Neutral detergent fiber % of DM van Soest and Robertson (1985)
ADL Acid detergent lignin % of DM van Soest and Robertson (1985)
CP Crude protein % of DM Kjeldhal, N × 6.25
IVDMD In vitro dry matter digestibility % of DM Tilley and Terry (1963)
ME Metabolizable energy MJ/kg DM Modified NRC (1996, 2000, 2001)
NEm Net energy for maintenance MJ/kg DM NRC (1996, 2000, 2001)
NEg Net energy for gain MJ/kg DM NRC (1996, 2000, 2001)
NEl Net energy for lactation MJ/kg DM NRC (1996, 2000, 2001)
Ca Calcium g/kg DM AAS (Harris 1970)
Cu                                                               Copper ppm, DM  AAS (Harris 1970)
P Phosphorus g/kg DM FIA (Harris 1970)
Fe Iron ppm, DM AAS (Harris 1970)
K Potassium g/kg DM AAS (Harris 1970)
Mg Magnesium g/kg DM AAS (Harris 1970)
Mn Manganese ppm, DM AAS (Harris 1970)
Na Sodium ppm, DM AAS (Harris 1970)
Zn Zinc ppm, DM AAS (Harris 1970)

      1. Dry matter is on dried basis. This is not the DM of the feed, but the DM of the feed sample after drying and grinding. Users need to know the DM of the feeds as they are used in the farm.
      2. AAS = atomic absorption spectrophotometry.
      3. FIA = flow injection analysis.
      4. ppm = parts per million (= mg/kg).
      5.MJ/kg = megajoules/kg.

Energy values

Digestible Energy (DE) was calculated following a modification of the equation used by NRC (2001). NRC (2001) estimated DE using data on true digestibility of the various feed fractions and their concentration of energy. Since this information was not available in the database, DE was calculated as:

        DE = 0.01 OM (IVOMD + 12.9) 4.4 – 0.3


  • OM is % of organic matter. For feeds for which data on IVDMD was available but OM was unknown, the latter was assumed to be 90% of the DM
  • IVOMD (in vitro organic matter digestibility) was assumed to be the same as IVDMD
  • 12.9 represents the endogenous losses of energy in faeces (van Soest 1982)
  • 4.4 is the average concentration of energy (Mcal/kg) in the digested OM (NRC 2000, 2001)
  • –0.3 is intercept from NRC (2001).

Values of ME, NEm, NEg and NEl were calculated from DE following NRC (2000, 2001) as follows:

            ME = 0.82 DE

            NEm = 1.37 ME – 0.138 ME2 + 0.0105 ME3– 1.12

            NEg = 1.42 ME – 0.174 ME2 + 0.0122 ME3– 1.65

            NEl = 0.703 ME – 0.19

            IVDMD values that led to EM values lower than 1.75 Mcal/kg DM or higher than 3.0 Mcal/kg DM were excluded from the database.

            For NEl, no adjustments for level of intake were used (NRC 2001), as milking cows in sub-Saharan Africa are rarely fed at levels above 1.5 times maintenance (Jenet 2004; Osuji et al. 2005).


Anindo DO, Said AN and Lahlou-Kassi A. 1994. Chemical composition and nutritive value of feedstuffs for ruminant livestock in sub-Saharan Africa. ILCA (International Livestock Centre for Africa), Addis Ababa, Ethiopia. 539 pp.

Harris LH. 1970. Nutrition research techniques for domestic and wild animals. Volume 1. Animal Science Department, Utah State University, Logan, Utah, USA. 86 pp.

Jenet A. 2004. Long-term and carry over effects of feeding level performance and energy partitioning of Boran (Bos indicus) and Boran × Holstein dairy cattle. PhD thesis. Swiss Federal Institute of Technology, Zurich, Switzerland. 105 pp.

NRC (National Research Council). 1996. Nutrient requirements of beef cattle. Seventh revised edition. NRC, National Academic Press, Washington, DC, USA. 242 pp.

NRC (National Research Council). 2000. Nutrient requirements of beef cattle. Update 2000. NRC, National Academic Press, Washington, DC, USA. 232 pp.

NRC (National Research Council). 2001. Nutrient requirements of dairy cattle. Seventh revised edition. NRC, National Academic Press, Washington, DC, USA. 381 pp.

Ogubai M and Sereke BS. 1997. Analytical methods for feeds, animal excrements and animal tissues. Nutrition Laboratory, ILRI (International Livestock Research Institute), Addis Ababa, Ethiopia. 90 pp.

Osuji PO, Nsahlai IV and Khalili H. 1993. Feed evaluation. ILCA Manual. ILCA (International Livestock Centre for Africa), Addis Ababa, Ethiopia.

Osuji PO, Saarisalo EM, Tegegne A and Umunna NN. 2005. Undernutrition of dairy cattle in smallholder production systems in East Africa. In: Ayantunde AA, Fernández-Rivera S and McCrabb G (eds), Coping with feed scarcity in smallholder livestock systems in developing countries. Animal Sciences Group, UR, Wageningen, the Netherlands; University of Reading, Reading, UK; Swiss Federal Institute of Technology, Zurich, Switzerland; and ILRI (International Livestock Research Institute), Nairobi, Kenya. pp. 97–120.

Tilley MA and Terry RA. 1963. A two-stage technique for the in vitro digestion of forage crops. J. Brit. Grassl. Soc., 18: 104-111.

van Soest PJ. 2002. Nutritional ecology of the ruminant. O&B Books, Corvallis, Oregon, USA. 374pp.

van Soest PJ and Robertson JB. 1985. Analysis of forages and fibrous feeds. A laboratory manual for animal science 613. Cornell University, Ithaca, New York, USA. 202 pp.