Citrus by-products (Citrus spp)

The  term  ‘citrus  by-product’   includes  numerous by-product  feedstuffs, which vary according to the originating  crop  and  method  of  production,  that are an important component of ruminant feeding systems in  many  areas of  the  world.  The genus Citrus  includes  several  important  fruits  with  the most important  on a worldwide  basis being sweet orange (C. sinensis), lemon (C. limon) and grapefruit (C. paradisi).

Citrus fruits are principally consumed by humans as fresh fruit or processed juice. After juice is extracted from the fruit, there remains a residue comprised of peel (flavedo and albedo), pulp (juice sac residue), rag (membranes and cores) and seeds. These components, either individually or in various combinations, are the source materials from  which  citrus by-product  feedstuffs (BPF) are produced. In India total  availability of grape and orange waste is about 2.20 million tones.

Nutritive value

The nutrient content of citrus BPF is influenced by factors that include the source of the fruit  and type of processing (Ammerman and Henry, 1991). The nutrient  composition  of citrus wastes varies depending on the type of waste and type of fruit. The selected values for total ash, crude fat, crude fibre, crude protein, NFE, total sugar, lignin and pectin ranges from  1.7-7%, 1.2-2.1%, 5.7-8.6%, 2.2-4.2%, 65-75%, 10.2-16.5%, 1.3-6.5% and 4.4-12.8% respectively, for different types of wastes (Javed Ali et al., 2010).

Inclusion

The fresh citrus pulp waste is palatable to cattle, when they are accustomed to the feed and a mature cow  can consume about 10 kg per day. Dried citrus pulp has been used as the main energy source for  beef cattle and heifers, and up to  45 percent has been used in rations. However, the pulp should not be used at high levels for milking cows as milk production tends to decrease. Digestibility trials with sheep show that its digestibility decreases when citrus pulp is included at levels in excess of 30 percent of the ration (Gohl,

1978). It is more  advantageous to  mix  the fresh pulp  with  partially dried  grass or  with legumes which cannot be successfully ensiled on their own.