Bioconversion of Organic Residues for Rural Communities (UNU, 1979)
 Indian experience with treated straw as feed
 (introduction...) Introduction Experience with straw treatment Field testing and demonstration of straw treatment General considerations Summary Annex 1. The energy efficiency of the two-stage, feed-fuel processing of straw in indian villages Annex 2. Method of calculating the value presented in table 2 for the efficiency of naoh energy usage Annex 3. Recommendations to farmers on the treatment of straw Annex 4. Calculated efficiency of milk production by straw-fed village buffaloes References Discussion summary

### Annex 4. Calculated efficiency of milk production by straw-fed village buffaloes

Table 4 shows the calculation of milk-production efficiency. The data for the consumption of various feeds on untreated straw diet represent average village feeding rates and are taken from Amble et al. (20). Lactation milk yield for the untreated straw diet is estimated as the national average, as is the frequency of calving, namely, once every two years (21). Urea energy is not included in the total for energy input, on the grounds that much of it can be recovered and used as a fertilizer on crops. This procedure results in crediting the NaOH with all the improvements in productivity; thus the last three figures in the table, relating to the MJ NaOH energy per MJ milk or milk protein energy, are underestimated.

TABLE 4

 Untreated straw diet Treated straw diet Mature weight (kg) 400 400 Life span (years) 11 11 Age at first calving 5 35 Number of lactations/lifetime 3 4 Lactation yield (kg) 900 1,200 Lifetime milk production (kg) 2,700 4,800 Daily feed consumption (average over lifetime; kg)straw 4.5 55 grass/forage 6 6 concentrates 0.250 0.250 urea, 1% straw 0.055 NaOH, 4% of straw 0.220 Lifetime milk consumption (kg) 100 100 Lifetime energy intake (MJ) from feeds only 372,902 430,703 from feeds + NaOH 475,751 Lifetime energy output (MJ) milk 12,420 22,084 calves 600 800 carcass 4,000 4,000 Total 17,020 26,884

Efficiency

4.6 6.2

5.7

7.3

1.7

5.4

For the method of calculating the ratio MJ NaOH energy/MJ output, see Annex 2. The increased production due to alkali treatment is a very rough estimate. Growth rate can be doubled, leading to a reduction in age at first calving of about 1.5 years, making it possible for an animal to have one extra lactation in its lifetime. Data from a substitution trial with milk cows (22) indicate that treated straw fed ad libitum to cows is equal to at least 0.5 kg concentrate mixture/day. This, in turn, should be equal to 1 litre of milk/day in village buffaloes on the plane of nutrition indicated in the table (23). Energy values (MJ/kg) used in calculations are as follows, assuming straw and concentrates contain 90 per cent dry matter and grass/forage contains 25 per cent.

 Straw 14.4 Grass/forage 3.6 Concentrates 16.2 Milk 4.6 Protein in milk 1.0 NaOH (manufacturing cost) 51.0 (24)

Assumed energy contents of carcasses (MJ) are:

 Calf 200 Buffalo 4,000 Protein in calf 150 Protein in buffalo 3,000

The efficiency of a bullock with similar feed intake will be only slightly less than the buffalo in this example (untreated straw) if it works 1,200 hr/yr over a 6-year working life and has an 11-year total life span; i.e., 0.5 hp x 0.7455 kw x 1,200 hour x 6 x 3.6 MJ/kwh = 9,662 MJ energy output (2).