Livestock Research for Rural Development 2 (1) 1990

Citation of this paper

Feeding value of steam treated sugar cane bagasse in ruminant rations

Fernando Basile de Castro and Pablo Fernando Machado

Fundacao de estudos agrarios Luiz de Queiroz, Av. Padua Dias 11, 13400 Piracicaba - SP, Brazil.

Sponsered by International Foundation for Science (Research Grant Agreement B/1220-1)


In order to evaluate the effects of steam treatment upon sugar cane bagasse three experiments were conducted. The first was to determinate the best conditions to treat the bagasse. Four pressures were tested (13; 15; 17 and 19 kgf/cm2) during 3 to 10 minutes in a factorial design. The condition that gave the highest in situ digestibility was 19/6 (kgf/cm2)/(min). The second experiment was to evaluate the potencial and the effective degradation of the bagasse treated under the best condition set above. The results indicate a high potential degradation (68.96% in 48 hr), a value very close to 74.22% in 48hr from a high quality hay. Nevertheless, the effective degradation was only 47.90% in 48hr, indicating poor rumen conditions. The third experiment was to study the effects of treated bagasse upon the rumen environment. It was concluded that the main constraint of using steam treated bagasse was its fast rate of passage through the rumen.

Key words: Sugar cane bagasse, steam treatment, rumen degradation, rumen environment, cattle


A series of trials was carried out to determine the effect of steam treatment of sugar mill bagasse on its potential and achieved degradability in the rumen of steers.

Materials and methods

Experiment 1: Determination of optimum conditions to steam treat sugar cane bagasse to be fed to ruminants

Sugar cane bagasse was steam treated under pressure in a commercial sugar cane mill. The treatments were: 13, 15, 17 and 19 kg/cm2 of pressure during 3 to 10 minutes. Samples were conveniently collected and submitted to in vitro and in situ degradation by rumen microorganisms. The in vitro system was the one developed by Tilley and Terry (1963) and the in situ by Orskov et al (1980).

The in situ test was done in two fistulated Jersey cows receiving hay. These animals were also the source of inoculum for the in vitro analysis. Three assays were run for each determination.

Experiment 2: Determination of potencial and effective degradation of steam treated sugar cane bagasse by ruminants.

Sugar cane bagasse treated under 19 kg/cm2 steam pressure during 6 minutos was put into nylon bags and allowed to be degraded by rumen microorganisms in the rumen of two fistulated Jersey cows. The animals received hay, or raw bagasse, plus grain (47:53), or steam treated sugar cane bagasse (19 kg/6 minutes) plus grain (65:35). Each diet was fed for 4 weeks. During the last 20 days, three in situ assays were run. For each assay, besides the treated bagasse, hay and raw bagasse were used as standards.

Experiment 3: Study of the effect of steam treating sugar cane bagasse upon its digestion by ruminants and rumen physiology.

Six fistulated dry cows received two diets: raw bagasse plus grain (47:53) or steam treated bagasse (19 kg/6 minutes) plus grain (65:35). The animals received those diets for 30 days and then the diets were interchanged. The experiment consisted of three periods of 30 days, 10 days of adaptation to the new diet and 20 days of sample collection. During the first day after adaptacion, Folley catheters were introduced into the gallblader of the animals; the following 6 days, feces and urine were collected for total dry matter determination. Afterwards, a serial sample collection during 24hr was used to determine volatile fatty acids, ammonia nitrogen, and pH; another serial sample collection for 76 hr was for rate of passage of solids and liquids through the rumen.

Results and discussion

Experiment 1:

The results are given in Table 1.

Table 1: Effect of steam treating sugar cane bagasse on total in situ (TISD), insoluble in situ (IISD) and in vitro dry matter degradation (IVD) by rumen microorganisms (% 48hr)
Treatment (kg/cm2) TISD IISD IVD
13/6 70.12 55.36 60.82
13/8 71.12 58.08 59.57
13/10 75.52 62.45 62.71
15/4 76.70 62.13 61.32
15/6 75.83 62.05 61.05
15/8 76.99 63.50 61.49
17/3 71.88 56.47 61.20
17/5 74.62 60.53 60.98
17/7 79.10 67.43 62.52
19/2 78.52 64.08 62.88
19/4 81.61 68.87 64.01
19/6 80.59 60.58 63.69
STANDARD 79.40 73.72 73.99


It can be seen from Table 1 that the best treatments were 19kg/cm2 pressure for 6 minutes (19/6) and 19/4. The values represented an improvement of 20% above the treated bagasse receiving commercial steam processing at the mill. Another important observation was that the in vitro dry matter degradation was not a sensitive enough method to evaluate the effect of the treatment.

Experiment 2:

It was assumed that animals receiving a high quality hay would have an adequate environment in the rumen for degradation of cell wall carbohydrates; and that therefore in situ dry matter degradation would represent the potential degradability of the material. On the other hand, in situ dry matter disappearance in animals receiving treated bagasse would represent the effective degradation.

The results obtained can be seen in Tables 2, 3 and 4.

Table 2: In situ degradation (% in 48 hr) of a high quality hay, raw and steam treated sugar cane bagasse (19 kg/cm2; 6 minutes) in cattle receiving hay or treated (19/6) or untreated bagasse.
  -------------------------- Diet of host animal --------------------------
Sample Hay Raw bagasse Treated bagasse
Hay 74.22 75.30 68.58
Raw bagasse 36.27 35.70 17.29
Treated bagasse 68.96 67.76 47.90


Table 3: Degradation rate (%/hr) of high quality hay, raw and steam treated sugar cane bagasse (19/6 kg/cm2) in cattle receiving hay or treated (19/6 kg/cm2) or untreated bagasse.
  -------------------------- Diet of host animal --------------------------
Sample Hay Raw bagasse Treated bagasse
Hay 9.19 8.54 6.06
Raw bagasse 5.89 5.50 3.71
Treated bagasse 7.49 5.92 4.41


Table 4: Lag time (hr) in digestion of a high quality hay, raw and steam treated sugar cane bagasse (19/6 kg/cm2) in cattle receiving hay or treated (19/6 kg/cm2) or untreated bagasse.
  -------------------------- Diet of host animal --------------------------
Sample Hay Raw bagasse Treated bagasse
Hay 0.68 1.57 2.55
Raw bagasse 1.23 3.50  
Treated bagasse 3.23 4.68 3.40


From the data shown in Table 2 it can be seen that the potential degradation of the treated bagasse is very close to that of the high quality hay (69 vs 74 % in 48 hr). The potential degradation of raw bagasse is 36% in 48 hr. This means that steam treating the bagasse almost doubles its potential degradability. Nevertheless, the effective degradation of the treated bagasse is only 48% in 48 hr.

It would appear that something in the diet containing the treated bagasse is interfering with its degradation since on the raw bagasse diet no such depressing effect was observed.

The data in Table 3 show similar results indicating a lower rate of degradation in animals receiving a diet based on treated bagasse. Date from Table 3 and 4 indicate that despite almost the same degradation after 48 hr, lag time was longer (3.23 vs 0.68 hr) and rate of degradation lower (7.49 vs 9.19 %hr) for treated bagasse and hay, respectively. It shows that in order to be degra- ded at the same rate, the bagasse would have to stay longer in the rumen; this in turn, almost certainly would decrease feed intake.

Experiment 3:

Data on intake and dry matter digestibility of the diets are given in Table 5.

Dry matter digestibility was higher for raw bagasse than for the steam treated material (Table 5). However, digestible dry matter intake was 38.4% higher for treated bagasse. This could explain the higher body weight gain observed for animals receiving treated bagasse compared with the untreated material. Assuming that the digestibility of the grain component was 85%, it can be calculated that the effective degradation of the bagasse was 40 and 30% for the treated and raw material respectively, a value very close to the one observed in situ.

Table 5: Dry matter digestibility (DMD), intake (DMI) and digestible dry matter intake (DDMI); rumen fermentation parameters and rumen kinetics for diets based on raw and steam treated bagasse.
  Raw bagasse Treated bagasse
DM digestibility (%) 60.2 54.7
DM intake (kg/d) 7.36 10.8
Digest DM intake (kg/d) 4.42 5.92
Molar % VFA    
Acetic 70.0 66.1
Propionic 18.2 22.1
Acetic/propionic 4.0 3.0
Total VFA (meq/100ml) 8.5 12.0
N-NH3 (mg/100ml) 3.47 4.19
pH 6.90 5.89
Liquid phase kinetics:    
Dilution rate (%/hr) 5.97 8.36
Turnover time (hr) 16.8 12.3
Solid phase kinetics:    
Retention time (hr) 47.3 33.5


In an attempt to identify factrs affecting rumen degradation, samples from the rumen of the animals were analyzed for VFA, NH3-N, pH and rate of passage of liquids and solids (Table 5).

The data show that the fermentation pattern is almost the same on both diets, but that the intensity of fermentation is 32% higher for the treated bagasse. This is in agreement with the higher rate of intake of digestible dry matter.

Ammonia nitrogen levels were similar to those recommended by Satter and Slyter (1974) but lower than the minimum value (15 mg/100 ml) suggested by Preston and Leng (1987) as being necessary for optimum rates of digestion of fibrous feeds. The rumen pH in the animals receiving the treated bagasse was below the critical level (6.5) considered as providing a good environment for cellulolytic bacteria.

The rate of passage of liquids and solids and therefore the rate of turnover was higher for the diet of treated bagasse than for the raw bagasse (Table 5). This means that the time available for microorganisms to degrade the feed was shorter on the diet with treated bagasse, which may explain the lower effective degradation.


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