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Poster 9.2: Use of dehydrated sugar cane (Saccharum officinarum) as an additive to Napier grass (Pennisetum purpureum) ensilage - José Neuman Miranda Neiva, Ana Cristina Holanda Ferreira and Maurício Teixeira


José Neuman Miranda Neiva, Ana Cristina Holanda Ferreira and Maurício Teixeira

Federal University of Ceará
Caixa Postal 12168
Fortaleza-CE,
Brazil CEP: 60355-970
E-mail: [email protected]

INTRODUCTION

Tropical grass biomass increases with maturity, but decreases in nutritive value. To overcome this problem, these grasses are frequently ensiled at an early growth stage. However, young plants have a high moisture content, high buffering capacity and a low level of soluble carbohydrates. According to Woolford (1984), these factors have a negative influence on the fermentation process, preventing a rapid lowering of the pH and thus allowing unwanted secondary fermentation, consequently damaging the quality of the final product.

Assuming that the above problems are the main limitations to the ensilage of Napier grass, research was undertaken with the objective of finding practical solutions to enable the production of good quality silage from Napier grass.

Amongst the existing alternatives, the addition of dehydrated sugar cane to the Napier grass to be ensiled appears to be interesting, because it has high contents of DM and WSC.

The aim of this study was to evaluate the chemical and fermentation characteristics of the Napier grass silage with different levels of added dehydrated sugar cane.

MATERIALS AND METHODS

This experiment took place at the Forage Section of the Federal University of Ceará. The chemical and fermentation characteristics were studied of Napier grass silage with the addition of 0, 5, 10 and 15% of dehydrated sugar cane on a fresh material basis. The Napier grass biomass, approximately 80 days old, was chopped and mixed with the dehydrated sugar cane. The sugar cane was ground in a mill fitted with a 3-mm sieve. A replicated, completely randomized design was used.

Polyethylene laboratory silos were used, 100 mm in diameter and 340 mm deep. Sixty days after filling, the silos were opened and homogeneous samples of approximately 300 g were taken to determine DM, CP, pH and NH3-N. Analyses of variance and regression were used to test the data.

RESULTS AND DISCUSSION

The DM content of the silage increased linearly with the addition of dehydrated sugar cane (Table 1). Almeida et al. (1986) and Tosi et al. (1989), studying the addition of sugar cane and sugar cane bagasse, respectively, in the ensilage of Napier grass, also observed a rise in the DM levels.

Table 1. Average value of the levels DM, CP, ammoniacal nitrogen (NH3-N), pH and regression equations

Parameter

Sugar cane

Mean

Regression equations

0%

5%

10%

15%

% DM

21.2

25.2

27.5

29.9

25.9

Y = 25.9465+2.8442x R2 = 98.05%

% CP

7.3

5.7

5.6

4.9

5.9

Y = 5.8895-0.6954x R2 = 99.25%

NH3-N

4.6

3.9

4.9

4.4

4.5

NS

pH

3.6

3.6

3.6

3.7

3.6

NS

CP levels decreased linearly with the addition of dehydrated sugar cane. Similar results were obtain by Almeida et al. (1986). Tosi et al. (1989), using sugar cane bagasse as an additive in Napier grass ensilage, observed that the CP level of the silages fell below 4%. This drop is due to the very low CP concentration in sugar cane bagasse (ca 2%).

We have not observed significant differences in NH3-N and pH value between the silages. The quality of the silage without sugar cane was as good as that with. Almeida et al. (1986) and Tosi et al. (1989) also found that wilted Napier grass made well-preserved silage without sugar cane or bagasse.

CONCLUSIONS

From the data obtained in this study we can conclude that the addition of dehydrated sugar cane did not change the characteristics of the fermentation of the silages, but reduced its CP levels.

As the CP reached very low levels with the addition of the sugar cane, further studies are needed to evaluate the benefit of inclusion of a nitrogen source together with sugar cane.

REFERENCES

Almeida, E.X., Pinto. J.C., & Pérez, J.R.O. 1986. Cama de frango e cana-de-açúcar na qualidade da silagem de Pennisetum purpureum Schum. cv. Cameroon. Revista da Sociedade Brasileira de Zootecnia, 15: 193-199.

Tosi, H., Bonassi, I.A., & Iturrino, R.P.S. 1989. Avaliação química e microbiológica da silagem de capim elefante, cultivar Taiwan A-148, preparada com bagaço de cana. Pesquisa Agropecuária Brasileira, 24: 1313-1317.

Woolford, M.K. 1984. The silage fermentation. New York: Marcel Dekker.


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