Condensed tannins in cassava hay and fecal egg counts

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Effect of condensed tannins in cassava hay on fecal parasitic 
egg counts in swamp buffaloes and cattle

 
N Netpana, M Wanapat, O Poungchompu and W Toburan

Department of Animal Science, Faculty of Agriculture, 
Khon Kaen University, Khon Kaen 40002, Thailand

Abstract

A comparative study was conducted with grazing cattle and buffaloes which received the following treatments: control (no interventions), drenching with anthelmintic or feeding cassava hay as a supplement.

During the 6-week period, the animals receiving cassava hay had lower nematode egg counts than those in the control group, and similar counts to those drenched with anthelmintic. It is concluded that cassava hay can provide not only protein, but also appears to have a role as a gastrointestinal anthelmintic agent.

 Key words: Cassava hay, condensed tannins, intestinal nematodes

Introduction

Parasitic infestation in the gastrointestinal tract is a serious problem for ruminants in the tropics. Infested animals usually exhibit poor performance. Drenching with anthelmintic is the traditional solution to this problem but the treatment is often expensive. Condensed tannins have been reported to have  potential as a means of reducing nematodes in the gastrointestinal tract (Kahn and Diaz-Hernandez, 2000) but the mode of action is not yet  fully understood.

The objective of this preliminary experiment was to study the comparative effects of anthelmintic drenching and supplemental cassava hay on nematode egg counts in feces of swamp buffaloes and cattle grazing on ruzi grass pasture.  

Materials and Methods   

Swamp buffaloes (4) and crossbred dairy cows (4) were randomly assigned to receive one of three treatments:

• CON = control, grazing only (one buffalo; one cow) 

• DRE = grazing + drenching with ivomectin (one buffalo; one cow)

• CH = grazing + supplementation of cassava hay at 1 kg/head/day (two buffaloes; two cows)

All animals were allowed to graze on ruzi grass pasture from 08.00h to 04.00h during the first 2 weeks before the respective treatments were imposed. In addition, urea-treated rice straw was given during the evening.  Fecal samples from the rectum were collected from all animals two times during the first two weeks and every week for four weeks after imposing the treatments. Counting of fecal nematode eggs was done according to a modified McMaster fecal egg count technique, as reported in Niezed et al (1995). Cassava hay was prepared as reported by Wanapat et al (1997, 2000) and analyzed for chemical composition (AOAC 1990) and condensed tannins using the vanillin-HCl method (Burns 1971). Statistical analyses were done with pooled data of cattle and buffaloes to compare treatment effects using the GLM procedure (SAS 1987). 

Results and Discussion

Crude protein and condensed tannins were 23.5% and 32.6 g/kg DM, respectively (Table1). These values are similar to earlier data reported by Wanapat et al (2000). Condensed tannins in this  range were reported to be beneficial to ruminants (Barry and Manley 1984; Reed 1995; Norton 2000). The presence of condensed tannins was postulated as a mechanism for protecting the protein in cassava hay, which in turn would be expected to enhance it’s rumen by-pass properties (Wanapat et al 2000).           

Nematode egg counts in all groups were variable during the adjustment period. For the control group, the egg counts remained in the same range during the experimental period, while in the anthelmintic and cassava hay treatments the egg counts were significantly decreased. The same trends were found in both cattle and buffaloes. These results support the conclusions of Kahn and Diaz-Hernandez (2000) that condensed tannins could be a means of reducing numbers of nematode larvae in the gastrointestinal tract of ruminants.  

Conclusions

Based on the results of this preliminary experiment, it can be concluded that feeding a supplement of cassava hay, containing moderate levels of condensed tannins, will have the effect of  reducing nematode egg counts in both cattle and buffaloes. However, further research is needed to determine the effects of long-term supplementation and different levels of cassava hay. 

Figure 1: Trends in fecal nematode egg counts prior to treatment (weeks 1 and 2)
 and after imposing the treatments (weeks 3 to 6)

 
References

AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. 15^th edition (K Helrick editor) Arlington pp 1230

Barry T N and T R Manley 1984 The role of condensed tannins in the nutritional value of Lotus peduculatus for sheep 2. Quantitative digestion of carbohydrates and protein. Br. J. Nutr. 51:493.

Burns R 1971 Method for estimation of tannin in grain sorghum. Agronomy Journal, 63: 511-512. 

Kahn L P and Diaz-Hernandez A 2000 Tannins with anthelmintic properties. In Proc. International Workshop on Tannins in Livestock and Human Nutrition (Ed.J D  Brooker), ACIAR Proceedings No.92. 171pp. 

Niezen  J H,  Waghorn  T S,  Charleston W A G and Waghorn G C 1995  Growth and gastrointestinal nematode parasitism in lambs grazing either lucerne (Medicago sativa) or sulla (Hedysarum coronarium) which contains condensed tannins. J. Agric. Sci.  Cambridge, 125:281-289.

SAS  1987  SAS/STAT Guide for Personal computers, Version 6, Cary, NC:SAS Inc.

Wanapat  M, Pimpa  O,  Petlum A and Boontao U 1997  Cassava hay: A new  strategic feed for ruminants during the dry season. Livestock Research for Rural Development, 9(2): http://www.cipav.org.co/lrrd/lrrd9/2/metha9

Wanapat  M,  Pimpa O,  Sripuek W, Puramongkol T, Petlum A, Boontao U, Wachirapakorn  C and  Sommart K 2000 Cassava hay: an important on-farm feed for ruminants. In Proc. International Workshop on Tannins in Livestock and Human Nurition (Ed. J D Brooker), ACIAR Proc. No. 92, p. 71-74.

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