Mini-project Research protocol  

MSc in Tropical Livestock System (2005-2007)
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Citation of this paper

Body of Text

 

Effect of a supplement of fresh water spinach on feed intake and digestibility in goats fed a basal diet of cassava foliage

Pathoummalangsy Khamparn

Faculty of Agriculture (NUOL), Lao
khamparnp@yahoo.com.au

Introduction

Cassava foliage is a protein source for many kinds of animal both monogastric and ruminant. Nevertheless according to Chhay Ty and Preston (2003), the increase in voluntary intake by pigs when water spinach replaced fresh cassava leaves is due to the higher digestibility of the diet especially the protein component. Other factors, such as the higher fibre content of cassava leaves, compared with water spinach, and the presence of cyanogenic glucosides and tannins, could be expected to reduce the voluntary feed intake. In addition voluntary intake of goats fed only fresh cassava foliage is lower than when jackfruit or mulberry foliage is given (Theng Kouch et al 2003). The reason may be the tannins or the cyanide glucosides present in the cassava. Goats fed cassava foliage as a supplement have been shown to have negligible nematode worm infestations (Sokerya and Preston 2003). Ho Quang Do et (2002) reported a curvilinear increase in feed intake and N retention in goats when fresh cassava leaves replaced grass as the supplement to untreated rice straw.

Water spinach (Ipomoea aquatica) is a water and marsh plant with creeping, hollow, water filled stems and shiny green leaves. The fresh leaves and stems of water spinach have a crude protein content of between 20 and 31% in DM (Le Thi Men et al 2000) and ash concentrations of around 12% of DM. It has been used successfully to replace part of the protein in a diet of sugar cane juice for breeding sows in Vietnam (Le Thi Men and Bui Hong Van 1993).

Objectives:

The aim of this experiment focuses on the nutritive value of cassava foliage with fresh water spinach as supplement at different feeding levels for goats by comparing feed intake, digestibility and nitrogen retention of the animals.

Hypothesis:

Feed intake and digestibility in goats fed cassava foliage as basal diet will be improved when water spinach is given as a supplement

Materials and methods

Location:

The experiments will be carried out at the Livestock Research Center (Nam Xuang village). The duration is from September 15th to October 15th, 2005

Treatments and experimental design

The treatments are three levels of water spinach:

Fresh cassava foliage will be fed as basal diet given ad libitum (offered at 120% of recorded intake). Three goats are used and the design is a  3*3 Latin square arrangement with periods of 10 days on each treatment.

Experimental animals, feeds and feeding system

3 female goats will be used and the beginning live weights are: 10.8, 10.9 and 11.9 kg, with average of 11.16 kg

The sources of cassava foliage and water spinach will be taken from LRC farm. Cassava foliage will be supplied ad libitum (120% of recorded intake), it will be fed 3 times per day. The leaves and stems will be separated and calculated in percentage before and after feeding. The water spinach will be separately from the casava at 7 am and 4 pm. Both cassava foliage and water spinach will be hung for feeding. Pure water will be available whole day.

The goats will be housed in wooden cages designed for separate collection of feed, faeces and urine.

Experimental layout

Period/goats

1

2

3

1

WS0

WS1

WS2

2

WS2

WS0

WS1

3

WS1

WS0

WS0
Measurements, sampling, data collection and chemical analysis.

Animals will be weighed at the beginning of each period. Feed offered and refused will be measured daily. Urine and faeces will be collected daily during last 5 days of each period. 10% of the faeces and urine willbe taken and stored in the refrigerator until the end of each collecton period when they will be analysed for N and crude fibre (AOAC 1990), DM by micro-wave radiation (Undersander et al 1993) and water soluble DM and N (Ly and Preston 1997). HCN will be measured in the cassava (Ly and Chhay Ty 2001). Samples of rumen fluid will be taken on the last day of each period using a stomach tube. Ph and ammonia will be measured.

Statistical analysis:

The data will be analysed using the GLM option of the Minitab software (Minitab release 13.3, 2000). Sources of variation will be treatments, animals, periods and error.

References:

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

Chhay Ty and Preston T R 2005  Effect of water spinach and fresh cassava leaves on growth performance of pigs fed a basal diet of broken rice; Livestock Research for Rural Development. Volume 17, Article # 76 Retrieved September 17, 2005, from http://www.mekarn.org/proctu/chha27.htm

Ho Quang Do, Vo Van Son, Bui Phan Thu Hang, Vuong Chan Tri and Preston T R 2002 Effect of supplementation of ammoniated rice straw with cassava leaves or grass on intake, digestibility and N retention by goats. Livestock Research for Rural Development (14) 3 http://www.cipav.org.co/lrrd/lrrd14/3/do143b.htm

Le Thi Men and Bui Hong Van 1993 Evaluation of diets based on simulated sugarcane juice and water spinach (Ipomoea aquatica) for breeding sows. In: Sustainable Livestock Production on Local Feed Resources. Ho Chi Minh City.

Le Thi Men, Ogle B, Vo Van Son 2000 Evaluation of water spinach as a protein source for BaXuyen and Large White sows. M.Sc. Thesis. Swedish University of Agricultural Sciences, Uppsala.

Ly J and Preston T R 1997 An approach to the estimation of washing losses in leaves of tropical trees. Livestock Research for Rural Development 9(3): http://www.cipav.org.co/lrrd/lrrd13/1/ly131.htm

Chhay Ty and Ly J 2001 Manual of laboratory. Centre for Livestock and Agriculture Development. UTA-Cambodia. 19 p.

Onwuka C F I 1992 Tannin and saponin contents of some tropical browse species fed to goats. Trop Agric. (Trinidad) 69, 176.

Seng Sokerya and Preston T R 2003 Effect of grass or cassava foliage on growth and nematode parasite infestation in goats fed low or high protein diets in confinement. Livestock Research for Rural Development 15 (8) 2003.