Effect of method of offering foliages of Gliricida sepium and Stylosanthes guianensis CIAT 184 (Stylo) to goats on intake and digestibility

Toum Keopaseuht, Chhay Ty*, Bounthong Bouahom and T R Preston**

Livestock Research Center, Namxuang, Lao PDR
bbouahom@laotel.com
^*UTA, Cambodia
chhayty@utafoundation.org
^**University of Tropical Agriculture, Columbia
regpreston@utafoundation.org

Abstract

A study was made of different ways of offering two plant species (Stylosanthes guianensis CIAT 184 [ST] and Gliricidia sepium [GS]) to growing goats. The feeding methods were stripping the leaves from the plants and putting them in the feed trough (L), putting the foliage (leaves attached to stems) in the feed trough (T) or hanging it from a bar above the feed trough (H). The design was a 3*3 factorial arrangement for each foliage with 3 feeding methods and 3 periods of 14 days.

In both plant species, leaves were higher in DM and lower in crude fibre and NDF than  stems. Intake of leaves and of total foliage DM, and DM digestibility, were lower when only leaves were offered compared with offering the whole foliage.

It is concluded that factors associated with eating behaviour and / or with components present in stems (or in leaves) could have been responsible for the lower values of DM intake and digestibility associated with feeding only the leaves as compared with feeding intact foliage in which the leaves are attached to the stems.

Key words: digestibility, foliage, gliricidia, intake, leaves,  stylosanthes

Introduction

Farmers raising goats in Cambodia and Lao traditionally hang the foliages (with leaves attached to the stems) from the sides of the pen (Photo 1), or on some raised structure (Kouch et al 2003a).

Photo 1: Farmer feeding her goats in Cambodia

It has recently been shown that this method resulted in higher intake and digestibility by goats of three tree foliages (Jackfruit - Artocarpus heterophyllus; Cassava - Manihot esculenta and Mulberry - Morus alba) compared with giving only the leaves in the feed trough (Kouch et al 2003b).

This paper reports a comparison of these feeding methods applied to goats offered as the only feed two plant species commonly available in Lao (Gliricida sepium and Stylosanthes guianensis CIAT 184).
 

Methods and materials

Location and duration

The experiment was conducted at the Livestock Research Center, Nam Xuang about 44 km from Vientiane City, Lao PDR. The experiment started on 3 November 2003 and finished on 21 December 2003.

Experimental animals

Six growing goats (local breed) of 14 to 17 kg live weight were confined in cages made from wood and bamboo fitted with plastic mesh and plastic sheet to collect separately the faeces and urine (Photos 2 and 3).

Photo 2: Metabolism cage for goats made from bamboo and wood	Photo 3: Hanging the foliage in the feed trough

Experimental design

The design was an arrangement of two 3*3 Latin Squares (one for Gliricidia sepium [GS] and the other for Stylo CIAT 184 [ST]), .with 6 goats (3 in each square) and 3 periods to compare 3 feeding methods: hanging the foliage above the feed trough (H); putting the foliage in the feed trough (T) or putting only the leaves (L) in the feed trough. 

Feeds and feeding system

The foliages were collected from within the Livestock Research Center. In the case of the Gliricidia, the foliage comprised green stems, petioles and leaves. For stylo the components were stems and leaves.

For GSH and STH, the branches of Gliricidia and stylo were hung from a bamboo stick placed above the feed trough  For GST and STT, these feeds were placed in the feed trough. For GSL and STL the leaves were separated and put in the feed trough. In all cases feeding was ad libitum with an offer level of about 20% above actual intake.  Feeds were offered twice daily: about 7.00am and 14.00pm.Days 1 to 8 of each period were for adaptation to the new treatment; on days 9 to 13 faeces and urine were collected.

Measurements

Faeces were collected twice daily and stored at -20ºC until analysed. Urine was collected in a bucket with 50 ml of 25% sulphuric acid to maintain the pH below 4 so as to prevent escape of ammonia. Feeds offered and refused were weighed and samples separated into leaves, petiole and stems, which were then analysed for DM to determine the amounts that were consumed.  The goats were weighed at the beginning of each adaptation period in the morning before offering feed. Dry matter was determined by microwave radiation (Undersander et al 1993), crude fibre according to procedures of  AOAC (1990) and NDF by the method of  Van Soest et al (1991).

Statistical analysis

The data were analyzed separately for each forage, using the GLM option of the ANOVA software of Minitab (Version 13.31) 2000.  Sources of variation were periods, animals, feeding method and error. Comparisons between forages were analysed by combining the data for both Latin squares. In this case the sources of variation were forage sepecies, periods and error. When the "F" test was significant (P<0.05), the means were compared using the Tukey test in the Minitab software.
 

Results and discussion

Feed characteristics

The leaves accounted for slightly over 50% of the dry biomass in both plant species (Table 1), the stems making up the rest in stylo whereas in gliricidia the non-leaf biomass was divided between petioles and stem. The DM content of both leaves and stems was higher in gliricidia than in stylo.

Feed intake

In both plant species, the intake of DM as leaves and as total biomass was lower when the leaves were stripped from the stems and given as the only feed (Tables 2 and 3 and Figure 1). This result is similar to the findings of Theng Kouch et al (2003) with Jackfruit, Mulberry and Cassava foliages and Samkol (2003) who fed foliage of Muntingia calabura. .DM intake was higher for Gliricidia than for Stylo 184 (Table 5).