Effects of incorporation of selected browse species on performance of growing small East African goats

F Kemboi, J O Ondiek, A M King’ori and P A Onjoro

Egerton University, Department of Animal Science, P O Box 536-20116 Egerton, Kenya
kemboifred15@gmail.com

Abstract

A seventy (70) day feeding trial was conducted to determine the nutritive value, dry matter intake, weight gain, feed conversion ratio (FCR), and apparent digestibility coefficients in 30 growing Small East African goats with a bodyweight of 10.5 ± 1.3Kg (mean ± SD). They were randomly assigned to the experimental diets at 0, 15, 30, and 45% of Acacia brevispica, Balanites aegyptiaca, and Berchemia discolor with Rhodes grass (Chloris gayana) hay and 100g maize germ as the control. Experimental diets were offered in a completely randomized design in a factorial arrangement with three replications. The proximate composition of the experimental diets varied between the experimental diets. The crude protein contents of AB30 (Control plus 30% A. brevispica) were considerably higher than TC (Control). The organic matter (OM) content was 869.7 gkg^-1DM in BA15 and 965.5 gkg^-1DM in BC15. The total extractable phenolics (TEPH) and condensed tannins (CT) contents ranged from 2.4 to 25.1gkg^-1DM and 1.3 to 16.1gkg^-1DM, respectively. The Neutral detergent fiber (NDF), acid detergent fibre (ADF) contents of TC was higher than the other dietary treatment. All the experimental diets had positive weight gains; however, the higher average daily gain was observed in AB30 (30% A. brevispica) and lowest in TC(basal). There was no significant difference in daily weight gain (P < 0.05) between AB30 and AB45. Dry matter intake was higher in AB30 and lowest in TC. It was concluded that supplementation of the basal diet with indigenous browse species resulted in higher feed intake, better growth rate, and feed conversion ratio. Therefore, these indigenous browses can be utilized in the dry season as a supplement to improve animal performance in arid and semi-arid areas.

Key words: nutritive value, supplementation, weight gain, indigenous browses

Introduction

Small ruminants especially goats and sheep form the majority of the ruminant livestock population in developing countries and add greatly to the pastoralists family economy (Redae et al 2020). Rearing of livestock in the rural areas plays a significant part in allowing smallholders farmers to have resilient livelihood and to avoid both poverty and food insecurity (Deng et al 2017). Indigenous browses in the arid and semi-arid regions play a substantial role in providing fodder for ruminants in many parts of the world (Kemboi et al 2017).

In spite of the existence of indigenous browse species in the arid and semi-arid regions of East Africa, there is limited data available on their nutritive worth (Osuga et al 2012). The nutritive value and quantity of available fodder for small ruminants drops during the dry periods. Thus, small ruminants especially the goats consume feeds from poor natural pastures which are low in protein content leading to low productivity and performance (Brown et al 2016). Indigenous browses have high crude protein, mineral and organic matter content, and can be utilized as supplements to alleviate the effects of the low quality feeds (Ondiek et al 2013).

During the dry season, the natural grasses are high in fibre and low in nitrogen, crucial for performance of small ruminants especially in arid and semi-arid regions. Earlier studies have revealed that their nutritive value makes them a possible supplement to low quality diets consumed by ruminants especially the goats (Mangara et al 2017 and Osuga et al 2006). Indigenous browse species can form alternative feed resources to maintain satisfactory performance in goat without the utilization of expensive concentrate diets (Okoruwa et al 2020). The objective of this study was to determine the nutritive value, dry matter intake, weight gain, feed conversion ratio (FCR) and apparent digestibility coefficients in growing Small East African goats fed on increasing levels (0, 15, 30 and 45%) of Acacia brevispica, Balanites aegyptiaca and Berchemia discolor with Rhodes grass hay and maize germ as basal diet.

Materials and methods

Experimental and Forage Collection Site

The experiment was conducted in Marigat Sub-County, Baringo County, Kenya, which is 1080m above sea level. It receives 700 – 950mm rainfall per year with peaks in April/May and July/August, but it is generally very erratic. The annual mean temperature is 23ºC (FAO, 1992). The forage was collected from indigenous browse trees and shrubs in the study area.

Preparation of experimental diets

Leaf samples of the Acacia brevispica, Balanites aegyptiaca and Berchemia discolor were harvested by hand stripping from the trees on communal grazing ranges in Marigat Sub-County during the dry season. After harvesting, the forages were spread on a polythene sheet and air dried under shade for 7 days. The dried forages were stored in jute sacks in a well-ventilated room. The basal diet (control) was Rhodes grass (Chloris gayana) hay plus maize germ that was formulated according to the animal requirements (NRC, 2007). Rhodes grass was purchased and chopped through a 4 mm screen hammer mill. Forages for the experimental diets were ground to pass through a 4mm sieve.

Photo 1. Balanites aegyptiaca	Photo 2. Acacia brevispica
Photo 3. Berchemia discolor	Photo 4. Small east African goat eating experimental diet

Experimental Animals, Design, Feeding and Management

For the growth performance trial, 30 growing goats weighing 10.5kg ± 1.3 (mean ± SD) were randomly assigned to the experimental diets with different increasing inclusion levels of the browse leaves in a completely randomized design in a factorial arrangement with three replications. The browse leaves were supplemented at 0, 15, 30, and 45% of the Acacia brevispica, Balanites aegyptiaca, and Berchemia discolor, respectively. The goats were allocated to individual pens. Feed and water were offered ad-libitum. Before starting the feeding trial, goats were weighed, grouped according to their weight, drenched against internal parasites using Nilzan⁺ (Coopers Ltd), and sprayed against external parasites using Delete® (Highchem Ltd). All animals were in good health up to the completion of the feeding trial.

The basal diet and supplements in the study were offered individually. The supplements were offered at different levels per head on a daily DM basis from 08:00-9:00hr to let the goats eat the supplements before offering the basal diet. The feed refusals from supplements were collected before offering the basal diet, weighed, and recorded. The mixture of Rhode grass hay and maize germ was introduced at 09:00hr after goats had consumed the supplement. The mixture of hay and maize germ was offered ad-libitum (450g/head on a DM basis). Feed refusals from hay and maize germ were collected, weighed, and recorded every day in the morning before offering fresh hay. The initial body weight of the goats was taken as the mean of two consecutive weighing after overnight fasting. Subsequent body weight measurements were taken every seven days after overnight fasting after the start of the experiment until the end of the experiment. The data was collected for eight weeks. The experimental diets were:

TC. Rhodes grass hay ad libitum plus 100g maize germ (control).

AB15. Control plus 15% A. brevispica

AB30. Control plus 30% A .brevispica

AB45. Control plus 45% A. brevispica

BA15. Control plus 15% B. aegyptiaca

BA30. Control plus 30% B. aegyptiaca

BA45. Control plus 45% B. aegyptiaca

BC15. Control plus 15% B. discolor

BC30. Control plus 30% B. discolor

BC45. Control plus 45% B. discolor

Data Collection

Performance was measured as weight gain and feed intake recorded weekly. Goats were weighed every week. Average daily gain (ADG) which is the rate of weight gain per day over a specified period of time was determined. The FCR was calculated as the mass of feed eaten divided by the output (live weight gain) over a given period of time. Feed offered and refusals were recorded every day. Feed dry matter intake (FDMI) was calculated by difference between feed offered and refusal.

Chemical analysis

Samples of experimental diets offered, refusal, and faeces were dried in an oven at 105^oC and ground through 1mm for proximate determination of dry matter (DM, crude protein (CP), and ether extract (EE)according to the standard methods of AOAC (2006).

The CP was calculated as (N x 6.25). Neutral detergent fiber (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) were analyzed according to the procedure described by Van Soest et al (1994). Phenolics were extracted using 70% aqueous acetone following the procedures of Makkar (2003). The total extractable phenolics (TEPH) were determined using Folin Ciocalteu procedures described by Julkunen- Titto (1985). The condensed tannins (CT) were measured and computed as leucocyanidin equivalent, using the method described by Porter et al, (1986).

Digestibility Trial

The digestibility trial was conducted in digestibility cages after 10 days of adaptation to the experimental diet. Total collection of feces for the 30 growing goats was done for seven consecutive days. The daily fecal material collected for each animal was mixed thoroughly and kept in airtight plastic containers. This was followed by drying at 60 ^oC for 72 hours and then ground and stored in airtight containers pending chemical analysis.

Statistical Analysis

Data collected on feed intake, digestibility, FCR and average daily gain(ADG) were subjected to the analysis of variance using the General linear model procedure of statistical analysis system (SAS 2002) version 9.0. Initial live weight was fitted as a covariate in the analysis of feed intake and live weight changes. Significant means were separated using Tukey’s HSD (Tukey’s Honestly Significant Difference Test) at 5% significance. The model used for statistical analysis was:

Y_ijk = µ + _Ai + B_j + (AB) _ij + Ɛ_ijk

where:

Y_ijk= is the response variable

µ = the overall mean

_Ai = is the effect of browse inclusion level

B_j= is the effect of treatment diet during feeding (T1, ...T3)

(AB) _ij= the effect of the interaction between the browse inclusion level and treatment diet

Ɛ_ijk= random error term

Results and discussion

Chemical composition

The chemical composition of Experimental diets is presented in Table 1.

The proximate composition of the experimental diets (TC, AB15, AB30, AB45, BA15, BA30, BA45, BC15, BC30, and BC45) varied between the experimental diets (Table 1). The composition of the basal diet (TC) in this study in terms of CP and OM was similar to those reported by (Ondiek et al 2013; Osuga et al 2012 and Kemboi et al 2017). The crude protein contents of AB30 (Control plus 30% A. brevispica) were considerably higher than TC (Control). The OM content ranged from 869.7 gkg ^-1DM (BA15) to 965.5 gkg^-1DM (BC15). The TEPH and CT contents ranged from 2.4 to 25.1gkg^-1DM and 1.3to 16.1gkg ^-1DM, respectively. The NDF and ADF contents of TC were highest for dietary treatments. The nutritive values of supplements were within the animal requirements, CP of more than 70gkg-¹DM, which is the minimum required for rumen function (NRC, 2007).

The TC had higher NDF fibre content (581.9 gkg^-1DM) compared to the other experimental diets. This was similar to results reported by Ondiek et al (2010) and Deng et al (2017). The crude protein content of the browses (150-249g/kg^-1 DM) provided enough nutrients to utilize indigenous browse leaves to supplement low-quality natural grasses (Osuga et al 2006).

The growth performance of the Small East African goats is shown in Table 2.

The results on the performance of goats indicated significant (P< 0.05) dietary treatments’ effects on growth performance among the growing goats. All the experimental diets positively affected weight gain; however, the highest average gains were observed in AB15, AB30, AB45 and lowest in TC (Table 2 and figure 1). There was no significant difference between AB15, AB30, and AB45 in terms of daily weight gain. Dry matter intake was higher in AB30, AB45 and lower in TC(basal). Dry matter intake increased with supplementation with indigenous browse diets (BA15, BA30, and BA45), which is in agreement with the previous studies involving similar forages (Osuga et al 2012; Deng et al 2017 and Mangara et al 2018).

Figure 1. Effects of indigenous browse diet at different inclusion levels on average daily gains of growing goats

Feed conversion ratio (FCR) was highest in TC compared to the other dietary treatments (Table 2). The animals readily ate all supplements in the study. A high intake of AB30 and AB45 could be due to low levels of anti-nutritive factors, especially tannins.

Protein supplementation with indigenous browses species has been established to increase total DMI in poor quality roughages (Sanchez and Ledin 2006). The apparent digestibility coefficient of the nutrients (g/kg^-1DM increased significantly (P < 0.05) in BA30 than in TC. The apparent digestibility coefficient of crude protein and dry matter increased when the basal diet (TC) was supplemented with the indigenous browse species. An increase in digestibility could have resulted from decreased levels of acid detergent fibre and lignin in the experimental diets (Ondiek et al 2013). Findings reported on feed supplementation trials with indigenous browse species revealed high live weight gain against basal or control diet (Ndemanisho et al 2007; Osuga et al 2012; Ondiek et al 2013 and Mangara et al 2018).

Conclusions

• Supplementation of basal diet with indigenous browse species resulted in higher feed intake, increased growth rate and lower feed conversion ratio.
  
  
• The performance of the animals was greater at level 30% A. brevispica of supplementinclusion.
  
  
• Apparent digestibility of crude protein and dry matter were increased when the basal diet (TC) was supplemented with leaves from Acacia brevispica, Balanites aeyptiaca and Berchemia discolor.
  
  
•  A. brevispica, resulted in the best performance followed by B. discolor and B. aeyptiaca, respectively, in various level of supplementation.

Acknowledgement

The authors are grateful to CESAAM program for funding the research, Egerton University Animal Sciences Department for laboratory analyses services, M Mutumba, K Mwavishi, N K Kibitok for technical assistance and to the Dryland Research Training and Ecotourism Centre Chemeron, Baringo County, Kenya for providing the goats and research facilities.

References

AOAC 2006 Official Methods of Analysis. 18th Edition, Association of Official Analytical Chemists, Arlington, Texas., USA.

Deng M T, Ondiek J O and Onjoro P A 2017 Chemical composition and in vitro gas production of lesser known South Sudan browse species. Livestock Research for Rural Development. ISSN 0121-3784.

FAO (Food and Agriculture Organization) 1992 Fuelwood/ Afforestation and Extension in Baringo–Phase II, Kenya. Project findings and recommendations. FAO/Government cooperative program. FO: GCP/KEN/051/AUL.

Julkunen-Tiitto, R 1985. Phenolic constituents in the leaves of northern willows: methods for the analysis of certain phenolics. Journal of agricultural and food chemistry, 33(2), 213-217.

Kemboi F, Ondiek J O and Onjoro P A 2017 Evaluation of nutritive value and in-vitro degradation of selected indigenous browses from Semi-Arid areas of Kenya.Livestock Research for Rural Development. Volume 29, Article, 92.

Makkar H P S 2003 Effects and fate of tannins in ruminant animals , adaptation to tannins , and strategies to overcome detrimental effects of feeding tannin-rich feeds. Small Ruminant Research, 49: 241-256.

Mangara J L I, Guliye A Y, Migwi P K and Ondiek J O 2017 Nutrient composition of selected indigenous tree browses in Central Equatoria State of the Republic of South Sudan. Livestock Research for Rural Development. Volume 29, Article #80. Retrieved December 8, 2019, from http://www.lrrd.org/lrrd29/4/loro29080.html.

Mangara J L I 2018 Evaluation of the nutritive value of selected indigenous tree browses as feed for ruminant livestock in South Sudan (Doctoral dissertation, Egerton University).

Ndemanisho E E, Kimoro B N, Mtengeti E J and Muhikambele V R M 2007 In-vivo digestibility and performance of growing goats fed maize stover supplemented with browse leaf meals and cotton seed cake based concentrates. Livestock Research for Rural Development, 19(8), 23-37.

NRC 2007 Nutrient requirements of small ruminants: sheep, goats, cervids, and new world camelids.

Okoruwa M I and Ikhimioya I 2020 Influence of browse-tree leaves supplementation on digestibility, rumen fermentation and performance of goats fed mixed grass hay. Livestock Research and Rural Development, 32(6).

Ondiek J O, Ogore P B, Shakala E K and Kaburu G M 2013 Feed intake, digestibility and performance of Small East African goats offered maize (Zea mays) stover supplemented with Balanitesaegyptiacaand Acacia tortilis leaf forages. Journal of Agricultural Science and Review, 2:21-26.

Osuga I M, Abdulrazak S A, Ichinohe T, Ondiek J O and Fujihara T 2006 Degradation characteristics and tannin bioassay of some browse forage from Kenya harvested during the dry season. Animal Science Journal, 77(4), 414-421.

Osuga I M, Abdulrazak S A, Muleke C I and Fujihara T 2012 Effect of supplementing Rhodes grass hay (Chloris gayana) with Berchemia discolor or Zizyphusmucronata on the performance of growing goats in Kenya. Journal of animal physiology and animal nutrition, 96(4), 634-639.

Porter L J, Hrstich LN and Chan B G 1985 The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin. Phytochemistry, 25(1), 223-230.

Redae M, Gebremariam T and Aregawi, T 2020 Effect of Supplementation on Feed Intake and Body Weight Gain of Abergelle Goats in Tigray, Ethiopia. Asian Research Journal of Current Science, 80-94.

Sánchez N R and Ledin I 2006 Effect of feeding different levels of foliage from Cratyliaargentea to creole dairy cows on intake, digestibility, milk production and milk composition. Tropical Animal Health and Production, 38 (4), 343-351.

SAS 2002 Statistical Analysis System Institute. SAS User’s Guide. Statistics, Software Version 9.00, SAS Institute, Cary, North Carolina, USA.

Van Soest PJ 1994 Nutritional ecology of the ruminants. 2^nd edition. New York: Cornell University Press. ISBN: 9780801427725, pp 476.