Performance of Galla goats fed different cultivars of Brachiaria in the coastal lowlands of Kenya

Background: Inadequate quality and quantity of feed is the major constraint to livestock production in the arid and semi-arid regions of Kenya. The productivity of livestock in Kenya is strongly linked to feed resource availability. This study was therefore done to determine the chemical composition and dry matter digestibility of three Brachiaria cultivars namely; Brachiaria brizantha cvs. Piata and MG4, Brachiaria hybrid cv. Mulato II and their effects of live weight changes of Galla goats in the coastal lowlands of Kenya. They were compared with the commonly grown grass, Rhodes grass Methods: Sixteen Galla goats ranging from 10-24 kg were randomly allocated to the four dietary treatments with four animals per treatment. Each goat was supplemented with 100 g/day of maize germ. Mineral licks and water were provided ad libitum. Results: The cv. Piata had the highest (P<0.05) crude protein (CP) (12.60% of dry matter) while cv. Mulato II had the lowest (3.01% of dry matter) for the Brachiaria forages. When compared to the control (Rhodes grass), the control grass had a significantly higher CP content (6.74% of dry matter) than Mulato II but lower compared to cvs. MG4 and Piata at (P<0.05). The cvs. Piata and MG4 were also more digestible that Mulato II and Rhodes grass. There was no significance difference (P>0.05) on intake of grass among the goats and ranged from 513-661 g/goat/day. Average daily weight gain were higher (P<0.05) in goats fed Piata (45.21 g/day) and MG4 (41.28 g/day) than those fed Mulato II (1.99 g/day) and Rhodes grass (9.64 g/day). Likewise goats fed on Piata (3.80 kg) and MG4 (3.47 kg) had the highest (P<0.05) total weight gain compared with goats fed on Mulato II (0.17 kg) and Rhodes grass (0.81 kg). Conclusion: Based on body weight changes and nutritive values, Piata and MG4 showed the greatest potential to address feed quality constraints to livestock production especially in the arid and semi-arid regions of Kenya. *Corresponding author: Ngila P, Kenya Agricultural and Research Organization (KALRO) Katumani, P.O Box 340, Machakos, Kenya, Tel: +254 721 730 227; E-mail: pngila@seku.ac.ke Received October 06, 2016; Accepted December 28, 2016; Published December 30, 2016 Citation: Ngila P, Njarui DM, Musimba NK, Njunie M (2016) Performance of Galla Goats Fed Different Cultivars of Brachiaria in the Coastal Lowlands of Kenya. J Fisheries Livest Prod 5: 210 doi: 10.4172/2332-2608.1000210 Copyright: © 2016 Ngila P, et al.. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Introduction
Arid and semi-arid lands (ASALs) cover 80% of Kenya's landmass [1]. These areas are characterized by low rainfall, high temperatures, poor quality feed resources, and high incidences of livestock diseases [2]. The ASALs also support 60% of the livestock population and the largest proportion of wildlife [3]. According to Mbogoh SG and Shaabani [4], agro-pastoralism and pastoralism are the main economic activities in the ASALs and majority of the peoples attain their livelihoods from them. This is mostly based on cattle (the small East African Zebu -SEAZ and Boran), goats, sheep and camels, and thus constitutes a major source of Kenya's meat [5].
According to Njarui et al. [6], the productivity of livestock in Kenya is strongly linked to feed resources availability. The reason for this is that; feed is the major input factor in all livestock production systems and account for between 60-70% of the production cost. The same author goes on to say that, the productivity of ruminant livestock is considered low due to inadequate and poor quality feeds. There is a feed resource deficit for about 4-6 months in a year across many regions particularly during the dry season when there is limited pasture growth. Livestock is considered as one of the key asset for rural households in most parts of the world and it is a primary livelihood resource for rural communities. According to FAO [7] about 752 million of the world's poor keep livestock mainly to; generate cash income, produce food for subsistence use, manage risks and build up assets for security purposes. Another limitation of livestock production is that there is lack of suitable fodder crops that can produce green forage year [8].
This situation becomes severe in the areas that are constrained by low rainfall.
Most small ruminants in the ASALs suffer from nutritional stress [9]. Most of the grasses have low crude protein (CP) falling below 7% minimum level that is required for optimum microbial growth [10]. When this occurs, it prompts supplementation, which is not always possible for resource poor farmers [11]. There is a need, therefore, for pasture species that can improve the quality of the natural pastures and significantly increase the dry matter production that will enhance livestock productivity. One of these pastures has been found to be Brachiaria forages [12][13][14] report that apart from the good adaptability, tolerance and resistance of Brachiaria forages, the grasses have high forage quality and show high dry matter production making them capable of meeting the nutritional requirements of animals especially during the dry seasons.
Goats are found in many parts of Kenya and are an important Performance of Galla Goats Fed Different Cultivars of Brachiaria in the Coastal Lowlands of Kenya source of income to many small-holder farmers. They are preferred to cattle as they can be converted to cash quicker. They also provide a higher offtake compared to cattle because of their shorter generation interval and higher prolificacy [15].
The full potential of the ASALs for livestock production can be exploited by expanding the forage resource base by introducing climate smart forage species which will be able to boost nutrient quality and quantity hence supplying the nutritive requirements of livestock. There have been several studies on climate smart Brachiaria grass species that have been developed elsewhere and could be the key to improvement of livestock production and could also serve as boost to composition and nutritive values of Brachiaria cultivars.
However, studies on feeding trial of goats by Brachiaria grasses are lacking and this study was done to determine its suitability on animal performance. The objective of this study was to evaluate the growth of Galla goats fed selected Brachiaria grasses cultivars.

Site
The feeding trial was conducted at the sheep and goat multiplication centre, Matuga (4° 9'6'S, 39° 32'40'E), in Kwale County, Kenya. The centre is located in a low altitude zone (60 m.a.s.l) coastal lowland 3 (CL3) agro-ecological zones, also referred to as the Coconut-cassava zone [16]. The average annual rainfall is 1100 mm while the relative humidity ranges from 70-80% and an average temperature from 22-30°C.

Management of animals
Galla goats, also known as Somali or Boran goats are indigenous to the arid and semi-arid regions of northern Kenya and are kept mainly for meat, although they also produce milk [15]. Sixteen Galla goat bucklings [16] were selected and divided into four groups of four animals each. The animals from each group were randomly assigned to four dietary treatments (Brachiaria brizantha cvs Piata and MG4, Brachiaria hybrid Mulato II and Rhodes grass) based on their age (6-12 months) and live weight (10-24 kg). They were then grouped into four replicates. The heaviest animals which were the oldest were in rep 1 ad the youngest goats with the least weight in rep 4. The goats were kept in well ventilated pens with each goat put in individual pen. Dry grass was used for beddings at night. Both the feeding and sleeping areas were disinfected before the goats were brought in. During this adjustment period, animals were dewormed against endoparasites and sprayed weekly against ectoparasites. Individual pens were cleaned every morning.

Feeds and feeding
The Brachiaria cultivars used for feeding were (Brachiaria brizantha cvs. Piata and MG4 and B. hybrid Mulato II). Chloris gayana (Rhodes grass) was used as the control grass. All animals received commercial concentrate supplements (100 g/day) made of maize germ that was purchased to last the whole experiment. This was given before the basal diets were offered at 7.00 a.m. in the morning. Water and mineral blocks were provided ad libitum. The grasses were harvested 5 cm above ground. The harvested grasses was allowed to dry for 3 days, baled into hay and transported to Matuga. The harvested forages were chopped (5 cm length) using a motorized chaff cutter before feeding. Chopping the forages into 5 cm lengths was useful as it prevented diet selection by the goats.

Data collection
After an adaptation period of 14 days, daily feed offers and refusals, respectively, were weighed and recorded for a period of 12 weeks (from 20 th April to 13 th July 2016). Animals were weighed on a weekly basis at around 9 a.m. (fasting weight) using a portable electronic weighing scale.
Daily feed dry matter (DM), organic matter (OM) and crude protein (CP), were calculated as the difference between feed offer and refusal corrected for the respective contents in the original sample [17]. Feed conversion ratio was obtained by dividing the feed intake and average daily gain.

Chemical composition of feeds used
Small amounts of herbage were taken from each bale used for feeding and composite sample of about 2 kg constituted for analysis. The samples were grinded to pass through 1-mm screen. The samples were then analysed in duplicates for chemical composition at the Animal and Nutrition Laboratory at KALRO-Muguga.

Ash
Ground dried samples were weighed and then ignited in a furnace at 600°C for 2 hours, to oxidize all organic matter. Ash was the determined by weighing the resulting inorganic residue [18].

Calcium
The samples were ignited at 550°C to burn all organic material. The remaining minerals are digested in 6 M HCl to release calcium, which is then determined using a spectrophotometric assay based on reaction of calcium with o-cresolpthaleincomplexone (CPC) in alkaline solution. The Calcium was then calculated as follows; Where, C: Concentration calcium in measure solution (mg/litre), V: Volume of solution (in litres, i.e., 0.025 (L)), DF: Dilution factor (normally, i.e., 1), W: Weight of the sample (g), and 10: Factor to convert g/kg to % [19,20].

Phosphorous
Feed material was ashed following digestion in hydrochloric acid. Molybdovanadate reagent is added which results in a characteristic yellow colour after reacting with phosphorus, which was measured spectrophotometrically. Percentage of phosphorous is calculated; Where, C: Concentration phosphorus in measured solution (mg/ litre), V: Volume of solution (in litres, i.e., 0.025 L), DF: Dilution factor (normally, i.e., 1), W: Weight of the sample (g), and 10: Factor to convert g/kg to % [21].

In vitro dry matter digestibility
The samples were incubated under anaerobic conditions with rumen microorganisms for 48 hours at 39°C, under anaerobic conditions. This was then followed up by a 24 hour acid-pepsin digestion phase at 39°C, also under anaerobic conditions. Following this 72 hour incubation, residual plant materials was later collected, filtrated and oven dried (105°C for 12 hours).

Crude protein
The Nitrogen content of the feed is the basis for calculating the crude protein (CP). The method established by Kjeldahl converts the nitrogen present in the sample to Ammonia which is determined by titration [24]. Assuming that the average nitrogen content of proteins is 16% multiplying the nitrogen content in% obtained via Kjeldahl analysis with 6.25 gives an approximate protein content of the sample.
CP=6.25 x %N where CP is crude protein and N is nitrogen.

Crude fibre
Fibre analysis was done using the Ankom fibre method which is a modification of the  of forage analysis. The carbohydrates in a feed sample are retrieved in two fractions; Crude fibre, Nitrogen free extractives (CF, NFE) of the proximate analysis. The fraction, which is not soluble in a defined concentration of alkalis and acids, is defined as crude fiber (CF). This fraction contains cellulose, hemicellulose and lignin. Sugars, starch, pectins and hemicellulose etc. are defined as nitrogen-fee extractives (NFE). This fraction again is not determined chemically it is rather calculated by subtracting CP, EE and CF from organic matter.

Data Analysis
Chemical composition (DM, CP, OM, Ash, NDF, ADF, ADL, Ca, P) of feeds over 12 weeks were analysed using the general linear model (GLM) procedures of the Statistical Analysis System [26]. Means were compared using least significance difference (LSD) option of SAS [20]. Data from experiments on feed intake and live weight gain were subjected to analysis of variance (ANOVA) in a completely randomised design using GLM procedures of the Statistical Analysis System [27] based on the following model:

Feed composition
Chemical composition of feeds used in this experiment is presented in Table 1. There were significance differences (P<0.05) in the CP content, In vitro dry matter digestibility (IVDMD), Acid detergent fibre (ADF) content, acid detergent lignin (ADL) content, Ash, Ca and P content for all the forages. The cv. Piata had the highest CP content (12.6% of DM) while cv. Mulato II had the lowest (3.0% of DM). Rhodes grass had a significantly higher CP content (6.74% of DM) compared to Mulato II but significantly lower when compared to cvs. Piata and MG4. In vitro dry matter digestibility (IVDMD) was highest in cvs. MG4 (55.47%) and Piata (54.96%) and lowest in Mulato II (41.36%). Rhodes grass had IVDMD (44.62%) which was lower than that of cvs. Piata and MG4 but not significantly different to that of cv. Mulato II (Figure 1).
The cv. Mulato II had the lowest ash content (5.04%) for the forages while cv. Piata (10.77%) had the highest. Rhodes grass had a significantly higher ash content (7.72%) when compared to Mulato II but lower when compared to cvs. Piata and MG4. Mulato II had the highest NDF, ADF and ADL content while cv. Piata had the lowest in all the three components. Rhodes grass had the highest Ca content (0.39%) than the Brachiaria cultivars. Rhodes grass had the lowest P content (0.08%) for all the forages while MG4 had the highest (0.22%).

Intake
Total feed intake for the period are shown in Figure 2. There was no significance difference (P>0.05) in the feed intake in all the weeks among the goats. The average intake ranged from 513-661 g/goat/day.

Body weight gain and conversion ratio
Results from live weight gain (LWG) and feed conversion ratio (FCR) are shown in Table 2. Average daily weight gain (ADWG) differed significantly in the four treatments (P<0.05). Bucklings fed Piata (45.21 g/day) and MG4 (41.28 g/day) had the highest ADWG while those fed Mulato II had the lowest (1.99 g/day). Bucklings fed Rhodes grass had a similar ADWG (9.64 g/day) with those fed Mulato II but lower when compared to those fed Piata and MG4. The total live weight gain also was higher in goats fed Piata (3.80 kg) and MG4 (3.47 kg) compared to those under Mulato II (0.17 kg) (P<0.05). Feed conversion ratio (FCR) for DM, OM and CP was significantly different (P<0.05) in the four diets. Piata and MG4 had the lowest FCR meaning the animals were efficient utilizers of feed and this is observed by the high body weight gain. Figure 1 shows the average weekly live weight of the goats during the experimental period. Goats fed Piata and MG4 maintained the highest weights during the entire period.

Feed quality/composition
Reported that Crude protein (CP) and digestible dry matter (DDM) are the most important component of a feed. In this study, two cultivars of Brachiaria brizantha (Piata and MG4) were found to be better sources of protein compared to cultivar Mulato II and Rhodes grass [28]. Piata and MG4 met the required minimum of 7.5% suggested as necessary for optimum rumen function by Van PJ [29]. Crude protein requirement for small ruminants for maintenance is 9.6%, 11.2% for pregnant ewes and does, 11.7% for kid finishing     as prescribed [30]. These requirements were only met by cvs. MG4 and Piata. The 7.0% requirement for the satisfactory development of ruminal cellulolytic bacteria as quoted by Van PJ [29]  The CP content of Mulato II was low compared with that obtained in semi-arid region of Eastern Kenya 12% and in Central highlands of Kenya of 15% [33]. This attribute to poor management of the grass at harvesting and baling. Generally Mulato II has higher CP than Piata and MG4 when cut at the same stage of growth. In other sites where it was well managed its CP content was high. Another factor that could have led to the low CP of Mulato II was that it was established in the coastal area. Due to the high temperatures in the coastal area, the grass grew very fast and accumulated fibrous content very fast. This has a negative impact on its digestibility as well as the quality. Establishment of grasses in the coastal area done by Ondiko et al. [34] confirm this theory as the grasses had very low CP (3-6%) when cut at 12 weeks.
Cultivar Mulato II and Rhodes grass digestibility ranged between (41 and 44%). This is lower than that reported by [35] that the digestibility of cultivated tropical grasses lie between 50 and 65%, while that of temperate grasses is slightly higher and ranges between 65 and 80%. Lord et al. [36] reports that the age of cutting forage crops has an influence on the in vitro digestibility, and is a function of the chemical constituents of forages. These results agree with Njarui DMG, et al. [37] who reported that the proportion of potentially digestible components decline as the fibrous content increases (Table 1).
According to Morais et al. [38], when the quality of supplement and supplementation frequency remain the same, the difference in weight gains of an animal will be based on the quality of the roughage. As the four groups of Galla goats had received the same amount of the commercial concentrate, the major factor which influenced differences in their weights might have been the quality of roughages; where Piata and MG4 had higher CP content than Rhodes and Mulato II.

Live weight gains
Bucklings fed cvs. Piata and MG4 had the highest average weight gain. This was also the case with Average daily weight change (ADWG). The ADWG for Piata and MG4 were higher than those reported by Njarui et al. [37] for Kenya dual purpose goats fed different forage legumes. Another study done by Sani I [39] on German Alpine crosses of goats when supplemented with Tithonia, Calliandra and Sesbania had high ADWG of up to 82.7 g/day for Tithonia and Calliandra of 57.3 g/day. Goats under Sesbania for this experiment had a lower ADWG of 39.3 g/day. Piata and MG4 had higher ADWG when compared to Sesbania in this experiment.
Average weight gain was highest (P<0.05) in animals under Piata (3.80 kg), this could have been due to the high content in the feed. The average live weight gain obtained in this study was higher than that obtained by Sani I [39] of 2.55 kg when cotton seed cake was fed in combination with Brachiaria ruziziensis fed to Yankassa sheep. It was also higher than that obtained by Nyako HD, et al. [40] when cotton seed cake was fed with Digitaria decumbens (Pangola grass).
Bucklings under Mulato II had the lowest gain and this could be attributed to the low CP content in the diet. This was also the case with ADWG. Feed conversion ratio (FCR) values were different for the four dietary groups of goats. The FCR for DM showed that for the goats to gain 1 g of live weight per day it should eat 15.98 g of MG4, 13.36 g of Piata, 259.48 g of Mulato II and 56.19 g of Rhodes grass. A smaller FCR indicates how efficient a feed is and FCR also showed that diets that had low CP had poor FCR [39].

Conclusion
An average daily weight gain of 45.21 g/day was obtained on Galla goats fed B. brizantha cv. Piata compared to 9.64 g/day for those in the control group (fed Rhodes grass). This showed an increase in daily weight gain by 78.68% for animals on Piata over those fed Rhodes grass. This could bring about greater economic gains in terms of profit to livestock farmers due to increased daily and total live weight gain when animals are fed cv. Piata relative to the lower daily gain and total live weight gain as well as economic gain when fed Rhodes grass. From the results and findings in this study, it is recommended that cvs. Piata and MG4 should be integrated in both grazing as well as cat and carry feeding systems for better growth and live weight gain of goats.