EFFECTS OF FERTILIZER LEVELS AND HARVEST TIME ON YIELD OF Panicum maximum cv. Mombasa AND ITS NUTRIENT DIGESTIBILITY BY RED SOKOTO BUCKS

ABSTRACT

The first study was carried out to determine the effects of application of varied levels of fertilizer (NPK 15-15-15) and harvest time on yield and chemical composition of Panicum maximum cv. Mombasa in Shika, Northern Guinea Savannah of Nigeria.The experiment was laid out in 4×3 factorial arrangements in Randomised Complete Block Design (RCBD) with 3 replicates (Blocks). The 2 factors were fertilizer levels (0, 200, 300 and 400 Kg/ha NPK 15-15-15) and harvest time (8, 10, and 12 weeks after planting, WAP). The fresh and dry matter yields of Panicum maximum cv. Mombasa were influenced positively with increasing levels of fertilizer and harvest time. Total dry matter increased significantly (P<0.05) from 2.30 tonnes/ha in the control to 4.20 tonnes/ha in 400kg fertilizer applied treatment and total fresh weight also increased significantly (P<0.05) with age, from 8.6 tonnes/ha at 8th week to 21.00 tonnes/ha at week 12 after planting. Results from the study revealed that Crude protein content of the forage increased significantly (P<0.05) from 7.83% in the control (0kg/ha NPK) to 11.66% in treatment with 400kg/ha NPK. Crude fibre decreased from36.94% in the controlto33.96% in treatment with 400kg/ha NPK. CP of Panicum maximum cv. Mombasa declined with maturity (from 10.29%at 8to 9.24% at 12 weeks after planting). CF and Ash’s percentages increased (P<0.05) with age. DM, OM, CP and NFE of the forage were highest in week 8 after planting and declined thereafter. ADF values indicated a decrease as NDF values showed an increase as fertilizer levels were increased. NDF and lignin content of the forage increased with age. P (from 1.46 g/kg at in the control to 1.75 g/kg in treatment with 300kg/ha NPK) and K (from 4.73 g/kg at in the control to 8.42 g/kg in treatment with 300kg/ha NPK) content of the forage was affected positively whereas Ca and Na did not change significantly (P>0.05) with fertilization. It can be concluded that the application of NPK (15-15-15) at the rate of 400kg/ha improved the nutritive value and yield of Panicum maximum cv. Mombasa. Panicum maximum cv. Mombasa was at its best nutritive value at 8th week after planting but yielded more dry matter at 12th week after planting. Thus, farmers are encouraged to apply NPK (15-15-15) at 400kg/ha and harvest Panicum maximum cv. Mombasa at 10^th week for better forage in terms of nutritive value and yield. The second experiment was conducted to investigate the effects of Concentrate inclusion levels on nutrients digestibility and Nitrogen balance in Red Sokoto bucks fed Panicum maximum cv. Mombasa based diets. The Concentrate inclusion levels were 15, 30, 45 and 60 % (Treatments 1, 2, 3 and 4, respectively). Twelve (12) Red Sokoto bucks were randomly assigned to the four treatments in a Completely Randomised Design (CRD).Dry matter digestibility was significantly (P<0.05) higher in bucks fed diet containing 60% Concentrate (75.21%) compared to the other three Treatments. Bucks fed diet containing 60% Concentrate had the highest (P<0.05) Organic matter digestibility (75.32%) compared to the other Treatments. Nitrogen free extract and Neutral detergent fibre digestibility followed a similar pattern of change as in Organic matter. Bucks fed Treatments with 45 and 60% Concentrate inclusion showed significantly (P<0.05) higher ether extract digestibility compared to those fed 15 and 30 %. Crude fibre digestibility was significantly (P<0.05) higher in bucks fed diet containing 30% Concentrate (84.59). Treatments 3 and 4 were similar, whereas Treatment 1 recorded the lowest (68.74%) crude fibre digestibility. Crude protein digestibility increased with increasing Concentrate levels. Highest (P<0.05)CP digestibility values were observed in bucks fed diet containing 60% Concentrate (81.77%) while bucks fed diet containing 15% Concentrate recorded the least values. Acid detergent fibre digestibility followed a trend similar to that of crude protein. Nitrogen intake increased significantly (P<0.05) with an increase in Concentrate levels. Bucks fed diet containing 60% Concentrate (8.36g/day) were significantly higher (P<0.05) in Nitrogen intake. Faecal nitrogen loss decreased significantly (P<0.05) as Concentrate inclusion levels increased (from 1.52 g/day in treatment with 60% Concentrate to 2.32 g/dayin treatment with 150%), while Urine nitrogen loss followed a trend opposite to that of faecal nitrogen loss. The highest (P<0.05) Total Nitrogen excreted was observed in treatment 3 (3.00g/day). Nitrogen retained was similar in bucks fed diet containing 30 and 60% Concentrate but was significantly higher (P<0.05) in bucks fed diet containing 15 and 45% Concentrate. Nitrogen absorbed as a percentage of intake and Nitrogen retained as a percentage of intake followed the same pattern. Bucks fed diet with 60% Concentrate inclusion were significantly higher (P<0.05) while bucks fed diet containing 15 and 45% Concentrate were lower in these parameters. In conclusion, the inclusion of Concentrate in Panicummaximum cv. Mombasa based diet increased the diet’s intake, digestibility and Nitrogen retention in Red Sokoto bucks. It is therefore recommended that farmers could incorporate 60% Concentrate in a Panicummaximum cv. Mombasa based diet for improved digestibility and nitrogen retention in Red Sokoto bucks.

CHAPTER ONE

Introduction

Nigeria is an agricultural country with diverse vegetation, varying from rainforest to the Sahel. About 32.42 million hectares of grazing land and 39.41 million hectares of cropland in Nigeria provide a substantial amount of feed for the country’s livestock(Shiawoya and Tsado, 2011). The savannah zone is home to about 80% of ruminant livestock population. Availability and quality of feedstuff are major constraints in the development of the livestock industry in this region. Extensive areas of the grazing lands are composed of indigenous species, which are of low quality (Shiawoya and Tsado, 2011). There is a wide variation in the quality and quantity of pasture available from one time of the year to another (Adamu, 2015). Hence, there is need to develop or adopt strategies, or technologies to provide highqualityforage for livestock in this region.

Several forage species, especially grasses have been introduced into Shika, Northern Nigeria and screened for productivity and adaptively over the past years. This has been in search of outstanding materials that could be used to partially or completely replace the low productive native grassland species (Whiteman, 1980). In some of the screening trials, Agishi (1978) on upland and Akinola and Olorunju (1990) on lowland reported some forage species that are well adapted to the Northern Guinea Savannah and produced a substantial amount of forage biomass.

There are many grass species that are used for pasture in the tropics and subtropics due to their high dry matter yields and good animal feed quality. Panicum maximum is one of these extensively used forage grasses (Correa and Santos, 2003). Panicum maximum (Guinea grass) is a native of tropical Africa, extending to the sub-tropics of South 1

Africa. It occurs at forest edges in the bush, as a pioneer grass covering the land cleared from the forest and in grassland with scattered trees where it tends to grow in high shades under trees (Whiteman, 1980). Proper soil fertility management and understanding the nutritional requirement of this grass species are extremely important for pasture management, which is reflected by higher feed yield and their availability for animals. The use of inorganic fertilizers can significantly increase forages production, providing greater capacity and thus resulting in higher milk and meat production per unit of area used (Pereira et al., 2011; Iwanmoto et al., 2015). The increased yield due to fertilizer application could be attributed to increased in both leaf production, increased number of tillers and photosynthesis directly (Aderinola et al., 2011).Dry matter yield also generally increases with increasing fertilizer rates (Carvalho et al., 2000; Adewumi, 2013). Fertilization enhances nutrient digestibility, which can improve livestock Production (Peyraud and Astigarraga, 1998). Fertilizer contributes to the greater productivity of Mombasa Guinea Grass by increasing production per cycle and the number of harvest cycles (Pereira et al., 2012; Hare etal., 2015). Increasing rates of nitrogen significantly increased CP and NDF concentrations in stems and leaves and; ADF concentrations in stems (Peyraud and Astigarraga, 1998; Adewumi, 2013; Hare et al., 2015) andreduction in the crude fibre content of stem (Onyeonagu et al., 2012).In addition, it can also provide other supplementary effects that will increase the efficiency of the system as a whole, such as the production of soilage or hay to be used during the dry season (Cecato et al., 2001). Stage of maturity also affects the quality and quantity of Panicum maximum. Dry Matter yield increases with advancing maturity, but quality declines (Taute et al,2002). Onyeonagu (2012) noted that cutting interval and fertilizer application havesignificant influence on the chemical composition of Panicum maximum forage. Ruminant production is one of the major livestock activities in most of the developing countries in the tropics (Okoruwa and Agbonlahor, 2016). Ruminant livestock play an important role in the economic development of Nigeria in terms of feeding the steadily growing population and providing the investible resources for national development (Bolaji et al., 2016).Over the years, there has been a great increase in the production of goats in Nigeria which has resulted in poverty alleviation and the supply of high-quality animal protein in order to meet the demand of the teeming population (Ibrahim et al., 2014). Goats are classified as an important small ruminant on account of their unique ability to adapt and maintain themselves in a harsh environment. (Bolaji et al., 2016). Goats are one of the most prolific of all domesticated ruminants under tropical and subtropical conditions (Webb and Mamabolo, 2004) and their small size relative to cattle contributes to their wide distribution and easy management among Farmers. (Bolaji et al., 2016). The Red Sokoto, is the most important goat breed in Nigeria, accounting for about 70% of the estimated 34.5 million goats in Nigeria (Osuhor et al., 1998). Animal protein is one of the most important components of human diet and its consumption varies from country to country (Okai et al., 2005). Goats as a multipurpose animal are a major source of milk, skin and manure apart from meat. Goats also provide income for meeting household needs (Peacock et al ., 2005). Nigerian small ruminant industry is faced with the problem of meeting the nutritional requirements of the animals (Jones and Wilson, 1987; Fasae et al., 2005). Goats in Nigeria suffer several nutritional stresses in the dry season as a result of seasonal variability that affects the availability and nutritive quality of pastures which in turn causes marked decrease in nutrient intake and performance of the animal (Bolaji et al., 2016).Therefore, study on the effects of fertilizer and harvest time on Panicum maximumcv. Mombasa and Concentrate inclusion levels in Panicum maximumMombasa based diets isvery important.

1.1 Justification ofthe Study

The main limitations to animal production in Nigeria include lack of green feed for at least half of the year, coupled with the low nutritive quality of the forages (Jones and Wilson, 1987; Alan et al., 2013). Also, soil fertility problems are found in most tropical pasture situations (Adewumi, 2007). Thus, the introduction of more nutritive forages and the use of fertilizers can help in alleviating these problems. Forage production is gaining more attention in the tropics and sub-tropics; in both developed and developing countries. New species, varieties and cultivars of forage and pasture plant have been introduced from areas and countries rich in forage and pasture plant to areas where they are scarce (Yossif and Ibrahim, 2013).Goats are one of the most important small ruminants in Nigeria, providing meat, skin and manure to farmers. Therefore, there is a need to adopt new strategies to provide feeds that will meet the nutritional requirements of goats in the dry season.

Panicum maximum cv. Mombasa being forage with high Crude protein (10-14%) and herbage yield of up to 40.2 tonnes dry matter per annum (Jank, 1995) can be useful in alleviating the ruminants’ nutritional crisis in Nigeria. There is little or no work on this new cultivar (Panicum maximum cv. Mombasa) in this part of the country. It has been established that Concentrate inclusion in a forage based diet improves nutrient intake and digestibility of the forage (Yang et al., 2001; Gaafar et al., 2009; and Lima et al., 2016). Therefore, this study is aimed at evaluating the effects of fertilizer levels and harvest time on yield and nutritive composition of Panicum maximum cv. Mombasa in Shika and Concentrate inclusion levels on nutrients intake, digestibility and Nitrogen balance of Panicum maximum cv. Mombasa hay – based diets in Red Sokoto bucks.

1.2                         Objectives of the Study

The objectives of the studies include:

• To evaluate the effectsof fertilizer levels on dry matter yield and chemical composition of Panicum maximum Mombasa.
• To evaluate the effects of harvest time on dry matter yield and chemical composition of Panicum maximum Mombasa.
• To determine the effects of Concentrate inclusion levels on nutrient intake and digestibility of Panicum maximumMombasa hay- based diets in Red Sokoto bucks.
• To determine the effects of Concentrate inclusionlevels on nitrogen balance of Panicum maximum Mombasa hay- based dietsin Red Sokoto bucks.

1.3                         Hypothese

EXPERIMENT I:Effects of Fertilizer Levels and Harvest Time on Yield and Nutritive Composition of Panicum maximum cv. Mombasa.

• H_O: Fertilizer levels have no significant effect on dry matter yield and chemical composition of Panicum maximum Mombasa.
• H_A: Fertilizer levels have a significant effect on dry matter yield and chemical composition of Panicum maximum Mombasa.
• H_O: Harvest time have no significant effect on dry matter yield and chemical composition of Panicum maximum Mombasa.
• H_A: Harvest time havesignificant effect on dry matter yield and chemical composition of Panicum maximum Mombasa.
• Experiment II:Effects of Concentrate Inclusion Levels on Intake, Digestibility and Nitrogen Utilisation in Red Sokoto Bucks Fed Panicum maximumcv. Mombasa Hay – based Diets.

• H_O : Concentrate inclusion levels have no significant effects on nutrientintake and digestibility of Panicum maximum Mombasa hay-based diets in Red Sokoto bucks.
• H_A : Concentrate inclusion levels have significant effects onnutrient digestibility of Panicum maximum Mombasa hay-based diets in Red Sokoto bucks.
• H_O : Concentrate inclusion levels have no significant effects on nitrogen utilisation of Panicum maximum Mombasa hay-based diets in Red Sokoto bucks.
• H_A : Concentrate inclusion levels have significant effects on nitrogen utilisation of Panicum maximum Mombasa hay -based dietsin Red Sokoto bucks.

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