Energy efficiency and use of a parametric method for poultry production in Kwara State, Nigeria

Analysis of input-output was done to investigate energy utilization pattern and efficiency in selected poultry farms in Kwara State, Nigeria. The poultry farms used for the study were grouped into three as group I (small), II (medium) and III (large) respectively based on number of birds. Energy used in chemicals, chicks, electricity feed, fuel, labour, and wood shaving as inputs and eggs, poultry meat and litter as outputs were determined. The result has shown that that diesel and feed accounted for the biggest proportion of all energy inputs in the farms. Energy consumption of the farms was found to be 28006.41, 26450.19 and 21894.39 MJ (1000 bird)−1, respectively. The energy output was 179766.54, 193670.10 and 223307.50 MJ, respectively (1000 bird)−1. Impacts of renewable and indirect sources of energy were greater than that of nonrenewable and direct energy. The rate of return to the scale was estimated at -0.04, suggesting that a 1% rise in each of the power inputs would result in a 0.04% reduction in the production. R2 was found to be 0.81 for the estimated model. Therefore, energy inputs (independent variables) can capture about 81% of layer yield variations in the poultry farms.


Introduction
Poultry production was not considered to be an important industry until it occupies a significant place among the livestock enterprises. Nowadays, poultry industry presents diverse business opportunities to the unemployed youths. Many people had ventured into hatchery business, broiler production, egg production, and sales of poultry drugs and equipment [1]. Poultry meat and eggs are good sources of protein for man and animals. Poultry accounts for about 15% of the annual protein consumption in Nigeria with about 1.3 kg per head consumed annually. About 36.5% of the total proteins required by Nigerians are obtained from poultry products [2]. Developing countries are encouraging farmers to venture into poultry production system in order to increase the supply of animal protein [3]. The livestock sector contributes approximately 10% of the agricultural GDP of Nigerian. According to Ojo [4], cited by [5], poultry products' contribution to livestock share of GDP increased from 26% in 1995 to 27% in 1999 with egg production alone accounting for about 13% during the period. Despite the poultry industry's importance for the domestic economy, poultry farms face difficulties that are antithetical to the industry's development. Generally speaking, poultry production is being faced with low capital base, inefficient management, issues with illness and parasites, housing and marketing, and so on [6]. Recently, poultry industry in Nigeria has become a commercialized subsector of Nigerian agricultural production. There are many benefits in poultry production than other livestock. There is quick return of investments because production cycle is short [6]. Poultry products (eggs, broiler and layers) are relatively affordable compared to other proteins in animals. Poultry birds transform food into protein in meat and eggs which are good sources of protein required by man. Return on investment in poultry is high even though unit cost of production is low. Another advantage of poultry meat is that it is acceptable to all religions in Nigeria [7].
Climate change and rising in energy prices have made energy savings in animal production to be a necessity. To determine the potential savings, energy consumption and distribution in the system are required. Feed is the biggest energy input in poultry production [8]. This high input could be reduced by savings in crop and feed production chains. The use of energy in the agricultural industry is increasing in terms of demographic growth and requirements for a decent standard of living [9]. Understanding of energy input in a system's unit operations is a necessity for investigating high energy consuming areas [10]. Energy analysis of a production system is useful in comparing costs of energy inputs in a particular existing production system with a new production system. In addition, energy analysis allows farmers to compare their energy efficiency with that of a competitor or other plant in the same company. Hence, energy analysis is a very useful tool for planning ahead, assessing energy consumption pattern for a specific product or service, predicting energy requirements in such a production system, and planning for expansion.
Energy and agriculture are closely linked together. Agriculture utilizes energy and supplies the same as bio-energy [9]. In agriculture, energy use is classified as direct (DE), indirect (IDE), renewable (RE) and non-renewable (NRE) forms. Direct energy involves manpower, diesel and electricity in poultry production. Food, equipment, poultry litters, disinfectants, medicines, and chicks were included as indirect energies. Chick, feed, litter and human labor are covered by renewable energy, while non-renewable energy contains diesel fuels, disinfectants, energy and machines [11].
Sustainable agriculture depends on efficiency of energy usage in agricultural production [9]. Agricultural production can be improved if energy needed is available and it is used effectively [12]. This is because agricultural output (crop, animal, poultry products) and food supplies are connected directly to inputs of energy during production.
Many research works have been carried out on energy use pattern in crop and livestock production in different parts of the world. Heidari et al [13], investigated energy efficiency of broiler production. Results of their study revealed that output energy in broiler production in Yazd Province, Iran, were 186,885.87 and 27,461.21 MJ (1000 birds) -1 respectively. Rajaniemi and Ahokas [14] found that, if the energy equivalents of all production inputs were considered, the energy equivalent of broiler feed would be a key factor in broiler production. Rajaniemi and Ahokas [15] studied direct energy consumption in a broiler house in Finland and reported that heating energy was the highest direct energy input in the broiler house. Najafi et al [16] assessed the energy efficiency of chicken production in different farm sizes in Iran and concluded that large farms had a higher productivity rate than small and medium-sized farms. Oladimeji et al [17], researched on energy use and economic analysis of melon production technologies in Kwara state, Nigeria. However, there have been no studies related with emphasis on energy analysis in poultry production farms in Nigeria. The aim of this study was to determine energy use pattern in poultry farms in the North Central part of Nigeria. The study also compares energy inputs for egg, meat and litter production.

Study area and data collection
Kwara State, with a population of about 3.5 million people [18] and land area of about 36,825 km 2 is located between latitudes 7°45 N and 9°30 N and longitudes 2°30 E and 6°25 E [17]. Data were collected from poultry farmers through a face to face questionnaire administered in between 2017 and 2018. Poultry farms used in this study were selected randomly from the registered poultry farmers in Irepodun and Offa Where n is the sample size, N is the number of poultry farms in target population, Nh is the number of population in Group I (43 farms), II (23 farms), and III (14 farms), Sh is the standard deviation in the groups, S 2 h is the variance of the three groups, d is the precision, z is the reliability of coefficient, Permissible error in the sample size was defined to be 5% for 95% confidence.
Inputs used in poultry farms included chicks, chemicals, disinfectants, fuel, feed, human labour, electricity, machinery, medications, while the outputs were chicken, broilers and poultry wastes. Energy equivalent of inputs (chicks, disinfectants, electricity, feed materials, fuels, labor, and medications) was calculated by multiplying their total consumption for 1000 birds by their equivalent energy shown in Table  1. The production power equivalent (egg, meat and poultry) (Mcal U -1 ) were calculated by multiplying the output amount by equivalent energy.
Differences in poultry output with energy input differences were predicted with the return to scale by adding coefficients for each regression equation. Sensitivity of energy inputs used in the poultry production was calculated by using marginal physical productivity (MPP). MPP estimates the difference in yield (egg, meat and litter) with one input if other inputs are constant. MPP was calculated by using Equation (12) Where; MPPxj is marginal physical productivity for j th input, aij is regression coefficient of the input, GM (Y) is geometric mean of poultry yield and GM (Xij) is geometric mean of energy consumed.
MPP is positive when production increases in relation to increased input. This suggests that if the fixed resource is not fully used, the use of the variable inputs should be boosted. A negative MPP value shows, however, that further use of inputs has negative impacts on production. Table 2  These results were in agreement with the studies of Saeed et al [11] and Amid et al [20] that diesel fuel and feed ranked the first and second energy inputs for broiler production.

Energy inputs and outputs
In Table 2, energy inputs required for the production of poultry were also disclosed in the three poultry farm size groups. Farms I, II or III had total energy inputs of 28006.41, 26450. 19 and 21894.39 Mcal (1000 birds) -1 , respectively. The average total energy input of different poultry farms differs. There was noticeable reduction in the total input of energy with increasing farm size. This has to do with increased management in the large farms. In this regard, it is of great importance to scientifically design broiler farm structures and manage the broilers' nutrition, based on environmental conditions and the birds' growth.  Figure 1. Share of energy inputs in the surveyed farms Table 3 presents the energy indices of the surveyed farms. Energy ratios were estimated to be 6.42, 7.32 and 10.20 for group I, group II and group III farms. The mean energy ratio was found to be 7.98. Energy productivity was calculated to be 6.175, 7.086 and 9.924 kg Mcal -1 for group I, II and II farms respectively, indicating the higher productivity of large-sized farms. Specific energy for the respective farms was revealed to be 0.162, 0.141, and 0.132 Mcal kg -1 . These indicate that the energy needed to produce 1 kg of poultry meat in group III farms is lower than those of group I and II farms. Net energy gain for the surveyed farms was 151760.1, 167219.9 and 201413.1 kg (1000 birds) -1 , respectively, showing an ascending trend with the farm size. This finding implies that large-sized farms have more optimum energy advantage. Table 3 also showed the amount of different energy forms used for poultry production in this study.    Table 4 shows results of the estimation model in terms of equivalents energy inputs in poultry production in the surveyed farms. Impacts of diesel fuel and that of electricity were significant at 5% confidence level, showing regression coefficients of 0.074 and -0.235, respectively. From the Table,  Return to scale -0.04

Modeling energy inputs in poultry production
Note: *significant at 5% probability level, ns = non-significant