Effect of Climate Variability on Livestock Population in the Sokoto Rima River Basin, Nigeria

The study examines the effect of climate variability on livestock population in the Sokoto Rima River Basin, Nigeria. The cluster sampling technique was used to administer the questionnaire to 450 farmers who were sampled from 15 agricultural settlements in fifteen local governments in the basin. Data were analysed using frequency, percentages, and multiple regression. The population of cattle and sheep decreased while that of goats increased during the period of study. However, the slaughtered cattle, sheep, and goats increased tremendously. The annual rainfall and temperature had no significant influence on cattle, sheep, and goat population in Sokoto-Rima River Basin, except at Sokoto where temperature significantly influenced goats positively at p<0.05. The coefficient of determination revealed that annual temperature explained 72% of the variation in the goats' population at Sokoto while 28 % of goats' population variation was explained by non-climatic elements including forage quality, management practices, ill-health, epidemic disease, and so on. DOI: https://dx.doi.org/10.4314/jasem.v26i1.8 Open Access Article: (https://pkp.sfu.ca/ojs/) This an open access article distributed under the Creative Commons Attribution License (CCL), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Impact factor: http://sjifactor.com/passport.php?id=21082 Google Analytics: https://www.ajol.info/stats/bdf07303d34706088ffffbc8a92c9c1491b12470 Copyright: Copyright © 2022 Adejuwon et al. Dates: Received: 23 August 2021; Revised: 21 December 2021; Accepted: 06 January 2022

Several studies have shown that climatic variability affects livestock production (Oba, 2001;Australian Bureau of Statistic, 2004;Güney et al., 2009;Oladele and Moilwa, 2010). Studies have also shown that relationships exist between rainfall variability and livestock population dynamics (Desta and Coppock, 2002;Begzsuren et al., 2004;Kgosikoma, 2006). Most of these studies suggest that the seasonal cycle of reproductive activity in both males and females is driven by an endogenous annual rhythm being synchronized by photoperiod which is directly affected by climate changes (Güney et al., 2009). Sweet (1998) observed that drought is an aspect of climate variability that directly reduced livestock holdings through mortalities and indirectly through distress sales. Globally, climatic change has several effects on animal production (Guney et al., 2009). In drylands, livestock populations are characterized by fluctuations in response to rainfall variability (Desta and Coppock, 2002). Ellis and Galvin (1994) observed that if rainfall variability is high, the livestock populations are modulated by frequent droughts and subsequently never reaching equilibrium. In arid and semi-arid zones, seasonal and annual drought has a serious effect on rangelands and consequently on livestock (Coppock and Reed, 1992;Oba, 2001). Rainfall fluctuation affects the quantity and quality of herbage available to animals. Regeneration of vegetation becomes difficult during drought extensions. The vulnerability of livestock to drought comes about because of a decrease in range resources. In such situations, the available livestock population will be difficult to maintain on natural rangelands throughout the year. This leads to chronic inadequate feed supply for livestock, with dramatic consequences in dry years. Hence, drought directly reduced livestock holdings through increase mortality and reduced birth rates (Ellis and Swift, 1988;Sweet, 1998;Kgosikoma, 2006). This present study has incorporated several issues which had hitherto been neglected or deliberately avoided even though studies existed on livestock production (Ndamukong et al., 1989;Adejuwon et al., 2019). The effect of climate variability on the livestock population and its statistical analysis in the study area has not been documented. The existing study on the livestock population in Nigeria was based on projected figures with a growth rate of 0.129 percent (RIM, 1992). Projected figures do not take factors including drought, ill-health, epidemic disease, and death that might cause variation in livestock population figures into consideration. Therefore, this study addressed gaps identified in previous works towards establishing effective climate change response on livestock population and help in the strategic planning of the response to food security challenges.

MATERIALS AND METHODS
Study Area: Sokoto Rima River Basin is situated in the northwestern part of the country. The study area lies between latitude 10.8o N and 13.58o N and longitude 3.30o E and 7.13o E (Figure 1), covering an estimated land area of 106, 547 square kilometers (Iliya and Kwabe, 2000;Mamman, 2000). It is bounded by the Niger Republic to the north, Niger and Kaduna States to the south and southeast, the Benin Republic to the west, and Katsina State to the east. Sokoto-Rima Basin experiences a tropical climate, governed by the Intertropical Discontinuity (ITD;Obasi, 1965). The ITD marks the boundary line between two air masses -the tropical maritime (mT) air mass from the Atlantic Ocean and the dry tropical continental (cT) air mass from the Sahara Desert (Adejuwon, 2016). The prevailing air mass at a particular period has a strong influence on the climate. The climate exhibits a definite and marked wet and dry season. The mT dominates during the wet season while the cT air mass predominates during the dry season The wet season is between May and September in the southern part and June to September in the north (Adejuwon, 2012). Annual rainfall amount varied from about 1013 mm in the southern part to about 650 mm in the northern part and is single maxima in character (Emielu, 2000;Mistry, 2000;Adejuwon, 2018). The rainfall decreases in both duration and amount from the south northward. High humidity is experienced in the wet season while low humidity of less than 30% is often experienced in the dry season (Oboli, 1967;Emielu, 2000). The area is characterized by the dry and dust-laden northeast trade winds called 'Harmattan' that blows from the Sahara under cloudless but dusty conditions from January to February. This period is marked by very low temperatures and thick fog at this time. The mean annual temperature range is between 5 o C and 10 o C while the mean annual temperature is 34.5 o C (Adejuwon, 2019). The extremes diurnal and seasonal range is affected by seasonal and latitudinal variations. The highest temperatures are normally in the dry season, March to April while the minimum temperatures are usually recorded in January to February.
Data Collection and Analysis: Data for this study were obtained from field investigations, involving direct interaction with the respondents. A total number of four hundred and fifty copies of the structured questionnaire were administered to farmers in fifteen agricultural settlements in fifteen Local Governments (Table 1).
A cluster sampling technique was used for the study. Agricultural settlements and the local governments were selected by purposive sampling technique. Thirty copies of questionnaires were administered in each of the settlements. This was because the settlements were small, hence the number of farmers. Data were analyzed using frequency, percentages, and multiple regression.

RESULT AND DISCUSSION
The fluctuation in cattle population in Sokoto-Rima River Basin is shown in Figure 2.  (Adejuwon, 2012). Adefolalu (2007) reported that increasing drought occurrences in the semi-arid region of northern Nigeria were majorly caused by the increase in temperature and declined rainfall. However, the goat population increased while slaughtered goats decreased at the same period. The thriving of goats at this period could have resulted from their ability to survive and reproduce in harsh environments because of their low metabolic requirements and body mass (Silanikove, 2000: Chukwuka et al., 2010. Goats with thermal comfort zone ranges from 0-30 o C, can withstand heat stress and endure protracted water deprivation, making them more adaptable to adverse climatic and geographical conditions, where cattle and sheep cannot survive (Assan, 2013;Adejuwon, 2019     The livestock population of cattle, sheep, and goats in the River Basin followed upward and downward fluctuation, which Kgosikoma (2006) referred to as a "boom and bust" pattern. Such results have been reported in the literature (Perkins, 1991;Desta and Coppock, 2002;Kgosikoma, 2006). Sokoto-Rima River Basin is one of the areas controlling the bulk of livestock production in Nigeria. The major species of domesticated animals are mostly cattle, sheep, and goats. With a total estimated population of 10.9 million ruminants in 1986, Sokoto State (now Sokoto, Kebbi, and the Zamfara States) contributed about a quarter of the national populations of the three species (UDUCONSULT, 1990). According to Yakubu and Yakubu (2008), the effect of harsh weather and climate results in low productivity and brings about low livestock production. population. The coefficient of determination revealed that annual temperature explained 72% of the variation in the goats' population at Sokoto. This means that 28 % of goats' population variation was unexplained by temperature. They were explained by other factors than climatic elements considered. These include forage quality, management practices, ill-health, epidemic disease, and so on (Seleka, 2001;Kgosikoma, 2006). The results of the present study support findings in the literature that goat populations were more resilient to harsh conditions than sheep and cattle (RIM, 1992;Toulmin, 1996). Toulmin (1996) observed that small stocks especially goats are more resilient under adverse conditions. This was corroborated by Wilson (1987) who noted that environmental factors have little influence on goats.

RF -Rainfall TP -Temperature t value -Figures in bracket
Conclusion: The study has examined the effect of climate variability on livestock production in the Sokoto Rima River Basin, Nigeria. The goat's population and the slaughtered cattle, sheep, and goats increased while cattle and sheep population decreased. Only annual temperature significantly influenced goats positively at Sokoto and explained 72% of the variation in the goats' population. This means that 28 % of goats' population variation, the slaughtered cattle, sheep, and goats increase was unexplained by temperature.