Sustainability Performance in Supply Chain of Dairy Products: Examining the Constraints of Dairy Sector Using Value Chain Approach in Northern Regions, Tanzania

The aim of this study was to investigate the sustainability performance in supply chain of dairy products in Tanzania. The study conducted in Simanjiro district using cross-sectional survey method and focus group discussions. The findings of this study show that processing facilities, access to market, storage facilities, distribution and delivery system are the main enormous supply chain constraints which affect the sustainability performance of diary sector. This study recommends that in order to ensure sustainable performance of dairy sector, a multidisciplinary approach, value chain techniques, diverse strategies and dialogues should be taken involving all key actors (i.e. LGA’s, civil society, respective ministries, smallholders’ farmers, processing firms, and dairy entrepreneurs).

as a linked sequence of activities in which each activity and its stage in the value chain adds value to the product or service in question, a value for which the end consumer is willing to pay (Faulconbridge, 2007).
According to Kilelu et al. (2017), value chain framework is increasingly promoted as holistic intervention frameworks for inclusive smallholder development in evolving agri-food markets in Sub-Saharan Africa. VCA is integrated with multi-stakeholder processes to facilitate the value chain upgrading of smallholders which originate from a wide perspective of global value chain framework (Kilelu et al., 2017). The framework is proclaimed to be keen in improving overall value of small scale farmers in supply chain of agri-food (Taylor, 2005).

Sustainability of dairy products in Tanzania
Sustainability is an important agenda in modern agri-business. In agricultural perspective, sustainability can be referred to situation in which the agricultural sector continues to meet demand for food indefinitely while incurring farm-level economic and environmental costs that societies find acceptable (Anderson, 2019). Rose et al. (2019) argue that "sustainable agriculture intend to balance the economic, environmental, and social aspects of farming, creating a resilient farming system in the long-term". Global warming, scarcity of resources, starvation, and drought has made a drastically changes in thinking of sustainability in agri-food supply chain for future generation and society (El Semary, 2019).
In today world, sustainable agriculture is inevitable (Gafsi, Legagneux, Nguyen, & Robin, 2006). As the world concern and attention is on the climate changes, Tanzania is not excluded (Omambia & Gu, 2010). Agriculture is a life blood and economic back born of Tanzania (Manyilizu et al., 2016;Temu, 2011). As mentioned earlier, dairy sector is one among the important contributor of agricultural GDP of Tanzania, the sustainability of the sector should be a concern of every one (Kimaro, Mor, & Toribio, 2018;Maleko et al., 2018). Despite the fact that, smallholder dairy farming is growing at steady rate of 6% per year and climate are appropriate in majority parts of Tanzania but the supply of milk and milk products has not kept pace with the rapid increase in the human population (E. S. Swai & Karimuribo, 2011).
Northern zone of Tanzania is characterized as the leading region having large number of smallholder dairy farming (Kurwijila & Henriksen, 1995). However, there are number of challenges which face the smallholder dairy farming in northern part of Tanzania which rise the alert on the sustainability of the sector. Some of the issues include land scarcity (Hillbom, 2011), dry season fodder scarcity (and access to water) for cattle kippers (Kurwijila, Omore, & Grace, 2012;Maleko et al., 2018), rise in temperature, prolonged and frequent periods of drought in the regions (Kimaro et al., 2018), massive cattle deaths due to outbreaks of diseases (Kimaro et al., 2018;Ojija, Abihudi, Mwendwa, Leweri, & Chisanga, 2017) and etc.

Upgrading value chain of dairy products in Tanzania
Upgrading refer to how firm produce a better product, making them more efficiently or moving into more skilled activities and improving their performance and rewards in high-value markets (Giuliani, Pietrobelli, & Rabellotti, 2005). In agricultural context, upgrading in value chain is a very common concept which enhance the overall improvement of smallholder in downward-upward stream of supply chain. Humphrey and Schmitz (2002) emphasized and come up with typology which smallholder should be concerned as the upgrading strategy: First is process upgrading, second is product upgrading, third is functional upgrading and last is intersectoral/interchain upgrading.
According to Kilelu et al. (2017) upgrading value chain of dairy products in Tanzania need four comprehensive strategies (1) improving value chain coordination, this include vertical and horizontal coordination (Bolwig, Ponte, Riisgaard, du Toit, & Halberg, 2013) (2) improving process and product, this involve the process upgrade (i.e. reduce production cost) as well the product upgrade (i.e. improve quality) (3) changing and adding functions, this include functional upgrading as well the inter-chain upgrading and (4) upgrading the institutional environment, this involve the upgrading of the institutional organs that constrains the value chain of smallholders like support services, legal and policy frameworks (Charles Urassa, 2014).

Supply chain constraints of dairy products in Tanzania
Supply chain is defined as a "set of three or more entities (organizations or individuals) directly involved in the upstream and downstream flows of products, services, finances, and/or information from a source to a customer" (Mentzer et al., 2001). Christopher (2016) define supply chain as the network of organizations that are involved, through upstream and downstream linkages, in the different processes and activities that produce value in the form of products and services delivered to the ultimate consumer. In agriculture context, the supply chain involved the multiple players, the upstream part (i.e. smallholders, processing firms) and the downstream part (i.e. distribution and ultimate consumers). There are extant of literatures which investigate the challenges and constraints that affect food supply chain worldwide (Bhagat & Dhar, 2011;Chang, Droli, & ISEPI, 2014;Vasileiou & Morris, 2006) , but not much have been explored the in the dairy sector (Nicholson et al., 2011).

Methodology
Simanjiro district was selected for this study due to plenty of reasons (1) it is recognized as the third district in Manayara region with large number of smallholder dairy farmers including cattle keepers and small milk processing units (URT, 2012) and (2) it is mentioned as the one of the Maasai pastoral area which experienced severe climate changes and need effective sustainable framework for long term survival (Sewando, Mutabazi, & Mdoe, 2016;Watkiss et al., 2011). Furthermore, due to the nature of this study, Arusha municipal was selected as the downstream strategic point and milk market area which originate from Simanjiro district (Hillbom, 2011). This study persuaded two main research methods (1) cross-sectional survey method and (2) focus group discussions. The cross-sectional survey method was employed which involved all key informants in this study by collecting information out at one time point or over a short period (Levin, 2006). The method was appropriated as recommended in the contemporary agricultural studies (Kilelu et al., 2017;Kivaria et al., 2006;E. Swai et al., 2005). Another complementary method that used in this study was focus group discussions. Focus group discussion was conducted to some specific representative of the respondents involved in this study including key actors-farmers, collectors, processors and consumers of dairy products. The FGD included all key participants involved in the supply chain of dairy from the upward stream to downward stream in Simanjiro district. The Focus group discussions was conducted between January -March 2019 using Swahili language and translated back into English language by language experts.

Results
For reliability and validity, this study use Narasimhan and Jayaram (1998) guideline. The researcher calculates the Cronbach's alpha (α), composite reliability (CR) and factor loading to determine the reliability of each item. Table 2 show the results of FA, Cronbach's alpha and composite reliability. The items used for measurement had higher loading more than 0.5. All constructs used in this study had value of CR and α above the required cutoff stipulated in study of (Lance, Butts, & Michels, 2006). The value of AVE indicated in Table 2 imply that convergent validity is adhered in this study. Table 2 show the measurement of scale with reliability and validity.  SE=0.342,p <0.01) and transportation system and physical infrastructures SE=0.243,p>0.05). The regression revealed a significant result for Processing facilities (X1), Access to market (X2), Distribution and delivery system (X3), and Storage facilities (X4). In this study Transportation system and physical infrastructures (X5) was found insignificant. Surprising Processing facilities (X1) and Storage facilities (X4) were found with negative unstandardized coefficient which imply as the worsen constraints in supply chain of dairy products in Northern regions of Tanzania. The study proposed the following supply chain equation: . Durbin-Watson F Notes: †p < 0.10; *p < 0.05; **p < 0.01; ***p < 0.001

Discussions
The aim of this study was to investigate the sustainability performance in supply chain of dairy products through European Journal of Business and Management www.iiste.org ISSN 2222-1905(Paper) ISSN 2222-2839(Online) Vol.11, No.32, 2019 85 examining the dairy sector constraints using value chain approach in Tanzania. Findings from this study have revealed that there is a growing concern on the sustainability performance of dairy sector in Tanzania as the sector is subjected to many supply chain constraints and impediments (Table 3). Despite the paramount importance of this sector and contribution of smallholder dairy farming in Tanzania (E. S. Swai & Karimuribo, 2011), supply chain constraints hinder the growing of smallholder dairy farming in Northern region of Tanzania to the large extant.
The findings show that processing facilities, access to market, distribution and delivery system, storage facilities are the main enormous supply chain constraints which affect the sustainability performance of diary sector in Tanzania. This findings are consistent with (Eskola, 2005;Kilelu et al., 2017;Kivaria et al., 2006;Kurwijila et al., 2006;Ruteri & Xu, 2009;Schoder et al., 2013). Surprisingly, this study found that transportation and physical infrastructures is not a challenge in Northern regions which is contrary to study of Jeckoniah et al. (2013). This is attested by this participant: Although some of the smallholder's farmers stayed and worked in interior areas but to the large extant government has provide us with effective infrastructures specifically the road which pass in Simanjiro district and go to Arusha municipal (Focus group participant).

Conclusions, recommendations, limitations and future research 6.1 Conclusion
In conclusion, this study concurred with the on-going debate about the concern of sustainability in agri-business diary sector in developing countries. The debate of agri-cultural sustainability has dominated over the past decades where majority of studies focused on the environmental paradigm like climate change, this study provides the dimensions on the supply chain perspective. The study underpins the importance of different policy makers like ministry of agriculture and livestock to invest on eliminating the supply chain constraints associated with diary sector elaborated in previous part. This study provides quantitative evidence about the impediments and stabling blocks which affect the smallholders dairy sector in Northern region of Tanzania. For instance, inadequate and poor processing facilities of dairy products are dominant challenges for the sustainability of this sector in this region. Presently most of the processing centres in Simanjiro and Arusha are working at less than 12% of the installed capacity. Another enormous challenge for small holders' farmers of dairy products is access to market like asymmetry of information and lack of capital to access markets for selling their dairy products etc. In this study, storage of dairy products is seemed to be a problem to most emerging smallholder farmers in Tanzania. In additional to that is poor distribution and delivery system. Majority of smallholder farmers like Maasai used a local means like bicycles over long distance for distribution and delivery for their milk for sale at collection centres in Simanjiro and Arusha municipal.

Recommendations
On the basis of this study, we recommend to all stakeholders including policy makers, smallholders' farmers and entrepreneurs in dairy sector to take appropriate actions in order to eliminate the constraints in the downward and upward stream of supply chain. In order to ensure sustainable performance of dairy sector in Tanzania, a multidisciplinary approach, value chain techniques, diverse strategies and dialogues involving all key actors like the LGA's, civil society, respective ministries, smallholders' farmers, processing firms, and dairy entrepreneurs should be comprehensive discussed and implemented.

Limitations and future research
Although this study contributes to the extant literature in sustainable dairy supply chain, it also has some limitations. First, data collected using a mixed method of cross-sectional survey and focus group discussions which are both subjected to some limitations. Future studies should complement this by conducting longitudinal studies instead of cross-sectional survey which didn't take onboard the dynamic nature of dairy sector. Second, generalizability of this study should be taken with great cautions as the data was collected in one district of Tanzania. Future studies should collect data in more than one district with diverse diary activities. Finally, the gender imbalance should also be acknowledged. The study was dominated by women's which could imposed some gender biasness. Future studies should try to incorporate both gender to the study in order to bridge the social and economic inequality.