Milk is one of the most important sources of animal protein for human diets and dairy production is a key element of agriculture worldwide (FAO, 2018). Milk from dairy cow represents nearly 100% of the milk produced in Latin America and Oceania (FAO, 2019). In Africa, above 75% of the milk comes from cow grazing natural pastures (Gebrekidan et al., 2019). Despite the economic importance of dairy production systems and their major role for the household security of millions of people, the productivity is low (Lobago et al., 2007; FAO, 2019). The total numbers of dairy cattle in the world are in Africa (77%) and Asia and (33%), in Europe and North America (21% and 51%, respectively) of the world’s milk production (FAO, 2018).
Ethiopia is the first country in rank that keeping and producing largest population of livestock in Africa (Metaferia et al., 2011; Ayeneshet et al., 2018 and; CSA, 2018; Kasa et al., 2018 and Alemu, 2019). The sector contribute significantly to the national economy and the livelihood of the people especially in the rural area by generating income to the farmers, ensuring food security and contributes to the asset, social, cultural and environmental values in order to sustain the people livelihoods (Anteneh et al., 2010; Azage et al., 2011; Mebratu et al., 2018; FAO, 2019; Gebrekidan et al., 2019). According to the report of CSA (2018), from the total cattle population of the country is estimated to be about 60.39 million; the female cattle constitute about 54.68%, out of this dairy-cows are estimated to be around 6.66 million (11.03%) and 45.32% are male cattle.
Dairy cows offer an important source of cash income, calories and key nutrients, and mitigate the effects of often large seasonal fluctuations in availability of cereals through milk production (Aynalem et al., 2011; Kebede et al., 2017 and Kasa et al., 2018). Milk is a good source of dietary fat, energy, protein and other nutrients in general and provides substantial amounts of nutrients such as calcium, magnesium, selenium, zinc, riboflavin, vitamin B12 and pantothenic acid particularly (Azage et al., 2013; Ayalew, 2017 and Kiros et al., 2018).
Despite the largest population and these importance, the production and reproduction performances of dairy cows are very low due to a number of reasons such, the low genetic capacity of the indigenous cattle for milk and meat production, low adaptation ability of exotic and hybrid dairy cows, substandard feeding, poor health care and other management practices (Belay et al., 2012; Azage et al., 2013; Abunna et al., 2018; Kasa et al., 2018; Mebratu et al., 2018). Consequently, the milk production to be provided from dairy cows is still under expectation throughout the country (Hailu et al., 2012, Ayeneshet et al., 2018 and Alemu, 2019). In order to identify the major factors that affecting the performance efficiency of the dairy cows, the investigation of the all aspects of management practices under small holders in their production systems is very important task to be encouraged (Azage et al., 2013; Belay and Janssens, 2016; Mebratu et al., 2018).
Several studies have been carried out only at the top towns in the country level to investigate the production and reproduction performance of dairy cows (Asrat et al., 2013; Belay and Janssens, 2016, Kiros et al., 2018; Alemu, 2019). However, a lot of previous studies neglects the dairy cows being kept under small holder in dairy production systems like rural area (Belay et al., 2012, Ayalew and Feyisa, 2017). Thus, the milk production and its supply in the small towns and rural area needs findings to assess and explore the reproductive efficiency of dairy cows under small holders within the rural, peri-urban and urban dairy production systems (Belay et al., 2012; Azage et al., 2013; Dejene, 2014; Ayeneshet et al., 2018, Ayalew, 2017 and Alemu, 2019).
In Ethiopia, dairy cows play a crucial role in development and represents a significant part of the urban, peri-urban and rural economy (Azage et al., 2013; Alemu, 2019). Unfortunately, the reproductive efficiency of crossbred and indigenous dairy cow is poor in most cattle production systems, mainly because of cows fail to become pregnant primarily due to management problems, shortage of feed and high prevalence rate of reproductive diseases as well as high calf mortality (Belay et al., 2012; Ayneshet et al., 2018). In the study area, there has been a substantial effort to holding crossbred and indigenous dairy cow by smallholder farmers under urban, peri-urban and rural production system (SZLFRD, 2020). However, farmers are being troubled due to the factors such; shortage of feed, feed resources and problem of reproductive diseases. Besides, the reproduction performance of dairy cow has not been studied in the study area. Moreover, the milk demands of the society is still not enough fulfilled in Werabe town of the zone and its surrounded towns. Consequently, there is a need to assess the current reproductive performance of dairy cows. Therefore, the aim of the present study was to assess age at first service and calving, calving interval, open days, and number of service per conception of dairy cows under small holder in study area.