Cattle are undoubtedly the most important livestock species in the Borana range land system both for economic and social functions (Coppock, 1994). Boran cattle breed is originated in arid and semi-arid agro-ecologies of Southern Ethiopia. Beyond its home country, the breed is widely distributed in many parts of Africa, including Kenya, Tanzania, Uganda, Somalia, Zambia, Zaire and other countries of the world including USA and Australia.  The  breed  is  known  for  its  large  size,  high degree of heat tolerance, and resistance to ticks, roughage feeds and water shortage (Albero and Hailemariam, 1982). It is also considered by FAO as one of the five breeds that should be given priority for further development and conservation (Philipsson, 1992).

Due to their better meat quality, the Boran cattle were reported as an excellent beef animal both for local and foreign market (Albero and Hailemariam, 1982). The potential of Boran  cattle for meat production under ranch conditions is also considerable (Trail et al., 1985). They are predominantly serving as dam line in most small holder dairy cross breeding program (Haile Mariam et al., 1993). However, the breed has been subjected to little artificial selection either for increased milk or meat production, particularly in its breeding area. Further, there is a growing concern of genetic erosion of the breed due to blood dilution which has been caused by restocking of other local breeds in response to death of the productive Boran breed (“Qorti sub type”) due to shortage of feed caused by recurrent drought, bush encroachment, crop farm land expansion (Hurst et al., 2012, Coppock et al., 2011; Desta and Coppock, 2004; Tache, 2000). These calls for urgent action to carrying out conservation program while improving the breed for beef as well as milk production.

Dida Tiyura ranch has been engaged for over the last two decades in improvement, multiplication and distribution of bulls for the communities, and is the only remaining ranch for Boran cattle genetic improvement. The dissemination strategy is in such way that a bull is sold to selected pastoralists on individual basis. Individual ownership and use of bulls could lead to underutilization of bulls for breeding purpose given that a pastoralist owns few breeding cows. Individual ownership (unlike collective ownership) made it easy for pastoralist to sell the bulls for quick-profit benefits rather than long term genetic improvement. Further, there is no feedback on the status of the distributed bulls. Moreover, there have been loose institutional links between pastoral bureaus, multiplication ranch and research centre. Therefore, there is a need to redesign the dissemination strategies, participation and create a link between different stakeholders so as to bring sustainable genetic improvement. Those villages breeding programs carried out by the communities with involvement of various stakeholders, often at the subsistence level (Sölkner et al., 1998), can easily be adapted and contribute sustainably to the improvement of productivity of local breeds. Therefore, this improvement program was designed with the objective to conserve Boran cattle breed through disseminating improved Boran sires to the local communities and to evaluate pregnancy, calving and mortality rate of Boran cattle breed under cooperative/communal use of breeding bulls for mating.

Study sites

The study was conducted at Danbela Wachu ranch in Dubluk district of Borana Zone, Southern Oromia (Figure 1). The area has semi-arid climate with bimodal rainfall distribution during the major wet season, from mid-March to May and the short rainy season extending from September to November. A cool dry period occurs from June to August while warm dry season extends from December to February (Coppock, 1994). The area is characterized by extensive pastoral production system (Teshome et al., 2022).

Pregnancy rate (PR) of breeding herd per mating year is presented in Table 2. The overall pregnancy rate in cows mated in the given breeding years was 89.9%. Pregnancy rate showed considerable variation (χ²<0.001) among breeding years, ranging from 68.56 to 96.40%. This result is consistent with that of the study conducted by Cruz et al. (1976), where PR of various tropical breeds was significantly affected by mating year. However, the PR  (75.40%) reported by the mentioned authors for Boran breed in Zambia is lower than the PR obtained in the present study. The lower PR observed in 2016/2017 compared with those of the remaining mating years was due to a serious drought, which resulted in scarcity of green fodder resulted to early withdrawal of breeding herd from the community ranch.

Table 3 presents calving (CR) and abortion rate (AR) of Boran cows over different breeding season, together with the overall performance of the breeding herds across the given breeding years. Out of the 1286 dams detected pregnant, 94.71% calved live calves and the rest (5.29%) aborted. Comparing CR and AR in association to the given  breeding  years,  the  mentioned  parameters were found significantly different (χ²<0.001). The difference observed was mainly due to higher rate of abortion occurred in the 2012/2013 breeding year, which was attributed by >30 head of cows were found infected with Brucella abortus. The current CR is inconsistent with the  CR of 70, 75 and 85% for local cows in dry, wet and humid region research stations, respectively, reported by Galal et al. (1981) for local zebu and F₁crossbredcows. However, the value reported for humid regions coincided with 85.68% observed in the first breeding year of the current study (2012/2013). Several studies revealed management of the breeding herd is the most important key to confirm reproductive performance. In view of that, the CR observed in the current study is in agreement with the one observed by Azage (1989), who reported CR under a single-sire mating system can be improved to above 80%, but is in contrast with the CR (45%) under pastoral management conditions reported by Coppock (1994). On the other hand, the current AR is within the research findings of 4% reported by Sabine (2004) for Boran cattle.

Mortality data based on 1258 calves born over a 4-year period is presented in Table 4. Of all calves born during a given breeding season; 96.82% were born alive and survived to 45 days and 3.18% were born alive but died before the mentioned period. Of all beef calves born during a given breeding season; 93.60% were born alive and survived to 45 days, and 3.40% were born alive but died before the mentioned period. Percentages of calves that were  born  alive  and  survived  to  45 days and born alive but died before the mentioned period were not similar (χ²<0.01) across years. The current result is within the range of earlier findings of pre-weaning calf mortality rates of 3.4% for Boran and their Friesian crossbred animals in the Abernossa ranch (Haile-Mariam et al., 1993) and 5.6% in crossbred animals bred using bull in and around Fitche town, North Shoa Zone of Oromia region (Tesfaye et al., 2017), in the central high land of Ethiopia. However, it is lower than the one reported by Homann and Rooyen (2007), who cited a smallholder herd mortality rate of 18%, with disease accounting for 60% of herd mortality for smallholder cattle in Masvingo district (Mavedzenge et al., 2006).

Community/cooperative bull scheme is one of the best suited breeding programs for conserving Boran Qorti breed. Generally, values for parameters such as pregnancy rate (PR), abortion rate (AR), calving rate (CR), and calve death loss based on calves born (CDLBCB) considered under the current study indicated as the selected breeding scheme has got paramount importance in conserving Boran Breed. Overall, the reproductive performance of Boran cattle under the community breeding scheme was found to be relatively encouraging. Thus the government should support and focus   on   conserving   cattle  breeds   those   that  have important economic values to the community and the country by enlightening pastoralists on improved management practices of rearing cattle and also advocate the importance of community/cooperative bull scheme to pastoral community to the broader area. Generally, to succeed in today’s cattle business it is vital to understand the comparative position of pastoralists cattle production operation, to be aware of broader industry trends and issues, and to make use of available resources designed to aid management decisions towards the wellbeing of pastoral community.

The authors have not declared any conflict of interests.