The crowd presses forward to goad the animal, tweaking its tail or dancing just out of its angry range. The teasing ritual, in the middle of the bush in the Sudanese province of Bahr el Ghazal - the area worst hit by last year's famine - begins an hour after sunrise, and continues for a full two hours. "You die so that we can have peace!" shout the crowd.
A tribal chief, dressed in a safari suit with a gold-braided black hat, declares: "Anybody who fights again will go down like this bull." The spearmasters move in for the final act. A knife across the throat; a spear into the open, spurting wound; cries of jubilation. A dull-red crescent of blood soaks into the dusty ground. The bull thrashes a few times more, and finally lies still.
This grisly Sudanese death in the morning was intended to serve a bigger purpose: to help people stay alive. The history of the conflict is horrific. Almost 2 million Sudanese are reckoned to have died in the south in recent years through a mixture of war and famine, usually ignored by the rest of the world. The famine that devastated the region last year, when 50,000 died in just a few months, briefly brought the international spotlight on to Sudan, especially Bahr el Ghazal. The famine was partly triggered - and its effects were immeasurably worsened - by the almost invisible war. The Sudanese hope that if the death of the bull serves its intended purpose, then perhaps these will not be dying-fields in years to come.
The ritual slaughter was intended to create good omens for the extraordinary peace talks that took place between the two main tribes of southern Sudan, the Dinka and the Nuer. The peace meeting, brokered by the New Sudanese Council of Churches, went almost unreported: no press conferences, no international news agencies, no camera crews. This month's week-long conference in remote south-west Sudan could, however, have important implications for the region.
The general secretary of the New Sudanese Council of Churches, Haroun Ruun, describes this as "a rare chance" and "an historic event". Certainly, the delegates are taking it seriously. Many walked for days to get to the meeting, in a region where vehicles are scarce or non-existent. Others were flown in on planes specially chartered by the Council of Churches, landing on a nearby airstrip (ie, an open and more or less flat piece of ground), then travelling by lorry or on foot to their destination.
An entire purpose-built village - a south Sudanese Milton Keynes, as it were - has been erected. Dozens of brand-new toukel, the traditional round huts of the region, are scattered between the trees. In the conference hall - a long, low mud building, thatched with elephant grass - long boughs are laid in line for use as delegates' benches.
In many respects, this is very different from any other peace conference. Dress code is seriously mixed. Some are in ancient suit and tie; some are in traditional garb; many outfits are eclectic combinations - baseball cap and ceremonial fly-whisk, bishop's purple shirt and trainers, T-shirt ("Futureworld: Niagara's largest indoor entertainment centre") and robes.
Applause is usually in the form of musical interludes, of which there is no shortage. People regularly get to their feet and sing. After a minute or five, everybody sits down again, and the proceedings resume as though nothing had happened.
The proceedings are polite: when one side disagrees, there are rarely any interruptions, just a murmuring of discontent - followed by a retort that afternoon or the next day. Oh, for the Stormont talks on Northern Ireland, or the Kosovo talks at Rambouillet, to have been so civilised.
If the peace agreement sticks, the implications could be considerable. Clare Short, Secretary of State for International Development, courted controversy when she was sceptical about last year's Sudan famine appeal: she argued that the buck stops with local politicians who worsen the famine, not least by refusing to allow aid convoys through. Aid agencies working in the south retorted that starving people need emergency aid, whatever the immediate causes of their hunger may be. None the less, few dissent from her core point: that politics and war are at the root of the evil. If politicians can be forced to compromise, then much else will follow.
Peace between Nuer and Dinka seemed an impossible challenge. Relations have become increasingly bitter. Traditionally, it was just a matter of the occasional cattle raid, with few casualties. But things got much worse in the past few years. As one Dinka puts it: "We used to attack each other with spears. Now, there are automatic rifles. That's a big change." It has literally been a case of rape, pillage and slaughter. Both sides believe that the other side has committed terrible crimes. Everybody has a story of bloodshed to tell - of how people from the other side came to steal and kill, before fleeing into the darkness.
Not everybody is pleased that the conference, which was partly sponsored by Christian Aid, came to fruition. The Sudanese government has instituted an effective system of divide and kill, to prevent the (black, animist- Christian) south from making headway in its 15-year war against the (Arab, Islamic) north. The Khartoum regime therefore needs a Nuer-Dinka peace deal like a hole in the proverbial head.
Even those who seem to have most reason to be keen on reconciliation have sometimes been less than enthusiastic. The southern rebel force, the Dinka-dominated Sudanese People's Liberation Army, holds huge swaths of territory across the south. An end to Nuer-Dinka fighting could theoretically make life easier for the SPLA and its leader John Garang ("Dr John", as he is universally known) in their struggle with Khartoum.
SPLA leaders appeared to shower warm words on the conference. The movement's senior field commander, Salva Kiir, complete with Castro-style rebel's beard, stands declaiming about reconciliation between Nuer and Dinka. "Let us beat the drums of peace." Eight bullets gleam on his gun holster; his bodyguards clutch Kalashnikovs; outside the doorway, a young soldier squats behind a sub-machine gun. The SPLA talks peace, but is obsessed with war.
Despite the proclaimed enthusiasm of Kiir and others, SPLA leaders are not keen on the conference - because they are not in control of the process. The pressure came largely from the grassroots and local churches, not from national leaders such as Garang and his Nuer counterpart, Riek Machar. As one of the chants at the bull-slaughtering declared: "They [Machar and Garang] cannot decide anything. We are more powerful than they. They cannot lay down the law."
It is as if Gerry Adams and David Trimble were banned from taking part in anything except the opening session of the Stormont peace talks, before handing the floor over to local community leaders. In other words, a remarkable set-up. Salva Kiir used his speech to launch what amounted to a recruiting drive for the SPLA, while praising "your show". Not everyone was impressed. Deborah Nyadieu, a small bundle of energy in a neat blue dress, retorted that women no longer want to give birth to babies who would be sent out to die.
"We want to ask the men: why have our children been dying? Have any men died pregnant? Have you experienced the pain of labour? You are not so clever, you must take what we are saying seriously. Otherwise, next time we'll make a revolution. We'll stop having intercourse with you. We are not the women of the past." Laughter, singing, applause.
Even if the south-south agreement holds, Sudan's wider problems are far from over. Despite an alleged ceasefire, government forces continue to attack the south. A hospital in the town of Yei, for example, was severely damaged by Sudanese government bombing raids this month.
Some believe that a weakened Khartoum government could agree to a referendum on secession within the next two years; that option is more on the cards than ever before. Already, south Sudan is in a separate limbo of its own. Whatever happens next, the participants in the peace conference are proud of what they have already achieved. Henry Chuir, a Sudanese bishop recently released from a Khartoum jail, believes southern peace might also lead to a northern settlement. "If the south says 'We don't want war, we want peace' then the north will say 'They are united; it's better that we let them go'."
The slaughtered bull may mark the achievement of a peace from below. In that sense, this was indeed a historic moment. But politicians and professional soldiers have not yet had their say. A generation in southern Sudan has grown up knowing nothing but war. They see it stretching out for years to come.
Ask Salva Kiir about the prospects for long-term peace and about attempts to set up civilian structures in the desolation that is SPLA-controlled southern Sudan, and he is almost tongue-tied. By contrast, when asked about the prospects of further war, the commander waxes lyrical. "We're prepared to take the struggle on for a hundred years." The international community, whose involvement in the peace process is stalled, does not seem much bothered either way.
Perhaps somebody should go and slaughter a few more bulls.