Give first-time novelist Petersen credit: Not many would have thought of exploring the hard lives of a farm family through the eyes of a dairy herd. And even fewer could have sustained the conceit as successfully as Petersen does. In his version of barnyard life, the cows are as varied in their tastes and interests as their owners and, on average, as intelligent. They listen to what Farmer Bob, his wife and children, and hired hand say; they gather news from overheard radio broadcasts; and they speculate about the world outside their pastures. Most of all, they worry. Bob is increasingly distant and harried--and with good reason: His son, Gerry, is anxious to leave the farm for good. Moreover, Gerry's future is further complicated by the fact that it's 1969, the Vietnam War is in furious progress, and he's likely to be drafted. Meanwhile, Bob's teenaged daughter Renee is discovering just how limited life on the farm can be--and how unpleasantly archaic. There are other problems, too: Bob, who has stubbornly opposed mechanization, sees his profits slipping, and the local power company is planning to take part of his pasture. Several of the cows take turns narrating the action, their voices interwoven with those of Bob and his family. The venerable Bossy wonders whether ``it is more important that we do what humans want, or that we live according to our beliefs?'' Poor doomed Calvin, convinced that he's been called to serve as cowkind's ambassador to humans, attempts to communicate with Bob. And the mystic Aretha, who can see the future, rallies the cows in the novel's most startling scene to offer Bob some small glimpse of their real life. Petersen's fabulistic evocation of cows is wonderfully detailed and moving: Their rituals, beliefs, troubled grasp of the world are all vivid and convincing. But their sheer strange reality doesn't always jibe with the domestic drama of Bob's family. Still, this is one of the most original and promising of recent debuts.