You know when the cows are coming long before you lay eyes on the first massive bovine trundling up the crest of an intervening hillock in the sprawling plains the Gaiser family rents in the La Grange area. There's the sound of disgruntled lowing, begrudging the interruption of its sedentary, placid lifestyle, but more than that is the scattershot drumbeat of 115 sets of hooves pounding into the ground, ricocheting off the stony face of the hill before reaching the group of people standing by at the corral. Five people, led by Bill and Dick Gaiser, the cattle's owners, lead the herd to their ultimate destination, a wood-walled corral. They'd come, in the cold pre-dawn light, to do a job, one that's been passed down through shared history, interest and blood. However, the weight of modernity intrudes on the business of the past, where even a trail of power lines visible in the distance stand as a testament to the strain current politics puts on traditional ways of life. The goal of the Saturday morning wrangling was to prepare the cows for their seasonal journey into the mountains, where they spend the hot summer months wandering free and munching happily across the open federal land. Ranchers rent the fields in La Grange. San Francisco County manages the lands and grades the roads that play host to power lines that ferry electricity from the Moccasin Power Plant. The grazing lands are separated by gates and fences, and ranchers mark the cows with both a brand located on the haunch and patterns cut out of their ears. The Gaiser brand, an upper-case GH with the straight leg of the G facing away from the curve, was recorded in 1918. The letters stand for Gaiser-Hess, the duo that held the business originally. Bill and Dick Gaiser represent the second generation of Gaisers that have worked cattle under that brand, the second to guide the docile cattle from pastureland to mountain country. The cows actually prefer the mountains, Dick Gaiser had said earlier that morning as he drove to the pasture land. Ranchers do too because the clean, open conditions prevent the spread of disease through the population. The tradeoff makes the inherent risks of leaving cows unattended worthwhile. "You can lose 5 percent of your cattle through disease and conditions," he said, "or 1 percent from predators and getting lost." But it takes time, space and resources that make the practice economically unviable for the larger ranchers in California. Dick Gaiser had shrugged as he put his rumbling diesel truck into gear and began the slow climb up the hill toward a railway line littered with the bodies of coyotes with the misfortune to have been caught by ranchers looking to minimize that one percent. "If you have more time than money, you do it this way," he said. "If you have more money than time, you do it the other way." The trip to the mountains used to take five days of hard riding, corralling the cattle and pushing them stolidly toward their final destination. Now, the ranchers load the cows onto a large truck and make the trip in a day. While the luxuries of modern technology simplify the process, the environmental implications of the process raise hackles. Some feel that cows are to blame for the degradation of streambeds and water quality, consequences that move the environmental community to push for limits on how close to the streams cows should be allowed to wander. Not all the cows will go to the mountains. They have to earn their keep, which means producing young to keep the herd going. The Gaisers keep three bulls and 62 cows in this pasture. Of that number, 52 are paired, meaning the female cow has one offspring to care for already. All have to prove their worth, or they'll be separated out of the herd and sold at auction. To make the determination is livestock veterinarian Jim Clayton. If not for the blue coveralls, the man looks like he could have fit in at a ZZ Top concert with his white beard and eye-obscuring sunglasses. He puts on a long plastic glove that runs clear up to his armpit, and straps on an additional protective layer of greencovering that secures over his right shoulder. There is no cow ultrasound, so the fastest and most efficient way to find out if a cow is pregnant is to stick your hand in and feel around, which is messy work at best. The cows, which have been separated from their calves, are taken in groups from their holding pen and guided into the alley, a high-walled wooden chute that forces them to line up single file. One at a time, they're let into a green metal cage with a complicated system of levers that allows the ranchers to trap a cow in a loose vise that prevents them from backing up or injuring any of the workers. Operating the vise is a study in timing. One person lifts a gate to the side, allowing one cow to enter the vise, and then lets the doorway fall back into place, cutting off the next cow in line. The door at the other end, opens slightly to allow the animal's head to make it through and then crashes closed. At that point, a third person shoves a metal pipe through the slots of the vise as close to the back of the cow's legs as possible, immobilizing it. With an enraged half-ton cow, this can be like threading a needle through a small hole with someone pushing on it … hard. Clayton then approaches the cow through a swinging wooden door next to the vise. He lubes up and pushes his protected hand into the cow where the sun don't shine. He's feeling for the calf, which should have been conceived around February. Seconds later, he holds up three fingers, signaling that the calf is three months along. Cows, like people, gestate for nine months. According to Clayton, it's the size that counts. "At two months, it's a mouse, at three it's a rat," he said. "Four and it feels like a small cat and five like a dog." Sometimes with older cows, you can't feel anything at all, and have to go by the thickness of the arteries in the uterine wall, Clayton said. The work goes quickly, which one could expect with a vet like Clayton who calmly estimates he's probably seen two or three million cows over his 30 years in the business. At the end, there are only two cows that won't be joining the others in the mountains, which all agree is an exceptional number. The pregnant cows and young cattle are outfitted with heavy bells attached to thick straps the Gaisers sewed themselves. Heifers, cows that have never calved or are pregnant for the first time, are new to the bell, as are the calves. When the bell is slung across their neck and secured with twists of metal, the surprised cattle try to escape the sound of their own bell. Bill Gaiser calls the bucking performance the "heifer hop." Dick Gaiser credits the long, wet winter, which improved the amount of feed available for the free range cattle, for the unexpected fertility of the cows. He doesn't expect the same result on the other half of the cattle, which range on harder ground nearer to the Chinese Camp ranch. The entire process will be repeated on the other half in one week's time. At the end of the day, a veritable parade of pick up trucks dragging horse trailers winds its way across the beaten earth road, through the collection of gates. Dick Gaiser pulls off the road and waits for the last truck to pass. It's his self-imposed task to ensure that the last gate is closed. "The motto is to leave everything exactly as you found it," he said.