A Year on a Dairy Farm

9. Chapter 09 October Breeding Back

It is the third week of October, and the leaves on the maples along the road are well into their orange and red, and Hazel is in heat.

That last part is something Tom has known for about an hour. She is at the back of the milking string, breathing in the steady focused way a cow breathes when something specific is happening inside her, but earlier this morning, in the parlor, she had the distinctive look of a cow about to come into heat, and the activity monitor on her collar had been showing higher-than-baseline movement since the previous evening, and at lunchtime in the dry pen Tom had watched her stand still and let another cow place her front feet on Hazel’s hindquarters for several seconds. Standing heat. The thing he had been waiting to see.

Hazel has been open since May.

That word — open — is what dairy farmers call a cow who is not pregnant. The opposite is bred. A bred cow is a cow whose body is, on the slow internal clock of nine and a third months, doing the work of building the next calf. An open cow is a cow whose body is between things. Open cows do not contribute, in dairy economics, what bred cows contribute. An open cow, the longer she stays open, becomes a problem.

Hazel was bred in late May, six weeks after Mabel was born. The semen was from a Jersey bull called 7JE08824, whose catalog photo shows him standing in profile in front of a fence, looking middle-distance, with the slightly bored expression of a celebrity at a press event. The breeding did not take. Tom checked her thirty days later and her uterus, by palpation, was empty.

He bred her again in mid-June. That did not take either.

By that point it was July, and the temperature was in the high eighties almost every day, and Tom did what every grass-based dairy farmer in the Northeast does when summer arrives: he stopped trying to breed his cows. The reason is heat. A cow in temperatures above seventy-five degrees, day after day, with a body that already runs warm and an internal furnace of forty pounds of milk a day, is in what dairy people call heat stress. Heat stress reduces conception rates by twenty to thirty percent. It also lowers milk production, weakens immune function, and makes everything in a cow’s life harder. You can breed her if you want; she will mostly not get pregnant. So you wait.

You wait until October. The leaves change. The temperature drops. The cows’ bodies come back to themselves.

This morning, Hazel is in heat.

How does Tom know? Two ways. The collar and the eye.

The collar. Around Hazel’s neck is a small black device — about the size of a deck of cards — that contains an accelerometer and a microcontroller and a battery. It tracks her movement. Cows in heat are restless: they walk more, they stand for shorter periods, they spend more time at the feed bunk and less time lying down. The collar collects this data and sends it, via a base station in the milkhouse, to a piece of farm management software Tom looks at every morning on his phone. When a cow’s activity spikes above her own baseline, the software sends Tom an alert. Hazel’s alert came in at six-thirty last night.

The collar is a relatively recent addition to the farm — Tom installed the system in 2019 — and it has roughly tripled the rate at which his herd’s heats are caught. Before the collars, dairy farmers detected heats by walking through the herd several times a day and looking. Looking still works. The collar just makes it less of a coin flip.

The eye. Even with the collar, Tom watches. He watched at five this morning when he brought Hazel in from the pasture. He watched at eleven when he was pushing up feed. He watched at noon when he saw the other cow place her feet on Hazel’s hindquarters. The collar said Hazel is showing increased activity consistent with estrus. The other cow said Hazel is in heat now. The two sources of evidence add up. Tom is going to breed her this afternoon.

Why this afternoon? The biology of timing.

A cow’s estrus cycle is twenty-one days long. For most of that cycle her ovaries are doing slow internal work that produces no outward sign. For about twelve to eighteen hours of every cycle she is in standing heat — the brief window when her body is releasing an egg and is biologically ready to be bred. That window is the thing Tom is trying to catch.

The egg, once released, lives for about ten hours in the cow’s reproductive tract before it deteriorates. The sperm, once introduced, lives for about twenty-four hours and is most vigorous in its first six. The two have to meet in a specific section of the oviduct at a specific time. If you breed her too early — before standing heat starts — the sperm may die before the egg arrives. If you breed her too late — more than ten hours after the egg has dropped — the egg may be gone by the time the sperm makes it. The optimal window for AI is somewhere in the middle of standing heat, give or take a few hours. Tom watched her at noon. She is most likely in the middle of her standing heat right now. The window of greatest fertility closes by tonight.

So this afternoon, between three and four, while Marcelino starts the evening prep in the parlor, Tom will go to the AI tank in the milkhouse, take out the small straw of frozen semen he selected three weeks ago, thaw it carefully, load it into a stainless-steel insemination gun, walk back to the cow he has known for six years, and put a calf inside her.

The semen comes in a thin plastic straw about the size of a coffee stirrer. Each straw holds about a quarter milliliter of bull semen — roughly fifteen million sperm — frozen in liquid nitrogen at minus three hundred and twenty degrees Fahrenheit. The semen is stored in a tank in the milkhouse, a tank Tom keeps filled with liquid nitrogen, which is replenished by a delivery service from Ithaca every three weeks.

The semen Tom selected for Hazel this round is from a Jersey bull called 7JE16204 — different from the one that did not take in May. Tom used to breed her to Holsteins for the volume; he stopped a few years ago, when he made the math come out for himself: on grass, his Jersey-cross daughters held up longer and cost less to keep, even at lower production. Mabel, who is upstairs in the heifer barn now, is the first of Hazel’s calves from this new arithmetic. The catalog from Select Sires, which is one of the largest of the dairy genetics companies in the country, has a page on this bull. His name is Greenview Dior. He was born in 2019 on a farm in central Wisconsin. He is a Jersey of strong grass-based parentage. His daughters, the catalog says, calve easily, produce well on grass, and have what the genetics people call good udder conformation, which means their udders attach to their bodies in ways that hold up over time. A straw of his semen costs Tom thirty-two dollars.

This is one of the strange things about modern dairy.

A bull at a place like Select Sires lives in a barn somewhere in Ohio or Wisconsin and is collected, by trained technicians, two to three times a week. His semen is processed, evaluated, divided into straws, and frozen. From any one collection the company may produce three hundred straws. Over the course of his productive life, a single popular bull may sire — through artificial insemination — fifty thousand or one hundred thousand or three hundred thousand calves on dairy farms across the United States and around the world. He never meets a single one of them. The cows never meet him. The semen travels in liquid-nitrogen tanks in the back of refrigerated trucks; the bull stays where he is until he dies or stops being productive.

A modern dairy cow’s father is, almost invariably, a bull she will never see. So is her grandfather. So is, going back many generations, the entire male line of her family tree. A small number of bulls have, in this way, become the genetic ancestors of an enormous portion of the world’s dairy cattle. Mabel — the Mabel born in March, who is now seven months old in the heifer barn — has, in her ancestry, perhaps two dozen bulls in the past century who account for a majority of her DNA.

This is genetic management at industrial scale. It is also not, in any meaningful sense, what the word breeding used to mean.

At three-fifteen Tom takes the semen straw out of the tank with a long pair of tweezers, drops it into a small metal cup of warm water at thirty-five degrees Celsius for forty-five seconds, dries it, slides it into the insemination gun — a stainless-steel rod about the length of his forearm — and walks back through the milkhouse to where Hazel is now standing in a head-lock at the end of the milking string, contained but not stressed, eating a small handful of grain.

He puts a long plastic glove on his right arm — the glove goes up to his shoulder — and reaches into Hazel’s rectum with his gloved hand. Through the wall of her rectum he can feel her cervix and her uterus, and he uses his hand from inside her body to position her cervix in line with the gun. With his other hand, the bare one, he inserts the insemination gun through her vulva, through her vagina, finds the cervix with the tip of the gun, and threads the gun through the soft folds of the cervix into the body of her uterus. There are five or six small folds in the cervix, and the gun has to navigate each of them. This is the part that takes practice. Tom has done this approximately four thousand times in his life. He is good at it.

When the tip of the gun is in the right place — at the junction of the uterine horns, where the egg will be coming down — he presses the plunger. The semen is released. He withdraws the gun. He withdraws his arm from her rectum. He removes the glove and drops it in a hamper. The whole procedure has taken about three minutes.

Hazel, throughout, has been chewing her grain. She has, as far as one can tell, noticed almost nothing.

Why are we doing all of this?

The biological answer: a cow gives milk because she has had a calf. The system does not work otherwise. Lactation, in mammals, is part of the reproductive cycle. The udder fills up because there is a calf to nurse, and the udder will keep producing milk as long as it keeps getting emptied — by the calf, or, in dairy, by the milking machine — but not forever. Milk production peaks about six to eight weeks after calving and then declines, slowly at first and then more steeply, until at about ten months the cow is producing too little to be worth milking anymore. To keep her in production beyond that, you have to start the cycle again. You have to breed her back.

The economic answer: every day a cow is open is a day she is moving toward the end of her productive lactation without anything to follow it. If she does not get bred back, eventually she runs out. She has to be dried off, at some point, regardless. If she is pregnant when she is dried off, she will calve in two months and start a new lactation. If she is not pregnant when she is dried off, she is simply a cow standing in a barn eating feed and producing no milk, until you decide what to do with her. What to do with her is, on every dairy farm, an active question.

A cow who has been bred unsuccessfully four or five times, with no clear medical cause, is a cow whose value to the operation is approaching zero. There is a number, in every farmer’s head, of dollars per day she is costing him: feed, bedding, water, parlor time, the opportunity cost of the stall she is in. If that cost runs long enough, she will be culled. She will be sent to the auction or to a beef farmer. Her place in the herd will go to a heifer who has just freshened — a young cow in her first lactation — and the cycle will continue.

This is what the cow’s life is, in exact terms. She lives so long as she keeps producing. She produces because she is bred. She is bred because the system requires her, on a roughly annual cycle, to start a new pregnancy. The continuity of her life is contingent on the continuity of her pregnancies. Hazel’s existence on this farm is the expression, in the body of one animal, of an arrangement that has been worked out over centuries between the cow and the human, and which is, by both biology and economics, what it is.

By four o’clock Hazel is back in the alley, walking slowly toward the water trough. She drinks. She turns her head and looks at Tom, who is in the milkhouse cleaning up the AI gun. She looks back at the trough. She drinks again.

In thirty days Tom will check her. If her uterus has the small firm shape of a six-week pregnancy, she has taken. If it does not, she will come back into heat in three weeks, and Tom will breed her again, and they will see.

The light through the milkhouse windows is yellow now, the long horizontal yellow of October afternoons in the Finger Lakes. Outside, in the heifer pasture, Mabel is grazing. She was weaned in August and turned out with the other heifers in early September. She is half her mother’s height already. By next winter she will be the size of a small adult cow. By a year and a half from now she will be ready to breed. She does not know any of this.

Hazel drinks her water. Tom puts the gun away. The sun moves another inch across the floor of the milkhouse. Outside, somewhere over the hill, a tractor is running, and Marcelino is on it, and one of the things that gets done in October on a farm that does not stop is getting done.

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