Formulate feed for grass grazing
Feeding a seasonal herd of 300 cows, pastured and milked three times a day, isn’t as challenging as you might think. Rob Hunt of Vergennes, Vt., ought to know. He’s been doing it successfully for years.
“For me, the biggest thing is getting enough energy into them,” he adds. “If they’re losing too much body condition, they’ll lose production and need more energy.
“If cows don’t have the body weight, especially on grass, they can’t keep going. They’ll drop drastically in production —and stay there.”
• Hunt Farm cows produce 20,000 pounds milk on grass plus total mixed ration.
• Seasonal dairying and calving makes freshening TMR crucial.
• Farm’s feed costs were under $6.50 despite energy for thrice-daily walks.
But compared to conventional herds, “nutrition for grazing isn’t any different,” asserts Dave Santos of Phoenix Feeds and Nutrition, New Haven, Vt. He’s the herd nutritionist for Hunt and wife Suzanne.
“Grass is just a commodity,” adds Santos. “You have to formulate the ration around its variability.”
Finer points of grazing and TMR
Hunt Farm’s herd milking average is between 19,500 and 20,500 pounds a year. They milk in a double-10, rapid-exit parlor at 3 and 11 a.m., and at 6 p.m.
During grazing season, cows are let out between milkings into paddocks enclosed with polywire.
The Hunts use about 800 acres for feed: 240 acres of mixed grass and clover pasture — some of which they harvest if needed — plus 225 acres of corn silage. The rest is alfalfa for haylage.
When the herd first hits spring pastures, “they’ll graze anything,” says Hunt.
After rotating through the paddocks a few times, the grass becomes less palatable. So he adjusts the total mixed ration, or TMR, fed in the barnyard at milking time, to how much cows eat.
“We monitor the feed bunk. What we’re looking for is the last cow out of the barnyard to eat the last bite of feed.”
When cows are on pasture, Santos bases the TMR on 15 to 19 pounds of dry matter. He used 20 pounds as a base this year to compensate for less corn silage and lack of carbohydrates.
Santos adds two or three extra megacals of energy to make up for a thrice-daily walk from pasture to parlor. That walk can total as much as six miles.
Feed costs per hundredweight of milk produced run between $4 and $6.50. Last year’s total cost of production ran $15.97 per cwt. of milk.
The herd grazes until about Nov. 1. Mud can be as big a problem as grass availability. Rain wreaks havoc on the farm’s clay soils and dirt cow lanes. Dry cows are grazed as a group for the first four weeks after dryoff and then are fed TMR.
Freshening’s nutritional challenge
Calving season runs April through November. That makes getting fresh cows off to a good start a bigger challenge than feeding on grass, says Santos.
A low-energy diet is crucial. Two pounds of straw and three pounds of dry hay in the diet keep transition cows in good shape with few metabolic diseases, he notes.
Seasonal calving has drawbacks. “When cows are calving, that’s all we do,” Hunt says. It’s intensive. But with warm-weather calving, the farm can use minimal housing and enjoy calf mortality of less than 1%.
“In winter, there are no retained placentas, no baby calves, no frozen teats,” he points out. “Winter is hard enough without having to deal with fresh cow issues.”
Harlow is a Vermont-based ag writer.
This article published in the December, 2010 edition of AMERICAN AGRICULTURIST.