The type of grass they are grazing will also guide the supplement decision.
“With a cool season grass like fescue, if it is green underneath the brown grass on top, it will still have good protein and digestibility and can meet the nutritional requirements of the cows,” Lancaster said.
The decision on when to put out hay also has a cost component, said agricultural economist Dustin Pendell.
“Our research shows that the most profitable cow-calf operations tend to have the lowest non-pasture feed expenses,” Pendell said. “Some producers are making trade-offs between grazing the cows a little longer on pasture versus feeding hay.”
As cattle move closer to calving, veterinarian Bob Larson said he prefers cows calve out in pasture rather than in a barn or dry lot.
To keep from damaging the new growth of those pastures during calving season, Lancaster said it is important to move the location of the feed source so that the cows are spreading their manure and minimizing the concentrated damage to the grass that comes from cows standing around a hay feeder.
Larson added: “It is important to unroll the hay in a different location each time.”
Lancaster said producers need to move the cows a little early off the pastures to allow the grass time to rest before summer grazing.
“Newly green pastures where the cows graze all the leaves off the grass early will actually stunt the growth of that grass for the growing season, which is why it is important to rotate pastures,” Lancaster said.
Source : k-state.edu