UNIVERSITY PARK, Pa. — Grassfed and organic dairy operations can feed molasses as a primary source of energy for cows.
“Molasses is a high energy feed that contains about 14 different sugars,” said Kathy Soder, animal scientist at U.S. Department of Agriculture, Agricultural Research Services, Pasture Systems and Watershed Management Research Unit.
“It can be a less expensive per pound feed depending on your local prices and current organic grain prices,” Soder said during a webinar hosted by eOrganic.
Dairymen are looking for an alternative energy supplement since organic corn prices have been high and availability spotty, Soder said.
“One of the biggest drivers is the growing consumer market for grassfed milk,” she said. “In our region, the price for grassfed milk is $4 per hundredweight over the organic price.”
However, Soder said, some dairymen have fed molasses to their herds and experienced problems.
“There can be nutritional issues especially if molasses is overfed because of high sugar levels and low starch levels,” she said. “Sugar degrades a lot more rapidly in the rumen than starch and if you get too much sugar in the rumen, it is toxic to the rumen bugs and they won’t function properly.”
In a research project, the effects of molasses on ruminal fermentation were evaluated in simulated rumens by comparing molasses with corn meal.
Four diets were fed including orchardgrass only, molasses at 5 percent and pasture, corn meal at 7 percent and pasture and molasses, corn meal and pasture.
“The only difference we saw was with crude protein that was a little higher with the molasses, the lowest for pasture and intermediate when corn meal was included,” Soder said. “For ammonia concentrations, the pasture was the highest, and we only got a decrease when we combined molasses and corn meal, but it was not a huge difference.”
There is a lot of variability of on-farm response to molasses supplementation, Soder said, and one of the big factors could be forage quality as well as the molasses source or other supplements fed to the animals.
“Greater supplementation rates may be warranted but it could depress nutrient digestibility and you have to look at the cost,” she said.
Soder discussed a study that evaluated the interaction between molasses and forage quality. The researchers fed two levels of molasses at either 5 or percent 10 percent with good quality pasture at 27 percent protein or lower quality pasture at 20 percent protein.
“The lower quality forage was slightly lower in dry matter digestibility than the good quality forage, but we saw no difference in crude protein digestibility,” Soder said. “The ammonia concentration was not significantly different, there were no differences in bacterial efficiency and no significant interactions between forage quality and molasses.”
Disparity in animal production on farms may be due to a number of factors, Soder said.
“Those factors may include the timing of supplementation of molasses fed in relation to when the forage is fed, the level of molasses fed or the adaptation of cows to pasture and molasses,” she said.
A study with grazing dairy cows in an organic operation compared the effects of feeding cornmeal or molasses on milk production, milk composition and nitrogen metabolism.
“We fed molasses or corn meal at 12 percent dry matter intake, top dressed on alfalfa baleage,” Soder said. “The Jersey cows grazed day and night and were brought in two times per day.”
Pasture intake was not different for corn meal versus molasses, Soder said.
“There was a difference in supplement intake, the molasses cows had greater supplement intake than the corn meal cows,” she said.
“The milk urea nitrogen was much higher in the corn meal cows than molasses cows,” she said. “The sugars in the molasses seem to be a better match to recapturing the protein in the pasture than the corn meal.”
Liquid molasses fed at 3.5 pounds can replace the same amount of corn when fed as the only energy source, Soder said.
“We didn’t see an effect on milk yield or components,” she said.
“Molasses can be fed to dairy cows but it is not a silver bullet,” she said. “It can be considered if you can’t get organic corn or the price is too high.”