It's always fun in the Spring to feel like all of a sudden I am seeing so many more animals on the landscape - sheep, horses, pigs, cows, but what about the Winter? If grass-fed meat means that the animals are grazing or eating "grass" their whole lives, what happens in the winter?
Cattle are well equipped to handle below freezing temperatures - if they are dry, adequately fed, and have plenty of water. All of these things help to boost their metabolism and produce body heat. Farmers take the necessary action to ensure that water sources don't freeze, windbreaks are in place on pasture, and provide salt and mineral licks for the animals to supplement the winter diet. Also, some cattle breeds like Devon, Belted Galloway, Ayrshire, and Highland are more genetically adapted to colder climates than others.
During the winter, 100% grassfed animals are either eating stockpiled feed that was collected in late summer/early fall after grazing or hay harvest OR grazing corn crop residues (maybe a little of both!). According to the Iowa Beef Center, a pasture that was grazed will produce approximately 1 ton of stockpiled forage per acre and provide 47 cow-days of grazing per acre. Whereas, corn crop residues from one acre will provide approximately 35 days of grazing. While slightly less productive per acre, corn crop residues are the least expensive forage source in Iowa and turn waste into wealth.
Grazing cattle all year helps to maintain their long-term calf production by matching their nutrient requirements with the nutrient supply of available forage. Peak forage production of the cool season grasses that are common in Iowa is in June/July; and peak nutrient needs of the animal is during lactation (6-8 weeks post calving). So, if the animals are calving in April and May their major nutrient needs will naturally line up with nutrient production. Therefore, they can consume a more meager diet in the winter months.