Thought not commonly considered a hay crop, Oats make good hay, particularly for a dairy cow’s dry period, which is the last month or two before she calves again, when she is no longer making milk. Hypocalcemia, or “milk fever,” is a complex metabolic disorder involving calcium. It strikes quickly and is usually fatal if not treated immediately by intravenous administration of calcium. And it strikes Jerseys worst of all dairy cattle, mainly because they are the highest production diary cattle per pound of body weight. Sort of like a Porsche or Ferrari, Jerseys are high performance, but you better treat them right.
There are several prevention strategies for milk fever, and some involve purchasing anionic salts or administering vitamin D or adjusting phosphorus in the diet, but the one we employ is to feed a moderate-to-low calcium diet during the dry period. The ordinary hay we make is NOT low calcium. Clover (all the legumes actually) and good grasses like Ryegrass and Bluegrass are relatively high in calcium, and so is grain besides corn. Corn silage is low calcium content, and so is Barley silage/haylage and straw. Oats, Rye, and plain Timothy grass hays are moderate-to-low in Calcium, and so are just about right. We don’t grow plain grass hay (which would require nitrogen fertilization or manuring), and we have no practical way to make corn silage, and I think it makes pretty lousy feed anyway, and Lizzy doesn’t particularly care for Rye hay. Immature green-chopped Rye is a different story, but in June it’s long past its prime. Spring-planted Oats, however, are just right for mid-June harvest as hay, and Oats are a clearly better hay than Rye.
According to extension publications the ideal time to cut Oat hay is at the “milk” or “soft dough” stage, and these descriptions are of the developing grains on the heads. I think it is preferable to mow before this stage, and I’ve found that Oats are not nearly as consistent genetically as other grains. Some Oats will be heading while others are still jointing (growing the stem that will form seeds), so I mow when I start to see about 10% of the plants heading out (June 9th this year), and this hay will dry faster and be better quality anyway. Also, if you let too much grain develop on the Oat hay, you may develop a colossal rodent problem. Rodents can’t survive on hay, but they will devour all the little grain heads in there, as well as nest in the stuff. So do yourself a favor and mow early. Waiting another couple weeks for a bit more yield is very counterproductive if all your hay is ruined by rodents!
It’s pretty simply to do, really. Just mow like you would grass hay, let it dry, ted maybe if needed, and then rake up, move (or bale), and store. I move my hay by raking it into large windrows and then forking it into my all-purpose trailer. Then I loose stack in the barn. Since this hay will be eaten at the end of the hay-feeding season (late February and March) it gets put in the back. Oat hay is a bit more slippery than regular legume-grass hay, so it forks a bit slower, at least when cut with a sickle-bar mower. It also dries faster since the stems of Oats are hollow and large diameter (compared to grass and legumes). The taste-tester likes it so much it can be used as a lure!