The difference between good hay and poor hay (with less nutrient content or moldy and dusty) is primarily timing of harvest.
Glenn Shewmaker, state forage specialist, University of Idaho, says the stage of harvest is crucial. For some classes of animals mature hay is adequate, but for livestock that need a higher nutrient level — such as lactating dairy cows, weaned calves or cows with calves at their side — you want early-cut, immature plants that are higher in protein. Overly mature or weather-damaged hay can generally only be utilized by non-lactating beef cattle.
Kevin Sedivec, North Dakota State University, says harvest strategy is different for grass hay than for alfalfa, or for mixed grass and alfalfa.
“The best time to cut grass hay is just after boot stage, right before heading, to optimize quantity and quality,” explains Sedivec. “We did some research, looking at timing, and cut a different piece of the field every two weeks. When you get to the heading-out stage (just after boot stage) versus seed-set stage, you have about 90% to 95% of the potential growth of that plant. Quality is still fairly high. Protein level at that stage is about 9% to 10% (depending on the type of grass), and this is the quality you’d need for lactating beef cows,” said Sedivec.
This stage of growth occurs earlier in southern regions and later in northern regions with shorter growing season and depends a little on the year and weather conditions.
“If you wait until seed-set stage you might gain 5% more production (a little more total mass and quantity) but quality drops from about 10% protein level down to about 7%, which is only good for a dry cow.
“If the fields are not too dry yet, grasses regrow faster if you cut them at that stage, and you’ll have a lot more regrowth for fall pasture. Once the plant starts to produce seed, it puts all its energy into seed production instead of leaf production. It won’t regrow much at all,” he explains.
“If you cut it before the heading stage, it will still try to regrow leaf tissue because it wants to grow and produce seed. The best time to cut grass is the boot stage, for quality, but you give up about 30% of growth.”
It’s better to compromise a little quality to get more tonnage, waiting until just before it heads, and still get regrowth.
Some grass species regrow better than others.
The time of day you cut grass hay also makes a difference on quality, especially sugar content.
“If you cut it in the evening the sugar will be higher than if you cut it in the morning,” Sedivec says.
Shewmaker explains that plants accumulate sugars and starches during the day, through photosynthesis, then use up these nutrients at night as they grow. Time of day can also be a factor for humidity. If you cut in early morning, it will be wet if there’s dew, and it might be too wet to cut.
ALFALFA HAY: “The main thing with alfalfa is what your plan is in terms of feeding, such as dairy versus beef cattle,” Sedivec said.
If you want dairy quality alfalfa, cut it at bud stage — well ahead of any blooms. You give up quantity and tonnage for that first cutting when you cut it early, but if you cut it in the bud stage you almost always gain an extra cutting later in the season—unless weather gets too dry and you run short on water.
“Rule of thumb when cutting alfalfa for beef cattle is to cut when it’s about 10% bloomed,” said Sedivec. “By the time you see blooms you don’t have much window. If it’s 10% bloomed, it can be at 20% the next day. When I see one bloom, it’s time to cut that field!”
You give up a little quality, for beef cattle, once it starts to bloom, but relative feed value will still be in relatively high, but even higher if it’s still in the bud stage when cut.
“At first bloom, you only give up about 10% of potential biomass. Don’t wait any longer because once it starts to bloom it gets more stem and there’s more leaf shatter (and leaf loss) when baling. When it’s this mature, cattle only want to eat the leaves and sort out the stems,” explains Sedivec.
“When hay is at that stage of maturity you really have to watch timing of baling to make sure it’s not too dry. You need enough to humidity to keep leaves on, but not so much moisture the hay will mold,” he said.
You may have to bale in the evening just as dew comes on and quit when dew gets heavy.
Shewmaker says some producers use moisture meters to check hay and determine when to bale a field, though some who’ve been putting up hay for a long time can assess moisture levels in the hay just by feeling the stems — using various twisting and snap tests to check stem dryness.
GRASS/ALFALFA MIX: Sedivec recommends cutting mixed hay by maturity of the alfalfa, not the grass.
“When you start to see alfalfa bloom, it should be cut, even though the grass won’t be quite ready. Alfalfa usually matures quicker, starting to bloom before grass is in boot stage, so you give up some biomass on the grass. If you wait until you see that first bloom in the alfalfa you are giving up about 20% of the potential biomass for the grass, but still have a high-quality feed that works well for almost any class of livestock,” Sedivec says.
Grass is very high quality when cut at that stage because it doesn’t have seeds yet.
“The alfalfa is a little bit into the bloom but its nice mix, and high enough in protein for any livestock except dairy cows,” he says.