Adjust cutting schedules for forage yield, quality needs
With escalating costs, hay growers and dairymen need to produce quality forage as cost-effectively as possible. Dan Undersander, University of Wisconsin forage specialist, offered suggestions, utilizing results from university studies, at a recent World Dairy Expo talk.
“Think of the quality that you want to harvest,” said Undersander, who suggests harvesting before mid-bloom. Studies comparing milk production of cows fed 20%, 35% and 54% concentrate with pre-bloom, early bloom, mid-bloom and full-bloom alfalfas showed two things. “Adding more concentrate increased milk production, but by the time we got to mid-bloom, it did not do as much as if we harvested that forage earlier.”
Adjust your cutting schedule to harvest the yield and quality you need, Undersander advised. A three-year study compared quality and yield on plots cut three times by Sept. 1 — yielding 6.5 tons/acre dry matter — and four times by Sept. 1 — yielding 4.5 tons/acre.
“We were looking at a 32% yield reduction to take that extra (fourth) cutting to get that quality (150 RFV) forage, plus there was the extra labor of the cutting. I'm not saying that's a bad idea, but it's important to understand there's a cost for that quality.”
A northeastern Wisconsin farmer raising heifers cut alfalfa haylage at about 10% bloom and took one less cutting. “He did increase his haylage yield by 30% compared to previous cuttings at mid-bud stage. He was still getting the quality he needed for growing his heifers — not enough for a dairy herd, but enough for growing heifers,” Undersander said.
Providing for the horse market? Think of quality before you plant or harvest.
“We obviously want to put a little bit of grass with the alfalfa, but we're also going to want to harvest a little bit later. Horses don't need anything as rich as dairy cows. We want a little bit more fiber and a little bit less energy. We can take one less cutting and get more tonnage.”
The longer the wait between harvests, the more tonnage produced; but there's also a linear decline in protein. Studies show that quality decreases by 5 RFV points/day on first cutting, 2-3 points on second and 1-2 points on third or fourth cuttings taken during the growing season. Forage cut from mid-September to early October shows little change in quality.
Fiber digestibility also declines in a linear fashion. “Both RFV and RFQ are going to decline about 5 points/day on first cutting in the spring,” Undersander said.
Feed the lowest quality the animals need, he added. To figure what quality is needed and still get a profit, use a University of Wisconsin spreadsheet that calculates changes in first-cutting yield and RFV (www.uwex.edu/ces/crops/uwforage/haycutdate.xls).
“For example, I put in that a field was growing 100 lbs/acre of hay per day, an RFV change of 5 and $1/point of RFV with the idea of harvesting an additional ton of hay at $15.”
The first ton of hay would cost around $60, including costs of harvesting and hauling it off the field. “Our engineers tell us it's not too much more if we harvest a higher yield. So I plugged in $15 to harvest the additional ton. As RFV declines, it plots the yield going up and the optimum return. The most profit to the grower is slightly below 150 RFV with these conditions. In this day and age, we're going to need $1 or a little more per point of RFV to make up for the yield loss.”
To minimize the cost of growing quality alfalfa, consider keeping stands only three years, he said.
“Our data is clear that, east of the Mississippi, if we seed in spring, the first year we'll get about 50% of alfalfa's potential yield. The first production year, a 100% yield is possible and the second year, 102% is likely. Then it starts to fall to 83% in the third production year and 64% in the fourth production year.
“Would you grow a corn hybrid that yielded 17% less than you thought you could get?” Undersander asked. “You probably shouldn't keep an alfalfa field, either. We're looking at three years of rotation (including establishment year) as being optimum for alfalfa east of the Mississippi. I think we can add a year on as we get west of the Mississippi.”
Cut hay at the right time, too. “Quality is changing about 5 points a day in spring. RFQ changes about 4 points a day on the second and third cuttings. At some point it becomes worthwhile to say ‘I just can't get that hay up like I'd like. I might as well let it go to 10% bloom, take a little bit more yield and feed it to heifers.’ ”
Minimize losses by reducing ash content in hay to 10% and store hay off the ground and/or cover it, he said.