With the Dog Days of Summer behind us, we’re approaching the “Cow Days of Fall” here on the farm.
We’ve been lucky so far this fall. We’ve gotten some relief from the drought with a handful of decent rains this September, and there’s still plenty of warmth around to keep the grasses growing as much as they can with the short window of daylight we have around the fall equinox.
But likely within a week or two, the pastures will stop growing and the blades of grass we have standing out in the fields is all we’ll have for forage until we run out and have to start feeding hay. It’s that window of time, from the halting of pasture growth until the first cow takes its first bite of baled hay, that we call the Cow Days of Fall.
A “cow day” isn’t a term unique to our farm. It’s a well-established unit of measurement used to describe how much grass a cow will eat per day. A cow day, technically speaking, describes how much forage 1,000lbs of cattle will eat in a 24 hour period. So a 1,200lb full-grown cow would use 1.2 cow days of grass per day, while a 700lb yearling would use 0.7 cow days of grass per day. The find out approximately how many cow days your herd will consume each day, you add up their total weight and divide by 1000.
Roughly speaking, we have about 20,000lbs of cattle in our herd, and so we need approximately 20 cow–days worth of grass per day to keep them well-fed.
Measuring the requirements of the herd is the easy part. It’s measuring the volume of grass in the pasture that’s more difficult, and certainly relies more on intuition than science or mathematics.
So it’s in these waning days of summerish-fall when we start taking mental notes of how many days each pasture could adequately feed our herd.
The paddock we’ll move the herd to later this week, roughly 8 acres, looks to hopefully have about 200 cow days worth of grass in it, hopefully feeding them for about 10 days. A couple of our other 8 acre paddocks, however, only look to have 80-120 cow days in them (the drought really slowed regrowth during July and August).
Although we’d typically aim to try and graze as late as possible, this year we’d be happy if we could make it into early November before we start feeding hay. And so the grass that’s out in our fields will need to last roughly 5-6 weeks, something it may be hard-pressed to do this year.
Throw in a snowstorm like we got in mid-October 2020, and all bets are off. A pasture that has short grass might get completely covered up by a decent storm, and if things freeze hard soon thereafter, a thin layer of ice can prevent the cows from being able to eat through the snow.
But farming is about eternal optimism. So we’re planning for a long, extended fall with friendly, calm rainstorms and without our first real snow until mid-late November. Does that sound good to you?
Thanks for reading,