Last week we told you why we don’t use Brix to measure the value of forage in pasture. Our primary reason is that it’s not a very reliable tool for looking at the nutritional value of a specific plant. Another reason is that so many people have measured forage value for so long, that you can get a pretty good idea of what’s going on in your pasture without taking any measurements at all.
What We Already Know About Forage Quality
One tool that we’ve all used to get a measure of forage quality is manure. What’s coming out is a good indication of what went in, as scientists have discovered from actually studying manure. Thanks to near infrared spectroscopy (NIRS) they were able to correlate forage quality with typical manure pats. So now, we can use these pictures of cow manure to get an idea of how good our forage is. You can see pictures of poop and their associated forage values here, and even download an app for your iPhone or iPad that will help you judge your pasture forage. (Sadly, it’s no longer available for non-Apple app users.)
With enough experience and science behind you, you can even use manure to estimate how much your cattle are gaining per day. Jim Gerrish’s article, The Proof is in the Poop Pudding, shows you what he’s found manure looks like when an animal is gaining two pounds per day and compares it to what manure looks like that’s producing a pound and a half a day.
Of course a truer measure of your forage value would require sending it off for chemical analysis. But don’t worry – the scientists are ahead of you there too. It turns out folks have been measuring forage values for so long, that we’ve got a pretty good idea of what a whole range of plants can provide in terms of energy and protein at different times during the growing season. The National Academy of Sciences gathered all that information for you in the “Atlas of Nutritional Data on United States and Canada Feeds.” Not only does it have most plants, it also has nutritional values for just about anything you might consider feeding to poultry and livestock – from potatoes to fish and more! (Just click to download your copy. If you’d rather have a hard copy, there are a number of them for sale at AbeBooks.com and at Amazon.com.) Will this data always precisely reflect our individual plants? Maybe not exactly, but it’s close enough for a good understanding of our pasture and its capabilities.
When You Need to Know More About Feed Quality
While these are all good resources for finding out about your forage value in pasture, there are times when you’ll want to do an actual forage analysis. Winter feeding might be a good time to know what’s in your swath, pasture or bales to help you figure out how much feed your livestock need, or how much you should pay for it. Having a precise measure is also important if you’re feeding dairy cows and mixing a supplemental ration to ensure good milk production. Low quality hay can cause a serious drop in milk production.
If the nutritional value of your hay is critical to your operation, don’t think you can eyeball a bale and get it right. As an example of what can happen, a group of 80 or so forage producers and industry people were asked to look at four bales of hay, ranging from pure alfalfa to an alfalfa-grass mix, and rank them in order of forage quality. Their rankings were all over the place and didn’t match the lab-tested Relative Feed Value (RFV) for the bales at all. The bale that looked best to the most voters turned out to have the lowest RFV of the four.
As the Penn State folks who ran this exercise said, “Appraisal of a forage based on sight, smell, and touch can provide some general information, but chemical analyses are needed to assess the economic potential of the forage.” You have to analyze your sample to really know the value of your forage.
Save Time and Money
What we like about all of these resources looking at forage quality is that they’re based on science that has been tested and replicated enough times to give us confidence in the results. They solve the main problem we found with Brix measurements – they can be replicated over time so that decisions can be made on the most solid information available.
