FEED ANALYSIS AGAIN! by Mike Mehren Ph.D.

Feed analysis is a subject dear to my heart. The are two types of feed analysis. Each has its attributes. The biggest problem with any feed analysis is actually getting a good sample of the feed

We wanted to get an analysis of the grass in several different pastures. The best way to do that is to wander around like a cow or calf and grab or cut clumps of grass that you think an animal might like. Make certain that there is no dirt on the sample. That will show up as mineral in your report. You won’t be able to duplicate what the animals actually graze, but research shows us that the minerals will be pretty accurate. The protein and energy (TDN) will be lower than the feed that the animals graze. Apparently we don’t know which plants the animals actually like, and why they like a particular plant.
A rancher I was working with decided to kill two birds with one stone. First he put out new bags of mineral, then cut grass samples from all around the pasture. When we got the test back, some of the minerals were at toxic levels. After reviewing what happened, I think the mineral was transferred from hand to wet grass sample, thus the high levels. Samples of the pasture taken later had minerals in normal ranges. I like to preserve wet samples by cooling them or freezing them after collection. When shipping to a lab, I use a freezer pak in the shipping package to prevent rotting while in transit. This is used for silage, fresh grass, and wet rations.

Sometimes baled alfalfa is sampled by simply grabbing a handful of hay and sticking it in a bag. Invariably leaves are lost and the sample comes back much lower in protein and energy than it really is. Any feed having leaves or flowers should be sampled using a probe. The probe cuts a plug that includes leaves, stems, and other plant parts. A Minimum of 10 bales should be included in a single sample.

Sampling errors can also occur at the lab. If you send in a fairly large sample, the lab may only use a portion of your sample for analysis. Since your sample is divided, it can lead to error. It’s impossible to analyze a portion of something and be certain it is exactly the same as the original. Labs use this because of the grinding and drying process and limited time and space. They are very careful to do all samples the same.

Now back to the two basic types of analysis. One is called N.I.R. the other is called Wet Chemistry.

N.I.R. is an abbreviation for near infrared reflectance spectroscopy. I love abbreviations!
Basically it measures colors and relates the color to nutrients.

It is very rapid
It is relatively inexpensive
Feed Analysis

Does a good job measuring protein, dry matter and ADF on a single forage or silage. Should not be used for mixed silage, grain mixes with added mineral, total mixed ration. Should be compared regularly with wet chemistry values by the lab.
Should be calibrated for your area. NIR results determined in Kentucky for alfalfa hay grown in Oregon may not be accurate. This is because of the differences in the plants.
Should not be used for mineral analysis.

WET CHEMISTRY.

Offers a complete analysis of feed. Can include dry matter, crude protein, ADF, NDF, fat, ash, calcium, phosphorus, sodium, potassium, magnesium, sulfur, iron, manganese, zinc, copper, iodine, cobalt, and selenium (note: iodine, cobalt, and selenium are not part of a typical analysis).
Takes several days
More expensive than NIR
Can be used for all different kinds of feeds; grain, ethanol by-product, mixed hays, straws, vegetable waste, and silages.

Why bother with feed analysis? Maybe these examples will help show you the value.
DRY MATTER
We want to feed 10 lb of hay or substitute a silage or by product. Hay is 90% dry matter, so we get 9 lb of dry matter when we feed 10 lb. Corn silage is 28% dry matter, so we need to feed 32 lb to get 9 lb dry matter. Asparagus butts are 9% dry matter, so we need to feed 100 lb. to get that dry matter.
PROTEIN
We want to supplement 0.5 lb of actual protein.
Alfalfa hay with 18% protein as fed, requires feeding 2.8 lb
Alfalfa hay with 15% protein requires 3.3 lb
Pea hay with 10% protein requires 5 lb.
Corn distillers grain w/ solubles has 25% protein, requires 2 lb
TDN
We want to feed 4 lb of TDN.
Corn can be fed whole, is has 90% TDN dry matter, and requires feeding 5.2 lb
Good quality alfalfa hay 60% TDN, requires 7.4 lb.
Corn silage has 72% TDN (dry matter); requires 20 lb
Corn distillers grain w/ solubles has 99% TDN, requires 4.5 lb feed

If you have a feed test that doesn’t show TDN, you can figure it at home. For hay, the formula is 88.9 minus (% ADF times 0.79). Our hay sample has an ADF value of 40, so 88.9 minus (40 times 0.79) = 88.9 – 31.6 = 57.4% TDN

For straw the formula is different. It is 85.9 minus (% ADF x .837). Our wheat straw has an ADF of 58%, so 85.9 – 48.5 = 37.4% TDN.

Not all labs use these equations, however when used, they clearly define the difference between straw and hay for TDN. I’ve seen lab tests for grass seed straw that showed
a TDN of 57% and in the same group was an alfalfa hay showing 60%. I don’t believe that cattle will perform as closely as those numbers imply.

The tests shown are those that are most commonly done. This doesn’t mean that they are all you need to know about your feed. Labs offer mineral ‘packages’ that give a single price for macro minerals (such as calcium and phosphorus) and another package that reports trace minerals (such as zinc and copper). Phosphorus is a very expensive mineral. It makes up a huge portion of the cost of a vitamin-mineral supplement. If a feed test shows that you have sufficient phosphorus (0.25% for all but the highest stages of production by beef cattle), elimination of phosphorus from your mineral can save hundreds of dollars per ton!

In the Northwest we continue to identify copper problems in beef herds. To get a true picture of the copper status of your forage, your test needs to include iron, sulfur and molybdenum because these minerals interact with copper and affect the amount of copper that your animals get out of your feed.

Feed labs do not test for vitamin content of feeds. This is left to labs that specialize in these analyses. These tests are quite expensive. I’d rather assume that the vitamin content of dry forages, straws, and hays is low and include Vitamins A, D, and E in a supplement.

You now have my feed testing sermon. It only costs about $45 for a very complete analysis. Your extension agent should have a hay probe that you can borrow for hay testing. All feed company reps that I know also pack hay probes, and are happy to assist you with getting samples and recommending the lab that they have confidence in. Different labs have different expertise. You can take the information from a feed test and plug it into the OSU Cowculator to help determine how the feed tested will fit into your program. A livestock nutritionist should also be able to help you interpret protein energy and mineral values. Money spent on feed testing can return huge dividends. If you’d like the name of the feed labs I use or what feed test to request, don’t hesitate to contact me by email.

Michael J. Mehren Ph.D. is a livestock nutritionist trying to spend his feed test dividend somewhere near Hermiston, Oregon. To date he has had no success. He can be reached by email at mehrens@eotnet.net.

Information on wet chemistry vs N.I.R. from AS 99, 3/90. North Dakota State Univ.
Morse and Sedivec.



		FEED ANALYSIS AGAIN! by Mike Mehren Feed analysis is a subject dear to my heart. The are two types of feed analysis. Each has its attributes. The biggest problem with any feed analysis is actually getting a good sample of the feed We wanted to get an analysis of the grass in several different pastures. The best way to do that is to wander around like a cow or calf and grab or cut clumps of grass that you think an animal might like. Make certain that there is no dirt on the sample. That will show up as mineral in your report. You won’t be able to duplicate what the animals actually graze, but research shows us that the minerals will be pretty accurate. The protein and energy (TDN) will be lower than the feed that the animals graze. Apparently we don’t know which plants the animals actually like, and why they like a particular plant. A rancher I was working with decided to kill two birds with one stone. First he put out new bags of mineral, then cut grass samples from all around the pasture. When we got the test back, some of the minerals were at toxic levels. After reviewing what happened, I think the mineral was transferred from hand to wet grass sample, thus the high levels. Samples of the pasture taken later had minerals in normal ranges. I like to preserve wet samples by cooling them or freezing them after collection. When shipping to a lab, I use a freezer pak in the shipping package to prevent rotting while in transit. This is used for silage, fresh grass, and wet rations. Sometimes baled alfalfa is sampled by simply grabbing a handful of hay and sticking it in a bag. Invariably leaves are lost and the sample comes back much lower in protein and energy than it really is. Any feed having leaves or flowers should be sampled using a probe. The probe cuts a plug that includes leaves, stems, and other plant parts. A Minimum of 10 bales should be included in a single sample. Sampling errors can also occur at the lab. If you send in a fairly large sample, the lab may only use a portion of your sample for analysis. Since your sample is divided, it can lead to error. It’s impossible to analyze a portion of something and be certain it is exactly the same as the original. Labs use this because of the grinding and drying process and limited time and space. They are very careful to do all samples the same. Now back to the two basic types of analysis. One is called N.I.R. the other is called Wet Chemistry. N.I.R. is an abbreviation for near infrared reflectance spectroscopy. I love abbreviations! Basically it measures colors and relates the color to nutrients. It is very rapid It is relatively inexpensive Feed Analysis Does a good job measuring protein, dry matter and ADF on a single forage or silage. Should not be used for mixed silage, grain mixes with added mineral, total mixed ration. Should be compared regularly with wet chemistry values by the lab. Should be calibrated for your area. NIR results determined in Kentucky for alfalfa hay grown in Oregon may not be accurate. This is because of the differences in the plants. Should not be used for mineral analysis. WET CHEMISTRY. Offers a complete analysis of feed. Can include dry matter, crude protein, ADF, NDF, fat, ash, calcium, phosphorus, sodium, potassium, magnesium, sulfur, iron, manganese, zinc, copper, iodine, cobalt, and selenium (note: iodine, cobalt, and selenium are not part of a typical analysis). Takes several days More expensive than NIR Can be used for all different kinds of feeds; grain, ethanol by-product, mixed hays, straws, vegetable waste, and silages. Why bother with feed analysis? Maybe these examples will help show you the value. DRY MATTER We want to feed 10 lb of hay or substitute a silage or by product. Hay is 90% dry matter, so we get 9 lb of dry matter when we feed 10 lb. Corn silage is 28% dry matter, so we need to feed 32 lb to get 9 lb dry matter. Asparagus butts are 9% dry matter, so we need to feed 100 lb. to get that dry matter. PROTEIN We want to supplement 0.5 lb of actual protein. Alfalfa hay with 18% protein as fed, requires feeding 2.8 lb Alfalfa hay with 15% protein requires 3.3 lb Pea hay with 10% protein requires 5 lb. Corn distillers grain w/ solubles has 25% protein, requires 2 lb TDN We want to feed 4 lb of TDN. Corn can be fed whole, is has 90% TDN dry matter, and requires feeding 5.2 lb Good quality alfalfa hay 60% TDN, requires 7.4 lb. Corn silage has 72% TDN (dry matter); requires 20 lb Corn distillers grain w/ solubles has 99% TDN, requires 4.5 lb feed If you have a feed test that doesn’t show TDN, you can figure it at home. For hay, the formula is 88.9 minus (% ADF times 0.79). Our hay sample has an ADF value of 40, so 88.9 minus (40 times 0.79) = 88.9 – 31.6 = 57.4% TDN For straw the formula is different. It is 85.9 minus (% ADF x .837). Our wheat straw has an ADF of 58%, so 85.9 – 48.5 = 37.4% TDN. Not all labs use these equations, however when used, they clearly define the difference between straw and hay for TDN. I’ve seen lab tests for grass seed straw that showed a TDN of 57% and in the same group was an alfalfa hay showing 60%. I don’t believe that cattle will perform as closely as those numbers imply. The tests shown are those that are most commonly done. This doesn’t mean that they are all you need to know about your feed. Labs offer mineral ‘packages’ that give a single price for macro minerals (such as calcium and phosphorus) and another package that reports trace minerals (such as zinc and copper). Phosphorus is a very expensive mineral. It makes up a huge portion of the cost of a vitamin-mineral supplement. If a feed test shows that you have sufficient phosphorus (0.25% for all but the highest stages of production by beef cattle), elimination of phosphorus from your mineral can save hundreds of dollars per ton! In the Northwest we continue to identify copper problems in beef herds. To get a true picture of the copper status of your forage, your test needs to include iron, sulfur and molybdenum because these minerals interact with copper and affect the amount of copper that your animals get out of your feed. Feed labs do not test for vitamin content of feeds. This is left to labs that specialize in these analyses. These tests are quite expensive. I’d rather assume that the vitamin content of dry forages, straws, and hays is low and include Vitamins A, D, and E in a supplement. You now have my feed testing sermon. It only costs about $45 for a very complete analysis. Your extension agent should have a hay probe that you can borrow for hay testing. All feed company reps that I know also pack hay probes, and are happy to assist you with getting samples and recommending the lab that they have confidence in. Different labs have different expertise. You can take the information from a feed test and plug it into the OSU Cowculator to help determine how the feed tested will fit into your program. A livestock nutritionist should also be able to help you interpret protein energy and mineral values. Money spent on feed testing can return huge dividends. If you’d like the name of the feed labs I use or what feed test to request, don’t hesitate to contact me by email. Michael J. Mehren Ph.D. is a livestock nutritionist trying to spend his feed test dividend somewhere near Hermiston, Oregon. To date he has had no success. He can be reached by email at mehrens@eotnet.net. Information on wet chemistry vs N.I.R. from AS 99, 3/90. North Dakota State Univ. Morse and Sedivec.		About OFGA Services Join OFGA Meetings & Events OFGA Officers OFGA Bylaws Links Contact OFGA Articles Mike Mehren, Ph.D. Feed/Export Wheat Report