Test Hay, Don’t Guess

November 25, 2017 01:19 PM

Fall is here and the weather reminds us of the changing of the seasons. This is the time of year when many producers are hauling hay home for the winter as well as pricing and purchasing hay. There is a tremendous range in hay quality depending upon level of maturity, fertilization, growing conditions, harvest circumstances and storage methods. Accurately sampling and testing hay is the only way to get a real understanding of the nutritive value of feed. Using values from previous years or a “book value” can be costly since a producer may incorrectly develop a ration using values that aren’t representative.

Guidelines for sampling

When sampling hay, getting a representative sample is a critical first step. Samples must accurately represent the entire lot of hay. When obtaining a sample for analysis, it should be kept separate from other lots of hay. The UNL NebGuide “Sampling Feeds for Analyses” (PDF version, 655KB) states that a “lot” of hay should be harvested from the same field consisting of similar types of plants, cutting dates, maturity, variety, weed contamination, type of harvest equipment, curing methods and storage conditions. When these conditions differ, feed should be designated and sampled as a separate “lot”.

Hay samples should be taken using a hay probe or a core sampler. The hay probe should penetrate at least 12-18 inches into the bale and have an internal diameter of at least 3/8 of an inch. Using your hand to grab a sample will not consistently provide reliable results. Tips of hay probes should be kept sharp to cut through hay and prevent selective sampling. Avoid getting hay probes hot when using a drill to drive the probe into the bale, since friction from high speeds can heat the probe to a point where it damages the hay sample.

To get a representative hay sample from a “lot” of hay, select 15-20 bales in the lot. Knowing the total number of bales that are present can help identify a random method that should be used (such as sample every fourth bale) to obtain an accurate sample. Once all of the samples for a “lot” have been collected, the samples may need to be sub-sampled to get the feed down to a sample size that can be sent in for analysis. The UNL NebGuide “Sampling Feeds for Analyses” walks through a step-by-step process to do this. Being careful to ensure the sub-sample submitted is representative is important.

Once hay samples have been taken store in a plastic sealed bag in cool dry place until the sample is ready to be submitted. Samples that contain over 15% moisture should be frozen. Make sure to label the bag with your name, address, lot identification and feed type. Most commercial labs provide an information submittal form that allows producers to select a standard feed test for forages. Whenever possible, send samples into the lab early in the week to avoid having the samples sit over a weekend.

Analyze for moisture, protein and energy

Cattle feeds should be analyzed for moisture, protein and energy. Producers may also want to have forages tested for key minerals. Feed sample results are usually reported on an as-is and dry-matter basis.

When developing a ration for cattle or comparing feeds to one another, always utilize the nutrient analysis on a dry-matter basis. After formulating a ration on a dry-matter basis, the values can then be converted to an as-is basis using the moisture content of the feed to determine the actual amount of feed that should be fed to the cattle on an as-is basis.

Analyze forages for nitrates

In addition to moisture, protein and energy, annual forages harvested for hay such as foxtail millet, oats, sudan grass and sorghum-sudan hybrids should be analyzed for nitrates. These annual forages can accumulate high levels of nitrates under various growing conditions that can potentially reach toxic levels. The only way to know if high levels of nitrate accumulation have occurred is to test for it. See the UNL NebGuide “Nitrates in Livestock Feeding” (PDF version, 319KB) for additional information. For additional information on understanding the results from a hay analyses, please see the “Understanding a Feed Analysis” Learning Module on the UNL Beef website.


Accurately testing hay takes time and money. However, the value of this information is critical in accurately and cost-effectively formulating rations. Don’t let the small investment of time and money discourage you, it may be some of the best time and money you can invest in your operation.

Tips for Calf Feeding

During a recent Calf and Heifer VIP event hosted by Purina at the company’s Animal Nutrition Center in Gray Summit, Mo., calf experts offered advice on calf feeding:

  • It takes 85% less time for a calf to get 2 quarts of milk from a bucket compared to straight off the cow. It is 35% quicker on a nipple bottle versus off the cow
  • Feeding through a bottle with a nipple will help slow down the passage rate and increase salvia. Having saliva adds more enzymes that promote protein and fat digestion
  • Slowing down milk intake helps move digestion from the small intestine into the abomasum where nutrients will more readily be picked up
  • The hole in a nipple should not be too large in diameter. If it is too large it defeats the purpose of feeding with a nipple. This might require replacing nipples regularly when holes become too wide
  • If the nipple leaks milk when you turn it upside down, get a new nipple
  • “Full bucket syndrome” tends to happen with calves when there is more grain in the bucket than needed. For instance, a newborn or week-old calf isn’t going to eat much feed so there should be none to very little grain available starting out
  • A starter bucket that is shallow might be a better fit for younger calves to reduce feed waste or overfeeding. It also helps encourage calves to eat because they aren’t sticking their heads down where they can’t see
  • “Empty bucket syndrome” is another problem seen on dairies for older calves. Not having enough feed regularly to calves throughout the day can lead to calves eating too fast when they are fed causing digestive upsets or bloat
  • Use bright colored water buckets to help feeders see what is at the bottom of the bucket. Dark or black colored buckets are harder to see at the bottom if dirt or debris is present
  • Put a physical divider like plywood or plastic between the water and feed buckets
  • A trial from Purina showed that separating the feed and water with a divider increased average daily gain by 0.3 lb.

Sorting Profits: Cows are Picky Eaters

Dairy cows selectively consume their rations, generally sorting longer particles in favor of finer particles. Feed sorting decreases fiber intake while increasing the consumption of grains and co-products. It also creates instances where cows eat different rations throughout the day.

Are Your Cows Sorting?

In 2010, researchers from University of Minnesota evaluated ration change over time in 50 Minnesota freestall barns. At each farm, samples were collected from rations fed to high-producing cows. One sample was collected immediately after the TMR was delivered, three additional samples were collected every two to three hours after feed delivery, and the last sample was taken from the accumulated weigh-backs.

Researchers evaluated particle size in the TMR samples using a threesieve Penn State Particle Separator. On average, the researchers found a noticeable change in the percentage of material retained in the top screen from the initial TMR to the weigh-backs showing cows were selecting against long particle size. In addition, fiber content—percent of neutral detergent fiber (NDF)— of the TMR increased throughout the day.

Similar results were obtained in a Canadian survey including 22 freestall herds. On average, the refused ration was higher in the percentage of long particles recovered in the top screen (19.8% versus 33.1%) and physically effective NDF (17% versus 24.5% dry matter) than the average offered ration.

Effects of Sorting on Milk Components

Feed sorting causes fluctuations in rumen fermentation patterns, and can result in reduced ruminal pH and episodes of subclinical ruminal acidosis. A recent study showed the association between sorting behavior and milk production. The researchers evaluated feeding behavior in 28 lactating Holstein cows individually housed in a tiestall barn at the University of Guelph.

Cows sorted against long particles and in favor of short and fine particles. On average, intake of the longest particles was 78%. Milk production of the group was 90.6 lb. per day with 3.81% and 3.30% protein. The authors found negative associations between feed sorting and milk composition. For every 10% increase in sorting against long particles:

  • Milk fat content decreased by 0.10 percentage units
  • Milk protein content dropped 0.04 percentage units

Because the average sorting against long particles in the group was 22%, milk fat was reduced by 0.22 percentage units or 0.2 lb. per cow per day due to sorting. Similarly, milk protein was reduced by 0.09 percentage units or 0.08 lb. per cow per day. Using values from September FMMO Advanced Component prices (fat $3.03 per pound and protein $1.54 per pound), the economic impact of sorting in this research herd was 72¢ per cow per day or $263 per year.

In conclusion, feed sorting is a common behavior of dairy cows that could produce health issues and economic losses in the herd.

Fernando Diaz, DVM, Ph.D. is a dairy nutrition and management consultant with Rosecrans Dairy Consulting LLC. You can reach him at fernando@jration.com

Forage Analysis: What Numbers Do I Need

One the more common questions I receive with regard to analytical testing of forages and other feedstuffs is, “I have the sample, now what do I test for or what analysis package should I select?”

The basic components that nutritionists need to evaluate a feedstuff or develop a ration are dry matter or moisture, crude protein, an estimate of the energy content of the feedstuff — Total Digestible Nutrients (TDN), Net Energy for Maintenance (NEm), Net Energy for gain (NEg), and the macro minerals, Calcium and Phosphorous. These are the most basic numbers that are required but including some additional analyses in the report can give us additional insight into the quality of the feedstuff or improve our ability to predict animal performance, which is the primary reason we analyze feedstuffs.

I recommend that the report include acid detergent fiber (ADF) and neutral detergent fiber (NDF).  The amount of NDF in forage reflects the amount of cell wall contents (hemicellulose, cellulose, and lignin) within the sample. The NDF fraction is often associated with the respective bulkiness of forage and is correlated with dry matter intake of the forage or feedstuff. Therefore, the amount of NDF may be used to estimate the expected dry matter intake associated with the forage.  The ADF number represents the amount cellulose and lignin within the forage and is correlated with the respective digestibility of the forage.  In general, a higher ADF value is associated with forage that has a greater proportion cellulose and lignin and would likely be a more mature. Additionally, the ADF fraction is used to calculate the energy estimates TDN, NEm, and NEg that appear on the report. There are a number of different mathematical equations that the testing laboratory may use to calculate these numbers, based on the type of sample (corn silage, alfalfa, grass hay, etc.). If the ADF is included in the report, the nutritionist can adjust or recalculate the energy estimates if necessary.

If the forage will be fed in combination with a byproduct feed such as wet distiller’s grain, including an analysis for sulfur can be beneficial if the forage will be used in a growing or feedlot ration.  Additionally, if the forage is a known nitrate accumulator (forage sorghums, sudangrass) or may have been stressed due to drought, including a nitrate analysis should always be considered, especially if the forage will be fed to pregnant cows.

Most analytical laboratories have a number of different analysis packages which encompass the most common procedures or numbers that a nutritionist or producer needs to know about their feeds. These packages will typically include the basic procedures (DM, CP, TDN) and then add on specific analyses such NDF, or the Macrominerals (Ca,P, Mg, K, Na, Cl, S). Some laboratories may group analysis packages by the type of sample (Forage, vs. mixed ration) or production purposes (dairy vs. beef).

The objective of analytical testing of forages and feedstuffs is to improve our ability to meet the animal’s nutrient requirements and ultimately predict animal performance. The unequivocal best method of evaluating the quality of a feedstuff is feeding the feedstuff to an animal and evaluating performance over a set period of time, under a specific set of conditions. Since that would not be cost effective or timely, analytically evaluating feedstuffs in a laboratory is the next best the thing and although it is not perfect, it is unequivocally better than the “this looks like really good stuff” method of evaluating feedstuffs.

A Whole Lot of Water Goes Into That Milk

Water is important for most species’ survival. Dairy cows, in particular, require large quantities to produce the creamy white liquid for which they are famous. It is important for dairy producers to provide plenty of water within a convenient location to keep their herd well hydrated.

“Cows need to consume between 30 and 50 gallons of water per day,” said Donna Amaral-Phillips, extension dairy specialist for the University of Kentucky College of Agriculture, Food and Environment. “That’s more than 415 pounds of water every day.”

That number may sound extremely high until the consumer realizes it takes up to 4.5 pounds of water to make just 1 pound of milk, and cows produce, on average, 70 pounds, or 8 gallons of milk each day, which is equal to about 128 glasses.

Milk is 87 percent water, and without sufficient water intake, a cow’s milk yield will suffer.

Dairy cows rely on saliva and other fluids to assist them in digesting feedstuffs. If they don’t get enough water it starts a chain reaction—digestion, feed intake and energy decrease.

“Managing water on a per-cow basis in a dairy herd can be quite difficult for any producer,” said Jeffrey Bewley, UK associate extension professor. “For this reason, dairy producers have to make decisions that benefit the entire herd. That’s why we allow the cows ample access to water at the UK Dairy—so they can drink as much as they want.”

Dairy managers have to make sure cows have access to water in the barn at a centrally located trough. Ideally, the trough will be near a feed bunk so it’s easy for cows to drink after eating. Cows usually drink the most after eating and after being milked.

“It’s important for the water trough to have enough space for multiple cows to drink at the same time,” he said. “Three to 5 inches of water space per cow is usually adequate, and the height of the trough should be 2 to 3 feet from the ground.”

One waterer per 20 cows will help ensure cows stay hydrated. The waterers should hold at least 5 gallons at time, with a refill rate of at least 2.5 gallons per minute to keep the fresh, clean water flowing. So while it may be hard to monitor each cow’s water intake, providing enough fresh water and space for the entire herd usually gets the job done.