A Comment on Rain Damaged Hay

The other day while it was raining cats and dogs outside, a customer asked how that rain would affect his freshly cut alfalfa hay.  Unfortunately, rain after cutting and before bailing only decreases the nutritional value of the hay. As the freshly chopped forage lays in the field getting rained on, water soluble compounds leach out of the plant.  These compounds include some nitrogen, some fat, minerals, vitamins, and water-soluble carbohydrates. The loss of the water-soluble carbohydrates results in an increase in the fibrous carbohydrates and therefore a decrease in the energy provided by the forage.  For more on that check out my previous post Carbohydrates and Forage Quality.  The loss of vitamins and minerals may also increase the importance of feeding those nutrients as supplements.

In addition to a poorer quality resulting hay, rained on alfalfa can support more mold.  If the mold count is significant, between 2-3 million spores per gram, it can be a contributing factor in respiratory and reproductive illnesses in livestock.

Furthermore, it is important to allow the rain damaged hay to dry to at least 12% moisture before baling.  If baled too wet, heat damage can occur, further reducing the quality of hay and nutrient availability of the hay for feeding.

Best of luck this harvesting season!

For more information check out this publication by the Iowa Beef Center:

Rain Damaged Hay can be Costly for Farmers

Do I Need to Test For Nitrates?

Last week I attended both the Colorado Cattlemen’s Annual Convention and the Sandhills Ranch Expo at the Ward Laboratories Inc tradeshow booths.  At both locations, producers had concerns about nitrates.  The climate and weather however were contrasting conditions.  Colorado producers wondered how drought stress might affect the nitrate levels in their forages, while Nebraska and South Dakota producers were concerned if too much precipitation might have affect nitrate levels in forages.  Here are 5 factors that affect how nitrates accumulate in forages.

  1. Plant Species

Some plant species accumulate nitrates more than others.  These species should be tested for nitrates regularly before feeding to animals.  These species are: sorghum (milo), sudan grass, millet, oats, johnson grass, broadleaf weeds, corn and sunflowers.  There are other species which also accumulate nitrates but not to the same extent as those listed above: wheat, rye, and triticale fall into these categories.  Finally, under extreme stress alfalfa and soybeans can accumulate nitrates, however the stress must be extensive, and this situation is very rare.

  1. Maturity of the Plant

Young plants and regrowth take up nitrogen from the soil faster than it can be converted to protein.  Older more mature plants take up nitrogen at a slower rate and have had plenty of time to convert nitrogen to protein.  Therefore, younger plants and regrowth tend to accumulate more nitrates than older mature plants.

  1. Plant Part

The lower 1/3 of the stock of the plant is where the most nitrates are stored.  Leaves and stems do not store nitrates in the plant. When grazing, leaving the last third of the stock might be a good idea to avoid any nitrate toxicity issues.

  1. Environmental Conditions

Stress due to weather or climate may increase nitrate accumulation.  During drought stress, the plant may be able to take up nitrogen but not have enough moisture to convert it to protein.  On the other hand, coming out of a drought a dramatic increase in moisture may cause the plant to take up more nitrogen than it can convert to protein in a timely fashion.  Frost and freezing temperatures also cause stress to the plant and nitrate accumulation.

  1. Management

Nitrogen fertilization is a common cause of nitrate accumulation in forages.  Nitrogen fertilization may increase yield, but it also increases risk of nitrate toxicities.

Nitrates are tricky.  I often run into producers who want to tell me their situation and management practices and ask if they need to test.  The truth is no one can determine the nitrate levels based on an antidote.  Testing is the only way to have full confidence.  If there are concerns, send forage samples to Ward Laboratories, Inc for a nitrates test and use the table below as a guide to interpert your report.

Nitrates

7 Concepts on Hay Analysis for Horses with Metabolic Conditions

Over the past year, when I receive phone calls from equine enthusiasts, they all seem to have the same question. What do I need to analyze my hay for a horse that has been diagnosed with Equine Metabolic Syndrome, Cushing’s Disease, Equine Diabetes or is prone to Laminitis?

While the pathology and causes of each of these disorders may be very different, they all can be managed through diet. Each of these conditions requires the horse to consume a low, simple carbohydrate diet. This means feeding no cereal grains, which are high in starches, but instead feeding a high fiber, forage based diet. I typically recommend that these clients run an NIR plus TSI plus Starch. When choosing a hay or analyzing pasture grass for suitability to feed horses with metabolic conditions, there are 7 key concepts to examine.

1. Protein

When determining a forage to feed, it is important to realize that without grain supplementation, it will be important to meet the horses protein requirements. Most horses at maintenance require 10% crude protein on a dry basis. Growing, breeding, and working or performing horses have increased protein requirements depending on their physiological state and physical activity level.

2. Acid Detergent Fiber (ADF)

The ADF is an indicator of the digestible energy available in a feed. Most horses at maintenance require between 37-40% ADF on a dry basis. Higher fiber percentages in a forage indicates that there is more structural carbohydrates in the feed and therefore less water soluble carbohydrates such as sugars and starches, which should be avoided when managing a metabolic condition.

3. Neutral Detergent Fiber (NDF)

Similar to ADF, increased NDF also indicates that more carbohydrates have been converted from water soluble carbohydrates to structural carbohydrates, therefore forages with higher NDF tend to be better for managing a horse with a metabolic syndrome. Most horses at maintenance require between 50-65% NDF on a dry basis. The NDF is an indicator of dry matter intake and palatability, as NDF increases the horse will consume less of that feed, so avoid a hay with an NDF much higher than 65%.

4. Relative Feed Value (RFV)

The RFV is a calculated index based on the ADF and NDF. A good hay to maintain a horses condition would have a RFV between 83-112. Typically, grass hays and grass forages are going to meet the RFV recommendations for horses with metabolic conditions as opposed to commonly fed legumes such as alfalfa hay.

5. Non- Structural Carbohydrates (NSC)

The NSC are carbohydrates that do not make up the structural, fibrous portions of the plant. They are measured and include water soluble carbohydrates (glucose, fructose, and other sugars) and starches. It is recommended that the NSC be below 10% in horses with Equine Metabolic Syndrome, Diabetes, or Cushing’s Disease. Throughout the daylight hours, plants accumulate NSC and at night, those accumulated NSC are converted to cellulose and other fibers, making the NSC content of pasture grass cyclic. Therefore, when allowing horses with a metabolic condition to graze pasture, it is best to turn them out on to pasture in the early morning when sugars are low in the pasture grass and never allow grazing in the evening when sugars are high in the grass. If you are producing hay to be consumed by horses with the aforementioned conditions, hay should be cut in the early morning hours to obtain the least amount of NSC possible. Furthermore, if your cut hay were to get rained on, the sugars or water soluble carbohydrates would be removed from the hay, resulting in lower NSC content and increased fiber percentage, making that hay ideal for horses with metabolic syndromes. Be sure to bale hay that has been rained on after the hay has had a chance to dry to avoid any potential mold or heat damage issues.

6. Total Sugars Invert (TSI)

At Ward Laboratories, Inc. we do not measure water soluble carbohydrates, however we can measure the amount of glucose and fructose in a feed as TSI.

7. Starch

Starch is an indicator of feed energy. Unfortunately, when consumed, feed is broken down into glucose units which contribute to metabolic related issues. Starch, in addition to water soluble carbohydrates or in our lab TSI, is the measurement of NSC. To reiterate the very important recommendation from above; TSI + Starch should be less than 10% in a forage or hay to be used to manage a horse’s metabolic condition through the diet.

In conclusion, when feeding a horse with a metabolic condition, avoid grain as it is high in starch and choose a low quality grass hay that is at or above 10% crude protein on a dry basis. Keep the non-structural carbohydrates to less than 10% of the hay or forage you are feeding. Following these guidelines should prevent bouts of laminitis and keep the metabolic condition in check.