Prussic Acid and Nitrate Poisoning are Concerns After a Light Frost

Although late October has been very warm and “summer-like”, the average first frost date for much of the Southern Plains is here.  Soon a cold front will bring near-freezing to sub-freezing nighttime temperatures

It was discovered in the early 1900s that under certain conditions sorghums are capable of releasing hydrocyanic acid or commonly called prussic acid.  Prussic acid when ingested by cattle, is quickly absorbed into the blood stream, and blocks the animal’s cells from utilizing oxygen.  Thus the animal dies from asphyxiation at the cellular level.  Animals affected by prussic acid poisoning exhibit a characteristic bright red blood just prior to and during death.  Lush young regrowth of sorghum-family plants are prone to accumulate prussic acid especially when the plants are stressed such as drought or freeze damage.  Light frosts, that stress the plant but do not kill it, are often associated with prussic acid poisonings.

Producers should avoid grazing fields with sorghum type plants following a light frost.  The risk of prussic acid poisoning will be reduced, if grazing is delayed until at least one week after a “killing freeze”.  As the plants die and the cell walls rupture, the hydrocyanic acid is released as a gas, and the amount is greatly reduced in the plants.  One can never be absolutely certain that a field of forage sorghum is 100% safe to graze.

Cattle that must be grazed on forage sorghum pastures during this time of year should be fed another type of hay before turning in on the field, and should be watched closely for the first few hours after turn in.  If signs of labored breathing, such as would be found in asphyxiation, are noted, cattle should be removed immediately.  Call your local veterinarian for immediate help for those animals that are affected.  Be certain to read OSU Fact Sheet PSS-2904 “Prussic Acid Poisoning” before turning cattle to potentially dangerous fields.

Frosts also stress the plant before a hard freeze kills it.  Plant stress from frosts will impair the normal metabolism of the plant.  Therefore the plant continues to take up nitrates from the soil but is inefficient at converting the nitrates to protein.  Therefore nitrate accumulations may reach dangerous levels.  Testing the forage before grazing or cutting for hay will provide important knowledge about the safety or danger in the forage.  Visit with an OSU County Extension office about testing procedures and read OSU Fact Sheet PSS-2903 “Nitrate Toxicity in Livestock”.

Five Colostrum Storage Tips

Maintaining colostrum quality should be a huge priority on the dairy. The quantity of colostrum a calf receives does not matter if the colostrum is junk. Here are five tips to ensure you’re storing and handling colostrum properly.

1. Don’t pool raw colostrum. Even if the colostrum is going straight into storage it should never be pooled, according to Kimberley Morrill, PhD regional dairy specialist Cornell Cooperative Extension.

2. Feed or refrigerate colostrum within one hour of collection. Colostrum can be stored in the fridge or the freezer. According to research from the National Animal Health Monitoring System of the dairy producers who store colostrum, 21% store it in the fridge and 73% of producers store colostrum in the freezer.

3. If storing in the fridge, only keep colostrum for one week. After that, Bethany Lovaas, DVM University of Minnesota, says quality declines. “If you refrigerate colostrum, be sure that the refrigerator is cold (33 – 35 degree F) to reduce the onset of bacterial growth,” she says.

4. Keep frozen colostrum for six months or less. While not everyone agrees on how long frozen colostrum can be stored without damage to the antibodies, Faith Cullens of Michigan State University Extension says most researchers agree the six month mark is safe.

5. Thaw frozen colostrum with warm water or a microwave. “The main concern regarding thawing frozen colostrum is to thaw the ice without degrading the immune proteins,” says Lovaas. She adds colostrum is best thawed with warm (not hot) water. Add more water to the bath as the frozen colostrum cools down the water. Alternately, Lovaas says colostrum can be thawed in a microwave oven with little damage to the Ig. “It is important to microwave the colostrum for short periods on low power,” she says.


Baleage is Different Than All Other Forage Making Practices

Baleage is made in round-bale and big-square hay packages so some people assume it is very similar to making dry hay. Others assume because the end product of baleage is a fermented wet silage that it is just like making haylage. According to Dr. Wayne Coblentz, from the USDA Dairy Forage Research Center in Marshfield, Wisconsin, making baleage is different in some significant ways than other forage harvesting practices and farmers need to understand those differences if they are to make better quality forage from baleage.

Coblentz spoke in August at the Michigan State University’s Ag Innovation Day in Lake City, Michigan. He highlighted the great advantages of making baleage which include: fewer weather delays, less wilting time required, reduced respiration of plant sugars resulting in better feed quality, reduced dry matter losses in the field compared to dry hay, less storage loss and oftentimes reduced feeding losses compared to hay. Also he added that baleage requires less expensive equipment and offers more flexibility for feeding than does a traditional haylage system. However, he also explained that there are some major differences that forage producers need to understand about baleage to be more successful in making it.

These differences include:

  • Baleage takes longer to ferment than chopped haylage. One reason for this is that the long plant stems in baleage do not release plant sugars as quickly to fuel fermentation as shorter, chopped haylage particles.
  • Baleage usually is not packed as tightly as haylage. This permits more oxygen to be trapped within the bale, allowing extended respiration that further slows fermentation.
  • Baleage is usually drier than chopped silages, which inherently restricts fermentation. Normally, the production of fermentation acids increases with higher forage moisture.

For these and other reasons, baleage goes through a slower and more incomplete fermentation than most chopped silages. This slower process usually allows the forage to remain above a pH of 5.0, and shifts even more emphasis towards maintaining anaerobic (oxygen free) conditions in order to preserve the silage. Air exclusion is then the key to making stable baleage and it is accomplished by wrapping the bales in air tight plastic. This is especially important with drier baled silages (less than 40 percent moisture) that are more permeable to air and are at risk for spoilage should holes in the plastic wrap occur during storage. Baleage that is too wet (greater than 60 percent moisture) can undergo a secondary fermentation that produces butyric acid and ammonia, which can cause depressed animal feed consumption. These clostridial-type of fermentations are more likely to occur in difficult to ensile crops, such as alfalfa, that have high buffering capacity and have very limited amounts of sugar. Cool-season grasses are usually more forgiving in this respect.

To make the highest quality baleage, and to avoid the feeding of a lower quality product Coblentz recommends the following:

  • Make baleage from forages that are harvested at the proper stage of maturity and are of good quality. Do not assume that baled silage techniques will magically improve poor-quality forage.
  • Harvest baleage in the moisture range of 45 – 55 percent. The bales will be lighter to handle, will optimize intake and performance, and will prohibit clostridial activity during fermentation and storage.
  • Make bales that are packed tightly with high density. Excluding as much air as possible from the bale is important. Maximize revolutions within the baler for each bale by slowing ground speed, maintaining appropriate engine rpm, and by baling only moderately sized windrows.
  • Wrap bales with six or more layers of plastic as soon as possible after baling; significant damage may occur after 24-hour or longer delays. Consider using a lactic-acid producing inoculant from a reputable manufacturer anytime conditions are less than optimum.

The key to making high quality baleage is to make a bale within the recommended moisture range that is as dense as possible (> 10 lbs DM/ft3), and wrap it in plastic as quickly as possible. This will allow oxygen depletion to occur rapidly inside the plastic. Once oxygen depletion is complete, fermentation will occur, but because of the slow and limited fermentation within baled silages, maintaining anaerobic conditions is absolutely critical. As such, plastic should be monitored closely for damage, and patched promptly when holes or leaks are discovered.

Some farms are successfully baling very dry silages (25 – 40 percent moisture), and preserving the forage in plastic. Coblentz says these bales typically will not ferment aggressively, and preservation is largely achieved by limiting air access. However, in the absence of air, preservation can be accomplished, provided the producers are diligent about maintaining the integrity of the silage plastic. As forages become drier, there may be increased risk of internal puncturing of the plastic as these drier plant stems become more rigid. This often occurs along the junction of the flat and circumferential sides of the round bale. A small investment in additional plastic layers may be appropriate for these very dry silages.

Baleage has many advantages and continues to grow in popularity. When done right it can make high quality forage that can optimize animal performance.

Maintain Your TMR Mixer

Mixer Wagon Maintenance

Want to get the most life out of your mixer while maintaining a high quality mix? Maintenance is the answer. Mixer maintenance, beyond greasing, is often overlooked but Mike Everson, a field support representative with Kuhn North America says taking the time to do it is crucial.

“We like to take care of our cattle, mixers need to be maintained on a weekly and monthly basis also,” he says. “We look at the outside on a daily basis but very seldom do farmers look inside.”

Everson recommends farmers take a look inside their mixer at the knives, scrapers and shoes every 90 days. Knives should be sharp. If your mixer wagon’s knifes are beginning to look like butter knives, it’s time to replace them.

“Sometimes a small investment in new knives or scrapers can make a world of difference,” he says.

Also look at the “shoe” at the base of the auger. According to Everson, this is a very inexpensive part, but one that is worn is often the cause of poor mix quality.

“The shoe is the lifeblood of a vertical mixer,” he says.

Everson’s biggest advice? Dig your operating manual, see what the manufacturer recommended for maintenance intervals and then actually follow their guide.

“Maintaining your mixer will insure good mixing quality for the lifetime of the mixer,” he says.