Mud, Forages, and Livestock Health

Spring is synonymous with mud in Pennsylvania, but realistically, it can happen any time of the year, depending on the weather. Mud creates a lot of concerns when it comes to livestock health, including foot rot or scald, loss of insulation due to matted hair, and naval infections in calves, among other disease concerns, but you may not always think about mud contamination on forages. Not only are muddy conditions hard on pastures and outdoor hay storage or feeding areas, but there are potential health concerns when livestock consume mud-contaminated forages.

So, What's the Problem?

Soils contain many soil-borne pathogens that can infect grazing livestock or livestock consuming contaminated stored forages. These organisms tend to persist in high moisture conditions. In pasture situations, mud is going to be a combination of mud and manure, which would contain additional bacteria and pathogens that can impact animal health. Young animals are particularly susceptible to muddy conditions through direct contact and consuming muddy water. 

One of the most common genera of pathogenic bacteria is Clostridium, which has many species naturally occurring in soil and manure and can also be found in poorly fermented forages. Common problems in livestock when consuming contaminated feed include botulism, blackleg, malignant edema, and listeria, among others. Clostridium organisms form spores and can live for long periods of time, even in adverse conditions. One type of Clostridium organism can grow in wet forage, altering the fermentation process and leading to excessive accumulation of butyric acid. Consumption of this poorly fermented forage can result in a metabolic disease of dietary ketosis, especially in late pregnant and early lactating animals.

Pastures

Mud in pastures is a fact of life, especially if you don't have a barn, concrete pad, or other stabilized area to house livestock during inclement weather. Left in a grassed sacrifice area or continuously grazed pasture system, livestock will consume all the available forage, leaving behind short stubble and exposed ground that will eventually turn into, you guessed it… mud. This can also occur in high-traffic areas like bale feeders, waterers, mineral tubs, and gates. Research has shown that mud up to eight inches deep will decrease feed intake up to 15% while mud up to ten inches can decrease intake by as much as 30%. This results in reduced gains, lower milk production, and an overall decrease in animal performance.

Additionally, livestock in continuously grazed systems will often have walking paths with little to no forage growth, which can carry muddy water across pastures during heavy rain. Pastures grazed too short, or grasses growing next to muddy areas, are prone to soil splashing onto the leaves that the livestock will then consume. The shorter the available grass, the more likely animals will inadvertently consume mud from the surrounding area.

Stored Forages

There will always be a need for hay and other stored forages in PA because we cannot graze year-round. And of course, when we need additional feed, like hay, we probably have muddy conditions, unless we are supplemental feeding during a summer drought. Issues may arise when livestock are able to walk on hay being fed in a muddy area, leading to contamination of that feed. Flooding can also lead to problems with bales stored in low-lying areas or outside on the ground when mud splashes onto them, or muddy water soaks into the bales. Not only does this introduce soil-borne pathogens, but it can also lead to mold growth inside the bales. Water soaking of baled forages can also lead to loss of soluble carbohydrates and proteins in the forage, leaving a high fiber and poor quality forage to feed.

Soil contamination in forages presents issues with elevated ash content and bacteria populations. High ash levels in forages can lead to premature tooth wear in ruminants and obstruct the lower rumen as ash particles settle out of solution. In grasses, ash content should be lower than 9% and less than 12% in legumes. In high-producing cattle, each pound of ingested ash represents a loss of digestible energy intake and may lead to depressed milk production or rate of gain. Introducing antagonistic bacteria (such as Clostridia) can interfere with proper fermentation and produce high levels of butyric acid during fermentation. As Clostridia reproduce, they consume the protein in silages and release free amines and butyric acid; this represents a loss of forage protein and creates smelly, low-energy silages that further depress animal performance.

What Can We Do About It?

Store hay on pallets to avoid bales laying in mud during wet periods, or store them indoors. Even if you initially place the bales in a grassy location, the grass will eventually die and have the potential to form mud in addition to producing a moldy environment due to direct contact with the ground. Remove hay from fields where they were baled, especially if those fields will lay wet during certain times of the year or are in a flood plain. The same goes for wrapped bales or bagged forages. Keep in mind the final storage location of these forages since moving them can be challenging or impossible. Scooping ensiled feeds from bags can introduce soil, and doing so in a muddy area can further increase that possibility. Mud from tractor tires can be introduced to feed being scooped and transported or if it is inadvertently driven over.

Add gutters to barns, storage sheds, or livestock run-ins and direct water away from feed storage or pastures. Create stabilized surfaces in high-traffic areas around feeders, waterers, gates, etc. This could be a concrete pad or gravel area with geotextile fabric, with or without a roof. Remember that methods like sand or gravel are temporary solutions and will need to be re-addressed in a few years. Properly grade these areas (1-5% slope) to allow water to flow away and decrease the likelihood of mud forming. Temporary fencing can also be used to keep animals out of low-lying areas or areas that lay wet during certain times of the year. Rotate bale feeders, mineral tubs, and waterers (when possible) to reduce mud formation and manure build-up or move them to higher, dry ground.

Incorporating a rotational grazing system will allow for higher stubble heights for grasses, better overall ground cover, and greater absorptive abilities. There will be less exposed ground to splash mud onto leaves, the larger root systems of grasses will be able to absorb more water, and those roots will also help stabilize soil structure and allow for better water penetration through the soil profile. It may be beneficial to evaluate current stocking rates to determine if there is enough forage for the number of animals on the farm. Rotate animals through a rotational grazing system based on the stubble height of the forages, rather than on a set calendar schedule. Move animals to a new paddock when grasses reach four inches. This will ensure adequate ground cover and rapid regrowth of those forages. 

When mechanically harvesting grass, legumes, or small grain forages, be mindful of cutting height. Maintaining a mowing height of 3-4" leaves mud-splashed material out of your silage and can also provide a small buffer against scalping when mowing uneven ground. Adjust cutterbar, merger header, and chopper pick-up header float pressures for proper floatation as these machines travel across the field; these machines need to quickly adapt to changing terrain for the high-speed farming (6+ MPH) that our weather patterns demand. Higher stubble height also keeps forage out of the mud, which can be useful when tedding to hasten dry-down. Adjust tractor tire track width to straddle windrows to avoid driving forages into wet soil.

At harvest, consider the use of a high-quality, properly applied bacterial inoculant that introduces at least 100,000 CFUs of bacteria. Targeting harvest moisture between 62-65% can discourage Clostridia growth if ash levels are high. Endogenous (naturally occurring) ash levels in forages are about 6-8% on a dry matter basis, depending on the amount of calcium and potassium available in their tissue. Ash levels above 10% (DM basis) indicate soil contamination of silages. Butyric acid levels above 0.5% (DM basis) indicate Clostridial fermentation and can lead to animal refusal and performance issues.

Consider developing a dedicated heavy-use area (HUA) or sacrifice lot where livestock can be housed during periods of inclement weather, such as when the potential for mud is high. This could be a section of pasture that is high and dry, a stabilized area, a barn, etc. Livestock can be fed supplemental forages until pasture conditions are more suited for grazing. A heavy-use area is typically a permanent space that doesn't have grass cover, whereas a sacrifice lot can be temporary when we don't want livestock out on pasture. We know that the area will get "beat up," but the goal is to spare the majority of the pasture, and the sacrifice lot can be restored afterward.

Unfortunately, there are no vaccines for many of these diseases, except for some Clostridium organisms. There is a multi-valent vaccine to protect against Clostridium species responsible for overeating disease, blackleg, malignant edema, and tetanus. If you ever suspect any illnesses in livestock, contact your local veterinarian for advice and treatment.