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May 2017

Prudent Use of Antibiotics for Vaccine Efficacy

By Acidosis and Shipping Fever, Cattle, Pre-Conditioning No Comments

As it has been evidenced in humans, antibiotic use can negatively impact the delicate microbial balance present in the gut. The same is true for cattle. Use of antibiotics can kill off colonies of beneficial bacteria in the rumen, making rumination less complete and more difficult. There is also the risk of developing antibiotic-resistant bacterial strains within a herd due to overuse. This can, in turn, impact a vaccine’s ability to properly immunize your cattle against disease. Your herd veterinarian can help guide you in prudent use of antibiotics to help not only preserve the gut flora and fauna but also work towards preventing the development of antibiotic-resistant bacteria amongst your herd.

Dietary Considerations

The cow’s rumen is a complex system of checks and balances to ensure that every bite of feed is utilized to the fullest extent possible. Cattle do best on a grass-only diet, but this is obviously not optimal for finishing cattle or keeping up with the nutritional demands of milk production in dairy cattle.

Cattle that receive large amounts of grain-based feeds have a particular set of challenges to overcome in their digestive process. Grass and forage contain large amounts of fiber, necessitating numerous cycles of regurgitation-chewing-swallowing before the process is complete. The low-carbohydrate makeup and slow breakdown of plant cell wall structures keep the acid production in check, and thus the pH is fairly neutral at around 6.0.

High-concentrate feeds such as grain, however, do not require nearly the same level of chewing and ruminating to be digested. This, in turn, shortens the length of time the feed is mixed with saliva, which contains enzymes such as salivary lipase and amylase, not to mention minerals such as potassium, bicarbonate, phosphate and urea. When there is less ruminating (also known as cud-chewing), the buffering effects in the rumen environment are reduced. The rapid production of VFAs (volatile fatty acids) lowers the pH to closer to 5.5, creating a more acidic environment that does not support the forage-utilizing microbes, leading to a die-off.

With a lower pH compounded by an increased lactic acid and VFA concentration, the rumen can fail to provide adequate buffering and efficiently absorb the VFAs. When this happens, metabolic acidosis poses a threat, in addition to damage to the rumen lining. These ulcerations can cause discomfort, inappetence and, thus, stress and cortisol release. Without adequate breakdown of feed compounded by a compromised barrier, larger, undigested feed particles can cross through tissues and membranes, creating the perfect storm — an inflammatory response that then triggers yet more cortisol being released into the bloodstream.

Both adult cattle and calves transitioning from a pasture or range setting to a confined environment can have a difficult time making the change. The differences in environment, in addition to being separated from herd mates and introduced to strange animals, causes a great deal of stress, regardless of how it is carried out.

Once in this new setting, they are also started on high-concentrate feeds that they have likely never encountered before. The change from a forage diet to a concentrated diet can increase physical stress and create a pH imbalance in the rumen. Poor digestion contributes to low weight gain or actual weight loss. For calves and adult cattle that have been out with the herd, this poses an even more difficult set of challenges. Not only do they have to adapt to separation from their group, but they also must become familiar with water sources that they may have never encountered, such as troughs (many range cattle drink only from streams or ponds). Dehydration is a major factor in acidosis and rumen damage.

At this juncture, it’s most important to support the digestive processes (and thus the immune system) to help animals adapt. Maintaining a healthy pH balance is the most efficient and cost-effective way of ensuring that animals being introduced to new feed and water sources thrive. A healthy, well-functioning rumen ensures that at the time of vaccination, the immune system is primed to respond properly for building immunity.

While there are many other stressors cattle may encounter, the aforementioned four factors are the most widely reported as having negative effects on cattle health and vitality.

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Foal Diarrhea 101: Causes of Infectious Foal Diarrhea

By Brood Mares, Foals, Horses No Comments

Foals can be extremely susceptible to infectious foal diarrhea; their immature immune systems put them at risk for contracting viral or bacterial diarrhea, or both. Being able to recognize and intervene can be the difference between a foal surviving infectious diarrhea or not.

Viral Causes

There can be different pathogens at play in viral diarrhea in foals, however, the most commonly seen is rotavirus. Because rotaviruses are highly contagious they can easily spread to other foals in a facility. This makes it doubly difficult to control and isolate. Rotavirus typically has an incubation period of 3 – 10 days. During this time they will develop clinical signs such as a decreased appetite, mild-to-moderate fever, watery stools, and depression.

Other viral causes of diarrhea can include coronavirus but this is less commonly found than rotavirus.

Bacterial Causes

Bacteria are found in various levels in the healthy gut. When one or another takes over, however, it can wreak havoc on a foal’s digestive and immune systems. Unlike a mostly singular viral cause, there are numerous causes of bacterial diarrhea in foals. Salmonella, clostridium, E. coli, and rhodococcus are most frequently found and, like viruses, can be highly contagious. Fecal smears and/or cultures are used to isolate which bacterium are present and in what numbers; foals are particularly susceptible to bacterial infection because of their immature immune systems.

Much like the symptoms that go with viral causes, foals present with runny or watery stools (consistency and color will vary depending on the specific bacterial culprit). In addition, they may develop hemorrhagic diarrhea, colic, tachypnea (abnormally rapid breathing), reduced appetite, lethargy or depression and dehydration.

Other Infectious Causes

While viral and bacterial disease are the most commonly seen causes of foal diarrhea, protozoans contribute to a fair number of foal diarrhea cases. Aeromonas hydrophila and Cryptosporidium parvum are two of the most frequently found. Others such as Giardia are also known to cause diarrhea in foals.

In the next foal diarrhea segment, we will delve deeper into the treatment and prevention of this potentially devastating condition.

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How to Minimize Travel-Related Ulcers in Horses

By Brood Mares, Foals, Horses, Performance/Competition Horses, Senior Horses No Comments

If you’re planning a big getaway with your horses this coming holiday weekend, remember that traveling can be stressful for them. Even though you’re itching to get out and go, they may need a little help from you to be in top form for your weekend’s adventures. Ulcers can be present, even when you don’t know they’re there.

Understanding Ulcers

A horse’s gut is a complex system of checks and balances. They are constantly secreting gastric acid to help break down food, however, a low pH (higher acidity) can take its toll on the lining of your horse’s stomach if it remains too low for too long.

When horses become stressed or move around excessively, their stomachs contract, forcing the stomach acid up into the upper sections. You can think of it kind of like having a balloon half-full of water. When you squeeze the lower portion the liquid travels into the upper areas of the balloon, including the neck. A horse’s stomach works somewhat the same way. When you compound this with no forage or other buffers within this part of the gut, the pH continues to drop, creating an increasingly acidic environment. This acid then begins to erode the mucosal lining of the gut and can even creep up into the esophagus. The discomfort created by these ulcers can manifest in many different ways, but some of the more common signs can include diarrhea, a lack of appetite, lethargy or acting antsy or “hot”, being “cinchy” and unwilling to have something around their girths, hunching of the back, kicking at the belly with their hind legs, tail swishing, and neck stretching.  The list goes on, but these are several that are indicative of possible ulcers.

How Ulcers Affect Hauling

Horses are creatures of habit (aren’t we all?) and become distressed when taken away from familiar surroundings. Many horses learn to cope well with these changes and will outwardly appear as though they’re fine or only mildly unsettled, but inside a storm can be brewing. Hauling can bring on internal stress responses in the calmest of horses.

As mentioned above, when a horse becomes active, either through stress or activity, their stomachs “shrink”, pushing acid upward. This rapidly lowers the pH. If they’ve had ulcers developing for some time — even mild ones — this acid further erodes those areas and causes pain and irritation. Many people experience the “trailering monster” phenomenon with their horses — full-on tantrums to avoid having to get into the trailer. This may not be so much behavioral as a physiological response to the acid washing over the linings of their stomachs.

How to Help Support Your Horse

None of this is to say that you shouldn’t be hauling your horse. There are, however, some things you can do to help minimize the impact it has on their overall well-being.

  • Always feed and allow them to eat before you head out. An empty stomach is more prone to acid damage, as there’s nothing in it to mix with and buffer the acids. If possible, avoid concentrated feeds such as grains, as this can lower the pH and create a more acidic gastric environment.
  • Provide adequate hay while traveling — even shorter distances. Horses are designed to be foraging and grazing all day long; as such, having access to feed will allow them to self-regulate their gut pH.
  • Administer a specialized buffering supplement prior to loading. This will keep the pH more neutral and help avoid the irritation that can cause your horse to “act up.”
  • Always make sure your horse receives adequate water stops while on the road and if needed, a chance to get off the trailer and walk around.
  • If you have a particularly sensitive horse, consider giving them another dose of buffering supplement upon arrival (as long as it’s indicated on the label that you can do so). The same goes for when you’re getting ready to leave and head back — they don’t know they’re going home. They just know they’re having to get in the trailer again.

With just a few small changes you can make traveling more comfortable for you AND your horse!

Sources:

www.vetmed.ucdavis.edu/ceh/local_resources/pdfs/pubs-Oct2012-sec.pdf

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The Immune Stress of Transportation and Poor Husbandry

By Acidosis and Shipping Fever, Branding, Cattle, Cow-Calf, Pre-Conditioning 6 Comments

It is likely that the most stressful event a cow will face in its lifetime is transportation. There are many factors that play into the toll shipping has on cattle. First, the trauma caused by loading can be fairly significant. If rough handling or poor conditions inside and outside of the trailer exist, this heightens that stress even more.

The inner environment of the trailer itself can also have a major impact on the herd’s well-being. Crowded compartments and unfamiliar animals contribute drastically to raising stress levels in cattle. Temperatures within transports can soar to almost unbearable levels during the summer and plummet to below freezing in the colder months.

Once on the road, an animal can remain in transport for more than 24 hours in some instances. During this time, access to water and adequate feed is limited. Fat cattle tend to fair the best, but they can still experience a fairly large amount of shrink. After 30 hours, the body cannot shed more water, so the weight being lost is tissue itself. Calves, cull cattle, and feeders tend to fare the worst in this scenario, consistently showing the largest amount of shrink. It’s important to ensure that cattle are well-prepared for a long trek prior to transport to ensure the least amount of stress and physical damage as they are conveyed to their destination.

 Husbandry

There is a direct correlation between poor husbandry and increased stress levels in both dairy and beef cattle. Every vaccination available can be administered, but with the wrong living conditions and lack of attention to care, there will be no marked benefit. This is due to the overwhelming stress put on the immune system while it attempts to cope with the influx of harmful microorganisms present in the environment.

In the case of dairy cattle, unsanitary living conditions can lead to mastitis, internal systemic infections, skin infections and hoof conditions, severely limiting their production potential. Most of these conditions require antibiotic intervention, during the course of which the cow’s milk cannot be included in the production stream. Mastitis treatment can be particularly painful for the cow, increasing stress levels regardless of how frequently she is handled.

Sub-par living conditions can wreak havoc on not only an animal’s physical well-being but also that of their psychological health. Waterborne and airborne diseases are common in poorly kept barns and stockyards. Dim lighting and cramped quarters lead to fighting, injuries, and distress. They’re also the perfect breeding ground for highly contagious diseases such as Bovine Respiratory Disease Complex (BRDC), Bovine Viral Diarrhea (BVD), scours, foot rot, conjunctivitis, ringworm and a large number of other aggressive pathogens. Additionally, bedding or footing saturated with water, feces or urine have the potential to create serious problems in the dermis and respiratory systems from exposure to fungus, bacteria, aerosolized fecal matter, and ammonia. Young calves are especially susceptible to poor air quality and easily develop calf pneumonia.

Sanitary conditions and adequate room, along with proper ventilation, is vital for maintaining health and reducing stress levels in cattle. Clean water and feed that is free of mold allow the animal’s body to better derive and utilize nutrients; supplements that support the immune system and fill in nutritional gaps allow the rumen to properly function.

Check back in on  Friday for more on the topic of vaccines and the role the existing immune systems plays in their efficacy. Missed the last installment? Check it out here

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Handling Techniques and Their Effects on the Immune System

By Acidosis and Shipping Fever, Branding, Cattle, Cow-Calf, Pre-Conditioning No Comments

There are several situations that can contribute to the overall stress level (and subsequent hormone release) in both individual cattle and the whole herd. While it’s not possible to completely avoid these situations, measures can be taken to prevent excessive exposure. Not only does stress have an effect on immunity and the outcome of finished cattle, but it can also have a negative impact on the quality of meat or, in the case of dairy cattle, the milk itself. The factors outlined below have been found to be the most detrimental to the well-being of cattle, both physically and psychologically. In this segment the first major factor — handling — is covered; next week the remaining stressors and situations will be addressed.

Handling Techniques

Over the last few decades, the cattle industry has seen major shifts in the handling and processing of livestock. Starting in the 1970s with the findings of Dr. Temple Grandin, the face of cattle management and “best practices” has changed significantly. It was realized that with certain equipment modifications and handling techniques, the stress (and subsequent loss rate) of livestock slated for slaughter could be reduced, therefore increasing production. The same methodology can be applied in the handling and care of dairy cattle as well. Frequent, gentle handling can create trust between cow and handler. Relaxed and non-fearful milk cows produce more milk of higher quality than their stressed counterparts.

The handling of beef cattle can be a virtually stress-free event for both the animals and the handlers. According to Principles for Low Stress Cattle Handling, “An animal’s previous experiences will affect its stress reaction to handling. Cattle have long memories. Animals which have been handled roughly will be more stresses (sic) and difficult to handle in the future. Animals which are handled gently and have become accustomed to handling procedures will have very little stress when handled. The basic principle is to prevent cattle from becoming excited. Cattle can become excited in just a few seconds, but it takes 20 to 30 minutes for the heart rate to return to normal in severely agitated cattle.” This indicates that a cow may remain in a nearly constant state of stress-induced arousal with repeatedly rough or unfamiliar handling over a prolonged period of time, increasing the release of cortisol into the system. More and more ranchers are rejecting the “ram and jam” method of cattle handling, trading it in for less aggressive methods.

Branding, vaccinations, and castrations can be arduous for both cattle and handlers. Hot branding is considered to be the most stressful means of animal identification, due to the pain levels that have been measured during the procedure. The American Veterinary Medicine Association (AVMA) has outlined practices for less painful (and subsequently stressful) identification, including freeze-branding, tagging, and ear-notching.

Vaccinating cattle is absolutely essential to ensuring herd health and immunity. When administering multiple vaccines to a cow, it causes less pain to the animal when needles are changed after each injection, as they dull exponentially upon each puncture. Subcutaneous injection is always preferable, as it tends to be less painful than intramuscular injections and as such, should be used whenever feasible. Further, the spread of disease from animal to animal is less likely with frequent needle changes.

Further studies have shown that abrupt separation and forced weaning between cows and their calves can cause heightened stress responses, both physiologically and psychologically. It can prove especially detrimental in range calves that have not learned to be in confined areas or around humans. Handling calves gently from birth (or first contact) can markedly increase their trust and subsequently diminish stress responses to routine handling and moving.

Another marked stressor for cattle is overly aggressive cattle dogs. It’s of the utmost importance to ensure that any dog that is working cattle does so in a calm, methodical manner. Cattle are prey animals, making it incredibly frightening and stressful to be faced with a predator that, by all appearances, is in attack mode. Exposing both calves and mature cattle to adequately trained dogs regularly helps dispel their perceptions of danger from herding dogs.

Check back in on Tuesday for the next part of this multi-part series where I’ll outline additional stress factors that can have a negative impact on vaccinations and their efficacy. Missed the first installment? Check it out here

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Foal Diarrhea 101: Non-Infectious Causes

By Foals, Horses No Comments

You head out to check on your week-old foal. All looks well until he turns and you notice a smeared green mess on his or her rump. This is a common occurrence in the majority of foals at some point before the age of 8 weeks, but can really happen at any age. Most of the time (before 2 months of age) it’s a passing issue that poses no threat of spreading to other horses, clearing up almost as quickly as it came on. Other times it can be an indication of a more serious or even life-threatening condition or contagious disease. It is helpful to be able to recognize the signs and symptoms of the different types of foal diarrhea.

What is “Foal Heat Diarrhea”?

You’ve probably heard this term before. “Foal heat diarrhea” refers to a bout of diarrhea around the first couple of weeks after a foal is born. It is the most common form of non-infectious foal diarrhea. It’s unclear exactly what causes foal heat diarrhea, but it’s speculated that it occurs in response to the foal’s digestive system beginning to establish its own functional “set” of gut flora and fauna.

The name “foal heat diarrhea” can a bit confusing. Many people mistakenly believe that it happens response to the hormones produced during the mare’s first estrus cycle and changes in milk after birth. In reality, the term is used to indicate non-infectious diarrhea that coincides with the mare’s first estrus cycle after foaling. Once the foal starts eating solid food, including some of the mare’s manure (this is a normal behavior for young foals and is referred to as coprophagy), new and beneficial microorganisms are introduced into the digestive system. This shift and maturation of the digestive system are believed to be what contributes to this type of diarrhea.

It’s important to note that a foal experiencing foal heat diarrhea will still be energetic and alert. Their appetites will not wane and they don’t display any signs of fever or lethargy.

What Else Can Cause Non-Infectious Foal Diarrhea?

Foal heat diarrhea isn’t the only culprit in the case of non-infectious diarrhea. Numerous other causes can create the perfect situation for foal diarrhea to occur. These other causes can include:

  • Over-feeding. If a foal takes in more food than it can adequately digest, this causes an overabundance of feed in the digestive system. The body reacts by expelling it. If this occurs, consider cutting back on the volume of milk or feed given at one time and instead increase the frequency of feedings. A typical scenario where this might happen is if a foal is separated from its dam for an extended period of time. When reunited it may gorge on milk, causing the digestive system to become overloaded.
  • Sand Ingestion. Foals are inherently “mouthy” and it’s not uncommon for them to ingest sand. Sand causes irritation to the lining of the digestive tract and results in loose, watery stools as the body attempts to remove the foreign material.
  • Lactose Intolerance. In some cases, lactose intolerance can lead to non-infectious foal diarrhea. Sensitivity to lactose, however, is often seen in conjunction with the actions of Clostridium difficile on intestinal villi. This will be reviewed in a later installment.
  • Antibiotic Use. Certain antibiotics can cause diarrhea symptoms in foals.

While non-infectious foal diarrhea typically isn’t fatal, it’s always important to make sure you know what type you’re dealing with. Consulting with a veterinarian is the wisest course of action to ensure that the health of your foal and herd as a whole is maintained.

Click here to read Part 2.

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Vaccinations Ineffective? It May Be More Than a Storage Issue

By Acidosis and Shipping Fever, Branding No Comments

Have you ever given vaccinations to an entire group of calves only to have a large number of them still end up getting scours or BRD? You may be blaming it on vaccine storage or handling. While this is always a possibility, there is also a strong chance that you are experiencing the negative effects of stress on vaccination efficacy.

No vaccination program can completely eradicate the possibility of disease in your cattle herd. Vaccines are meant to augment and strengthen immunity against the wide variety of diseases that can infect cattle and impact production. Even a fully vaccinated animal can contract any number of diseases if they are not in optimum health and receiving nutrition adequate enough to support a latently strong immune system. It is necessary to ensure that calves and adult cattle are in top shape before receiving vaccines, or the results will be sub-par at best.

It’s been established that there is a direct connection between the strength and effectiveness of a cow’s immune system and the amount of stress they experience. Stress hormones, namely cortisol, have a direct impact on the functioning of the rumen. Stress from any source (i.e. transport, poor or excessive handling, inadequate nutrition, cramped or unsanitary living conditions, heat stress, transitions from pasture to the feedlot, etc.) can create a myriad of problems, including a decreased positive response to herd vaccination programs.

Hormonal Stress Response and Vaccinations

When cattle are stressed, a complex physiological process takes place with the release of hormones such as cortisol, adrenaline, and norepinephrine. Although essential to help an animal escape danger, stress hormones can remain elevated due to environmental or health factors. Careful management of herds through proper handling, adequate nutrition, and immune support can markedly reduce the overall exposure of the body’s systems to the aforementioned hormones.

The most abundantly released of the stress hormones, cortisol is beneficial in normal amounts, but at elevated levels, it can start to have negative effects. When detected at heightened levels, it has been noted to result in less time spent in rumination; thus, a correlation exists between poor digestion and higher serum levels of cortisol. If cortisol concentration is elevated for extended periods of time, it suppresses immune defense, lowering the cow’s ability to fight off diseases.

Frequent release of cortisol and other hormones into the bloodstream can upset the delicate pH balance of the rumen by causing a die-off of the gut’s beneficial bacteria, allowing harmful bacteria to take hold, upsetting the pH balance. Gut flora is an integral element in a healthy rumen and allows for proper digestion and utilization of nutrients. Cattle depend on the fermentation processes of the rumen to break their feed down into easily assimilated components. When the bacterial balance is disturbed, fermentation doesn’t take place at the same rate or efficacy, creating a firestorm of problems throughout the cow’s entire system. In extreme cases, this can lead to acute or sub-acute acidosis. It has been established that at least 80 percent of a cow’s immune defenses lies within the rumen, emphasizing the importance of lowering stress levels in the herd.

As a result of the release of stress hormones during a stress response, body tissues can be broken down, potentially causing an inflammatory reaction. When this occurs, yet more cortisol is released. Further, stress hormones are metabolized by the liver and kidneys, placing an additional burden on the body as it attempts to break down and clear these neurochemicals. Reducing stress in cattle is of utmost importance to guarantee a healthy herd, and thus an effective vaccinations program.

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