Stressors Resource Center Sheds Light on Complex Issues
How do we save energy? It’s simple. We turn off the lights. Unfortunately, when it comes to stress in dairy cows, it is not so easy. Stress is not so easy to turn off.
Stress is caused by stressors. We are aware of more than 30 different stressors that affect the health and performance of dairy cows. However, if you read dairy related articles, you may notice that the dairy industry tends to focus on only a handful of stressors and address each one. The reality at the dairy farm level is that stressors interact and compound to negatively impact cow health, performance, reproduction, and longevity.
Stress in dairy cattle is complex. Knowing how stressors work and how they affect cows can reduce the negative impact on the herd and improve profitability.
Concepts of Stress and Strain
Domesticated food animals are predators. When they perceive a threat, their instinct is to avoid predator attack. In the modern dairy environment, the situation is different because there is little risk of cows being eaten by predators. In the modern world, threats (stressors) come from a variety of sources and often lead to metabolic strain. As a result, cows undergo physiological or behavioral changes to maintain balance.
An important step is to understand that different cows respond to these changes differently. in the Jefo RumiNation podcast “Impacts of Stress and Strain on Reproductive Health” (Series 3, Episode 6), University of Missouri Dr. Matt Lucy, professor at the University of Missouri, states that it is important to know the difference between stress and strain. All cows are stressed, but stress is how they react to that stress. For example, we have many cows in our herd that produce 100 pounds of milk per day. Stress is production. But stress is how cows react to it. We want to put very little stress on the cows.
According to Dr. Lucy, the impact of stress on production and reproduction depends on the magnitude of the burden. Genetics can help producers select more resilient cows. We want cows that can handle this type of stress,” he said. Once you have the right kind of cattle, you as a producer have to manage the rest of the burden. Genetics will not solve everything. You have to be a top producer and manage the rest of the burden, including heat stress, nutrition, and bedding space.
The key is to identify the stressors that are having the greatest impact on you, your cows, and your team and incorporate solutions to reduce the burden they cause.
Knowing Stress and Eliminating Stress
Do you know the old adage that “knowledge is power”? By learning more about stress, you can eliminate its effects, and Jefo Nutrition outlines five major stress categories and lists solutions to maintain cow comfort, health, and productivity:
- Feed intake problems
- Standard operating procedures
- Production phase
- Herd Health
As temperatures rise, we hear a lot about heat stress. Dairy cows become stressed when the heat load exceeds their ability to remove heat. Often they adapt by altering their metabolism to reduce heat production.
A whole-farm approach is essential to minimize the impact of heat stress on the herd. The goal is to maintain good health, feed intake, and production levels. This approach becomes even more important when the Temperature Humidity Index (THI) is above 68.
Producers should rely on heat mitigation measures such as fans, misting, and the use of shade. Ensure that these tools are well maintained and effective. This is an area that is sometimes overlooked but needs to be well established. Additionally, it is important to increase the supply of clean water and avoid overcrowding as much as possible. Other Notes
- Feed during the coolest part of the day.
- Increase nutrient density of forages in anticipation of reduced dry matter intake.
- Feed high quality forages.
- Increase feeding frequency and avoid heating feed.
During heat stress, it is also important to employ key precision nutrients. B vitamins are essential to support efficient glucose and protein production, and research has shown that a protected B vitamin blend can help cattle cope with heat stress. Supplementation during periods of known stress can help overcome many of the negative consequences of stress and, in turn, increase farm profitability.
Don’t forget dry cows in the heat. It is estimated that heat stress costs dry cows in the U.S. more than $800 million annually in lost milk production. Conversely, measures to cool dry cows have been shown to increase farm profitability. Studies have shown that supplementation with protective B vitamins (choline, folate, B12, and riboflavin) before and after calving reduced subclinical ketosis and decreased placental retention and uterine inflammation. Another reason to focus on dry cows is to help the calves they calve. Studies have shown that calves born to cows that experienced heat stress in late pregnancy have lower birth weights, reduced immunity, and lower first lactation milk production.
Heat is not the only “weather” stressor to be concerned about. Other weather-related stressors include extreme cold, humidity, excessive rain or snow, changes in daylight hours, and other inclement weather. Message Weather affecting dry matter intake affects cow performance.
2) Feed intake issues
In the RumiNation Podcast Impacts of Stressors on Physiology and Health of Dairy Cows (Season 3, Episode 4), Dr. Trevor DeVries of the University of Guelph states that cows can suffer from nutritional stress This is physiological. This is physiological, such as the literal response of the cow’s body to a change in diet. It can also be perceptual, where cows simply see a change in diet as foreign and stop eating. Or it can be behavioral, due to competition for bunk space, where the cow’s mealtime or meal frequency changes, negatively affecting rumen health, food absorption, and digestibility. Anything that negatively affects intake has a trickle down effect on energy balance, production, and overall cow health.
At this year’s annual meeting of the American Dairy Science Association, two research reports on DMI and nutritional stressors were presented by Faith Reyes and her University of Wisconsin colleagues who presented research related to stocking density and how competition for bunk space can reduce cow intake. She concluded: “It appears that as stocking density increases, cows become more competitive and enter the bunk less often, thus regulating the number of bunk entries and the amount they eat.”
In the second report, Francesca Mazza presented a poster on feed hygiene. In this report, she reviewed bacteria, yeasts, and molds commonly found in various types of feed on farms across the United States. These organisms, when ingested in large amounts, can have adverse health effects and further lead to reduced feed intake and milk production Mazza and colleagues examined 8,942 feed samples collected from farms in 35 states. They found that spoilage bacteria and potential pathogens were more prevalent in TMR than in individual fermented feed ingredients in the diets. This study underscores the importance of proper feed management practices and reducing feed contamination as a potential stressor.
Dr. Lucy concurs. He says there is no substitute for good, quality nutrition, and Dr. Lucy recommends consistency. He says, “In an ideal world, cows would be fed the same TMR at the same time by the same person with the same tractor. Such balance, he adds, is like armor for cows and helps them cope with the strain they are under from potential stressors. 3) Standard Operating Procedures (SOPs)
Daily activities affect cows. Daily or weekly routine tasks may seem harmless, but they can cause cows to spend too much time away from feed, too much time standing outside their stalls, or negatively impact social interactions. All of these can cause problems; implementing SOPs can maximize efficiency and reduce stress.
Below is a short list of potential management-related stressors
- Human-animal interaction
- Density of stocking
- Change of groups
- Sleeping space
- Housing issues
- Herd health checks
- Social Stress
According to Dr. DeVries, social stress can have a negative impact in many places. Cattle are social animals and prefer to be in a social environment,” explains Dr. DeVries. For example, overcrowding in feed bunks and parlor housing pens.
Dr. DeVries also mentions the problem of mixed herd sizes and the potential for stress, especially on younger cows, when young and older cows are mixed together.
Another important consideration to reduce management-related stress is cow comfort. A rule of thumb is that comfortable cows are cash cows.
Key factors to ensure cow comfort include
- Adequate feed and resting space
- Protection from wind and rain
- Access to high-quality feed and water
- Training of employees on how to properly interact with animals
Especially with regard to the last point, cows should not be fearful of the cattleman. Fearful cows are stressed and less productive, and according to Dr. DeVries, acute stressors such as poor cow handling can have a direct impact on cow physiology and productivity. A clear example of this is poor cow handling in the milking parlor,” said Dr. DeVries.
says Dr. DeVries. ‘Such stress can cause a cortisol spike in cows, inhibit or decrease oxytocin secretion, and limit milk production.’
There is a new tool called farm synchronization that can help eliminate stress and maximize feed efficiency.In the RumiNation Podcast Increase Milk Production with Farm Synchronization (Season 2, Episodes 6 and 7), Green Ag Solutions and David Green of Burton Kiefer and Associates Consulting Group discussed how this approach can help improve milk production and labor management. According to Greene, dairy synchronization links three major management centers: 1) feeding operations, 2) milking operations, and 3) herd management. He said, “The goal is to synchronize the milking and feeding schedules with the activities of the herd management team, whether it is breeding or herd health checks. If we can get these three areas to work well together, we can maximize feed efficiency,” Green says.
Green says the goal is to feed cows about two hours earlier than they are in the parlor. By doing so, they can reduce meal frequency, increase intake, improve efficiency, and raise healthier, more productive cows. If each department can communicate and work together, Greene says dairymen can see a two to three pound increase in milk production with the same or lower feed intake. Greene adds, “Every move on the dairy farm needs to be centered around maximizing milk production efficiency.”
4) Production Phase
Calf delivery is one of the most metabolically stressful and challenging times for cows. It is important to provide a quiet, clean, and comfortable calving pen to reduce environmental and social stress.
Dr. Lucy further explains that stress is a major factor in cow pregnancy. Traditionally, we have always thought about the effects of stress on ovarian function. Traditionally, we have always thought about the impact of stress on ovarian function. But recently, we are trying to understand specifically how stress affects uterine function and the preparation of the uterus for pregnancy.”
According to Dr. Lucy it is important for producers to understand that reproduction begins in the dry cow pen. It is important for producers to understand that breeding starts in the dry cow pen. “It is about not putting long-term stress on cows and taking care of them in the transition barn.
We know that stressors can negatively affect fertility, so it is important to focus resources on prevention and early detection. There are tools available to help us monitor how cows are responding to stress. For example, excessive weight loss in early lactation can be monitored with new technologies such as body condition scoring (BCS) and weight camera imaging. Why is it important to monitor weight loss in early lactation? A decrease in BCS within the first 30 days of lactation can result in decreased fertility and possible loss of fertility. Find time to monitor early lactation weight loss and use that data for improvement.
5) Herd Health
Exposing cows to unnecessary stress can increase their susceptibility to disease. Manage, prevent, and treat early, says Dr. Meagan King, Professor of Animal Science at the University of Manitoba, on the RumiNation Podcast Precision Technology to Monitor and Predict Animal Health (Season 3, Episode 5). The following is a brief overview of the key steps to take to prevent subclinical ketosis to intermediate ketosis She recommends addressing all problems early, from subclinical ketosis to moderate lameness and mastitis.
Dr. King’s research examines the effects of stressors such as lameness, overcrowding, and feed supply on production. She recommends using precision techniques such as ruminant and behavior tracking information to examine behavior, identify problems quickly, and make better management and nutrition decisions to treat problems.
Research also shows that supplying necessary nutrients in a form that allows them to be absorbed at appropriate levels can improve the health and metabolism of cattle. For example, supplementation with biotin
protective choline and B vitamins have been used to reduce clinical and subclinical ketosis.