Danny Nadler AGSC 215 Dr. Jessica Colpoys 10 November 2018
The Effects of High-Stress Handling in Cattle
Temple Grandin, born in 1947, is a gifted and autistic animal scientist. She has spent countless hours of her career focusing on one major issue- animal stress. This can be stress while in the pasture, stress while being handled, and stress going through facilities and various buildings. Much of today’s population has put quite an emphasis on animal welfare, and making the animal as comfortable as it can possibly be. This is especially prevalent in the cattle industry, whether it’s dairy, market, replacement, etc. Many people and scientists care about stress, but how do these stressful situations impact the animal and why should today’s consumer and producer be so worried? High stress handling in cattle may lead to several negative impacts in the animal’s life, such as, a compromised immune system, decreased meat quality and milk production, decreased reproduction and fertility, and an overall unhappy livestock herd.
The first step in analyzing the issue is to determine what stress is. Stress can be defined as anything, both physical and mental, which causes disturbance to homeostasis. In simpler terms, stress is anything that disrupts the natural behavior of an animal during their daily routine. Another term to define is “high-stress” handling. Producers need to have some way to move their livestock, and there are several different methods at their disposal. However, some of these handling routines cause much lower stress for the animal and can be considered as “preferred” methods. Common high stress methods include things like electrical prods, loud instruments to get them to move away from the noise, and the use of all-terrain vehicles. Although each of these gets the job done and the cattle moved, they have negative impacts on the animal’s health. These routines tend to scare the animal and have them moving out of fear, instead of a more comfortable and relaxed manner. Others methods, such as using horses, food, and utilizing the areas around the animal are considered lower stress. Many large ranches rely on horseback to move horses. This keeps the cattle moving in the herd, which they prefer, and seems a bit more natural. Using feed is another common method and simply lures the herd through the use of food, whether following the feed truck or following hay. Finally, the use of the area around the animal can be very beneficial. Livestock have certain zones that can dictate their movement. The point of balance is towards the middle of the animal. Stand there and the animal will not move. Move towards the shoulder area and the animal will begin to go backwards. Move towards the hip and the animal will begin moving forward. They also have blind spots where they can no longer see the handler and will move so they can. Finally, they have an area called the flight zone. This is the area when too close the animal will frantically attempt to get away. They begin their fight or flight mode. Using the area around the animal, properly, gets them moving in a safe and comfortable manner. Unfortunately, not all producers use low-stress handling methods for their cattle and this can make disease within the herd more common.
One of the main effects regarding high-stress handling, in cattle, is a compromised immune system. This is because stress releases the hormone steroid, cortisol. In small or normal amounts, cortisol is harmless and is actually beneficial to the animal. However, too much cortisol can cause problems for the animal, such as decreased immunity. When an animal is in a stressful environment, the release of cortisol essentially gives them a rush so that they can “escape” the situation. Cortisol increases heart rate, blood pressure, blood glucose, respiration, and muscle tension in the animal. Although beneficial in the moment, animals that frequent stressful handling could be in danger. With such high levels of cortisol released in the body, “opportunity” pathogens have the chance to attack. Many of these occur naturally and no effects are ever seen because a healthy immune system has the ability to fight them off. With a compromised immune system, the animal becomes more susceptible to diseases. For example, Pasteurellosis is very common in cattle undergoing stressful conditions. This is a respiratory infection that can lead to pneumonia and even death. It is not greatly understood exactly why stress has this affect but that it where it is most prevalent. It is thought that stress affects the body’s cells that fight off foreign material. The white blood cells then become less efficient and can no longer maintain the body’s need to fight off infections and other foreign bodies. Since the high-stress handling compromises the immune system, it also means increased vet related bills for the producer. Not only do you need to treat the infected animal, but there are also the animals that were in contact with the infected animal. Now, the producer may have not one, but multiple animals affected by their negligence of low-stress animal handling practices. Although not all low-stress handling methods are as convenient and quick, they increase the quality of life for the animals in that herd, and can help keep medical related costs down for the producer. Another effect of high-stress handling in cattle is decreased production.
For years, people all around the world have enjoyed the delicacy of a nice piece of meat, but what does that piece of meat say about the animal it was cut from? Studies have found that there is a decreased quality of meat coming from cattle present in chronic stress conditions. A cut of meat from a stressed cow will possess a higher pH. The pH levels in the meat indicate the acidity of the meat. With the higher pH, the color of the meat will be quite noticeably darker than healthy meat. Although consumers want a nice rich color for their meat, high-stressed product will not display a very appealing color. It will appear browner instead of red. This meat has also been known to take on a slight green color anytime it is vacuum sealed. Because of the stress experienced by the animal, this meat can be discounted an entire quality grade. Once again, the producer will be losing money because the quality of meat that they are producing is decreasing. The quality is decreasing because exposure to stress before slaughter causes the animal to tighten up and leads to less tender meat. This meat could almost have a “gummy” like texture, and be much less desirable by the consumer. It has a tendency to be more prone to spoiling much quicker, and leads to an increase in wasted product. The dairy industry can also have a decrease in production from high-stress handling. Many people just think of beef production when referring to cattle, but the dairy portion is just as important. These cattle are also negatively impacted through high-stress handling techniques. Dairy cattle are around a lot of equipment and have a lot of movement, so it is important that they be handled in as low of stress as possible. Keeping them relaxed helps their milk production so the producer can get more milk per cow. When handled in high-stress conditions, it has been shown that these cattle are more likely to develop mastitis. Performed studies have found a positive correlation between dairy cattle that are in stressful environments and mastitis. Mastitis is a bacterial infection that causes inflammation of the mammary gland and surrounding udder tissues. If left untreated, the cow may lose functionality of all, or part, of her udder. This is a major expense for dairy producers all around the world. It is estimated that between $400 to $500 million dollars are lost each year, in the dairy industry, due to mastitis (Journal of dairy science). This takes in to account decreased production from a less efficient udder, milk lost while antibiotics are in the cow’s system, and extensive medical costs associated with the infection. Again, the producer is losing money on something that could potentially be taken care of. It is impossible to create an entirely stress free environment or handling system, but measures can be taken to ensure the animals are as comfortable as possible. Stressful handling can also affect the animal’s reproduction behaviors.
One of the final main effects of high-stress handling in cattle is decreased reproduction and fertility. Stress, cortisol, and luteinizing hormone are all correlated with each other. When stress is high, cortisol is also high. With an increase of cortisol, there is a decrease in the luteinizing hormone. Luteinizing hormone, or LH, is a glycoprotein hormone produced by the anterior pituitary gland. It triggers ovulation in females, and stimulates the gonads of males. LH is also very important to the production of Progesterone, which increases during pregnancy. The luteinizing hormone triggers the development of the Corpus Luteum. This develops after ovulation and is required to support pregnancy in mammals (igrow.org). With low LH levels, ovulation is not triggered as often in females. This affects not only ovulation, but also conception and the general pregnancy. Even with that aside, animals are similar to animals with high-stress pregnancy. Pregnancy requires a lot of the body and requires a series of conformational changes along with hormonal differences. Like humans, high stress can lead to pregnancy complications such as increased risk for miscarriages, birth defects, and still born frequencies. Out of natural instinct, the body will go into fight or flight mode when threatened. If the body deems necessary, the pregnancy could be terminated