For decades, the agricultural community has been aimed at discovering the key factor that determines propensity for improved health and longevity. While physical, chemical and biological factors play a major role in animal health and life expectancy, it has been proven that longevity hazards also include physical and emotional stress. Stress can be formally explained as symptoms resulting to a situation or environment that is not normal for the animal. Stress manifests in two ways, namely psychologically and physically. It is regarded among detrimental cattle illnesses. As such, if the farming system is not properly managed, cows can die from stress.
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Effects of Stress
Studies have indicated that stress has an inhibitory effect on appetite and rumination. Resultantly, feed digestibility is negatively affected and so is performance as well as health. Stress is said to be among the leading causes of immune system failure. Studies indicate that stress affects cows in a specific manner and some types of defence against disease are affected. However, the results are almost always the same. The immune system is suppressed exposing cows to bacteria that can cause fatal diseases and infection. While physical stress is easy to identify, it may be difficult for farmers to notice cows suffering from psychological stress. It is believed that stress resulting from chronic fear increases in the prevalence of mastitis in dairy cows. Since cows can die from stress, it is important to understand various types of stressors that cause mortality.
Cows can die from stress caused by a poor feeding management system. Feeding management encompasses all the feed related tasks necessary to promote health, performance, and well-being of the work. A proper feeding management system is one that allows for the constant provision of a well-balanced dietary plan including the necessary feed additives. Additionally, feed rations should be carefully monitored and water troughs availed at all time. Failure to do so exposes livestock to stress. According to studies, lack of attention to feeding management practices can result in sorting, digestive upsets, cyclic eating patterns, and over- or under-conditioned cows, all potentially leading to or causing subacute rumen acidosis. The impacts of poor feeding management also include compromised immunity which is the leading cause of mortality.
Cows can die from stress, particularly social stress. This type of stress generally stems from the relationship of a cow with other animal species. Cows suffer from social stress due to number of reasons which include over-stocking, lack of sufficient feeding space and keeping young and mature cows in the same pen among other factors. This leads to poor comfort among cows with consequences being poor performance, health and the overall well-being of the cow. Like most stressors, if the cow’s living conditions are severe, they may contract some bacteria such as the Ecoli. These are known to quickly spread across the herd causing high mortality rates. To add on, cows can die from stress, particularly social stress caused by poor ventilation. Like all animal species including humans, cows need a constant supply of clean, fresh air. According to research findings, adequate ventilation removes excess heat, moisture, dust, microbes, and gases that accompany housed animals. This is of the essence in ensuring the safety of domestic animals because poor air quality can result in immune suppression and an increased incidence of pneumonia hence high mortality rates. As such, since cows can die from stress, care has to be taken to ensure that they are kept comfortable and healthy.
This occurs when the heat load of a cow is greater than its capacity to lose heat. Cows can die from stress when temperatures are greater than about 26ºC and relative humidity is greater than 70%. Studies reveal that at such temperatures, cows endure physiologic stress and so have an increased maintenance requirement to cope with the heat. Note that high temperatures do not normally cause death unless proper livestock management is not practised. Overstocked and cows provided with an insufficient water supply or dirty water are more likely to die from heat stress. Another factor to be aware of is that effects of heat stress vary in relation to weight and type of breed. Heavy cattle cannot handle heat stress compared to lighter weight cattle. Their increased fat deposition prevents them from regulating heat effectively. It is said that solar radiation is a critical component that can lead to death from heat stress. Also, Friesians and crossbreeds are more susceptible to heat stress and begin to reduce their feed intake exposing them to disease and infection. Jerseys are considered to be more tolerant of heat. To add on, cows can die from stress as they radiate heat during the night to the cooler surroundings. Warm cloudy nights can reduce cooling, increasing the risk of heat stress.
Do Cows Get Stressed?
Similar to humans as well as other animal species, cows can get stressed. It is important to be aware that cows can die from stress if it is not handled properly and timeously. According to research studies, factors that cause stress in cows can be conveniently divided into physical stressors, social and psychological stressors. These result from the interactions with other animals and stressors related to handling by humans and those caused by environmental factors. Depending on the severity of the stress, response includes several changes that may have negative effects on performance and even death. These include changes in the immune function and increased susceptibility to disease, decreased feed intake and rumination, inhibition of oxytocin release, and reduced fertility, among others.
How Do You Tell If A Cow Is Stressed?
Cows can die from stress and so it is important for farmers to be aware of its indicators. Biological responses to a stressor have been used most frequently as indicators of stress. Behavioural and the immunological responses also serve as indicators of stress and welfare of cows. Basically, a cows is stressed when there is a change in behaviour. Experts state that changes in vocalization, motor activity or the expression of stereotypic behaviour may be an early indication of a stressful situation. Also, salivary and urinary cortisol levels are good indicators of stress. Signs of stress in cattle also include:
- Increased respiratory rate (open mouth panting)
- Open mouth and laboured breathing
- Reduced feed intake
- Agitation and restlessness
- Excessive salivation
- Loss of body weight
- Increase in mammary gland infections
- Severe udder oedema
- Increased urination with heavy electrolyte loss
- Reduced milk yields by up to 50%
- Embryo mortality increases
- Calves are often premature and small
- Collapse, convulsions, coma