How Temperature Affects Cattle Performance in Feedlots

Feedlots are critical components of the beef production system, where cattle are confined and fed a high-energy diet to promote rapid weight gain before slaughter. The performance of cattle in feedlots is influenced by numerous factors including nutrition, genetics, health, and importantly, environmental conditions. Among environmental factors, temperature plays a pivotal role in determining cattle productivity, health, and welfare. Understanding how temperature affects cattle performance allows producers to implement management strategies that optimize growth rates and feed efficiency while minimizing stress and health issues.

The Relationship Between Temperature and Cattle Physiology

Cattle are homeothermic animals, meaning they regulate their internal body temperature within a narrow range despite fluctuations in the external environment. However, their capacity to maintain thermal balance has limits. When ambient temperatures deviate significantly from the thermoneutral zone—the range of temperature where the animal expends minimal energy to maintain body heat—cattle experience thermal stress.

The thermoneutral zone for beef cattle typically ranges from about 10°C to 26°C (50°F to 78°F), depending on breed, age, body condition, and acclimatization. Temperatures below or above this range cause physiological adjustments that impact metabolic rate, feed intake, and overall performance.

Cold Stress

Cold stress occurs when temperatures fall below the lower critical temperature of the animal’s thermoneutral zone. In cold conditions, cattle increase their metabolic rate to generate additional body heat through shivering and non-shivering thermogenesis. This increased metabolic activity raises maintenance energy requirements.

Physiologically, cold stress can lead to:

• Increased feed intake to meet higher energy demands.
• Reduced energy available for growth because more calories are used for heat production.
• Potential weight loss if feed intake does not compensate for elevated maintenance needs.
• Increased water intake due to dry air and higher metabolic water loss.
• Greater susceptibility to respiratory diseases due to chilling effects.

Heat Stress

Heat stress happens when ambient temperatures exceed the upper critical temperature of the thermoneutral zone. High temperatures hinder the animal’s ability to dissipate excess body heat through evaporation, convection, radiation, and conduction.

Heat-stressed cattle display:

• Decreased feed intake as a mechanism to reduce metabolic heat production.
• Elevated respiration rates (panting) and increased sweating for evaporative cooling.
• Altered blood flow patterns directing blood away from internal organs toward peripheral tissues.
• Increased water consumption.
• Impaired nutrient absorption and digestion.
• Elevated cortisol levels indicating physiological stress.
• Reduced immune function leading to greater disease vulnerability.

Impact of Temperature on Growth Performance

Cattle growth performance is most commonly evaluated by metrics such as average daily gain (ADG), feed conversion ratio (FCR), and final body weight. Both cold and heat stress negatively affect these parameters but through different mechanisms.

Cold Temperature Effects on Growth

While mild cold exposure can stimulate feed intake, sustained or severe cold stress often leads to energy deficits due to insufficient dietary energy consumption relative to heightened maintenance demands. Young calves and lightweight animals with less fat insulation are particularly vulnerable.

Key effects include:

• Increased maintenance energy reduces net energy available for growth.
• Greater dry matter intake can partially offset increased energy needs but rarely completely compensates.
• Feed efficiency declines because more feed is used for heat production rather than tissue accretion.
• Prolonged cold stress can stunt growth rates resulting in extended feeding periods and increased production costs.

Heat Temperature Effects on Growth

Heat stress has a more pronounced negative effect on growth performance than moderate cold stress. Reduced feed intake during heat exposure is the main driver of lower ADG. As intake drops, nutrient supply becomes insufficient for optimal weight gain.

Additional impacts include:

• Poor rumen function due to altered microbial populations under heat stress conditions reduces fiber digestion efficiency.
• Increased maintenance energy expenditure related to physiological cooling efforts.
• Muscle protein degradation may increase while synthesis slows down during heat stress.
• Compounded effects lead to reduced weight gains often ranging from 10% to over 30% depending on severity.

Influence on Feed Intake and Efficiency

Feed intake regulation is highly sensitive to temperature changes. Cattle modify their feeding behavior as a survival strategy; reducing intake during heat stress minimizes metabolic heat production from digestion while increasing intake during cold periods supports greater heat generation.

Feeding Behavior Under Cold Conditions

Cattle tend to consume more feed when exposed to cold temperatures; however:

• Feed conversion efficiency declines since a larger fraction of consumed energy is diverted toward thermoregulation rather than growth or fat deposition.
• This phenomenon results in higher feed costs per unit of gain when temperatures are low.

Feeding Behavior Under Heat Conditions

During hot weather:

• Feed intake can decline by 15%–40%, depending on how high temperatures rise and duration of exposure.
• Reduced dry matter intake leads directly to slower gains.
• Even if cattle consume similar amounts intermittently (e.g., cooler times of day), overall daily intake often decreases.
• Digestive efficiency might be compromised causing poorer nutrient utilization.

Health Implications Linked with Temperature Extremes

Environmental temperature extremes impose physiological stresses that predispose cattle to health problems affecting mortality rates, morbidity patterns, and veterinary intervention costs within feedlots.

Cold Stress Health Challenges

Exposure to prolonged cold can result in:

• Increased incidence of respiratory infections such as pneumonia due to compromised mucosal defenses from chilling.
• Frostbite in extremities under extreme conditions leading to tissue damage.
• Weakened immune responses making animals susceptible to opportunistic pathogens.

Heat Stress Health Challenges

Heat stress poses numerous health risks including:

• Heat stroke which may cause death during extreme heatwaves without adequate shade or water availability.
• Electrolyte imbalances resulting from excessive sweating disrupting normal cellular functions.
• Increased prevalence of lameness triggered by altered blood flow patterns during hyperthermia.
• Immune suppression leading to higher susceptibility toward infectious diseases including mastitis and bovine respiratory disease complex (BRDC).

Management Strategies for Mitigating Temperature Effects

To optimize cattle performance under varying thermal environments, producers must implement targeted management practices that alleviate thermal stress.

Mitigating Cold Stress

Effective strategies include:

• Providing windbreaks and shelter structures that reduce wind chill effects.
• Utilizing bedding materials such as straw or wood shavings that insulate animals from cold ground surfaces.
• Adjusting rations by increasing energy density during winter months so cattle can meet elevated requirements without excessive bulk consumption.
• Group housing animals strategically so they generate collective warmth through close contact.

Mitigating Heat Stress

Key interventions include:

• Offering ample shade structures positioned for maximum sun protection throughout daylight hours.
• Ensuring constant access to clean fresh water with increased flow rates during hot days.
• Using sprinklers or misters combined with fans for evaporative cooling in extreme situations.
• Scheduling feeding times during cooler parts of day such as early morning or late evening encouraging greater intake.
• Selecting breeds or genetic lines with better heat tolerance when possible.

Conclusion

Temperature profoundly influences cattle performance in feedlots by affecting metabolism, feeding behavior, health status, and overall productivity. Both cold and heat extremes challenge the animal’s ability to maintain homeostasis resulting in decreased growth rates and feed efficiency along with increased disease risks. Understanding these physiological responses enables producers to adapt management practices, nutrition plans, and facility designs aimed at minimizing environmental stresses. With climate variability becoming increasingly unpredictable worldwide, proactive temperature management will become ever more essential for sustainable and profitable beef production systems.