Neonatal hypothermia is a critical condition affecting lambs and kids, particularly in the first few hours after birth. It is a leading cause of early mortality, often triggered by exposure to cold, insufficient colostrum intake, or birth-related stress.

Neonatal hypothermia, defined as a body temperature drop below 39 degrees Celsius (102.2 degrees Fahrenheit) in newborn lambs and kids, leads to metabolic distress and increased susceptibility to disease. Newborns are highly vulnerable due to their limited fat reserves, high surface area-to-volume ratio, and immature thermoregulatory systems.

Hypothermia significantly contributes to perinatal mortality with losses ranging from 10 to 30 percent depending on environmental conditions and management practices.

Thermoregulation in Neonatal Small Ruminants

Multicolored newborn lamb

Lambs and kids, like other animals, are a precocial species. This means they are born with the ability to feed themselves and to move about almost immediately. As precocial species, these small ruminants possess some ability to regulate body temperature (thermoregulatory). However, they rely on various mechanisms to maintain body temperature:

• Non-shivering thermogenesis. Newborn lambs and kids rely primarily on non-shivering thermogenesis, a process driven by the metabolism of brown adipose tissue (BAT). The oxidation of brown fat generates heat to maintain body temperature, but reserves are quickly depleted if colostrum intake is delayed. Additionally, their hypothalamic response to cold stress is underdeveloped, making adaptation to temperature changes slow and inefficient.
• Shivering thermogenesis. Muscle contractions generate heat. This method is less efficient than non-shivering thermogenesis and becomes more relevant as the neonate matures.
• Behavioral adaptations. Neonates instinctively seek warmth by huddling with littermates or staying close to the dam. They may also assume curled postures to minimize heat loss.
• Vasomotor control. Peripheral vasoconstriction helps conserve heat by redirecting blood flow from the extremities to vital organs.

Consequences of Neonatal Hypothermia

Neonatal hypothermia can lead to severe complications, including the following.

• Reduced vigor. Affected neonates exhibit lethargy and decreased suckling behavior, worsening their condition.
• Hypoglycemia. Increased energy demands deplete glycogen stores rapidly, leading to hypoglycemia.
• Higher mortality rates. Severe cases can result in organ failure and death if not promptly addressed.
• Increased susceptibility to infections. Weakened immune responses make hypothermic neonates more prone to infections.

Risk Factors for Hypothermia

Environmental Factors

• Cold and wet conditions. Exposure to rain, wind, and low temperatures accelerates heat loss, leading to rapid hypothermia.
• Poor bedding and shelter. Inadequate or wet bedding increases conductive heat loss.
• Season of birth. Winter-born lambs and kids face higher risks due to extreme temperature fluctuations.

 Maternal and Colostrum Factors

• Delayed or insufficient colostrum intake. Colostrum provides vital energy and passive immunity. Delayed intake results in hypoglycemia and worsening hypothermia.
• Maternal inexperience or neglect. Poor maternal bonding and insufficient licking result in delayed drying and heat retention.

Neonatal Weakness and Birth-Related Stress

• Dystocia and birth asphyxia. Difficult births cause hypoxia, impairing metabolic heat production.
• Low birth weight. Premature or twin-born neonates have reduced body fat and BAT, increasing their susceptibility to cold stress.

Stages of Neonatal Hypothermia

Prevention Strategies

 Environmental Management

• Sheltered lambing areas. Provide insulated, draft-free barns with proper ventilation.
• Deep, dry bedding. Use straw or wood shavings to minimize conductive heat loss.
• Heat lamps and warming boxes. Use in extreme cold but monitor to prevent overheating.

 Ensuring Early Colostrum Intake

• Feed within 2 hours. Administer at least 50 ml/kg within the first 2 hours post-birth (Nowak & Poindron, 2006).
• Tube feeding for weak neonates. Use stomach tubing if suckling is delayed.
• Supplementing with energy sources. Provide oral glucose solutions to prevent hypoglycemia.

 Maternal Management

• Monitoring pregnant does/ewes. Ensure proper nutrition during gestation to improve birth weight and colostrum quality.
• Selective breeding for maternal behavior. Prioritize ewes and does with strong maternal instincts (Dwyer, 2010).

Treatment of Hypothermia

Rapid Warming Protocols

 Mild to moderate cases (34-39°C)

• Dry the neonate using towels or a heat lamp used from a a safe distance.
• Provide warm oral colostrum or electrolytes to restore energy.
• Encourage skin-to-skin contact with the dam to improve thermoregulation.

Severe cases (<34°C)

• Use warm water immersion (40°C/104°F) while keeping the head above water.
• Administer intraperitoneal glucose injections (20% solution, 10 ml/kg) to correct hypoglycemia.
• Reintroduce heat gradually to avoid circulatory shock.

Conclusion

Neonatal hypothermia remains a leading cause of mortality in lambs and kids, particularly in cold environments or when colostrum intake is delayed. Effective management of maternal nutrition, environmental conditions, and early colostrum feeding can significantly reduce the risk of hypothermia. Prompt detection and intervention, including rewarming techniques and glucose supplementation, are critical for improving survival rates. Future research should explore genetic resistance to cold stress, the role of gut microbiota in thermoregulation, and advancements in thermal imaging for early hypothermia detection.