Neonatal hypothermia is a serious, life-threatening condition characterized by the body temperature in newborns below the normal values
1. There is a balance between heat generation and heat loss in newborn lambs. If heat loss is higher than heat generation, the balance is distorted, and hypothermia occurs
6,10.
Hypoglycemia is a complex of symptoms manifesting itself in various clinical signs that result in a decrease in the blood glucose level. Hypoglycemia is defined as the level of blood glucose below 80 mg/dL in newborn lambs 5. Hypoglycemia develops as a consequence of the decreased calorie intake and/or increased catabolism. Hypoglycemia is observed in the next hours and days rather than in the first hours of life 1,2,11,12.
Neonatal hypothermia-hypoglycemia complex is sometimes understood as the life-threatening heat loss and the lack of energy in newborn lambs 13.
Body temperature (39.0-39.7 ºC) and blood glucose level (80 mg/dL) decrease below the normal values in HHC. The lambs with the body temperature between 39.0-37.0 ºC are considered to be mildly hypothermic, and the lambs with the body temperature below 37.0 ºC are considered to be severely hypothermic 1,2,5,9. These body temperature values were taken as the basis for the formation of groups in this study.
As stated in the literature 14, the body temperature of the lambs was determined by a thermometer, and the blood glucose levels were also easily determined by an inexpensive portable glucose meter. Glucometers, which can be easily used especially by cowmen, will provide great convenience for measuring the blood glucose levels in the field.
In the references 1,3,13,15, muscle tremors, kyphosis and irregularities in movements, bedridden cases and even deaths in some cases reported to be observed in HHC lambs are similar to the findings in the study.
It is considered that significant decreases in the clinical parameters (body temperature, respiration and heart frequencies) in mildly, and especially severely hypothermic lambs are due to the coma.
In lambs, the blood glucose concentration in neonatal hypoglycemia is less than 80 mg/dL 5. It has been reported by the researchers 2,5,11 that the blood glucose levels in severely hypothermic lambs fall from 80 mg/dL to 50 mg/dL or lower and become complex with hypoglycemia.
In the study, it was observed that the blood glucose values detected in mildly and severely hypothermic lambs were consistent with these notifications 2,5,11, and it was also determined that there were significant differences between the blood glucose values in the control, mildly and severely hypothermic lambs. However, it is noteworthy that the glucose levels were very low (average 20.20 ± 4.83 mg/dL) in severe cases. This is probably due to the fact that the lamb births in the study were in the winter months when the air was very cold and that the lambs did not take colostrum for a long period, in other words, they were hungry because environmental temperature and feeding are important factors in the regulation of the blood glucose values 1,4-6. Therefore, high-energy colostrum, which regulates blood glucose, needs to be taken timely and in the adequate amount exogenously 4.
Hypothermia and hypoglycemia complex is an important disease that results in not taking colostrum during the first 5 hours of newborn lambs. If the ambient temperature of newborn lambs is not warm enough, this complex emerges and causes large-scale losses in this period. Especially when the body temperature falls below 37 °C, the disease in lambs becomes heavy and may result in irreversible conditions 1,5. Death events in severely hypothermic lambs among the studied animals support this opinion. However, we believe that dystocia 1,4 and twin 1,16 births are effective in lamb deaths due to their effects on the HHC formation.
Albumin is the most important one among negative acute phase proteins. Although albumin levels in the study did not differ significantly among all groups, it was detected there were decreases in the mild and severe groups. Although these decreases suggest an acute phase response, when assessed together with decreases in the total protein values, the reason for these reductions can be explained by inadequate sucking or the insufficient intake of colostrum by lambs, in other words, starvation 17.
Passive transfer failure may be detected by determining the serum protein level. The serum protein level above 6 g/dL indicates sufficient passive immunity 18. Since the main source of passive immunity is colostrum, the total protein values in mildly and severely hypothermic lambs in the study were below 6 g/dL, which indicated that they did not take colostrum or took it inadequately.
In the literature 1,5,8, it is stated that hypoglycemia can be ameliorated by intraperitoneal glucose injections and hypothermia can be regulated by creating hot environments. In the study, 10% glucose was injected intraperitoneally in the direction of these statements, and the lambs were moved to a warm environment.
The fact that lambs older than five hours are in a coma may be due to the inadequacy of the herd observations because they have remained hungry for 1-2 days, have used all their glycogen and glucose reserves and brown fat tissue 8. Lambs are born with the limited energy reserves 13, such as glycogen and brown fat tissue, and especially twin-born lambs have a low body weight as well as less energy after birth 6,19.
It has been stated by Deinhofer 13, Huffmann et al. 20 and Owens et al. 21 that there is a significant correlation between lamb mortality and birth weights. This is supported by the fact that the mortality rates among the lambs with a low birth weight in this study are 25% in mildly hypothermic lambs and 70% in severely hypothermic lambs.
As a result, the early diagnosis and timely treatment of mild cases are important because of the high mortality rate in the cases of severe hypothermia-hypoglycemia-complex.