The influence of hypothermia prevention by application of skin moisture absorbent on the value of body temperature, body weight and blood parameters in piglets

Reducing the mortality rate is of a great economic importance for pig farming. Therefore, it is necessary to define the conditions in the farrowing unit based on the performance of the piglets, and specific hematological and biochemical parameters. Therefore, the aim of this paper is to examine the importance of using skin moisture absorbent and its influence in preventing hypothermia, which causes great economic losses in pig production. The experiment was set up on a commercial farm in Serbia and included 92 pigs divided into the experimental and control group. Body temperature values, body weight and blood parameters were monitored. The obtained values indicate that there is a significantly positive correlation of body temperature change and body weight values, and body temperature showed a significantly higher increase in the experimental group compared to the control group. The results obtained from hematological and biochemical parameters provide a clearer picture of the metabolic processes in piglets in the farrowing unit and can be used to further improve pig production and as a complement to genetic enhancement.


INTRODUCTION
For years the selection direction in pig production has been focused on increasing litter size. Ruthereford et al. (2013) state that the increase in the number of piglets per litter has gone from 0.16 thermoregulatory capacity in piglets (Berg et al., 2006), decreased muscular energy production (Rowland et al., 2014), while Staarvik et al. (2019) point out that piglets are born with little physiological ability to produce glucose in the first hours after birth, and other problems.
Piglets at birth have to deal with unfavorable environmental conditions, as they do not have the natural protection for external conditions as young offspring of some other species of animals, and also the genetic potential is not fully adapted to farm conditions. To mitigate these deficiencies, farmers try to dry the piglets by wiping or using a skin-dryer preparation. Andersen et al., (2009) state that drying piglets at birth can result in reduced mortality.
The role of skin dryers in piglets is to help piglets cope with changing the environment more easily, to suck up colostrum in a timely manner and to suck in an adequate amount of colostrum, to prevent hypothermia.
Hypothermia attracts a lot of attention in pig farming because it represents a major economic loss that is difficult to cope with. There are no medicines or vaccines for hypothermia. Prevention should, as a rule, cover many production aspects in order to reduce the effects of hypothermia. An important aspect in preventing hypothermia is preventive measures that reduce the risk of hypothermia occurrence or to reduce the effects of hypothermia. Caldara et al. (2014) point out that hypothermia is a major cause of neonatal mortality. Hypoxia can also significantly affect the prolongation of time from birth to first suckling, which can result in the appearance of hypothermia and hypoglycemia (Panzardi et al., 2013).
The body attempts to cope with hypothermia through the cardiovascular system by activating peripheral vasoconstriction, sinus bradycardia with prolonged QT intervals, thinned heart rate, decreased ejection fraction, and minute volume (Steen et al., 1979), and Groban et al. (2002) state that a more severe form of hypothermia (<30 ° C) results in a reduction of myocardial contractions. According to Malmkvist et al. (2012) mechanisms for preserving heat in newborns are piloreaction and peripheral vasoconstriction. Baxter et al. (2008) state that piglets with low body temperature are difficult to adapt to changes in temperature at birth, affecting homeothermic equilibrium. Hypothermia results in poor piglet mobility, which affects colostrum intake or struggling among each other to reach the glands. (Lay Jr et al., 2002;Herpin et al., 1996), and Vallet and Miles (2012) state that smaller piglets are weaker due to decreased cerebral myelination due to slower transmission of nerve impulse.
The main objective of the presented study is to show the effect of the moisture absorbent (Mistral®) used and to examine their effect in preventing hypothermia on body temperature, body weights and blood parameters in piglets.

MATERIALS AND METHODS
The research was carried out on a farm in Vojvodina with a capacity of 1,700 sows. The farm has a complete production cycle from sows to fatteners and the farm does the selection of pure breeds to produce F1 gilts. The study included piglets obtained from F1 generation sows (Yorkshire x Landras and Landras x Yorkshire) from the second to the 8th parities. 92 pigs (41 pigs from the control group and 51 pigs from the experimental group) participated in the experiment. The sows in the model were fed the same diet, and the sows that were treated, their piglets were not included in the experiment. The pigs from the experimental group were treated with the piglet skin dry preparation at birth, after which they were marked with plastic ear tags, after which the body weight and body temperature were measured.
Body weight measured at birth, 3h, 24h, 16, 25, 40 days of age. Body temperature measured by thermometer, 320x240 heat camera and IC thermometer were measured at birth, 3h and 24h after birth.
Blood was taken into EDTA vacuum tubes from the jugularis externa (regio colli lateralis) vein, three days after birth and sent to the laboratory for 2h after sampling, after which they were immediately processed in the laboratory. triglyceride, total bilirubin, AST, ALT, urea, alpha amylase and lipase were determined using standard Byosystem kits (Spain) using a Chemray-Rayto analyzer (China).
Differences in body temperature, body weight, and blood parameters between the experimental and control groups were examined by t-test to compare the mean value of the independent samples. The correlation between different methods for measuring body temperature in piglets was determined by statistical analysis of Pearson's correlation coefficient. The correlation between dynamic changes in body temperature and body weight in piglets in the first 24 h of life was determined by regression linear analysis. It was determined by partial correlation analysis whether dynamic change in body temperature (24-0h) was a factor controlling the linear relationship between dynamic change in body weight and total protein concentration. Statistical package SPSS (IBM, 2017) was used.

RESULTS
In piglets in the experimental group at birth (Table  1a), a lower rectal body temperature was found and a tendency towards lower values measured by the heat and IC thermometer, 3h after birth there was still lower body temperature in the experimental piglet group, whereas the difference in temperature measured by IC thermometer and heat camera was not statistically significant (NS).
No statistically significant differences were found between the experimental and control groups 24 hours after birth. Examination of dynamic changes in body temperature values expressed as a difference (0-24h) showed that body temperature showed a significant increase in the experimental compared to the control group of piglets, regardless of the method of measurement. The body weight of the experimental group was lower at birth, so that in the later test period the difference in body weight between the experimental and control group was lost. In the piglets of the experimental group there was a significantly higher weight gain in the first 24 hours compared to the control group of the piglets, while on day 40 there was no statistically significant difference between body weights (Table 1b).
Observed blood values indicate that there are highly significant differences (p<0.01) between the parameters of the experimental and control groups in mean corpuscular hemoglobin concentration, aspartat, cholesterol, total protein, globulin and lipase, while the significance level p <0.05 was determined among the following parameters: white blood cell, glucose, albumin. Significance level p <0.1 was recorded for urea parameter, while statistical significance (NS) was not determined for red blood cell, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, triglyceride, alanine aminotransferase, alpha amylase, total bilirubin parameters. The White blood cell concentration is lower in piglets from the experimental group, which may indicate that the organism does not need to produce higher white blood cell concentrations and that the ambient pressure that pathogens can create is significantly lower compared to white blood cell piglets from the control group. The experimental group is also characterized by a lower concentration of AST, which is often used to detect liver damage. Glucose concentration was increased in piglets of the experimental group, which is desirable because it is important for piglets in the first days of life. The increased concentration of total protein was also expected in piglets from the experimental group, because the concentrations of albumin and globulin were also increased. The lipase concentration was significantly lower in the control group compared to the experimental group (68.8 ± 13.8; 84.19 ± 12.8). The results are shown in Table 1c.  : measured by thermometer (rectal temperature) at birth; Heatc 0h: measured by heat camera at birth; ICth 0h: measured by IC thermometer at birth; Rectal 3h: measured by thermometer (rectal temperature) 3h after birth; Heatc 3h: measured by heat camera 3h after birth; ICth 3h: measured by IC thermometer 3h after birth; Rectal 24h: measured by thermometer (rectal temperature) 24h after birth; Heatc 24h: measured by heat camera 24h after birth; ICth 24h: measured by IC thermometer 24h after birth Dynamic changes in body temperature are in significantly positive correlation with dynamic changes in body weight (change 24h at birth versus 0h at birth) (Chart 1).
The correlation between total protein and increase of gain is controlled by the achieved difference in body temperature (Chart 2), correlation when excluding the influence of body temperature notice that the regression line tends to zero (graph 3). Dynamic changes in body temperature are a controlling factor which controls the correlation between total protein concentration and dynamic changes in body weight in the first 24 hours after birth.

DISCUSSION
The piglets from the experimental group had a lower body temperature in all three measurement methods compared to the control group at birth, 3h after birth, while the average values were approximately the same 24h after birth in both groups. Moreira et al. (2016) state that the piglet body temperature immediately after birth is 37.0±0.10°C, which is closest to the body temperature measured by the heat camera in piglets from the control group, which is 36.2±1.74.

Due
to the underdeveloped piglet thermoregulation system, even small differences in temperature can be harmful to piglets as indicated by Sahuquillo and Vilalta (2007) and Gunn et al. (2017) who, by measuring the forehead temperature, found that a decrease in 1C temperature can lead to a decrease in metabolic rate by 7-9%, a decrease in oxygen utilization and CO2 production due to hypothermia. Tuchscherer et al. (2000) and Casellas et al. (2004) examining piglet body temperature indicate that rectal temperature measured 1h after farrowing is largely variable trait and that better insight into thermoregulatory capacity is obtained by measuring rectal temperature within 24h of farrowing, according to Baxter et al. (2008) rectal temperature 2h after birth is a good indicator of thermoregulatory success. Chart 1. Trend of body weight movement in the first 24 hours after birth in relation to rectal temperature in the first 24 hours after birth (regression analysis) Chart 2. The correlation between total protein and body weight (0-24 hours) Chart 3. Correlation view when influence of body temperature was excluded The calculated regression coefficient indicates that the average body weight of the piglets in the first 24 hours of life increases by 0.0745 kg with an increase in one degree of rectal temperature. Berthon et al. (1993) and Herpin et al. (1994) point out that piglets achieve thermal homeostasis 24h after birth at a body temperature of 38-39 ° C, and Moreira et al. (2016) state that the average body temperature of piglets 24h after birth is 38.6 ± 0.04 ° C. Herpin et al. (2002) state that rectal temperature reaches a normal level of 39 ° C within 48h of birth, whereas piglets with a lower rectal temperature 24h after farrowing have poorer thermoregulatory capacity (Muns et al., 2013;Panzardi et al., 2013). Reasons for body temperature variability is as Panzardi et al. (2013) point out that body temperature 24h after birth is associated with birth weight of piglets (r = 0.35) and that 46% of piglets of birth weight <1275 g have a temperature below 38.1oC, compared to 17% of piglets weight ≥ 1275 g. Muns et al. (2015) state that body weight is an indicator of Arq. Bras. Med. Vet. Zootec., v.73, n.5, p.1058-1066, 2021 thermoregulatory capacity, and Kammersgaard et al. (2011) associate low rectal temperature 2h after farrowing with lower body weight. Decreases in body temperature are often caused by decreased locomotor activity and due to imbalances in gas exchange, acid base balance and energy metabolism, which consequently occur with prolongation of farrowing time and more commonly occur in pigs that were last farrowed (Orozco-Gregorio et al., 2010;Baxter et al., 2008).
Fetal glucose levels are maintained by transplacental maternal glucose transfer, while this transfer is abolished after birth whereby piglets rely on their own quantities, which is a critical period in piglet life and a reason for monitoring blood parameters in piglets. González-Lozano et al. (2009) and Mota-Rojas et al. (2015) state that for better estimation of neonatal survival rate it is necessary to evaluate the physiological and metabolic profiles of piglets, because according to Staarvik et al. (2019) piglets are not physiologically capable of producing sufficient glucose to maintain normal glycemia in the first hours after birth.
The analysis of blood parameters aimed to examine the correlation between blood parameters in assessing the health and productivity of piglets, since immediately after birth piglets rely on glycogen reserves and colostrum intake to preserve the presence of normal blood glucose. On the third day of birth, glucose was higher in piglets treated with a skindry preparation as opposed to control group.
According to Trayhurn et al. (1989) and Herpin et al. (2002) piglets are born with a small amount of brown adipose tissue, which according to Sjaastad et al. (2010) together with adipose tissue play an essential role in regulating body temperature. Soerensen and Pedersen (2015) point out that piglets are born with 2% and less body fat and that the amount does not increase in the first two weeks of life. As compensation for this physiological weakness, piglets attempt to replace heat production by shaking skeletal muscle, which requires glucose energy, which can be a problem as piglets are born with an immature mechanism of gluconeogenesis (Staarvik et al., 2019). The obtained results indicate that piglets from the experimental group produced a higher amount of energy in the first 24h of life, but that they had higher blood glucose content on the third day compared to the control group. The difference in glucose and body temperature in the experimental and control groups can be attributed to the use of skin drying absorbents. The piglets of the experimental groups did not have to spend more energy on drying their skin and warming themselves, which resulted in an increase in body temperature and lower glucose consumption. Increased blood glucose levels of piglets born at the same time Trujilo-Ortega et al. (2007) associate with difficult farrowing which results in the mobilization of energy reserves to compensate hypoxia. Herpin et al. (1996) and Martínez-Rodríguez et al. (2011) explain that increased glucose concentration at birth is due to catecholamine release and stimulation of secondary liver glycogenolysis due to decreased oxygen content. Panzardi et al. (2013) point out that low (24-30 mg / dl) and high (45-162 mg / dl) blood glucose concentrations at birth are associated with higher mortality at 3-7 days after birth due to physiological exhaustion, and Baxter et al. (2008Baxter et al. ( , 2009 state that blood glucose concentration 24h after farrowing is a better indicator of survival than glucose concentration at birth. Glucose concentration is a variable trait and can easily fall to the level of hypoglycemia (<2.2 mmol / l) within 24-36h of birth if pigs do not reach tits for sucking colostrum (Staarvik et al., 2019). According to Theil et al. (2014) piglets are born with glycogen reserves sufficient for 16h of life, and according to Staarvik et al. (2019) oneday-old piglets had an average glucose value of 5.48 mmol / l (standard deviation of 1.44 mmol / l), at a range of 1.2-10.6 mmol / l. Total protein levels are used to assess nutritional status, as well as to monitor various diseases and disorders. Cabrera et al. (2012) note that IgG concentration is associated with a positive correlation with the concentration of total protein in pig blood. According to Kósa et al. (2019) recorded concentration of total proteins is 50 ± 3.19g and 51.39 ± 21.29g. The same authors state that higher amounts of total protein occur as a consequence of improved gut function and increased food intake. Analysis of the partial correlation in the paper revealed that the body temperature (24-0h) is the influence that controls the linear relationship of the dynamic change of body weight and protein concentration, which can be seen in chart 2, where it can be seen that the regression line tends to zero when the body temperature influence is excluded.

CONCLUSION
The use of Mistral® leads to a significant increase in body temperature in the first 24 hours after the birth of piglets. The increase of body temperature correlates positively with weight gain within the first 24 hours of birth. Mistral®-treated piglets show better glycemia and higher total protein level and protein fractions. The correlation between the concentration of total proteins and the change in body weight was controlled by the change in body temperature in the first 24 hours after the birth of piglets. The administration of Mistral® allows significant changes in body temperature, body weight and blood parameters in piglets within the first 24 hours of birth.