The potential use of the eye temperature decrease in determining the time of death in the early postmortem period: studies in pigs.

The experiment was performed in pigs during which the postmortem body temperature was continuously measured. The study was focused on a period of time starting 0.5 hours after the animals' termination and consisted in computer recording of the cooling process of the eyeball (vitreous humor), orbit soft tissues, muscles, and the rectum. The experiment revealed the absence of a plateau phase of temperature decrease in eyeball and orbit soft tissues contrary to muscles and rectum, what demonstrates that temperature measurements in the eye could become an alternative method of determining the time of death during the initial phase of postmortem cooling. During this early postmortem period determination of the time of death based on measurements of the rectum or muscles temperatures due to existing plateau is not possible.

Impact of fat and selected profiles of fatty acids contained in the colostrum and milk of sows of native breeds on piglet rearing.

The aim of this study was to evaluate the effect of the level of fat and selected fatty acids found in the milk of sows on the rearing of native breed piglets. Simultaneously, in order to improve the accuracy of the performed analyses, atomic absorption spectrometry was employed in the applied analytic methodology. The experimental animal material comprised 60 sows of the indigenous White Zlotnicka breed. Colostrum and milk were collected on the first and 14th days of lactation. In all, 240 samples were collected. The following parameters were determined in the course of the experiment: number and weight of piglets, body weight gains as well as deaths of piglets. A total of 1270 born piglets was subjected to investigations. The performed experiments demonstrated that, with the progress of the lactation period, the content of fat and saturated fatty acids (SFA) turned out to be statistically significant and showed a growing tendency. Fat increased by about 2% and palmitic acid (C16:0) increased most, that is by 5%. Linolic (C18:2) and linolenic (C18:3) acids revealed decreasing trends. Irrespective of the day of lactation, the level of unsaturated fatty acids (UFA) determined in sows' colostrum and milk was higher in comparison with that of SFA, and the UFA to SFA ratio ranged from 1.84% to 1.33%. Proportions of n-6 to n-3 fatty acids were determined at the level of about 1.6:1.0 in the colostrum and 1.3:10 in milk. The highest daily body weight gains were recorded in the case of piglets derived from sows with the highest fat level - 294 g, while in the case of stearic acid (C18:0), the smaller its concentration in the colostrum and milk of the experimental sows, the better body weight gains of piglets - 262 g. At the same time, stearic acid (C18:0) was found to exert a statistically significant effect on piglet mortality at the level of P ≤ 0.05. Its highest concentration caused the highest proportion of deaths among piglets - 16.23%. The performed analysis of correlations that occurred between fat, fatty acids and traits associated with piglet rearing confirmed that linolic acid (C18:2; n-6) was highly significantly correlated with piglets' body weights (r = 0.456**) and was negatively correlated with piglets' deaths (r = -0.312). On the other hand, fat revealed correlation with body weight gains of piglets (r = 0.333*_ and a negative correlation with deaths of piglets (r = -0344*). Recapitulating, the results of the performed experiments revealed that differences in the levels of fat and fatty acids found in sows' colostrum and milk influenced results of piglet rearing. Together with the increase in the content of fat and UFA in sows' colostrum and milk, piglets were characterized by the best body weight, growth rate, as well as by small mortality.

Verification of the exponential model of body temperature decrease after death in pigs.

The authors have conducted a systematic study in pigs to verify the models of post-mortem body temperature decrease currently employed in forensic medicine. Twenty-four hour automatic temperature recordings were performed in four body sites starting 1.25 h after pig killing in an industrial slaughterhouse under typical environmental conditions (19.5-22.5 degrees C). The animals had been randomly selected under a regular manufacturing process. The temperature decrease time plots drawn starting 75 min after death for the eyeball, the orbit soft tissues, the rectum and muscle tissue were found to fit the single-exponential thermodynamic model originally proposed by H. Rainy in 1868. In view of the actual intersubject variability, the addition of a second exponential term to the model was demonstrated to be statistically insignificant. Therefore, the two-exponential model for death time estimation frequently recommended in the forensic medicine literature, even if theoretically substantiated for individual test cases, provides no advantage as regards the reliability of estimation in an actual case. The improvement of the precision of time of death estimation by the reconstruction of an individual curve on the basis of two dead body temperature measurements taken 1 h apart or taken continuously for a longer time (about 4 h), has also been proved incorrect. It was demonstrated that the reported increase of precision of time of death estimation due to use of a multiexponential model, with individual exponential terms to account for the cooling rate of the specific body sites separately, is artifactual. The results of this study support the use of the eyeball and/or the orbit soft tissues as temperature measuring sites at times shortly after death. A single-exponential model applied to the eyeball cooling has been shown to provide a very precise estimation of the time of death up to approximately 13 h after death. For the period thereafter, a better estimation of the time of death is obtained from temperature data collected from the muscles or the rectum.