A systematic review of the development and application of home cage monitoring in laboratory mice and rats.

BACKGROUND: Traditionally, in biomedical animal research, laboratory rodents are individually examined in test apparatuses outside of their home cages at selected time points. However, the outcome of such tests can be influenced by various factors and valuable information may be missed when the animals are only monitored for short periods. These issues can be overcome by longitudinally monitoring mice and rats in their home cages. To shed light on the development of home cage monitoring (HCM) and the current state-of-the-art, a systematic review was carried out on 521 publications retrieved through PubMed and Web of Science. RESULTS: Both the absolute (~ × 26) and relative (~ × 7) number of HCM-related publications increased from 1974 to 2020. There was a clear bias towards males and individually housed animals, but during the past decade (2011-2020), an increasing number of studies used both sexes and group housing. In most studies, animals were kept for short (up to 4 weeks) time periods in the HCM systems; intermediate time periods (4-12 weeks) increased in frequency in the years between 2011 and 2020. Before the 2000s, HCM techniques were predominantly applied for less than 12 h, while 24-h measurements have been more frequent since the 2000s. The systematic review demonstrated that manual monitoring is decreasing in relation to automatic techniques but still relevant. Until (and including) the 1990s, most techniques were applied manually but have been progressively replaced by automation since the 2000s. Independent of the year of publication, the main behavioral parameters measured were locomotor activity, feeding, and social behaviors; the main physiological parameters were heart rate and electrocardiography. External appearance-related parameters were rarely examined in the home cages. Due to technological progress and application of artificial intelligence, more refined and detailed behavioral parameters have been investigated in the home cage more recently. CONCLUSIONS: Over the period covered in this study, techniques for HCM of mice and rats have improved considerably. This development is ongoing and further progress as well as validation of HCM systems will extend the applications to allow for continuous, longitudinal, non-invasive monitoring of an increasing range of parameters in group-housed small rodents in their home cages.

Summer Season-Related Heat Stress Affects the Mineral Composition of Holstein Dams' Colostrum, and Neonatal Calves' Mineral Status and Hematological Profile.

This study examines the effect of season-related heat stress in dams on mineral status, and hematological profile of their calves. Ten Holstein dams (LowT group) were exposed to the 49-day-long period of low air temperature (5.2 ± 0.5 °C) and ten dams (HighT group) were exposed to a 53-day-long high air temperature (27.4 ± 0.4 °C). The dams' blood samples were taken one hour after parturition, while colostrum was sampled at 2, 14, and 26 h after calving. Ca, P, Mg, Na, K, Fe, Zn, Mn, and Se concentrations were significantly lower while Cu and Co concentrations were significantly higher at least in two examined colostrum sampling points in HighT group. Calf`s blood samples were taken before 1st colostrum intake, and on days 1, 2, 3, and 7 postnatal. Ca, P, Na, K, Fe, Cu, Zn, Mn, Se, and Co were significantly lower while concentration of Mg was significantly higher in calves that originated from HighT group at least at two examined sampling points. Season affected dam's blood mineral status but the pattern was not always the same as in calves, since Na, K, Cu, and Co were significantly higher in HighT group. Calves that originated from HighT group had significantly lower hemoglobin, hematocrit, MCV, MCH, and MPV values, as well as neutrophils and monocyte counts, while platelets, eosinophils, basophils, and lymphocyte counts were significantly higher. Season-related heat stress leads to a reduction of the most minerals in both dams' colostrum and calves' blood and certain minerals' deficiencies are linked to impaired calves' hematological adaptation.

Influence of different seasons during late gestation on Holstein cows' colostrum and postnatal adaptive capability of their calves.

Season may affect calves' thermal comfort and behavior, but the data related to the overall influence of seasonal variations on dams' colostrum and postnatal adaptive capability of calves are limited. The aim of this study was to measure the effects of a 49-day-long low air temperature (LAT) season (5.20 ± 0.46 °C mean air temperature) and a 53-day-long high air temperature (HAT) season (27.40 ± 0.39 °C mean air temperature) on dams' colostrum quality and physiological, biochemical, hormonal, and oxidative stress parameters of their calves during the first 7 days of life. The dams' colostrum was sampled at 2, 14, and 26 h after calving, before feeding of their calves. Calves' blood samples were taken before the first colostrum intake and on days 1, 2, 3, and 7 of life. Calves' physiological parameters were measured on days 0 and 7. HAT season significantly reduced the quality of dams' colostrum. The ingestion of the low-quality colostrum, combined with the thermal discomfort during HAT season, probably provoked impaired physiological, biochemical, hormonal, and oxidative stress parameters in samples taken from the post-colostral calves. Additionally, intravenous glucose tolerance test was performed on day 7, which suggested an enhanced insulin response in HAT season calves. This study highlights the importance of adequate supporting strategies for the care of the late gestation cows and postnatal calves during the HAT season.