Effect of Different Ambient Temperatures on Reproductive Outcome and Stress Level of Lactating Females in Two Mouse Strains

Abstract

Ambient temperature is an important non-biotic environmental factor influencing immunological and oncological parameters in laboratory mice. It is under discussion which temperature is more appropriate and whether the commonly used room temperature in rodent facilities of about 21 °C represents a chronic cold stress or the 30 °C of the thermoneutral zone constitutes heat stress for the animals. In this study, we selected the physiological challenging period of lactation to investigate the influence of a cage temperature of 20 °C, 25 °C, and 30 °C, respectively, on reproductive performance and stress hormone levels in two frequently used mouse strains. We found that B6D2F1 hybrid mothers weaned more pups compared to C57BL/6N mothers, and that the number of weaned pups was reduced when mothers of both strains were kept at 30 °C. Furthermore, at 30 °C, mothers and pups showed reduced body weight at weaning and offspring had longer tails. Despite pronounced temperature effects on reproductive parameters, we did not find any temperature effects on adrenocortical activity in breeding and control mice. Independent of the ambient temperature, however, we found that females raising pups showed elevated levels of faecal corticosterone metabolites (FCMs) compared to controls. Peak levels of stress hormone metabolites were measured around birth and during the third week of lactation. Our results provide no evidence of an advantage for keeping lactating mice in ambient temperatures near the thermoneutral zone. In contrast, we found that a 30 °C cage temperature during lactation reduced body mass in females and their offspring and declined female reproductive performance.

Isolation and Culturing of Primary Murine Chondroprogenitor Cells: A Mammalian Model of Chondrogenesis

“…Carefully consider the number of fertilized female mice necessary for the experiment. An abundance of factors has an influence on the pregnancy rate [including the amount and rhythmicity of light (Nakamura et al., 2023), room temperature (Kolbe et al., 2022), the number of mice in not just their cage, but also in the entire room (Svenson & Paigen, 2019), etc.]. With our recommendations above, this rate can be maximized; however, a small proportion of female mice will usually be pseudo‐pregnant.…”

Effect of heat stress on dairy cow production, reproduction, health, and potential mitigation strategies

“…The TNZ range of an animal depends on several factors, including its age, breed, species, kind of feed consumed, diet composed of, the initial state of temperature acclimatization, production method, special housing and pens, tissue insulation, external insulation, and behavior (Mota-Rojas et al, 2021). The best thermal neutral zone is an ambient temperature below 21 °C throughout the day (Kolbe et al, 2022). Dairy cows can only perform at their highest levels of efficiency if they maintain a constant core body temperature in the TNZ.…”

“…Dairy cows can only perform at their highest levels of efficiency if they maintain a constant core body temperature in the TNZ. TNZ ranges from 1.7 °C to 21 °C for lactating dairy cattle and depends on the breed, degree of acclimatization, milk production, and dry matter intake (Kolbe et al, 2022). When an organism's temperature deviates too far from its optimal level, it hinders its ability to carry out production operations (Heal & Park, 2016).…”