Reproductive traits of female rabbits as affected by heat stress and lighting regime under subtropical conditions of Egypt

Abstract

The present work was planned to study the effects of different lighting regimes in both mild and hot periods of the year on New Zealand White doe rabbit traits. The light regimes used were natural daylight as control, 16 h light and 8 h darkness, 12 h light and 12 h darkness, and 8 h light and 16 h darkness. The traits studied were thermoregulatory parameters (respiration rate and temperatures of ear, rectum and skin), type of mating necessary, conception rate, gestation period, fur plucking, behavioural indicators of stress, litter size, litter weight, kit body weight, kit daily gain in weight, milk yield, kit milk intake, efficiency of conversion of milk into live-weight gain and kit mortality, at weekly intervals between birth and weaning at 35 days. Estimation of temperature-humidity index indicated that the doe rabbits were exposed to very severe heat stress, during the hot period of the year. Period of the year (heat stress) affected adversely many of the doe traits studied. The effects were significant (P < 0·001, 0·01 or 0·05) on thermoregulatory parameters (respiration rate and temperatures of ear, rectum and skin), litter weight at days 21 and 28 of age, kit body weight at birth, milk yield of the doe at day 7 of suckling and milk intake per kit at 7 and 14 days of age. Exposure of doe rabbits to a long daylight regime affected adversely many of the traits studied, while the contrary occurred with short daylight. The effects were significant (P < 0·001, 0·01 or 0·05) on litter size at all ages except at birth, litter weight at 14, 21 and 28 days of age, milk yield on all days studied, efficiency of conversion of milk into live-weight gain at days 7, 21 and 28 and mortality at birth and pre-weaning. There was no significant interaction between period of the year and light regime on any of the traits examined. Therefore, only the main factors are reported.

Adaptive capability as indicated by behavioral and physiological responses, plasma HSP70 level, and PBMC HSP70 mRNA expression in Osmanabadi goats subjected to combined (heat and nutritional) stressors

“…RT also has been shown to be good indicators of the thermal stress and may be used to assess the adversity of the thermal environment (Marai et al 2002;Daramola and Adeloye, 2009). Onset and degrees of thermal stress in an animal are best reflected by a rise in RT and rely heavily on respiratory evaporative cooling mechanisms by rapid and shallow respiration (Marai et al 2002;Daramola and Adeloye, 2009;Sejian et al 2010a). RT also showed significant changes between the groups for the treatments both during the morning and afternoon.…”

Adaptability and growth of Malpura ewes subjected to thermal and nutritional stress

“…Respiration rate and rectal temperature have been shown to be good indicators of the thermal stress and may be used to assess the adversity of the thermal environment (Marai et al 2002;Daramola and Adeloye 2009). Onset and degrees of thermal stress in an animal are best reflected by a rise in rectal temperature and rely heavily on respiratory evaporative cooling mechanisms by rapid and shallow respiration.…”

Effects of Dietary Biological or Chemical-Synthesized Nano-Selenium Supplementation on Growing Rabbits Exposed to Thermal Stress

“…Currently, global warming represents a main menace not only for human health but also for different species of livestock. In Egypt, through the hot months, the elevated ambient temperature is exacerbated by the high relative humidity which is normally over 85% during the day and can reach 100% during the night [1][2][3][4]. Recently, the rabbit industry, as a source of animal proteins, has shown an increasing role in the national economies of in Mediterranean regions [5].…”