Effects of heat stress and its amelioration on reproduction performance of New Zealand white adult female and male rabbits, under Egyptian conditions

The temperature-humidity index values were 58.9 (no stress) during winter and 84.3 (severe heat stress) during summer experimental periods when calculated according to Livestock and Poultry Heat Stress Indices, Agriculture Engineering Technology Guide, Clemson University, USA. In summer, litter size, litter weight and pups gain weight were. in general, lower, while pre-weaning mortality, gestation period were higher than in winter. In males, the depression was significant (p<0.05) in ejaculate volume, mass motility and advanced motility, and not significant in sperm concentration in summer than in winter. In both females and males, feed intake decreased, while water intake, rectal temperature and respiration increased in summer than in winter. Treatment of heat-stressed rabbits with cooling by drinking cool water 10-15 square CARSPECIAUX 176 \f "Times New Roman Euro"C improved litter size and weight, pups gain weight at weaning and pre-weaning mortality rate as traits of the female, mass motility (P< 0.05), ejaculate volume, sperm concentration and dead spermatozoa in males, and feed intake, water intake, rectum temperature and respiration rate in both females and males. Conception rate decreased with 76.8% in summer than in winter. Treatment of heat stressed bucks with cooling by drinking cool water increased conception rate with 108.4% than in the summer control group, but that value was less than that of the winter with 51.7%. The results showed that the bucks were snore affected than the does by the summer heat stress, in Egypt.