A Comparative Study On Biochemical Parameters For Mature California And Chinchilla Rabbits In Sohag Governorate.

Rabbit as homeothermic species is able to keep its core body temperature within ± 1°C regulatory range. In Upper Egypt where high ambient temperature particularly at summer months, rabbit breeding ceases, by virtue of its fur, there is certain inability to dissipate excess body heat. Under uncontrolled ambient environment, most of the observed mortality at summer is due to heat stasis. In this study, we compared white (California) to black (Chinchilla) mature breeds of rabbits. Blood picture and serum hormonal profiles were assessed. The results showed many similarities between the two breeds in terms of blood picture, the serum concentration of tri-iodothyronine (T3) and thyroxine (T4), but T3/T4 ratio was higher and corticosterone was lower in California than Chinchilla rabbits (P< 0.5). Heat loss was higher in male California than other rabbits. The overall results referred to the higher ability of California breed to withstand heat stress compared to Chinchilla rabbits.