Regulating light is key in rex rabbit farming
1. Breeding stud rabbits need shorter and weaker light
Stud rabbits prefer shorter light duration, generally needing 12-14 hours per day. Continuous light exceeding 16 hours will cause a reduction in testicular weight and sperm count in stud rabbits, affecting breeding ability and even causing stud rabbit infertility.
2. Breeding does need longer and stronger light
Under conditions of 20°C-24°C and a completely dark environment, supplementing 1 watt per sq m with 2 hours of light, although does have some fertility, the conception rate is very low, with the conception rate of a single mating being only about 30%; if the light is increased to 5 watts per sq m with 12 hours of light, the conception rate of a single mating can reach about 50%. Under the same light intensity with continuous exposure for 16 hours, the conception rate of does can reach 65%-70%, and the survival rate of kits can also be significantly improved. Therefore, increasing light intensity and duration can significantly improve the conception rate of does and the survival rate of kits. Research by the French National Institute for Agricultural Research shows that 14-16 hours of light per day in the rabbit house, with no less than 4 watts per sq m of light, is beneficial for normal estrus, pregnancy and kindling of breeding does.
3. Commercial rabbits need weak light
Continuous darkness inhibits the development of the reproductive system of young rabbits and delays sexual maturity. This effect works through the pineal gland. After the retina receives light stimulation, it regulates the activity of the nerves innervating the pineal gland. These nerves release a transmitter that controls the pineal gland's formation of 5-hydroxy-indole-O-methyltransferase, an enzyme that controls the synthesis of melatonin (MLT). MLT is mainly synthesized in darkness, and it can inhibit the pituitary gland's synthesis and release of gonadotropins; extending light can reduce MLT production and reduce its inhibitory effect on gonadotropin secretion, thereby affecting reproductive function. In production, kits born in spring, after birth, are in an environment of lengthening daylight and increasing light intensity, and their sexual maturity time is 1-2 weeks earlier than that of kits born after autumn that grow in an environment of shorter daylight and weaker light intensity. Since light helps the development of the gonads, it promotes sexual maturity in domestic rabbits. Hyperactivity of sexual function affects feed intake and growth, so commercial rabbits need weak light in terms of growth.
In production practice, it has been found that rex rabbits raised in outdoor cages, exposed to strong light for a long time, gradually develop coarse and lusterless fur. Whereas rex rabbits raised indoors have fine and glossy fur. This shows that strong light exposure is not conducive to the growth of hair fibers. Therefore, in terms of improving fur quality, commercial rabbits also need weak light.