Rabbit Reproduction

The wild rabbit is a seasonal breeder with the peak of reproductive activity occurring in the spring and early summer. With domestic rabbits, genetic selection and environmental control have resulted in frequent sexual activity with periods of reduced fertility. These periods will be discussed in “Seasonal Problems.”

The rabbit does not show regular estrus cycles: that is, recurring periods of sexual desire. Ovulation in the female rabbit is induced by mating and occurs approximately 10 hours after the female is bred. When sexual activity begins, the follicles on the ovary remain active for 12 to 16 days if the doe is not fertilized. After this time, they begin to regress and are replaced by new follicles that begin developing toward the end of the 12 to 16 day period. There may be a transitional period, during which the new set of follicles is growing and the old set is regressing, in which the doe lacks interest in the male and is temporarily infertile.

The gestation period, or the period from breeding to kindling, is normally 31 to 32 days. Kindling (birth) may occur as early as 28 days or as late as 35 days; however, approximately 98 percent of the normal litters will be kindled between the 30th and 33rd day.

Sexual Maturity
The age of sexual maturity depends on breed and individual development. In the medium size breeds, the age for first mating is generally five months for does, and seven months for bucks. Although age is the main criteria for breeding readiness, does must be of proper size and weight to be able to produce good size litters without impaired birth weights. Replacement does should be bred when they reach sexual maturity; reduced fertility frequently occurs when breeding is delayed.

Breeding
Breeding does and replacement does should be housed in individual pens to reduce injuries from fighting and pseudo pregnancies. These false pregnancies may result from infertile mating or from sexual excitement when does “ride” each other in group housing. The duration of pseudo pregnancy is approximately 17 days. Therefore, does intended for breeding should be housed separately for at least 18 days prior to intended breeding to insure they will have passed through this period.

Due to the fact that sexually active does normally have follicles present on the ovary, the time of breeding is dictated, to a large degree, by the number of litters desired per year. The following schedules are used for five and eight litters a year.

Five litters/year - 73 day cycle

	Kindle	Rebreed	Wean	Kindle
#Days to	0	42	56	73

Six litters/year - 61 day cycle

	Kindle	Rebreed	Wean	Kindle
#Days to	0	28	42	61

Seven litters/year - 52 day cycle

	Kindle	Rebreed	Wean	Kindle
#Days to	0	21	35	52

Eight litters/year - 45 day cycle

	Kindle	Rebreed	Wean	Kindle
#Days to	0	14	28	45

Regardless of the schedule used, bunnies are to be weaned two weeks after rebreeding.

Breeding Suggestions

1. When the doe's vulva is deep red in color she is ready for breeding.

2. Take the doe to the buck’s cage for one service. When she slightly lifts her haunches and the buck mates with her, he will fall off to the side or backward. Let him try again. Technique is not a strong point of male rabbits. Return her to her cage.

3. If the buck fails to quickly attempt to service the doe, change bucks.

4. Should the doe fight the buck, restrain her. Does can be territorial and turn on a buck. If she insists on not cooperating, try tomorrow.

5. The doe ovulates about 10 hours after service.

6. Palpate does 10 to 14 days after breeding. Palpation (checking for pregnancy) should be done by an experienced rabbit handler. If not pregnant, rebreed.

7. The nest box should be placed with the doe 28 days after breeding. Have it filled with clean straw or wood shavings. Some breeders use both. Usually on the 31st night, the doe will pull fur and have her litter. If she should get confused on the first litter and scatter the litter on the cage floor, replace the bunnies in the box. Approximately 30 percent of first litters die.

Some breeders wean at 28 days, others wait longer. Whichever, the bunnies must be separated at 12 weeks before they start to fight.

Seasonal Problems
Many producers experience breeding problems during extremely hot weather when temperatures exceed 85º Fahrenheit. Research indicates that bucks start to lose fertility when temperatures exceed 85º F and the loss is extensive when temperatures exceed 90º F. It appears that older bucks are more affected than junior bucks. Bucks are affected before does are affected, so keep bucks in the coolest part of the rabbitry. Keep a good supply of young bucks for use during hot weather. Breed during the cooler portion of the day. Morning is best, but late evening is acceptable.

A fall slump is also often noticed. This phenomenon is often the result of summer’s high temperatures, but can also be related to the natural reluctance of rabbits to produce young in the fall and early winter. Good records allow producers to identify these suspect breeders and “cull” them to reduce the problem. Do not obtain replacements from does with histories of fall breeding slumps.

Herd Reproduction Suggestions

1. Depending upon the breeding cycle used, keep one buck for every 10 to 20 does.

2. Bucks can be used daily in cool weather, use every other day in hot weather.

3. Replace bucks having records of low productivity.

4. Replace approximately 1/3 of the bucks yearly.

5. Retain “junior” does to replace up to 1/3 of the breeding herd yearly.

6. Replacement does should be housed separately at least 18 days before breeding.

7. Purchase good replacement stock periodically to prevent inbreeding.

8. Keep bucks cool in the rabbitry to avoid heat induced sterility when temperatures
   exceed 85º F.

Selecting Breeding Stock (Medium breeds - New Zealand Whites, etc.).

1. Good production: 8+ uniform bunnies per litter

2. High meat yield - 57 percent or higher dressing percentage

3. Good milking ability - 10 or more teats with litter weights of 6 lbs.+ @ 3 weeks

4. Good weight gains - 1.25 lbs or more at 4 weeks; 4 lbs. fryers in 8 weeks

5. Good feed conversion

6. Consistent breeding and good mothering instinct - high offspring-survival rate

7. Good health and offspring free of genetic defects

8. Desirable coat quality

Kindling
Does will normally deliver at 31 days after breeding, and management practices at this time may make the difference between saving and losing litters.

Adjust the feeding program of dry does to prevent over-conditioning (getting fat). Fat does probably will have problems at birth, with milking, rebreeding and conception. The nest box should be placed in the cage at the 28th day of gestation so the doe can build her nest. Before adding the nest box, wash and disinfect the box and cage floor. The nest box should be approximately 2/3 full of bedding such as shavings, straw, etc. During cold weather, the addition of insulation board at the bottom will preserve heat. During hot weather (90º F and above) use a bedding that prevents bunnies from burrowing and remove some of the loose bedding and fur for better air circulation.

Quiet! is the word when nervous does are kindling. Avoid handling the does, if possible, and keep dogs and other animals from causing distractions. Strangers (to the rabbits) should not be allowed in the area, and routine chores should be performed in an organized, quiet manner. In all cases, avoid loud and unusual noises. Examine the nest the day after kindling, record the birth date and remove mortalities. Nest boxes can be removed when all bunnies have left it - usually by the 21st day.

For More Information contact AN_RabbitHelp@adm.com
ADM Alliance Nutrition, Inc. 1000 North 30th Street P.O. Box C1 Quincy, IL USA 62305-3155