Rabbit Production. James I McNitt

      Determining Pregnancy

      Test-mating does by returning them to the buck’s cage to determine pregnancy is not a dependable practice. Some does will accept service again after they have conceived, and others will not accept service even though they have not conceived. Noting the development of the abdominal region and the gain in flesh by the doe as the period of gestation advances is not always accurate and will delay definite diagnosis until late in the period.

      Palpating the abdomen with the thumb and index finger to feel the development of the young in the uterus is an accurate and quick method for determining pregnancy. To make this test, restrain the doe by holding a fold of skin over the shoulders in either the right or left hand, with your free hand placed under the body slightly in front of the pelvis (Fig. 5.7). To make the test accurate, you must relax the doe so the abdominal muscles will not be tense. Generally, you can hold the doe in the air or place the doe on top of the cage for palpation. If it is necessary to use a table or cart, cover the top with a feed sack or carpeting to prevent the doe from slipping.

      Fig. 5.7. Palpating a doe for pregnancy. (Courtesy of J.I. McNitt)

      You must be acquainted with the relative size and location of the uterus and the embryos as pregnancy advances. Figure 5.8 shows the position of the uterus (the digestive tract has been removed) and illustrates the size of the uterus of a non-pregnant doe (left) and of a doe at the end of 10 days of pregnancy (right). It should be noted that the uterus has expanded to accommodate developing embryos; as the period of gestation advances, the embryos grow larger and the uterus is pushed forward as shown in Fig. 5.9.

      Fig. 5.8. Specimens showing the relative location and size of the uterus of a non-pregnant doe (left) and of a doe that is 10 days’ pregnant (right). (Courtesy of USDA)

      Fig. 5.9. Specimens showing the relative location and size of the uterus and developing embryos at the end of 14 days (left) and 25 days (right) of pregnancy. (Courtesy of USDA)

      There is little danger in palpating, provided it is done at the proper stage of fetal development and the proper technique is followed, but you must use caution and not put too much pressure on the tissues, in order to prevent injury to the developing embryos. The test will be more accurate and there will be less danger of injury if the examination is made about two weeks following mating. Between the tenth and twelfth days of pregnancy, the embryos are each about the size of an olive and are distributed in the uterus as indicated in Fig. 5.9 (left). With the thumb placed on one side of the uterus and the index finger placed on the other side, apply sufficient pressure to note the marble-shaped bodies, or embryos, by allowing the thumb and finger to slide over them gently. If the technique has been perfected and no developing embryos are found, the doe should be returned to the buck’s cage for another service. Many does will not rebreed 10 to 12 days after the original breeding because of pseudopregnancy. The vulvas of these does should be checked daily and the does bred when the color of their vulvas turns red or pink (usually about 18 days after the original service). Non-pregnant does should be kept on a ration that is suitable in quantity and quality for dry does until they are known to have conceived or are culled.

      After a few days, the inexperienced person should re-palpate the does that were diagnosed as non-pregnant. If a mistake was made at the first handling and a doe is now found to be pregnant, she should be placed immediately on a management regime that is suitable for pregnant does.

      Day 12 of gestation is probably the best stage to learn to palpate. After the fourteenth day it is more difficult to distinguish between the developing young and the digestive organs when palpating (Fig. 5.9, right). After the technique has been developed, however, it is possible to determine pregnancy by the tenth day. If you palpate earlier than 10 days following mating, the embryos are very small and you must make sure that pellet-shaped fecal material in the large intestine is not confused with the small embryos in the uterus. You can avoid confusion by remembering that, with the animal in the proper position for palpating (Fig. 5.7), the uterus lies at the bottom of the abdominal cavity, with the large intestine above it and nearer the backbone of the animal.

      As you gain proficiency in the practice and become better acquainted with the anatomy of the organs in the abdominal cavity, it is possible to identify retained or mummified fetuses and the presence of abscesses or cysts in the reproductive tract. When any of these conditions are detected, the doe should be culled.

      It is a good idea to re-palpate does at the time the nest box is added to the cage (usually 28 to 29 days after breeding). The reason for the second palpation is that occasionally does will conceive normally but later will resorb the embryos. If the fetuses die before 19 days of gestation they are resorbed, whereas if they die after 19 days of gestation they are aborted.

      Palpation for pregnancy is a must for commercial rabbit raisers. The profit of an operation depends on the production of live litters on schedule. Palpation at 12 days of gestation saves 19 to 20 days of feed and labor, because if the doe is found to be non-pregnant, she can be rebred immediately.