The most common way of detecting pregnancy in rabbits is by manual palpation. Real-time ultrasonography may be an alternative to be used in rabbit production units in the future if it turns out to be practicable. There is a paucity of scientific knowledge on the suitability of real-time ultrasonography for pregnancy diagnosis in rabbits. In the present study pregnancy diagnosis by transabdominal ultrasonography was compared to manual abdominal palpation in 28 mated New Zealand rabbit does. Ultrasonography with the aid of a real-time scanner, equipped with five MHz linear-array transducer and manual palpation were executed by one individual daily, beginning at day five after mating. For ultrasound scanning, does were restrained in a dorsal recumbent position and, to establish firm skin contact, gel was applied to the clipped caudal abdomen. Manual abdominal palpation provided a reliable diagnosis by day 10.9 ± 0.3. By ultrasonography, uterine fluid was detected 6.2 ± 0.2 days after mating; fetal heartbeat by day 7.8 ± 0.1. In the 20 does that went to term (71%), the reliability of both ultrasonic pregnancy detection (based on the observation of heart beat) and manual palpation was 100%. No abortions or stillborn kits were recorded and the kits born were normal and viable. In conclusion, real-time ultrasonography, being accurate, rapid and safe, may be considered as a viable alternative for other means of early pregnancy diagnosis in rabbits.

A field study was conducted aimed at (i) evaluating the practicability of a fixed-time insemination regime for medium-sized dairy operations of north-western Germany, representative for many regions of Central Europe and (ii) substituting hCG for GnRH as ovulation-inducing agent at the end of a presynch or ovsynch protocol in an attempt to reduce the incidence of premature luteal regression. Cows of two herds synchronized by presynch and two herds synchronized by ovsynch protocol were randomly allotted to three subgroups; in one group ovulation was induced by the GnRH analog buserelin, in another by hCG, whereas a third group remained untreated. The synchronized groups were fixed-time inseminated; the untreated group bred to observed oestrus. Relative to untreated herd mates, pregnancy rate in cows subjected to a presynch protocol with buserelin as ovulation-inducing agent was 74%; for hCG it was 60%. In cows subjected to an ovsynch protocol, the corresponding relative pregnancy rates reached 138% in the case of buserelin and 95% in the case of hCG. Average service interval was shortened by 1 week in the presynch and delayed by 2 weeks in the ovsynch group. It may be concluded that fixed-time insemination of cows synchronized via ovsynch protocol with buserelin as ovulation-inducing agent is practicable and may help improve efficiency and reduce the work load involved with herd management in medium-sized dairy operations. The substitution of hCG for buserelin was found to be not advisable.

A field study was conducted aimed at a) evaluating the practicability of a fixed-time insemination regime for medium-sized dairy operations of northwestern Germany, representative for many regions of Europe in terms of applicability, reproduction figures and economic considerations and b) substituting hCG for GnRH as ovulation inducing Kapitel IV Efficiency of a fixed-time AI (TAI) in dairy cows following a Presynch-or Ovsynch protocol and the application of Buserelin or hCG as ovulation inducing agent in consideration of herd size