| Back to APPENDIX C: Per rectum ultrasound scanning for pregnancy detection in cattle |
1. Over the past few years the use of ultrasound for the detection of pregnancy in cattle has become more common. This has been partly because of the availability of better equipment, including more robust transducers that can be used for rectal work, and partly because the technique is capable of accurately detecting pregnancy at an earlier stage than most other methods.
2. The technique involves the manual insertion of a probe into the rectum. This probe, which includes a transducer, is about the thickness of a finger, has a smooth surface and is connected by a cable to a visual display unit. It is cupped in the hand and manipulated cranially within the rectum so that it lies over the uterus. The transducer emits a short pulse of sound which travels through the tissues until it meets an echo producing structure, returns to the transducer and produces an image on the screen enabling the detection of pregnancy. At the end of the examination the transducer is gently withdrawn from the rectum within the palm of the hand.
3. Although at first sight it would appear that in order to detect pregnancy it is only necessary to scan the body of the uterus, in practice, scanning the ovaries to detect a corpus luteum (or two in the case of a twin ovulation) increases the accuracy of detection in the early stages (23 to 30 days). It also assists in the detection of twin pregnancies and eliminates a false positive result when no corpus luteum is present. It is not necessary to palpate the ovaries with the ultrasonic technique but there are occasions when they may have to be manipulated to obtain a better scanning plane. In general the genital tract is left undisturbed. However, when the transducer is moved within the rectum this must be done carefully avoiding damage or stretching any of the tissues.
4. The Royal College of Veterinary Surgeons (RCVS) is concerned that the use of such procedures by untrained, non-veterinarians could cause welfare problems.
5. In its recent Report, the Committee to Consider the Ethical Implications of Emerging Technologies in the Breeding of Farm Animals (the Banner Committee) acknowledged RCVS concerns but noted that there was some controversy about whether there is a problem with this technique. The Committee therefore recommended that FAWC review the evidence on ultrasound scanning in bovines and that, if necessary, regulations be made.
6. MAFF asked FAWC to assess the welfare implications of the technique and to advise whether, in addition to the general provisions of the Agriculture (Miscellaneous Provisions) Act 1968, the practice should be subject to specific controls. If additional controls were thought necessary, the Council was asked to advise as to the nature of these controls and, in particular, whether performance of ultrasound scanning on bovines should be undertaken only by veterinarians, or others who have been trained and have reached an acceptable standard of competence.