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Submitted to: Cow Calf Management Guide and Cattle Producer's Library
Publication Type: Book / Chapter Publication Acceptance Date: 9/1/2000 Publication Date: 10/1/2000 Citation: GEARY, T.W. USE OF REPRODUCTIVE TRACT SCORING IN RANGE BEEF HEIFERS. COW CALF MANAGEMENT GUIDE AND CATTLE PRODUCER'S LIBRARY. 2000. v. 442. p. 1-4. Interpretive Summary: Usefulness of reproductive tract scoring depends upon the timing, accuracy, previous selection, and management factors. Higher reproductive tract scores (RTS) are associated with response to synchronization, AI conception rate, and pregnancy rate. In extreme conditions such as drought, RTS could be used to cull heifers that are less likely to conceive during a short breeding season. However, because such a low percentage of heifers with a RTS = 1 normally exist in a herd, and because the costs associated with developing heifers to that age is high, reproductive tract scoring may not be economical on a routine basis. Use of bulls with large scrotal circumference, selection of older heifers at weaning, developing heifers to a targeted breeding weight, and earlier pregnancy diagnosis may be more useful. Producers who are evaluating new heifer development programs may benefit from RTS to help pinpoint any weaknesses. Producers who use RTS need to build flexibility in their feeding program and breeding season dates in order to benefit from RTS. Technical Abstract: Reproductive tract scoring can be used to identify heifers that are adequately developed and ready for the upcoming breeding season. A scale of 1 to 5 has been developed for reproductive tract scoring with 1 indicating a prepubertal heifer with an infantile reproductive tract, and a 4 or 5 indicating a mature estrous cycling heifer depending on the current stage of her estrous cycle. Reproductive tract scores (RTS) need to be conducted by an experienced technician or veterinarian and are usually conducted about one month before the start of the breeding season. Heifers that have received a growth promotant may score lower during an examination and should be pointed out to the palpator. The use of RTS as a last minute culling tool is questionable because of the expense associated with an exam and the frequency with which a RTS of 1 is generally assigned. Heifers that are older and heavier at the time of the exam generally score higher than younger and lighter heifers. Producers may benefit more by using bulls with large scrotal circumference and selecting replacement heifers based on age than using RTS to identify possible herd replacements. |
