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Streyl, Dominik (2011): Establishment of a standard operating procedure for predicting the time of calving in cattle. Dissertation, LMU München: Faculty of Veterinary Medicine
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Abstract

Precise calving monitoring is essential for decreasing the consequences of dystocia in cows and calves. The progress of seven clinical signs (broad pelvic ligaments relaxation, vaginal secretion, udder hyperplasia, udder oedema, teat filling, tail relaxation, and vulva oedema) in the preparatory stage were evaluated in two studies on healthy cows (n = 104) and heifers (n = 41) for the investigation of their suitability alone and in combination to predict the time of parturition. The animals were examined during (at least) the last three days before calving on a daily basis at 8:00 a.m. A commercial progesterone rapid blood test (PRBT) was used as an additional tool for calving prediction, which was compared to a validated enzyme immune assay. The parturition score (PS) combines the sum of the PS-points of the relaxation of the broad pelvic ligaments (PS-points: 0; 2; 4; 6) and filling of the teats (PS-points: 0; 1; 2; 3) because these signs reported the best predictive value of all examined signs and the highest inter- and intra-observer reliability. In the PS, two thresholds of PS–points were defined (PS ≥ 4 and PS ≥ 5). Below PS 4 calving within 12 h could be ruled out with a probability of 99.3% in cows (95.5% in heifers). If a PS ≥ 5 is used calving within 12 h can be ruled out with a probability of 98.0% in cows (94.9% in heifers). Above this threshold, application of the PRBT (sensitivity: 90.2%; specificity: 74.9%) was recommended. If the PRBT indicates an inactive corpus luteum, intermitted calving monitoring every three hours is recommended. By combining the PS and PRBT (if PS ≥ 4), the prediction of calving within the next 12 h improved from 14.9% (PS alone) to 53.1% and the probability of ruling out calving was 96.8%. If a PS ≥ 5 is used the probability to predict calving within the next 12 h is 65.8% and the probability of ruling out calving 93.3%. The developed standard operating procedure that combines PS and PRBT will enable veterinarians the ability to rule out or predict calving within the next 12 h in peripartal animals with a relatively high accuracy under field conditions with only one single examination.