The predictive value of pelvimetry on beef cattle

Veterinary Infectious Disease Organization, Saskatoon, Saskatchewan.
Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire (Impact Factor: 1.02). 08/1993; 57(3):170-5.
Source: PubMed


To elucidate reasons for failure of pelvimetry to predict dystocia, we collected data from 1146 heifers and 210 cows in five beef cow herds in Saskatchewan. We assessed the reliability of pelvic area measurements, the generalizability of findings, various modifications of the technique, and the statistical association between pelvic area measurements and dystocia. The repeatability (kappa) of pelvic area measurements between and within veterinarians for the Rice and Krautmann pelvimeters were low to moderate, indicating pelvic area measurements were imprecise. The positive predictive values and sensitivities of pelvic area measurements were consistently poor across herds, years of study, breeds of heifers, times of measurement, various pelvic area cut-off points, and sires. Various modifications of the technique, including pelvic area/calf birth weight ratios, pelvic area/heifer weight ratios, and Ko's calving prediction equation were also poor on-farm tests for predicting dystocia. Although the mean pelvic area in heifers with dystocia was smaller than those without dystocia, there was a large overlap in the distribution of their measurements. Far too many heifers with a small pelvic area had no dystocia (false positives) and far too many heifers with a large pelvic area had dystocia (false negatives) for pelvimetry to be useful. We conclude there is little evidence to justify the continued use of pelvimetry as an on-farm test to reduce dystocia in beef cattle.

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    • "Also, small pelvic dimensions tended to cause higher difficulty scores. Donkersgoed et al. (1993) assessed the repeatability (accuracy) of obtaining pelvic measurements between and within veterinarians and found they were imprecise. Their average repeatability was 40 percent which compares to 85 to 95 percent reported from studies in Missouri and Ohio. "
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    ABSTRACT: Calf deaths caused by dystocia (calving difficulty) result in a $600 million annual loss to U.S. beef producers (Bellows and Short, 1994). Therefore, methods to reduce dystocia must be investigated, understood, and utilized to decrease the incidence and degree of calving difficulty. A review of early research was presented at the 1989 Range Beef Cow Symposium at Rapid City (Deutscher, 1989) indicating the major cause of dystocia in first calf heifers was a disproportion between the size of calf at birth (birth weight) and the cow's birth canal (pelvic area). A pelvic area/ birth weight ratio developed in Nebraska was suggested as a method to estimate the size of calf a heifer could deliver without assistance. At the 1993 Range Beef Cow Symposium in Cheyenne, Dr. R. A. Bellows presented an extensive overview of research conducted at Miles City on numerous factors affecting calving difficulty. He concluded the following: 1) high calf birth weights were the main cause of dystocia, 2) dam pelvic area must be adequate to deliver calf, 3) selection for pelvic size will increase frame size and calf birth weight, 4) low nutrition will not reduce dystocia, 5) maternal uterine environment affects calf birth weight, 6) exercise during gestation did not affect dystocia, 7) early obstetrical assistance increased calf survival and dam subsequent pregnancy rate, and 8) hormones of calf and dam are involved in calving difficulty. This paper will not review all the above factors but instead will try to expand on the most important and will summarize the latest research on dystocia. It will also recommend some strategies for selection and management of heifers and bulls to reduce calving difficulty.
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    ABSTRACT: Measurements describing pelvic conformation of pedigree Belgian Blue cows were obtained from a sample of nine herds in Flanders, Belgium, comprising 111 adult breeding cows, and from 11 herds in the United Kingdom comprising 108 similar cows. All herds in the Belgian sample (111 cows) managed parturition by elective caesarian section as did seven herds (56 cows) in the UK sample; the remainder of UK herds (52 cows) allowed cows the opportunity to calve naturally per vagina before resorting to caesarian section. The data described the external and internal measurements, and pelvic area characteristic of this breed, irrespective of the different selection pressures applied over a number of years to this breed through variation in farm management and market forces present in either country. From these data, generalized linear models were constructed to predict pelvic area; they correctly identified cows with either small or large pelvic areas. There were no significant differences in pelvic conformation between cattle bred either in Belgium or the UK, although those cows bred in herds where natural calving was allowed to take place had significantly larger internal pelvic height (p < 0.05) and area (p < 0.05) than other Belgian Blue cows. The correlation coefficients between internal pelvic height and width and external pelvic measurements were significant (p < 0.001). These results might facilitate the selection of breeding cows with larger pelvic area so that a higher proportion of cows can calve naturally than currently occurs. However, selection for other traits such as relatively low birth weight combined with higher weaning weight should be carried out at the same time.
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    ABSTRACT: The aim of this study was to use computed tomography for the evaluation of the suitability of external pelvimetry to determine obstetrically relevant parameters. External pelvimetric measurements obtained in vivo using calipers and internal pelvimetric measurements obtained in vitro using computed tomography were taken in 30 German Holstein-Friesian cows (Bos taurus). All measurements were highly reproducible with intraclass correlation coefficients >or=98%. Hip width was the external variable with the highest correlation to internal variables, particularly pelvic inlet area and circumference, pelvic volume, medial horizontal diameter of the pelvic inlet, and the narrowest horizontal diameter of the midpelvis (r(2) > 0.60, P<0.0001). The pelvic inlet area and circumference, the pelvic volume, and the diagonal diameter of the pelvis were sufficiently predicted with the aid of external pelvic measurements and age (r(2)>or=0.80, P<0.0001). The results of this study show that external pelvimetry yields reliable information about the size of the pelvis when the age of the cow is considered.
    Theriogenology 12/2009; 73(3):309-15. DOI:10.1016/j.theriogenology.2009.09.014 · 1.80 Impact Factor
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