Bovine pregnancy detection by nuclear magnetic resonance spectra of cervical mucus

Proton nuclear magnetic resonance spectra of bovine cervical mucous samples obtained 5 to 50 days postbreeding from 44 dairy cows were compared with reproductive performance of the animals to that breeding. Regression of relative changes of peak asymmetry at 20 and 50% peak height on the ratio of peak width, at half height, to peak height established a zone characteristic of animals subsequently delivering calves. All 13 animals whose mucous asymmetry indices were within this zone gave birth to calves; however, one calf was dead on arrival. Samples from 31 animals had indices outside the zone; 28 of these animals returned to heat and 3 delivered calves dead at birth. Using live birth compared with return to heat or birth of a dead calf as test criteria for the 51 samples gave a combined effectiveness rating of 98% contrasted with 94.1% if the criteria were birth of a calf, living or dead, or return to heat.