Genetic parameters for reproductive losses estimated from in-line milk progesterone profiles in Swedish dairy cattle

This study assessed the extent of reproductive losses and associated genetic parameters in dairy cattle, using in-line milk progesterone records for 14 Swedish herds collected by DeLaval's Herd Navigator. A total 330,071 samples were linked to 10,219 inseminations (AI) from 5,238 lactations 1,457 Red 1,847 Holstein cows. Pregnancy loss traits defined as early embryonic (1–24 d after AI), late (25–41 fetal (42 AI until calving), pregnancy (from 1 calving). The following classical fertility also analyzed: interval calving first service, last between interval, number per service period. Least squares means with standard error (LSM ± SE), heritabilities, correlations estimated a mixed linear model. Fixed effects included breed, parity (1, 2, ?3), estrus cycle when took place, regression on 305-d yield. year season AI, cow, permanent environmental effect considered random effects. Extensive (approximately 45%) was found, but no difference breeds. superior remaining with, respectively: 6.1 1.2% compared 13.3 1.1%, 7.0 12.3 1.2%, 54.4 1.4% 60.6 1.4%. had shorter than Holstein. Estimated heritability 0.03, 0.06, 0.02 embryonic, loss, respectively. Milk yield moderately genetically correlated both (0.52 0.39, respectively). several (?0.46 0.92). In conclusion, cows lower during stage, total, better estimates same order magnitude previously reported traits. These findings could be valuable work determine variation its potential usefulness an alternative trait or genomic evaluations.