Late embryo mortality in Holstein cows inseminated with Holstein or Limousine frozen semen.

P Melendez, P Pinedo, J Gibbons, J Bartolome, H Naikare

Reproduction in domestic animals = Zuchthygiene 2023 Jun

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The objective of this study was to compare the late embryo mortality (LEM) rate (losses approximately between 32 and 53 days of gestation) and Pregnancy Specific Protein B (PSPB) and progesterone (P4) concentrations on day 32 post AI in Holstein cows bred with either Holstein or Limousine semen. A sample size of 1082 cows per group diagnosed pregnant between 28- and 35-days post breeding was calculated. The study consisted of evaluating LEM (%) in a cohort of Holstein cows bred with Holstein semen (HO × HO) or Limousine semen (HO × LM), to compare pregnancy loss from 28 to 35 days post breeding to 50-57 days post breeding. A logistic regression model to compare embryo losses was developed considering as main explanatory variable the cohort (HO × HO embryo vs. HO × LM embryo), correcting by lactation number, breeding season, days to breeding and AI technician. HO × HO embryos had greater LEM (15.16%) than HO × LM embryos (9.79%). Cows bred in summertime had higher LEM (15.23%) than cows bred in no-summertime (9.88%). There were no differences among AI technicians. Within summertime there was no difference in LEM (%) between groups within each lactation number; yet, within no-summertime, LEM (%) was higher in HO × HO than HO × LM within each lactation number. Pregnancy SPB optical densities were significantly greater in the HO × HO than in the HO × LM (p = .023) group; yet, the concentration of P4 was not different between groups (p > .05). © 2023 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.

Citation

P Melendez, P Pinedo, J Gibbons, J Bartolome, H Naikare. Late embryo mortality in Holstein cows inseminated with Holstein or Limousine frozen semen. Reproduction in domestic animals = Zuchthygiene. 2023 Jun;58(6):734-739