<abstract xmlns="http://www.w3.org/1999/xhtml">

The present study aimed to determinate the effect of external progesterone (P4) supplementation on luteolysis in cows under heat stress. Forty-eight (n=48) dairy cows in the period from July–September 2018 were part of and at day 35±3 postpartum scored for BSC, synchronized using PG-3-G + Ovsynch protocol and randomly allocated into two treatments: PRID group (n=27) treated with external P4 device between G1 and PGF2α and CON group (n=21) left without treatment. Collection of blood samples to assess P4 concentrations was done at Pre-PG, at G1, at PGF2α, at 72 h after PGF2α (at timed artificial insemination TAI) and at d 21 after TAI. The pregnancy diagnosis was done at d 21 and d 30 after TAI by ultrasound. The average temperature-humidity index (THI) was 79.5±0.6. At G1, the P4 was significantly lower in the PRID group (1.84±0.99 ng/mL) in comparison to the CON group (2.97±1.82 ng/mL). In contrast, at PGF2α, there was a tendency (p=0.09) of increased P4 concentration in PRID group compared with the CON group (4.26±1.68 and 3.74±2.39 ng/mL), respectively. At TAI, more PRID cows (p=0.0001) had a lower P4 (0.06±0.03 ng/mL), in comparison to CON (1.28±2.41 ng/mL). At d 21 and d 30 after TAI, more PRID cows were predicted and diagnosed pregnant (16/27 or 59.25% and 13/27 or 48.14%) compared with the CON group (11/21 or 52.38% and 8/21 or 38.08%) respectively, but without any significant differences. Supplementation of the P4 during the Ovsynch protocol increases the P4 before TAI and reduces the incomplete luteolysis in heat stressed dairy cows.
</abstract>

The present study aimed to determinate the effect of external progesterone (P4) supplementation on luteolysis in cows under heat stress. Forty-eight (n=48) dairy cows in the period from July–September 2018 were part of and at day 35±3 postpartum scored for BSC, synchronized using PG-3-G + Ovsynch protocol and randomly allocated into two treatments: PRID group (n=27) treated with external P4 device between G1 and PGF2α and CON group (n=21) left without treatment. Collection of blood samples to assess P4 concentrations was done at Pre-PG, at G1, at PGF2α, at 72 h after PGF2α (at timed artificial insemination TAI) and at d 21 after TAI. The pregnancy diagnosis was done at d 21 and d 30 after TAI by ultrasound. The average temperature-humidity index (THI) was 79.5±0.6. At G1, the P4 was significantly lower in the PRID group (1.84±0.99 ng/mL) in comparison to the CON group (2.97±1.82 ng/mL). In contrast, at PGF2α, there was a tendency (p=0.09) of increased P4 concentration in PRID group compared with the CON group (4.26±1.68 and 3.74±2.39 ng/mL), respectively. At TAI, more PRID cows (p=0.0001) had a lower P4 (0.06±0.03 ng/mL), in comparison to CON (1.28±2.41 ng/mL). At d 21 and d 30 after TAI, more PRID cows were predicted and diagnosed pregnant (16/27 or 59.25% and 13/27 or 48.14%) compared with the CON group (11/21 or 52.38% and 8/21 or 38.08%) respectively, but without any significant differences. Supplementation of the P4 during the Ovsynch protocol increases the P4 before TAI and reduces the incomplete luteolysis in heat stressed dairy cows.

External Progesterone Supplementation During the Ovsynch Protocol Reduces the Incomplete Luteolysis in Dairy Cows Under Heat Stress

Ss. Cyril and Methodius University in Skopje

Macedonian Veterinary Review

This work is licensed under the Creative Commons Attribution 4.0 International License.

The present study aimed to determinate the effect of external progesterone (P4) supplementation on luteolysis in cows under heat stress. Forty-eight (n=48)...

External Progesterone Supplementation During the Ovsynch Protocol Reduces the Incomplete Luteolysis in Dairy Cows Under Heat Stress

Published Online: Mar 01, 2024

Page range: 45 - 50

Received: Dec 26, 2023

Accepted: Feb 24, 2024

DOI: https://doi.org/10.2478/macvetrev-2024-0015

Keywords
cows, heat stress, Ovsynch, luteolysis, PRID

© 2024 Boris Stojanov et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

External Progesterone Supplementation During the Ovsynch Protocol Reduces the Incomplete Luteolysis in Dairy Cows Under Heat Stress

Published Online: Mar 01, 2024

Page range: 45 - 50

Received: Dec 26, 2023

Accepted: Feb 24, 2024

DOI: https://doi.org/10.2478/macvetrev-2024-0015

Keywordscows, heat stress, Ovsynch, luteolysis, PRID

© 2024 Boris Stojanov et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
cows, heat stress, Ovsynch, luteolysis, PRID