<abstract xmlns="http://www.w3.org/1999/xhtml">We hypothesized that a single dose of PGF2α belatedly injected on day 8 after GnRH-1 in cows receiving a 7-day Ovsynch-56 protocol (GnRH – 7 days – PGF2α – 56h – GnRH – 16h – timed AI) will increase the proportion of cows with complete luteolysis. At day 35±3 postpartum, 70 lactating Holstein cows from one herd were scored for body condition and pre-synchronized with PGF2α and GnRH (3 days apart) and 7 days later submitted to an Ovsynch-56 protocol for first AI after random assignment to two treatments: (1) OV-7 (n=35) with an injection of PGF2α either on day 7; or (2) OV-8 (n=35) on day 8 after G1, respectively. Blood was collected before the first PGF2α, at day 7 and day 8 in OV-7 and OV-8, respectively, at AI and at 7 days after AI to assess progesterone concentration. Ten cows were classified as acyclic and were excluded from the analysis resulting in 60 cows (OV-8, n=27; OV-7, n=33). In total, more (P=0.01) OV-8 cows and more (P=0.04) primiparous OV-8 cows had complete luteolysis compared with their OV-7 herd mates. In addition, more (P=0.008) OV-8 cows with BCS&lt;2.75 had complete luteolysis compared with their OV-7 herd mates, whereas no difference was observed between treatments among cows with BCS ≥2.75. In conclusion, delaying the application of PGF2α by 1 day reduced the percentage of primiparous cows and cows with poorer BCS having incomplete luteal regression at the time of AI.</abstract>

We hypothesized that a single dose of PGF2α belatedly injected on day 8 after GnRH-1 in cows receiving a 7-day Ovsynch-56 protocol (GnRH – 7 days – PGF2α – 56h – GnRH – 16h – timed AI) will increase the proportion of cows with complete luteolysis. At day 35±3 postpartum, 70 lactating Holstein cows from one herd were scored for body condition and pre-synchronized with PGF2α and GnRH (3 days apart) and 7 days later submitted to an Ovsynch-56 protocol for first AI after random assignment to two treatments: (1) OV-7 (n=35) with an injection of PGF2α either on day 7; or (2) OV-8 (n=35) on day 8 after G1, respectively. Blood was collected before the first PGF2α, at day 7 and day 8 in OV-7 and OV-8, respectively, at AI and at 7 days after AI to assess progesterone concentration. Ten cows were classified as acyclic and were excluded from the analysis resulting in 60 cows (OV-8, n=27; OV-7, n=33). In total, more (P=0.01) OV-8 cows and more (P=0.04) primiparous OV-8 cows had complete luteolysis compared with their OV-7 herd mates. In addition, more (P=0.008) OV-8 cows with BCS<2.75 had complete luteolysis compared with their OV-7 herd mates, whereas no difference was observed between treatments among cows with BCS ≥2.75. In conclusion, delaying the application of PGF2α by 1 day reduced the percentage of primiparous cows and cows with poorer BCS having incomplete luteal regression at the time of AI.

Modification of the Standard 7-Day Ovsynch Protocol to Increase the Luteolytic and Synchronization Risks in Dairy Cows

Ss. Cyril and Methodius University in Skopje

Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine

Department of Animal Sciences and Industry

Macedonian Veterinary Review

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

We hypothesized that a single dose of PGF2α belatedly injected on day 8 after GnRH-1 in cows receiving a 7-day Ovsynch-56 protocol (GnRH – 7 days – PGF2α – 56h...

Modification of the Standard 7-Day Ovsynch Protocol to Increase the Luteolytic and Synchronization Risks in Dairy Cows

Publié en ligne: 15 oct. 2020

Pages: 161 - 167

Reçu: 16 juin 2020

Accepté: 28 août 2020

DOI: https://doi.org/10.2478/macvetrev-2020-0028

Mots clés
luteolysis, synchronization risk, Ovsynch, dairy cows, BCS

© 2020 Branko Atanasov et al., published by Sciendo

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

Modification of the Standard 7-Day Ovsynch Protocol to Increase the Luteolytic and Synchronization Risks in Dairy Cows

Publié en ligne: 15 oct. 2020

Pages: 161 - 167

Reçu: 16 juin 2020

Accepté: 28 août 2020

DOI: https://doi.org/10.2478/macvetrev-2020-0028

Mots clésluteolysis, synchronization risk, Ovsynch, dairy cows, BCS

© 2020 Branko Atanasov et al., published by Sciendo

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

Mots clés
luteolysis, synchronization risk, Ovsynch, dairy cows, BCS