Factors affecting treatment response to ovsynch protocol in Holstein dairy cows suffered from cystic ovarian disease

الملخص EN

The objective of this study was to evaluate the efficacy of using Ovsynch synchronization protocol as a treatment tool for cows affected with ovarian cysts.

In addition, the effects of season, parity, days in milk (DIM) and level of milk production in 100 days on the treatment response were also investigated.

On the day of cyst diagnosis (Day 0), 96 lactating Holstein dairy cows with cystic ovarian disease (COD) were treated with Busrelin® (GnRH), Cloprostenol® (PGF2aα) on Day 7, Busrelin® on Day 9, and TAI on 10th day (Ovsynch protocol).

Pregnancy was diagnosed between 42 and 48 days after timed artificial insemination (TAI).

Cows were classified according to the milk production level into high producers (above average) and low producers (below average) ; according to parity into primiparous (first lactation) or multiparous (second or more lactations) ; according to season into hot and cold season and according to DIM into below 100 DIM and above 100 DIM.

Data for conception rate (CR) were analyzed using SPSS statistical software.

The treatment of COD with Ovsynch protocol resulted in acceptable CRs regardless the cyst type.

Although the investigated factors exerted no significant influences on the treatment response, cows treated in cold season tend to become pregnant more than cows treated in hot season.

Primiparous cows were more likely to become pregnant than multiparous cows.

It appears that high-producing cows respond better to treatment compared to low-producing cows.

It was concluded that the Ovsynch-based TAI protocol can be successfully used for the treatment of ovarian cysts in lactating dairy cows and produce an acceptable CR that not significantly influenced neither by season, parity, and milk yield nor by days in milk.