Untersuchung zu Ovarialzysten beim Rind: Entstehungszeitpunkt und Beziehung zur Milchleistung und Gesundheit

It was the aim of this study to examine risk factors for the development of ovarian cysts (OC) such as milk yield, certain diseases, age and body condition loss. In addition, the effect of ovarian cysts on reproductive performance in dairy cows, especially in connection with therapeutic measures was analysed. Furthermore, relationships between stage of lactation at OC diagnosis and risk factors as well as reproductive performance were studied. In this retrospective field study, data obtained over a period of 15 years from 16 different herds which participated in the herd health program (14- or 28-days-intervals) offered by the Production Medicine Unit of the Clinic for Cattle of the University Medicine Hannover were used. The data included age, reproductive measure, milk yield, body condition and certain diseases. The experimental animals (with OC, n=787) were matched to control cows (without OC, n=787) of the same respective herd, with the same age and calving season. The following results were obtained: 1. The herd incidence of the OC was 15.0% ±8.5), 73.3% follicular cyst and 26.7% luteinized cysts. 220 of the OC were diagnosed within 42 days postpartum, 567 ovarian cysts beyond 42 days postpartum. 2. Cows with OC had a higher 305-d-milk performance (9116 kg ±1870 kg) and a higher milk yield in the first 4 milk-yield-recordings compared with control animals without ovarian cysts (8553 kg ±1699 kg). 3. Cows with OC more often had endometritis (20.7% vs. 11.7%), genital infections (5.5% vs. 2.9%), subclinical ketosis (26.7% vs. 21.2%) and mastitis (32.3% vs. 22.2%) than control animals without ovarian cysts. Cows with ovarian cysts diagnosed after the puerperium had a higher rate of genital infections than cows with ovarian cysts found within the puerperium (6.7% vs. 2.7%). 4. Relapses of ovarian cysts occurred more frequently in cows with OC diagnosis within than beyond 42 days postpartum (17.7% vs. 11.8%). 5. Over all, cows with ovarian cysts had inferior reproductive performance than cows without. Especially animals with ovarian cysts diagnosed after 42 d postpartum revealed a decreased reproductive performance compared with cows with ovarian cysts within the puerperium. 6. Fifty-nine% of follicular cysts and 53% of luteinized cysts were left untreated at the first time of diagnosis. Twenty-seven% of follicular cysts were treated with gonadotropin releasing hormone and 41% of luteinized cysts with prostaglandin F2α. Considering the disappearance of the ovarian cyst as well resumption of cyclicity, there were no significant differences between the treated and untreated cows, particularly with regards to the time of diagnosis of the ovarian cyst. 7. Treatment of ovarian cysts had a positive effect on fertility measures, but only when the ovarian cyst was diagnosed within the first 42 days postpartum. Treated cows with OC diagnosed after the puerperium had an impaired reproductive performance compared with untreated cows. 8. Regardless of time of OC diagnosis, OC were found more often in cows with more than two lactations (56.4%) than in cows with one (18.2%) or two lactations (25.4%). 9. Ovarian cysts were diagnosed more often in those cows that calved in autumn (30.0%, September to November) compared with cows that calved in one of the other seasons (24.9% in spring, 24.3% in summer, 20.8% in winter). 10. Cows with OC more often had a BCS loss over 0.25 points from the dry period to the first examination postpartum compared with cows without OC (64.6% vs. 50.9%). 11. Cows with OC more often had twin births at the preceding and following calving (3.9% and 8.1%) compared with cows without OC (1.3% and 3.8%). There was no association between treatment of OC and a twin birth in the following lactation. 12. The culling rate and culling reasons did not differ between cows with OC and the control cows. 13. In summary, cows with ovarian cysts had a higher milk yield, a higher incidence for certain diseases and a decreased reproductive performance than cows without OC. As to the latter, especially cows with ovarian cysts diagnosed after the puerperium were affected.