Diagnosis and Treatment of Ovarian Afunction Disorder with a Norgestomet Ear-implant (crestar) in Dairy Cows

In the study, 1118 Polish Black and White cows from a dairy herd were examined during a three-year period. In 388 (34.7%) animals no visible oestrus signs were observed until day 60 postpartum. In those cows clinical examinations were performed twice, with a 10 d interval, and blood samples for progesterone analysis were collected simultaneously. Progesterone was measured by RIA. Based on clinical examination and progesterone values ovarian afunction (OA) was diagnosed in 178 (15.9%) cows. Twenty-eight of the affected cows were treated with a norgestomet ear-implant Crestar over a 10 d period while 32 untreated animals served as controls. The oestrus rate (85.7% vs 71.9%), conception rate to all services (75.0% vs 68.8%) and the service period length (105.7 vs 173.1 d) were significantly better in treated than control group, respectively (P ≤ 0.05). Overall analysis of the obtained results shows the potential advantages of Crestar application in management of OA in multiparous dairy cows.