Risk factors associated with cystic ovarian disease in Norwegian dairy cattle

Abstract

BackgroundThe aims of this study were to establish the incidence of cystic ovarian disease (COD) and its geographical and seasonal variation in Norway, investigate the effect of COD on culling rates, and describe the effects of COD on subsequent reproductive performance and its association to twins.MethodsDiagnosis of COD was made by veterinary surgeons in the field. Four statistical models were made all including herd as random effect: The four different dependent variables investigated were: 1) Diagnosis of COD between 40 and 165 days in milk or not; (n = 511,657); 2) Twins or singleton; data restricted to lactations with new calving (n = 156,661): 3) Culling/removal or not (n = 573,184): 4) Culling due to reproductive problems; data included only lactations which ended in culling (n = 234,232). Model 1, 3 and 4 applied Cox regression models, and model 2 logistic regression. Independent variables were parity, twins/singletons, calving season, herd size, region, COD occurrence in present lactation (if not dependent), and COD diagnosis in previous lactation.ResultsThe incidence was 0.82% per lactation. COD increased with increasing parity, was smallest at herd size between 35 and 85 cows. Cows in 1st parity and calved in spring had lowest hazard of COD and hazard for COD diagnosis was highest in autumn with HR = 2.6 (1.9 - 3.4) compared to spring. There was an interaction between parity and season. COD incidence was lower south of 60°N. Cows which experienced COD had an increased odds of giving birth to twins OR = 2.2 (1.7 - 2.7). Of those that were culled, those with COD were culled more frequently because of reproductive problems; HR = 2.1 (1.9 - 2.3) for higher parity than 2. Having COD diagnosed in the preceding lactation was a hazard for diagnosis in the lactation studied.ConclusionCOD diagnosis is strongly associated with season (autumn calving) and parity. Herds north of 60°N have more COD. Occurrence of COD is associated with twin births as well as culling due to reproduction.

Cytological image of the endometrium in cows in follicular and luteal phases of the ovarian cycle and in cows with follicular and luteal ovarian cysts

“…The type of cyst was diagnosed by ultrasonography. Follicular cysts were 3-5 cm in diameter with a thin wall up to 0.3 cm thick, and persisted for at least 10 d. Luteal cysts, 3-5 cm in diameter with a cavity filled with fluid and a thick luteinised wall over 0.5 cm thick, persisted for at least 14 d (3,20). In addition to the ultrasound diagnosis of the structures appearing on the ovary, serum concentrations of progesterone and 17β-oestradiol were tested to confirm the associated hormonal activity.…”

“…In addition to the ovarian follicle and corpus luteum, which normally occur on the ovary, other structures such as ovarian cysts may disturb the physiology of the oestrus cycle. This disturbance can also change the functioning of the uterus, particularly of the endometrium (3,20).…”

Epidemiological Description of Cystic Ovarian Disease in Argentine Dairy Herds: Risk Factors and Effects on the Reproductive Performance of Lactating Cows

“…A recent study from Norway has reported a lower incidence rate of 0.82% (Nelson et al. ). Some factors predisposing to COD are as follows: heredity (Kesler and Garverick ; Hooijer et al.…”

“…; Peter ; Nelson et al. ) and phyto‐oestrogens (Roberts ). Also, retained placenta, milk fever and metritis are mentioned as possible factors associated with the prevalence of the disease (Bosu and Peter ).…”

Role of Glucocorticoids in Cystic Ovarian Disease: Expression of Glucocorticoid Receptor in the Bovine Ovary

“…Cystic ovarian disease (COD) is a cause of temporary infertility and one of the most common reproductive disorders in dairy cows [Nelson et al, 2010]. Cysts are dynamic structures, described as single or multiple anovulatory follicles, located in one or both ovaries, which have a diameter >18 mm and persist for more than 6 days in the absence of luteal tissue without uterine tone and with disruption of normal estrous cycles [Silvia et al, 2002;Bartolomé et al, 2005].…”