Investigation, Blood Clinical Pathology, And Warning Assessment Of Main Ovary Diseases Postpartum In High-Producing Dairy Cows

Ovarian diseases of dairy cows postpartum include inactive ovary, ovarian cysts, persistent corpus luteum and delay ovulation. With the increasing of milk yield in dairy cows, and some factors, such as environment, nutrition, management and disease, etc. have become a serious threat to cows’ reproductive efficiency, which may cause great economic losses in dairy farm. Therefore, in this study clinical investigation, blood pathology and early warning assessment of ovarian diseases in high-yielding dairy cows postpartum from two intensive dairy farms were performed to clarify the pathogenic factors and pathogenesis of ovarian disease, and provide an early warning technology for effectively monitoring and prevention of ovarian diseases in the future.An epidemiological investigation of main ovarian diseases postpartum in dairy cows. 110 cows 60-90 d postpartum included 70 cows in FarmⅠwith 34.55 ± 8.44 kg per day milk, 2.24 ± 1.01years; and 40 cows in Farm Ⅱ with 37.78 ± 8.21 kg per day milk, 1.48 ± 0.84 years) in Heilongjiang Province. According to the disease survey and diet nutritional analysis, results showed that(1) in FarmⅠincidence of ovary diseases was in turn 29.5% ovarian inactivity, 14.8% persistent corpus luteum, and 9.8% follicular cysts; in Farm Ⅱ incidence of ovarian diseases was 41.7% ovarian inactivity and 5.5% ovarian atrophy, respectively.(2) During early lactation, dietary crude protein level was 11.65% for Farm Ⅰand 16.50% for Farm Ⅱ respectively, which was less than NRC(2001) nutrition requirement. Dietary calcium and phosphorus levels were 0.52% and 0.43% for FarmⅠ, 0.40% and 0.28% for Farm Ⅱ respectively. However, dietary calcium level was less than NRC(2001) nutrition requirements, and phosphorus for Farm Ⅰwas higher than and for Ⅱ less than NRC(2001) nutrition requirements. Dietary net energy of lactation was 20.32MJ/kg for Farm Ⅰand 23.07MJ/kg for Farm Ⅱ respectively, which was less than NRC(2001) nutrition requirements. Thus, dietary nutrition levels of two dairy farms during early laction, especially energy, protein, etc., were closely related to the cows’ ovarian diseases postpartum.Blood clinical pathology and warning assessment of postpartum ovarian disease in dairy cows. Reproductive hormones(LH, FSH, P4, E2), energy metabolism(Glu, NEFA, BHBA), liver function(AST, TP, ALB, GLO) and mineral index(Ca, P, Mg) were analyzed 60-90d postpartum in dairy cows with estrus and ovary diseases(Ⅰ:28 of E and 33 of A; Ⅱ:19 of E and 17 of A), while energy metabolism, liver function and mineral were also measured 14-21 d postpartum in same two groups of cows. Results showed that(1) in Farm Ⅰplasma concentrations of LH, FSH, E2 and P4 in ovary inactivity cows, which were 17.92±4.86ng/L, 8.12±2.47IU/L, 73.12±14.96pg/ml and 0.09±0.05ng/ml, respectively, were significantly lower than in estrus cows. Plasma concentrations of LH, FSH and P4 in ovarian cysts cows, which were 19.76±4.64ng/L, 8.64±1.17IU/L and 0.09±0.02ng/ml respectively, were markedly lower than in estrus group. However, plasma concentration of E2(101.95±6.2pg/ml) was significantly higher than in estrus group. Plasma concentrations of FSH and E2 in persistent corpus luteum cows, which were 7.61±0.49IU/L and 64.75±6.05pg/ml, were lower than in estrus group. However, plasma concentration of LH and P4, which were 38.79±7.59ng/L and 0.43±0.0ng/ml, was significantly higher than in estrus group.(2) In Farm Ⅱ plasma levels of LH, FSH, E2 and P4 in ovary inactivity cows, which were 19.04 ± 7.49ng/L, 8.44 ± 2.23IU/L, 79.53 ± 5.87pg/m and 0.11 ± 0.04ng/ml, were lower than in estrus cows. In two farms Plasma levels of BHBA, NEFA and AST significantly increased 60-90 d and 14-21 d postpartum in ovary diseases cows compared with those in estrus cows, but plasma concentration of Glu significantly decreased in estrus group from Farm Ⅰ.(3) Pearson correlation analysis and binary Logistic regression model were used to assess the early warning role of plasma NEFA, BHBA and AST in ovarian diseases, and ROC analysis was applied to determine the diagnosis value of plasma NEFA, BHBA and AST, etc, for inactive ovary in Farm Ⅰand Ⅱ, ovarian cysts and persistent corpus luteum in Farm Ⅰ. In Farm Ⅰ, once plasma concentration of BHBA was more than 0.94mmol/L, NEFA more than 0.56mmol/L, AST more than 95.5U/L 14-21 d postpartum in dairy cows, ovarian inactivity risk would increase 60-90 d postpartum. Once plasma concentration of BHBA was more than 0.855mmol/L, NEFA more than 0.585mmol/L, AST more than 77.0U/L, Ca less than 2.225mmol/L, ovarian cysts risk would increase. Once cows plasma concentration of BHBA was more than 0.91mmol/L, NEFA more than 0.595mmol/L, AST more than 96.5U/L, Ca less than 2.23mmol/L, persistent corpus luteum risk would increase. In Farm Ⅱ, Plasma level of BHBA was more than 1.00mmol/L, NEFA more than 0.585mmol/L, AST more than 103.5U/L, and ovary inactivity risk would increase.Conclusion obtained that negative energy balance, resulting from insufficiency of dietary energy supply and the increase of milk production, were closely related to ovarian diseases during early lactation. Negative energy balance may affect the reproductive hormone secretion pattern and disorders, and cause abnormal follicular development and ovarian dysfunction. During early lactation plasma concentration of NEFA, BHBA and AST could be used to predict risk of ovary diseases, especially ovary inactivity 60-90 d postpartum.