Evaluation of changes in some blood metabolites affecting on postpartum anestrous in Holstein dairy cows

Reproductive efficiency of dairy cattle breeding industry needs to produce high. The objective of this study was to investigate changes in some blood parameters on postpartum anestrus in Holstein dairy cows. Anestrus cows were divided into four groups as inactive ovary, persistent follicle, persistent corpus luteum and ovarian cyst. Blood samples were obtained from 182 lactating cows and some blood parameters including glucose, urea, total protein, phosphorus and β-hydroxybutyrate were measured by spectrophotometric method. Also, effects of some important factor on postpartum anestrus including calving season, parity, body condition score and milk production were also evaluated. Anestrus cows which had no ovulation during 50-60 days postpartum, were classified into four groups as inactive ovary, persistent follicle, persistent corpus luteum, ovarian cyst and they were compared with normal cows which showed estrus during this period. Sera glucose concentrations in normal cows, persistent corpus luteum and ovarian cystic were almost the same and had a significant difference (P<0.01) with cows having inactive ovary or persistent follicles. Urea levels in normal cows were lower than anestrus cows (P<0.01). Blood phosphorus concentration in normal cows, persistent corpus luteum and inactive ovary were significantly different (P<0.05) from cows with persistent follicles or cows with ovarian cysts. Although total blood protein level was almost normal in all cows, it was higher than others in persistent follicle and cystic cows. Blood β-hydroxybutyrate concentration did not differ between normal and anestrus cows. Accordingly, results of the present study showed there is a close relationship between postpartum anestrus with increasing or decreasing of blood concentrations of glucose, urea, total protein and phosphorus.