| Holstein cows are one of the main breeds in the Ningxia region and improving their reproduction rate can increase their milk production and thus ensure the high quality development of the dairy industry in Ningxia.The rapid recovery of the cow’s uterus after giving birth is the key to shortening the interval between pregnancies and is an important factor in improving reproductive efficiency,which determines the economic efficiency of the farm.Therefore,in order to guarantee the high quality development of the dairy industry and improve the economic efficiency of farms,reducing the time required for uterine recovery is an urgent problem for producers and researchers in related fields.The development of strategies for the early diagnosis of incomplete uterine regeneration is a prerequisite for solving these problems.In this experiment,the changes in the diameter of the cervix,pregnant uterine horn and non-pregnant uterine horn were monitored by B-mode veterinary ultrasound scanner at 5 d,10 d,15 d,20 d,25 d,30 d,35 d and 40 d after parturition in both multiparous and primiparous dairy cows.Meanwhile,the concentrations of hydroxyproline,Estradiol(E2)and Insulin-like growth factor 1(IGF-1)were detected by ELISA method at 5,10,15,20,30 and 40 d after parturition in both multiparous and primiparous dairy cows.By collecting vaginal swabs from healthy and incompetent uterine involution cows at 5,10,15,20,30 and 40 d postpartum and blood samples from 5 d-10 d.Characterization of the vaginal microbiota of dairy cows at 40 d postpartum based on macrogenomic 16S rRNA sequencing and comparison of the vaginal microbiota of healthy cows with that of cows with incomplete uterine involution.Blood levels of inflammatory factors,reproductive hormones,Hp,CRP,liver enzymes and calcium and phosphorus are measured and the results are based on Pearson correlation,binary logistic and ROC analysis to obtain early warning indicators,diagnostic effects and cut-off values.in order to be able to identify several genera and biomarkers as early warning indicators of uterine insufficiency.The main results were as follows:1.The time to recovery of uterine morphology is 25 d in both multiparous and primiparous dairy cows,with the recovery of the uterine cervix in multiparous dairy cows being earlier than that in primiparous dairy cows.Secondly,plasma hydroxyproline concentrations during uterine recovery in cows were positively correlated with the recovery of the cervix and uterine horns,which can be used as an indicator of uterine recovery;2.The early postpartum vaginal microbiome of dairy cows was associated with the development of uterine recuperation.Compared to the healthy group,early postpartum vaginal microbial diversity was lower in cows with incomplete uterine regeneration and was higher at the phylum level for Bacteroidota,Fusobacteriota and lower for Firmicutes,and at the genus level for Fusobacterium,Porphyromonas,Prevotella The higher abundance of Fusobacterium,Porphyromonas and Prevotella at the genus level could be used as a target for predicting postpartum uterine regeneration in cows;3.CRP and ALT concentrations in postpartum blood can be used as early warning indicators of uterine insufficiency.Cows with CRP>4.597 ng mL and ALT>14.65 U L in blood 5 d-10 d postpartum are at risk of developing uterine insufficiency later in life.In summary,we found that the time to uterine involution in both multiparous dairy cow and primiparous dairy cows was 25 days.Secondly,preliminarily showed that the abundance of Bacteroidota,Fusobacteriota,Firmicutes,Fusobacterium,Porphyromonas,Prevotella,and the blood concentration of CRP and ALT could be used as early warning indicators of uterine incompleteness. |
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