Postpartum Uterine Involution and Embryonic Development Pattern in Chinese Holstein Dairy Cows.

Yuxin Lin,Hongzhen Yang,Hasan Riaz,Muhammad Jamil Ahmad,Wucai Yang,Yuze Yang,Liguo Yang,Shujun Zhang,Guohua Hua,Adili Abulaiti

doi:10.3389/fvets.2020.604729

Abstract

Understanding the postpartum uterine involution pattern and embryonic development could facilitate bovine reproduction management, improve reproductive efficiency, and diagnosis of the reproductive disorder, which would contribute to the success of the dairy business. This study aimed to investigate postpartum uterine involution and embryonic developmental patterns or postconceptional marks of embryonic fetal development in Chinese Holstein dairy cows using B-mode ultrasonography. The results revealed a significant decline in the involution period with an increase of parity and age. The uterine involution period was shorter in multiparous cows when compared with cows with lower parities. Consistently, cows over 4 years old recovered faster than younger cows (2 or 3 years). Besides, the elder cows (over 4 years) had a relatively larger size of resumed cervix uteri and horns. Postpartum uterine involution pattern analysis revealed that the reproductive tract recovered very fast during the first 16 days postpartum for all the parity. Results of postconceptional marks of embryo development revealed a slow increase in diameter of the gravid uterine horn and crown-rump length (CRL) before day 60. In contrast, this increase was dramatic and rapid after the 60th day. We also established two models to estimate gestational age based on gravid uterine horn diameter or CRL. A formula was established to determine the gravid uterine horn size during postconceptional on day 30th–day 90th (r = 0.8714, P < 0.01). In addition, a significant positive correlation between CRL and gestational age (r = 0.98151, P < 0.01) was built. In conclusion, these results illustrated that parity and calving age had significant effects on uterine involution in Chinese Holstein cows. Crown-rump length and gravid uterine horn diameter are both efficient for evaluating the embryo growth. These current findings broaden the understanding of basic reproductive pattern in Chinese Holstein cows and could benefit bovine reproductive management primarily in postpartum and early pregnant cows to reduce the calving interval and avoid periparturient metabolic diseases.

Highlights

The reproductive performance of dairy cows determines the profitability and success of the dairy business with the ideal goal of achieving one calf per cow per year [1]
This study investigated the effects of parity and age on the involution period by monitoring the resumption pattern of the reproductive tract to standard non-pregnant size in postpartum Holstein dairy cows
For the postpartum uterine involution pattern, a total of 109 Holstein dairy cows were divided into three groups based on parity

Summary

Introduction

The reproductive performance of dairy cows determines the profitability and success of the dairy business with the ideal goal of achieving one calf per cow per year [1]. Postpartum uterine involution is very critical to the recurrence of the reproductive cycle and pregnancy [2, 3]. Whether uterine involution has been successful or abnormal is a precondition for artificial insemination in bovine breeding [4]. Several physiological factors affect the uterine involution in dairy cows such as breeds, nutritional conditions, body condition score (BCS) at calving, and postpartum diseases [7,8,9,10]. Miettinen [12] reported that the parity of Finnish dairy cows has no significant effect on the duration for complete uterine or cervical involution. Further investigations of uterus, cervix, and horn are necessary to confirm whether parity and calving age influence uterine involution

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Results

Discussion

Conclusion