Effects of blood pathological changes before TAI on pregnancy of dairy cows with anestrus and estrus

C Zhao,F Zhang,C Xu,Y Di,Y Bai,D Wang,C Xi

doi:10.1590/1678-4162-12058

Abstract

ABSTRACT The objective of this study was to investigate the influence of plasma pathological changes before timed artificial insemination (TAI) on pregnancy of cows. The contents of estrogen (E2), progesterone (P4), glucose (Glu), selenium (Se), brain-derived neurotrophic factor (BDNF), and histamine (HIS) in plasma of 48 Holstein cows were measured before TAI. According to the estrus detection, the cows were divided into estrus (E) and anestrus (A) groups. After pregnancy testing at 28 d after TAI, two groups of E and A were divided into positive pregnancy of E group (EP+), negative pregnancy of E group (EP-), positive pregnancy of A group (AP+), and negative pregnancy of A group (AP-). The contents of E2, P4, Glu, Se, BDNF and hIS significantly differed among the four groups (P<0.01). The ROC analysis was used to determine the risk of negative pregnancy test (-) after TAI was increased when plasma E2 was less than 46.45 pmol/L in cows before TAI. The changes in E2, P4,hIS, Glu, and BDNF in the blood of natural estrus and natural anestrus cows affected the pregnancy after TAI. the level of E2 in plasma may be used to assess the risk of negative pregnancy after TAI.

Highlights

The technology of timed artificial insemination (TAI) is proposed, which mainly affects the estrus cycle of cows by use of exogenous reproductivehormones
The receiver operating characteristic (ROC) analysis was used to determine the risk of negative pregnancy test (-) after TAI was increased when plasma E2 was less than 46.45 pmol/L in cows before TAI
The changes in E2, P4,hIS, Glu, and brain-derived neurotrophic factor (BDNF) in the blood of natural estrus and natural anestrus cows affected the pregnancy after TAI. the level of E2 in plasma may be used to assess the risk of negative pregnancy after TAI

Summary

Introduction

The technology of timed artificial insemination (TAI) is proposed, which mainly affects the estrus cycle of cows by use of exogenous reproductivehormones. When gonarillin (GnRH) is injected after 12 d, the estrus cycle of all cows is ensured to be 5–12 d. The second injection of PG after 7 d dissolves the functional corpus luteum on the ovary. Luteinolysis leads to decreased progesterone (P4) level in blood, which may stimulate development of dominant follicles due to the increased synthesis and secretion of estrogen; when PG is injected again to dissolve the corpus luteum, all treated cows can be guaranteed tohave dominant follicles and develop. After 48h, GnRH injection can make cows ovulate 24–32h, ensuring the synchronization of ovulation Martínez et al (2002); Kafilzadeh et al (2014)

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Conclusion