Metritis in dairy cows is preceded by alterations in biochemical profile prepartum and at parturition

Highlights

• The biochemical profile and reproduction performance of cows with metritis were investigated.

• Metritic cows showed differences in serum AST, GGT, cholesterol, fibrinogen, calcium, BHB and NEFA before disease diagnosis.

• Fibrinogen can be used as an early marker of inflammatory process of metritis in dairy cows.

• The reproductive performance of cows with metritis was delayed during the postpartum period.

Abstract

Metritis in dairy cows is classified as a puerperal disease that affects all layers of the uterine epithelium and occurs during the first 21 days after parturition. The objectives of this study were to identify potential predictive biomarkers of metritis, to monitor the biochemical profile of pre-metritic dairy cows, and to evaluate the reproductive performance of dairy cows with metritis. Fifty-five cows without metritis and fifteen cows that showed clinical signs of metritis were enrolled in this study. Blood samples were collected at −21, −14 and − 7 days before calving and at parturition and assayed for urea, creatinine, aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), total cholesterol, fibrinogen, total calcium, β-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) concentrations. Serum fibrinogen on 21, 14 and 7 days prepartum and at parturition was the strongest discriminator between metritic and control cows. Moreover, metritic cows had lower (P < 0.05) concentrations of urea, creatinine, cholesterol and calcium and higher (P < 0.05) serum AST, GGT activities, and serum fibrinogen, BHB and NEFA concentrations when compared to control cows. The number of days to first ovulation, insemination, services per pregnancy and days to pregnancy were greater (P < 0.05) for metritic cows than the control group, and the follicle size was smaller (P < 0.05) for metritic cows than the control group. Our results indicate alterations in the biochemical profile of dairy cows with metritis and the negative impact on the reproductive performance of metritic cows raised in tropical conditions. In addition, this study showed that the serum fibrinogen could be used as screening biomarkers to indicate cows that might have metritis during the postpartum period.

Introduction

Metritis is a uterine disease that affects dairy cows during the first 21 days after parturition. Metritis may cause a profound impact on the health of cows, such as reduced milk production and delayed uterine involution, besides reducing the pregnancy rate of the herd (Dervishi et al., 2016; Paiano, 2018; Paiano et al., 2019a). During the peripartum phase, endocrine, metabolic and physiological changes occur due to parturition, lactogenesis and colostrogenesis (Paiano et al., 2019b; Machado and Silva, 2020; Sayiner et al., 2021). The adaptations that occur during this period, associated with reduced food intake, contribute to the state of immunosuppression, increasing the risk of dairy cows developing puerperal diseases (Contreras and Sordillo, 2011; Caixeta et al., 2017; Carvalho et al., 2019; Machado et al., 2020).

Changes in the biochemical profile of metritic cows have been described previously in dairy herds from North America (Dervishi et al., 2016); however, there is a lack of this information for dairy herds reared in tropical conditions. Most dairy farms located under tropical conditions are characterized by high pluviometric indices and high temperatures, which provide favorable conditions for forage growth and low-cost milk production (Baruselli et al., 2004). However, cows bred in tropical conditions have a high incidence of postpartum anestrus than animals reared under subtropical conditions, which increases the parturition to conception interval and, consequently, negatively affects reproductive performance (Baruselli et al., 2004).

The knowledge of the peculiarities of the biochemical profile of cattle raised in tropical conditions is essential to avoid financial losses caused by uterine diseases in the health of herds. In view of the damage caused by uterine diseases in animal health, strategies are necessary for their early diagnosis. Monitoring the health of dairy cows through blood tests is important to identify animals that may become ill and to prevent their death or early slaughter (Paiano et al., 2020a). Given this impetus, the objectives of this study are to characterize the interrelationship between early alterations in the biochemical status (urea, creatinine, aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), total cholesterol, fibrinogen, total calcium, BHB and NEFA) of dairy cows with metritis reared in tropical conditions in southeastern Brazil and to search for early screening biomarkers of disease state to determine the main metabolites that can be used as predictive biomarkers for metritis. Additionally, the reproductive performance of dairy cows with and without metritis was assessed.