# Evaluating the Impact of Clinical Mastitis on Ovarian Morphometry and the Effectiveness of the Synchronisation Protocol in Dairy Cows

## TL;DR

This study examines how mastitis in dairy cows affects their reproductive health and the success of fertility treatments.

## Contribution

The study investigates how mastitis impacts ovarian structure and the effectiveness of synchronization protocols in dairy cows.

## Key findings

- Mastitis affects ovarian morphometric parameters like area and number of functional structures.
- The G7G protocol showed higher conception rates in mastitis-affected cows after the second insemination.
- Cows with early mastitis had higher conception rates after the first insemination compared to those with later mastitis.

## Abstract

The overall population of cattle is in decline, whilst the size of agricultural enterprises is increasing; nevertheless, there is indication of an improvement in the overall productivity of farming. Reproductive losses are caused by several factors, with mastitis being particularly impactful. Mastitis is one of the most common and costly diseases in dairy cattle, affecting milk yield, reproductive performance, and profitability. Understanding the link between mastitis and reproductive performance is crucial to preventing its negative effects on fertility. Morphometric data on the ovaries are useful for evaluating and predicting the reproductive status of cows, as well as for selecting the appropriate synchronisation protocols. It is critical to investigate the interplay between mastitis, ovarian morphology, and reproductive management strategies in order to enhance fertility and overall productivity in the dairy sector. This study hypothesises that the presence of clinical mastitis in early lactation alters ovarian morphology and impairs reproductive outcomes and that the effectiveness of synchronisation protocols varies depending on the timing and severity of the mastitis. The significance of this topic is evidenced by its vital role in optimising the reproductive performance of dairy farms, a factor that is crucial for enhancing overall productivity and profitability. This is particularly pertinent in the context of diseases such as mastitis, which present not only challenges to the health of the cow but also to farm economics.

Inflammatory processes within the body have been hypothesised to be causative agents of various health complications, including reproductive issues. This study investigates the effects of mastitis on ovarian morphometry and fertility outcomes while also comparing the effectiveness of different synchronisation protocols in affected cows. Healthy multiparous Holstein dairy cows, in their second to fifth lactations and with an average milk yield of approximately 12,000 kg in the preceding lactation, were selected for this study. The average milk yield per lactation was approximately 12,000 kg, with an average daily milk yield of 30 kg. The aim of this study was to determine the impact of mastitis on the reproductive cycle, ovarian morphometry, and function in dairy cows, as well as its effect on synchronisation efficiency. This study focused on both clinically healthy cows and those diagnosed with clinical mastitis postpartum. Three different synchronisation protocols—OvSynch, G7G, and Presynch—were evaluated at 60 days in milk (DIM). A total of 110 cows were included in this study, with 53 being clinically healthy and 57 affected by mastitis. The results indicated that inflammation affects ovarian morphometric parameters such as the area and the number of functional structures. In addition, the G7G protocol was observed to result in higher conception rates in cows suffering from mastitis following the second insemination. This study demonstrated that cows that developed mastitis within the first 30 DIM exhibited higher conception rates after the first insemination compared to those in cows that developed mastitis later in lactation.