Evaluating the Impact of Clinical Mastitis on Ovarian Morphometry and Synchronization Protocol Efficiency in Dairy Cows

Objectives: To evaluate the impact of mastitis on ovarian morphometry and its derivatives, and to determine the effectiveness of different synchronization protocols in the presence of mastitis in dairy cows. Methods: A total of 110 Holstein Friesian cows, ranging from second to fifth lactation, were selected and monitored for clinical mastitis starting from the first day after parturition (pp). All cows in the study had uncomplicated calvings and were divided into two groups: Group 1 – cows with no clinical mastitis between 0 and 30 days after calving, and Group 2 – cows that developed clinical mastitis during the same period. The onset date of mastitis was recorded. Prior to initiating the synchronization protocols, the cows underwent an ultrasound to assess the ovaries. On day 60 pp, all cows were synchronized using one of three protocols: Ovsynch, G7G, or Presynch, irrespective of mastitis status. Following the completion of the synchronization protocols, pregnancy was assessed via ultrasound. Results: Mastitis influences ovarian morphometry. In healthy cows, the left ovary is 10.51 % larger than the right (p < 0.05), while in cows with mastitis, the right ovary is 6.52 % larger (p < 0.05). Both groups had more functional structures in the left ovary, but larger structures were found in the right ovary of cows with mastitis and in the left ovary of healthy cows. Mastitis affects insemination efficiency based on the synchronization protocol. Healthy cows had 28.53 % higher conception rates after the first insemination (p < 0.05). Mastitic cows had better success with Ovsynch (39.3 %) compared to G7G and Presynch, while healthy cows had better outcomes with G7G or Presynch. Mastitis affects conception efficiency regardless of its onset postpartum. Cows that developed mastitis within 30 days postpartum had higher conception rates compared to those that developed it later. Conclusions: Mastitis affects ovarian morphometry and reproductive performance. In cows with mastitis, the right ovary is larger than the left, whereas the opposite is true for healthy cows. Mastitic cows synchronized with the Ovsynch protocol had higher conception rates when mastitis occurred within 30 days postpartum, compared to those affected later. Healthy cows showed better outcomes with G7G or Presynch protocols. Further research is needed to understand the mechanisms behind these effects and optimize synchronization strategies for mastitic cows.