Precision Monitoring of Rumination and Locomotion in Relation to Milk Fat-to-Protein Ratio in Early Lactation Dairy Cattle

Samanta Arlauskaitė^1*Akvilė Girdauskaitė¹Arūnas Rutkauskas¹Karina Džermeikaitė¹Justina Krištolaitytė¹Mindaugas Televičius¹Dovilė Malašauskienė¹Lina Anskienė¹Sigitas Japertas²Walter Baumgartner³Ramūnas Antanaitis¹

• ¹Lithuanian University of Health Sciences, Kaunas, Lithuania
• ²Practical Training and Research Center, Lithuanian University of Health Sciences, Topolių g. 6, LT-54310 Kaunas, Lithuania, Lithuanian University of Health Sciences, Kaunas, Lithuania
• ³Clinical Centre for Ruminant and Camelid Medicine, University of Veterinary Medicine, 12 Veterinaerplatz 1, A-1210 Vienna, Austria, Vienna, Austria

The milk fat-to-protein ratio (FPR) is a useful indicator of metabolic health in dairy cows, particularly during early lactation when they are most susceptible to negative energy balance. This study aimed to investigate the relationships between FPR and changes in milk composition, blood biochemical parameters, and cow behavior. Milk composition was monitored in real time using the Brolis HerdLine in-line analyzer (Vilnius, Lithuania), while behavioral parameters-including rumination time, reticulorumen temperature, water intake, and activity-were recorded using SmaXtec boluses (SmaXtec animal care GmbH, Graz, Austria). Blood samples were collected at five-day intervals across five timepoints and analyzed for the following parameters: albumin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, calcium, C-reactive protein, nonesterified fatty acids, iron, gamma-glutamyl transferase, glucose, magnesium, triglycerides, and urea.A total of 27 early-lactation Holstein dairy cows were assigned to three groups -presumed low-grade ruminal acidosis (LGRA) (FPR < 1.2; n = 9), healthy (H) (FPR 1.2-1.5; n = 9), and subclinical ketosis (SCK) (FPR > 1.5; n = 9)-based on a combination of clinical observations and physiological parameters, including FPR thresholds (1). Cows in the SCK group exhibited significantly lower milk lactose and protein concentrations, reduced rumination time, and lower iron levels, while showing higher milk fat content, non-esterified fatty acid (NEFA) concentrations, and activity levels. FPR was negatively associated with lactose, rumination time, and iron, and positively associated with NEFA. These results suggest that FPR, when interpreted alongside behavioral and biochemical data, may support early identification of subclinical metabolic disorders in dairy cows.