Acid-base, electrolyte and oxidative status in dairy cows at different stages of the production cycle

Ljubomir Jovanovic,Radisa Prodanovic,Svetlana Milanovic,Ivan Vujanac,Milica Stojic,Danijela Kirovski,Sreten Nedic,Dusan Bosnjakovic

doi:10.2298/vetgl210130004j

Abstract

Previous studies in the field of acid-base and oxidative status in cows have mainly focused on the transition period (three weeks before and three weeks after calving). The aim of this study was to determine the differences in the parameters of acid-base and oxidative status and electrolyte balance in cows not only during the transition period, but also at other stages of the production cycle. Holstein-Friesian cows were divided into four numerically equal groups (n = 6): early lactating cows (9?2 days in milk - DIM), peak lactating cows (50?5 DIM), late lactating cows (170?10 DIM) and dry cows (10?1 days before calving). Venous blood samples were taken from the cows to analyze acid-base status, electrolyte concentrations and oxidative stress parameters, and to compare group means. Significantly higher pH was observed in early lactating cows than in late lactating cows. Sodium (Na+) concentration was significantly lower in early lactating and peak lactating cows compared to dry cows, while chloride (Cl-) concentration was also lower in late lactating cows compared to dry cows. Plasma glutathione peroxidase (GSH-Px) activity was higher in early lactating cows compared to peak lactating cows. Thus, the highest blood pH, lowest Na+ and Cl- concentrations and highest serum GSH-Px activity were observed in early lactating cows compared to other groups, indicating the highest metabolic and oxidative stress during this period. In conclusion, it would be useful to consider the inclusion of these parameters in standard health assessment procedures in intensive dairy production.

Highlights

In dairy science, metabolic profile testing and body condition scoring (BCS) are the commonly used approaches to assess the health, milk production, reproductive status and feed balance of dairy cattle herds (Roche et al, 2009; Horvat et al, 2014; Nozad et al, 2014)
The results of our study indicate the EL- and peak lactating cows (PL-cows), which were supplemented with sodium t bicarbonate, had numerically higher blood pH and bicarbonate concentrations s compared to other groups of cows (Table 2)
Our results show significant differences in blood pH, Na+ and Cl- concentrations and serum GSH-Px activity in cows at different stages of the production cycle

Summary

Introduction

Metabolic profile testing and body condition scoring (BCS) are the commonly used approaches to assess the health, milk production, reproductive status and feed balance of dairy cattle herds (Roche et al, 2009; Horvat et al, 2014; Nozad et al, 2014). Monitoring of acid-base status is considered an important procedure in assessing the health of dairy cows (Gärtner et al, 2019). E intensive dairy production is accompanied by increased nutritive demands that are associated with increased oxygen requirement. This creates conditions for the generation of reactive oxygen species (ROS), which in the case of depletion of in antioxidative capacities, can lead to oxidative damages of biomolecules and disruption of physiological integrity (Sharma et al, 2011; Halliwell and Gutteridege, 2015)

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