Studies On Concentration of Some Milk Metabolic Enzymes at Different Parities, Stage of Lactation and Their Correlation with Composition and Yield of Milk in Red Sindhi Cows

Abstract

The study investigated the impact of parity and lactation stage on milk metabolic enzyme concentrations and their correlation with milk composition and yield in Red Sindhi cows. A total of 45 apparently healthy cows were selected from two cattle farms in Pakistan. Milk samples were collected, tested for subclinical mastitis, and analyzed for chemical composition and enzyme activity. Notably, alkaline phosphatase (ALP) activity increased significantly from 1st parity to 3rd, 4th, and beyond 4th parity during early, mid, and late lactation. Aspartate amino transferase (AST) concentration was higher from 1st to 2nd parity across all lactation stages, followed by a decrease with increasing parity. Lactate dehydrogenase (LDH) concentration varied significantly during different lactation stages and parities concentration was significantly higher during early lactation of 4th parity cows, mid lactation of cows at >4th parity, and late lactation of 1st parity cows Additionally, milk fat and solid-not-fat (SNF) content were notably higher at >4th parity and 1st parity, respectively. Density of milk decreased and total solids (TS) increased with parity. Slightly higher pH was recorded in milk at 1^stand 2^ndparity. Protein, ash and chloride and milk yield increased with parity and lactation stage and milk yield .has positive correlation with AST and negative correlation with LDH and ALP. Ash, Fat Protein, and lactose have positive correlation with LDH, while chloride and pH have negative correlation with AST and LDH These findings provide valuable insights for the dairy industry.