# The Influence of Recombinant Bovine Somatotropin (rbST) on the Metabolic Profile and Milk Composition of Lactating Murrah Buffalo

## TL;DR

This study shows that using rbST in lactating Murrah buffalo is metabolically safe and only temporarily lowers milk protein.

## Contribution

The paper provides new empirical evidence on the metabolic safety and milk composition effects of rbST in Murrah buffalo.

## Key findings

- rbST treatment did not cause imbalances in fat metabolism or overload liver or kidney function.
- Milk production increased temporarily, with a transient decrease in milk protein observed only on the third day.
- The majority of buffalo showed increased milk production within the first week after treatment.

## Abstract

This study was undertaken to evaluate the effects of a single subcutaneous dose of 500 mg rbST on the lipid profile, liver and kidney function, and physical, chemical, and cellular constitution of buffalo milk. Our data indicated that the use of rbST in buffalo from the 100th day of lactation is metabolically safe since the treatment neither caused imbalances in fat metabolism nor overloaded the liver or renal function. The changes in milk composition were transient and limited to a decrease in milk protein.

The use of recombinant bovine somatotropin (rbST) leads to an increase in variable amounts of milk production in buffalo, but there is a lack of information on the influence of rbST on their metabolism. This study looked at the effects of a single 500 mg dose of rbST on the lipid profile, liver and kidney function, and physical, chemical, and cellular constitution of milk in 14 buffalo over 14 days, from the 100th day of lactation, compared with 14 animals in a control group. From the first day after rbST, there was a rise in beta-hydroxybutyrate (β-HBO), possibly due to higher dry matter intake or the biotransformation of NEFA into β-HBO. The treatment did not influence blood glucose, non-esterified fatty acids (NEFAs), triglycerides, cholesterol, total protein, albumin, AST, GGT, bilirubin, urea, or creatinine levels. In 71.3% of the buffalo, there was a gradual increase in milk production, with the maximal response occurring in the first week followed by a gradual decrease, whilst in 21.4%, the increase in production occurred between 7 and 10 days. Only 7.1% of the animals did not respond. On the 3rd, 5th, 7th, and 10th days after treatment, an increase was found in daily milk production between the two groups equal to 1.04, 1.52, 1.42, and 1.06 L, respectively. In relative terms, this means an increase in milk production, respectively, of 15.1%, 21.0%, 19.8%, and 15.1%. The constitution of the milk showed no difference in the amounts of fat, lactose, total solids, or somatic cell count; however, on the third day after rbST administration, there was a decrease in protein. Notably, from the fifth day, the protein values showed no statistical difference. It can be concluded that the use of rbST in buffalo from the 100th day of lactation is metabolically safe since the treatment neither caused imbalances in fat metabolism nor overloaded the liver or renal function, and the changes in milk composition were transient and limited to a decrease in milk protein.