Effects of bupleurum extract on the haematological, mineral, and hormonal profiles of heat-stressed dairy cows

Abstract

This study was conducted to investigate the effects of Bupleurum extract (BE) on the haematological profiles, the mineral and hormone levels of heat stressed dairy cows. Forty Holstein cows (75 ± 15 days in milk, 37.5 ± 1.8 kg of milk/d, and 1.7 ± 0.4 parity) with heat stress were randomly assigned to four treatments, which consisted of 0, 0.25, 0.5, or 1.0 g BE/kg DM (Dry Matter). Compared with the control group, cows that were fed 0.5 g/kg BE had a higher red blood cell count, haemoglobin, haematocrit, and white blood cell count. Compared with the control group, the supplementation of 0.25 and 0.5 g/kg BE decreased creatine kinase levels. Compared with the cows that were fed 0 or 1.0 g/kg BE, glutamic-oxaloacetic transaminase and alkaline phosphatase activities were lower in those given 0.5 g/kg BE, while serum glutamic-pyruvic transaminase was lower in those given 0.25 and 0.5 g/kg BE. Compared with the control group, the supplementation of 0.5 and 1.0 g/kg BE decreased sodium concentrations and increased potassium and calcium concentrations. In addition, the supplementation of 1.0 g/kg BE decreased phosphorus concentrations, while that of 0.5 g/kg BE increased chloride concentrations. As for hormone levels, triiodothyronine and prolactin levels increased in cows given 1.0 g/kg BE, while cortisol levels were lower in cows given 0.5 g/kg BE. Further, growth hormone levels were elevated in cows fed 0.25 g/kg BE. These findings suggest that supplemental BE at 0.5 g/kg could have positive effects on the blood metabolism of heat-stressed cows.HIGHLIGHTS Supplementation of 0.5 g/kg Bupleurum extract improved the haematological parameters of heat stressed dairy cows; Bupleurum extract can be used as a feed additive for cows.

Keywords

• bupleurum extract
• holstein cows
• heat stress
• blood metabolites