Effects of rumen-protected methionine supplementation on production performance, apparent digestibility, blood parameters, and ruminal fermentation of lactating Holstein dairy cows

Yuanxiao Li; Jialin Wei; Mengying Dou; Shuai Liu; Bichuan Yan; Cuiyu Li; Muhammad Zahoor Khan; Yinghui Zhang; Jianxin Xiao

doi:10.3389/fvets.2022.981757

Effects of rumen-protected methionine supplementation on production performance, apparent digestibility, blood parameters, and ruminal fermentation of lactating Holstein dairy cows

Front Vet Sci. 2022 Dec 12:9:981757. doi: 10.3389/fvets.2022.981757. eCollection 2022.

Authors

Yuanxiao Li¹, Jialin Wei^{1

2}, Mengying Dou¹, Shuai Liu², Bichuan Yan², Cuiyu Li², Muhammad Zahoor Khan³, Yinghui Zhang⁴, Jianxin Xiao^{5

2}

Affiliations

¹ College of Animal Science, Henan University of Science and Technology, Luoyang, China.
² State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
³ Department of Animal Science, Faculty of Veterinary and Animal Sciences, University of Agriculture Dera Ismail Khan, Dera Ismail Khan, Pakistan.
⁴ Evonik (China) Co., Ltd., Beijing, China.
⁵ Key Laboratory of Low Carbon Culture and Safety Production in Cattle in Sichuan, Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.

Abstract

This study aimed to evaluate the effects of reducing dietary CP and supplementing rumen protected-methionine (RPM) on production performance, blood parameters, digestibility of nutrients or ruminal fermentation in lactating Holstein dairy cows. A total of 96 lactating cows were randomly assigned to 1 of 2 treatments: a diet containing 17.3% CP without RPM (control group; CON; n = 49) or a diet containing 16.4% CP and supplemented with 15.0 g/d of RPM (treatment group; RPM; n = 47). No effect was observed in the RPM group on milk yield, milk composition and digestibility of nutrients. The results of blood parameters showed that cows in the RPM group exhibited lower blood urea nitrogen concentration than in CON group. Rumen microbial crude protein (MCP) was higher in the RPM group compared to the CON group. Ruminal volatile fatty acid (VFA) concentrations were not different between treatments except for butyrate and isovalerate, which were higher in the RPM group than the CON group 2 h after feeding. In conclusion, reducing dietary CP with RPM supplementation did not limit milk yield, milk composition or digestibility of nutrients, but could improve nitrogen utilization, synthesis of MCP and partially increase VFA production 2 h after feeding cows.

Keywords: blood parameters; dairy cows; digestibility; rumen-protected methionine; ruminal fermentation.