Milk Production and Quality of Lactating Yak Fed Oat Silage Prepared with a Low-Temperature-Tolerant Lactic Acid Bacteria Inoculant.

Mingming Zhu,Rongqing Xie,Minghong You,Yimin Cai,Ping Li,Chao Chen,Wenlong Gou,Liangyin Chen

doi:10.3390/foods10102437

Abstract

This study aimed to investigate the effect of oat silage treated with a low-temperature-tolerant lactic acid bacteria (LAB) inoculant on milk yield and the quality of lactating yaks. Oat silages were prepared in big round bales, treated without (control) or with a low-temperature-tolerant LAB inoculant (a mixture of Lactobacillus plantarum BP18, Pediococcus pentosaceus HS1 and Lactobacillus buchneri LP22; the application rate of 105 cfu/g on a fresh matter basis). Eighteen lactating yaks were divided into nine pairs with a similar milk yield. Each pair of yaks was randomly allocated to the control or LAB-inoculated silage treatment. The inoculated silage increased the dry matter intake and the total volatile fatty acid (mainly acetate, propionate and butyrate) in rumen fluid compared with the control. The inoculated silage also enhanced the yield of yak milk with high contents of total N, fat and lactose. In addition, high levels of essential amino acids (Thr, Leu and Phe), polyunsaturated fatty acids and low saturated fatty acids were observed in milk when lactating yaks were fed with the inoculated silage. Therefore, inoculation with a low-temperature-tolerant LAB during ensiling could promote the milk yield of lactating yaks by enhancing dry matter intake and ruminal fermentation.

Highlights

Yaks (Bos grunniens) are the only bovine with adaptability to the extremely harsh environment of the Qinghai–Tibet Plateau at an altitude of 2000–5000 m above sea level [1]
Intake was observed when Lactobacillus buchneri-inoculated silages were fed to dairy cows
The improvements in intake and performance were mainly due to the higher content of water-soluble carbohydrates in feeds [28], which further affected the availability of readily fermentable energy for rumen microbiota with potential hydrogenation of fatty acids in rumen [29]

Summary

Introduction

Yaks (Bos grunniens) are the only bovine with adaptability to the extremely harsh environment (low humidity, low temperature, low oxygen, gale and high UV radiation) of the Qinghai–Tibet Plateau at an altitude of 2000–5000 m above sea level [1]. Due to the long cold season with heavy snow, forage shortage induced a dramatic body weight loss and mortality of yaks, which caused a reduction in milk, meat, hair and cheese for the people living on the Qinghai–Tibet Plateau [3]. Yak milk is more nutritive than dairy cow milk in nutrient composition, especially for essential amino acids [4] and fat [5].

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Conclusion