Effect of Dietary Types on Feed Intakes, Growth Performance and Economic Benefit in Tibetan sheep and Yaks on the Qinghai-Tibet Plateau during Cold Season.

Tianwei Xu,Na Zhao,Li Ma,Hongjin Liu,Shixiao Xu,Zhe Liu,Xinquan Zhao,Linyong Hu,Bi-Song Yue

doi:10.1371/journal.pone.0169187

Abstract

Pastoralists on the Tibetan alpine rangeland suffered great economic loss in cold season, due to serious live-weight loss of domestic livestock under traditional grazing management. This study aimed to evaluate the effect of dietary types (crude protein levels) on feed intakes, growth performance and economic returns of local Tibetan sheep and yaks during cold season. Twenty-four yearling Tibetan sheep (25.29±3.95 kg LW) and twenty two-year-old yaks (100.62±4.55 kg LW) with familiar body conditions were randomly assigned to four groups, fed oats hay (OH), oats silage (OS), total mixed ration (TMR) and traditionally grazed on the local cool-season pasture (TG), respectively, over a 135-day experiment. Daily dry matter intake was determined; all animals were weighed at the beginning and every 15 days of the 135-day experiment. Then, the total live-weight gain, average daily live-weight gain, gain rate, feed efficiency and net economic benefit were calculated. Results indicated that feed and nutrient intakes (DMI, DMI/kg LW, DMI/kg LW0.75 and CPI) of TMR, OH and OS were higher than TG (P < 0.05). Grazing animals suffered serious live-weight loss, while TMR, OS and OH significantly (P < 0.05) improved total live-weight gain and gain rate in both Tibetan sheep and yaks during the entire experiment. TMR worked better in animal performance and feed efficiency, obtained the highest breeding profit in both Tibetan sheep and yaks among four treatments (P < 0.05). When expressed on net economic benefit, TMR shared the highest net economic benefit in Tibetan sheep, OH shared the highest net economic benefit in yaks, but, no significant difference of net economic benefit in yaks fed TMR and OH diets was determined (P > 0.05). Results indicated that TMR was a reasonable diet in promoting feed intakes, animal performance, feed efficiency and economic returns in domestic livestock, which should be considered by local herdsmen to increase their breeding profit during cold season.

Highlights

Qinghai-Tibet plateau (QTP) is an ecological functional zone and ecological security defense for China and even Asia due to its unique geographical location and climate characteristics [1,2]
DMI/kg LW was in the order total mixed ration (TMR) > oats silage (OS) > oats hay (OH) > TG in Tibetan sheep and TMR > OH > OS > TG in yaks
Our results indicated that total mixed ration was an appropriate diet in improving feed intakes, growth performance, feed efficiency and economic returns in both Tibetan sheep and yaks, which should be considered by local herdsmen to improve their breeding profit during cold season

Summary

Introduction

Qinghai-Tibet plateau (QTP) is an ecological functional zone and ecological security defense for China and even Asia due to its unique geographical location and climate characteristics [1,2]. Tibetan sheep (Ovis aries) and yaks (Bos grunniens) are the two major ruminant species, playing an increasingly important role on the Tibetan rangeland due to their excellent adaptability and production performance [4,5,6,7]. It is estimated with a population of about 13 million domestic yaks and 50 million Tibetan sheep are living on the QTP [8,9], providing local herdsmen with daily necessities like meat, milk, wool, skins, fuel and economic benefit [4,8,10]. The vicious cycle was aggravated yearly due to over-stocking rate of livestock and irrational utilization of natural pasture on the QTP [16,17,18]

Objectives

Methods

Results

Discussion

Conclusion