WITHDRAWN:Hematological and vasodilator characteristics for high altitude acclimatization in Holstein heifers ascended to high altitude.

Shuxiang Wang,Zhijun Cao,Shengli Li,Arash Azarfar,Quangui Shi,Yajing Wang

doi:10.5713/ajas.18.0224

Shuxiang Wang, Zhijun Cao + Show 4 more

Open Access

https://doi.org/10.5713/ajas.18.0224

Copy DOI

Abstract

This study was conducted to investigate hematological and vasodilator characteristics for high altitude acclimatization in Holstein heifers ascended to high altitude. Holstein heifers resided at low altitude (LH; Beijing, China 43 meter), and Holstein heifers ascended to high altitude (Lhasa city, Tibet; 3,658 meter) after one year exposure including hypoxia acclimated Holstein heifers (AH; with mean pulmonary arterial pressure mPAP < 41 mmHg) and Holstein heifers affected by high altitude pulmonary hypertension (HAPH; with mPAP > 49 mmHg) and crossbred cattle (CB; Holstein × Tibet cattle) born and resided in Tibet were selected to compare parameters of blood gas, blood cells and vasodilators. Each group included 15 animals with 16 to 18 month of age. The HAPH had greater mPAP than other cattle classes (P < 0.01). Alveolar ventilation (as indicated by partial pressure of carbon dioxide; PaCO2) was improved in AH and HAPH compared to LH, but it was lower in HAPH than in CB and AH (P < 0.05). In addition, LH had the greatest and HAPH had the lowest partial pressure of oxygen (PaO2) among the four cattle classes (P < 0.05). Erythropoietin and mean corpuscular hemoglobin concentration were greater in AH and HAPH than LH (P < 0.05). Serum iron was greater in AH than LA and HAPH (P < 0.05). Hypoxia exposure increased plasma nitric oxide and endothelin-1 in cattle resided in Tibet compared to LH. Additionally, AH had greater brain natriuretic peptides than HAPH and LH, and AH had greatest C-type natriuretic peptides than the other groups (P < 0.05). High altitude hypoxia acclimatization was achieved in Holstein heifers ascended to high altitude via augmented alveolar ventilation, serum iron, mean corpuscular hemoglobin concentration, natriuretic peptides and nitric oxide, it enables them to tolerate the high altitude.

Highlights

High altitude hypoxic environment presents extreme challenges for cows because they have a small lung volume relative to oxygen consumption [1, 2]
The low barometric pressure at high altitude causes pulmonary hypoxia, which result of high prevelance of high altitude induced pulmonary hypertension (HAPH) in Holstein and Angus [2, native breeds inhibitng at elevations lower than 4,000 m it adapting at high altitude [7]
Tibet cattle likely confers an advantage in the hypoxic adaption to CB, just like Han-Tibetans born and residing at 3,658 m as previously decribed [28], which allowing them have little incidence of HAPH

Summary

Introduction

High altitude hypoxic environment presents extreme challenges for cows because they have a small lung volume relative to oxygen consumption [1, 2]. Holstein and Angus cattle at high altitude were found to have high prevalence of brisket disease (BD) [3, 4] that imposes huge financial losses to farmers. High altitude native breeds such as domestic Yaks (Bos grunniens) and Tibet cattle (Bos taurus) have genetic phenotypical and physiological adaptations such as greater red blood cell (RBC) count, hemoglobin (HGB). Holstein (frozen semen) were widely resided because they inherited high milk production of Holstein cattle and high altitude genetic adaptation features of Tibet cattle. Research has indicated that hypoxia exposure promotes body formation of vasodilators to prevent vascular dysfunction and high altitude induced pulmonary hypertension (HAPH). High altitude Tibetan people [10], Tibet sheep [11] and Yak [12] have augmented

Methods

Results

Conclusion