Journal article

Comparative Assessment of Thermotolerance in Dorper and Second-Cross (Poll Dorset/Merino x Border Leicester) Lambs

Aleena Joy, Frank R Dunshea, Brian J Leury, Kristy DiGiacomo, Iain J Clarke, Minghao H Zhang, Archana Abhijith, Richard Osei-Amponsah, Surinder S Chauhan

ANIMALS | MDPI | Published : 2020

Abstract

The objective of this study was to compare the thermotolerance of second-cross (SC; Poll Dorset × Merino × Border Leicester) and Dorper lambs. Dorper and SC lambs (4-5 months of age) were subjected to cyclic heat stress (HS) (28-40 °C). The temperature was increased to 38-40 °C between 800 and 1700 h daily and maintained at 28 °C for the remainder of the day (30-60% relative humidity (RH)) in climatic chambers for 2 weeks (n = 12/group), with controls maintained in a thermoneutral (TN) (18-21 °C, 40-50% RH) environment (n = 12/group). Basal respiration rate (RR), rectal temperature (RT) and skin temperature (ST) were higher (p < 0.01) in SC lambs than in Dorpers. HS increased RR, RT and ST (..

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