Comparative Growth Performance of Nellore Brown Lambs under Conventional and Elevated Housing System during the Summer Season

Abstract

Housing system plays a crucial role in regulating the microclimate of animal shelters and directly influences growth performance and welfare of sheep, particularly during periods of thermal stress. The present study was undertaken to evaluate the effect of conventional and elevated housing systems on growth performance, feed efficiency, morphometric traits, and thermal comfort of Nellore Brown lambs during the summer season under intensive management. Twenty Nellore Brown lambs aged 3–4 months with an average initial body weight of 9.53 ± 0.56 kg were randomly allotted to two groups in a completely randomized design. Ten lambs were housed in a conventional housing system with moorum floor, while the remaining ten lambs were maintained in an elevated housing system with wooden slatted flooring for a period of 90 days. Temperature-humidity index (THI), dry matter intake (DMI), average daily gain (ADG), feed conversion ratio (FCR), body weight, morphometric measurements, and body condition score (BCS) were recorded at regular intervals. The results revealed that evening THI was significantly (P < 0.05) higher in the conventional housing system compared to the elevated housing system, indicating greater thermal stress. Lambs housed under the elevated system showed significantly (P < 0.01) higher DMI, body weight, and ADG, along with a lower FCR, reflecting improved feed utilization. Morphometric parameters such as body length, chest girth, height at withers, and abdominal girth were significantly higher in the elevated housing system, whereas thigh circumference and BCS did not differ significantly between housing systems. It can be concluded that elevated housing with slatted flooring effectively reduces heat stress and enhances growth performance and feed efficiency of Nellore Brown lambs during summer, making it a more suitable housing option under intensive rearing conditions.