Effect of protection against hot climate on growth performance, physiological response and endocrine profile of growing lambs under semi-arid tropical environment

Our plain-English summary of Effect of protection against hot climate on growth performance, physiological response and endocrine profile of growing lambs under semi-arid tropical environment, by K. De, D. Kumar, A.K. Singh, et al (Tropical Animal Health and Production, 2017).

The study

• Authors: K. De, D. Kumar, A.K. Singh, K. Kumar, A. Sahoo, S.M.K. Naqvi
• Journal: Tropical Animal Health and Production
• Published: 2017;49(6):1317-1323
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In the hot semi-arid tropical region, extreme summer is a major constraint in sheep production. The growth performance of growing lambs is impaired during the summer. Therefore, the present study was conducted to assess the effect of protection against hot climate on growth performance, physiological response, and endocrine profile of growing lambs under semi-arid tropical environment. All the data in the experiment were presented as mean ± SE. Thirty Malpura lambs with the age of 122.7 ± 6.05 days and body weight of 19.52 ± 0.42 kg were allotted into three groups, viz. G1 (control, lambs kept in open area under tree shade), G2 (lambs kept in conventional asbestos-roofed shed), and G3 (lambs kept in designed shed). The allotment was based on their initial body weight so that the mean body weight of each group was similar. In all three types of protection, lambs were provided with sufficient space to move and social interaction. In asbestos-roofed shed (G2), all the four sides from ground to the roof were fenced with strong galvanized iron chain link. But in G3, all the four sides were constructed in a manner that there was 0.13 m air space between inner and outer solid brick columns of the wall up to 1.37 m height, and rest up to the roof was fenced with bamboo splint net. The air space between the two columns of the wall was filled with sand, and it was kept in moist condition by continuous water drips which provide extra evaporative cooling. The designed shed was basically constructed with bamboo. Tree shade was assured under the natural shades of large trees. The shaded area was protected by wire fences. The experiment was conducted for 45 days during very high temperature (May-June). The lambs were provided with ad libitum green fodder, dry roughage, 300 g concentrate, and ad libitum drinking water. The respiration rate at morning and afternoon, pulse rate at morning and afternoon and rectal temperature at afternoon was significantly (P < 0.05) lower in lambs of G3 as compared to other groups. The final body weight did not differ significantly between the groups, but average daily gain (g/day) was higher in G3 (150.06 ± 11.13) as compared to the G1 (109.69 ± 18.10). The feed conversion rate (FCR) was significantly (P < 0.05) better in G3 (5.49 ± 0.08) as compared to G1 (7.65 ± 0.08) and G2 (6.60 ± 0.08). The hemoglobin level was significantly (P < 0.05) higher in G1. The endocrine profile did not vary significantly (P > 0.05) among the groups, but insulin-like growth factor-1 (IGF-1) was higher in G3. It can be concluded from this study the lambs provided with better protection during summer remained in more comfortable condition, showed better FCR, and although not statistically significant showed better growth performance.

In plain English

This was a 45-day experiment on sheep, not a study of asbestos and human or animal disease. It was run during May–June at a research sheep farm in Avikanagar, Rajasthan, India. Thirty Malpura lambs, seven female and three male per group, were kept in one of three settings: a fenced area under tree shade (G1), a conventional asbestos-roofed shed (G2), or a bamboo shed designed by the authors with sand-filled, water-moistened brick walls for evaporative cooling (G3). The asbestos roof was only one of the housing types compared. No fiber exposure or asbestos-related disease was measured. In the afternoon, lambs in the designed shed had significantly lower respiration rate, pulse rate and rectal temperature than the other two groups. Feed conversion rate was significantly better in G3 (5.49) than in G2 (6.60) and G1 (7.65). Final body weight did not differ significantly. Average daily gain was 150.06 g in G3 and 109.69 g in G1, a difference the table does not mark as significant. Hormone levels did not differ significantly. The authors concluded that better heat protection kept lambs more comfortable and improved feed conversion.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Controlled housing experiment in lambs, with three groups compared over 45 days (short communication)
• Who was studied: 30 Malpura lambs (10 per group: 7 female, 3 male), mean age 122.7 days and mean body weight 19.52 kg, at the ICAR-Central Sheep and Wool Research Institute farm, Avikanagar, Rajasthan, India, during May–June
• Exposure: Summer heat under three types of protection: tree shade (G1), a conventional asbestos-roofed shed with wire-net sides (G2), or a designed bamboo-thatched shed with evaporatively cooled brick walls (G3). Asbestos appears only as a roofing material. No asbestos fiber exposure was studied.
• Main results:
  • Afternoon respiration rate was significantly lower in G3 (34.95 per minute) than in G2 (49.98) and G1 (87.13). All three groups differed from each other.
  • Afternoon pulse rate was significantly lower in G3 (57.93 beats per minute) than in G1 (64.47) and G2 (70.75).
  • Afternoon rectal temperature was significantly lower in G3 (38.83 °C) than in G1 (39.06 °C) and G2 (39.09 °C).
  • Feed conversion rate (dry matter intake divided by average daily gain; lower is better) was 5.49 in G3, significantly better than 6.60 in G2 and 7.65 in G1.
  • Final body weight did not differ significantly between groups. Average daily gain was 150.06 g in G3, 126.65 g in G2 and 109.69 g in G1, and Table 2 marks these values as not significantly different.
  • Water intake was significantly higher in G1 (2.75 L per animal) than in G3 (2.57 L).
  • Hemoglobin was significantly higher in G1 (12.53 g/dL) than in G2 (11.01 g/dL).
  • Hormone levels (growth hormone, IGF-1, T3, T4) did not differ significantly between groups. IGF-1 was numerically higher in G3 (131.36 ng/mL) than in G1 (82.95) and G2 (77.40).
  • The temperature-humidity index was 37.60 in G1, 33.73 in G2 and 32.42 in G3. Only G3 and G1 differed significantly. Mean maximum temperature was highest in the asbestos-roofed shed (45.48 °C), compared with 43.46 °C under tree shade and 41.42 °C in the designed shed.
• The authors' conclusion: The authors concluded that the type of protection against summer heat affected the lambs' growth performance and physiological response. In their view, the designed shed's combination of roof shading and evaporative wall cooling gave the best microenvironment and the most efficient feed conversion.

Related studies

• Effect of altered ambient temperature through shelter modifications on physiological indicators of Malpura lambs reared in semi-arid region during winter — K. De, D. Kumar, et al. (2018)
• Physiological and subjective responses to working in disposable protective coveralls and respirators commonly used by the asbestos abatement industry — M.K. White, T.K. Hodous, et al. (1989)
• Water-cooled suit for protection against hot environments — J.W. Hill (1970)
• Fungal weathering of asbestos in semi arid regions of India — S. Bhattacharya, P.J. John, et al. (2016)
• ATR-FTIR and LC-Q-ToF-MS analysis of indoor dust from different micro-environments located in a tropical metropolitan area — M. Vishnu Sreejith, K.S. Aradhana, et al. (2021)
• Inflammasome inhibition under physiological and pharmacological conditions — E.A. Caseley, J.A. Poulter, et al. (2020)

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