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Energetics, behavior and performance of growing swine at constant and cyclic high temperatures
Abstract
Eighteen ad-libitum-fed individual Whiteline (Large White x Landrace) x Duroc gilts with overall average weight of 39 kg were exposed respectively to (a) constant air temperature of 30.8 C (CON); (b) reduced peak diurnal cyclic temperature of 36 to 33 C with mean temperature of 30.8 C (RPK); and (c) reduced night diurnal cyclic temperature of 23.4 to 40 C with mean temperature of 30.8 C (RNT). Six replicates were involved per temperature treatment. Daily average and 24-hr dynamic feed intake, heat losses, water consumption, growth rate, respiratory quotient and the related behaviors were measured for a five-day period. Daily feed intake, heat losses, water consumption, growth rate and feed conversion of RPK pigs could be predicted with the same responses of CON pigs. This relation holds in the case of RNT pig responses except for feed intake and growth rate. Feed intake (1.56 kg/day-pig) and growth rate (0.70 kg/day) of RNT pigs were significantly reduced (P $<$ 0.01) compared to RPK pigs (1.78 and 0.84) or CON pigs (1.71 and 0.82). Thus a cycle of 16 C impaired feed intake and growth rate of 40-kg pigs when the mean of cyclic temperatures was above thermoneutral zone. Ingestion behaviors of the pigs were characterized by meal and drinking size of 160-170 g/meal-pig and 250 to 270 g/drink-pig; frequency of 9 to 11 meals/day and 36 drinks/day; and duration of 13.7 min/meal and 0.61 min/drink respectively. Pigs showed high average hourly feed intake of 117/pig-hr from 1200h to 2100h at CON; 87 g/pig-hr from 1300h to 0800h at RPK; and 120 g/pig-hr from 2000h to 0800h at RNT respectively. High heat loss rate generally followed the feed intake hike with about two hours of lag. Data Dependent Systems (DDS) analysis indicated that CON and RPK pigs had more dynamic feed intake systems and thus more active memory of their feeding history than RNT pigs. RNT pigs appeared unable to adjust their heat dissipation as freely as CON pigs or RPK pigs. Dynamic respiratory quotient appeared positively related to dynamic growth of the pig.
Subject Area
Agricultural engineering
Recommended Citation
Xin, Hongwei, "Energetics, behavior and performance of growing swine at constant and cyclic high temperatures" (1989). ETD collection for University of Nebraska-Lincoln. AAI9019590.
https://digitalcommons.unl.edu/dissertations/AAI9019590