Temperature preferences of newly-weaned pigs

Morris, Jenny Rebekah

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https://hdl.handle.net/2142/116163 Copy

Description

Title

Temperature preferences of newly-weaned pigs

Author(s)

Morris, Jenny Rebekah

Issue Date

2022-06-29

Director of Research (if dissertation) or Advisor (if thesis)

Ellis, Michael

Doctoral Committee Chair(s)

Ellis, Michael

Committee Member(s)

• Knox, Robert
• Condotta, Isabella
• Shull, Caleb

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• nursery pig
• temperature
• environment

Abstract

Weaning is a stressful event for the pig resulting in major changes in all aspects of the environment for the animal. Providing the optimum environmental temperature during this critical period is essential to minimizing the impact of weaning on animal health and performance. Current, widely applied recommendations for the optimum temperature for pigs in the nursery period are based on historical research carried out 30 to 50 years ago. Since that time, there have been major changes in the pig and in production systems that are likely to impact the optimum temperatures. Genetic selection programs have been successful at reducing the body fat content and increasing litter sizes. In addition, pigs are weaned at younger ages than historically was the case. These changes are likely to have increased the optimum temperature for pigs immediately after weaning; however, there has been limited recent research to validate this concept. This dissertation reviewed the literature with regard to thermoregulation in the pigs and on the major factors influencing the response of the animal to changing environmental temperature, particularly in the newly-weaned pig. In addition, experimental approaches for determining temperature requirements and current recommendations for temperature regimes for nursery pigs were reviewed. The research conducted for this dissertation focused on establishing the preferred temperature of pigs weaned at 21 d of age during the first 4-wk post-weaning. Estimates of preferred temperature were based on the time that pigs spent in areas of the pen which were at a range of different temperatures that span the probable optimum levels. Preferred temperatures were determined in three studies and temperature regimes based on either preferred temperature or current temperature were compared in the fourth study. For the first three studies, the temperature treatments evaluated were 26, 30, and 34 ℃ which were all available to the pigs within the same pen. Studies 1, 2, and 3 used a total of 40, 120, and 320, respectively, housed in pens with 20 pigs per pen. Study 1 was carried out for 2 wk and Studies 2, and 3 were carried out over 4 wk periods. The average start and end weights for Studies 1, 2, and 3 were 5.8 ± 1.21 and 10.0 ± 1.82 kg, 6.2 ± 0.99 and 15.3 ± 2.40 kg, and 6.1 ± 1.27 and 15.4 ± 2.84 kg. Pig growth performance was measured and camera images were recorded every 15 min to evaluate pig behavior. Study 1 confirmed that the methodology used to create the three distinct temperature treatment areas in the same pen and maintain the treatment temperatures within 1°C of the target was feasible. For Study 2, the preferred temperatures were estimated for pens of pigs with a typical range of weaning weights and were 31.1, 31.7, 29.6, and 27.7°C for wk 1, 2. 3, and 4 post-weaning, respectively. In Study 3, the effect of weaning weight on preferred temperature was evaluating by dividing the population of pigs into weaning-weight quartiles. The mean start weight for quartiles 1, 2, 3, and 4 was 4.5, 5.6, 6.5, and 7.7 kg, respectively and the estimated preferred temperature over the 4-wk study period was 30.0, 30.3, 29.3, and 28.6℃, respectively. Study 4 evaluated room temperature regime of Preferred Temperature (32℃, 32℃, 30℃, and 28℃) and Control (28℃, 26℃, 24℃, and 22℃) for wk 1, 2, 3, and 4 of the study period, respectively. Study 4 was carried out over a 4-wk period following weaning at 21 d of age using a split-plot design to evaluate the effect of: 1) Room Temperature Regime (main plot): Preferred (based on Studies 2 and 3; 32℃, 32℃, 30℃, and 28℃ for wk 1, 2, 3, and 4 of the study period) vs. Control (based on current recommendations; 28℃, 26℃, 24℃, and 22℃, respectively); 2) Weaning Weight (sub plot): Light vs. Heavy (the lightest and heaviest pigs within each litter). The study used 256 pigs housed in mixed-sex pens of 8 in 4 rooms (2 rooms/Room Temperature Regime treatment; 8 pens/room; 16 pens/Weaning Weight treatment). There was no effect (P > 0.05) of Room Temperature Regime on growth performance for the overall study period. As expected, Light Weaning Weight pigs grew slower (P < 0.05) and had lower (P < 0.05) feed intake than Heavy pigs. However, there was no effect (P > 0.05) of Weaning Weight on feed efficiency. There was an interaction (P < 0.05) between the Room Temperature Regime and Weaning Weight treatments for mortality during the 4-wk study period. For Heavy pigs, there was no effect (P > 0.05) of Room Temperature Regime on mortality; however, mortality was lower (P < 0.05) for Light pigs on the Temperature Preference than on the Control treatment (1.6 vs. 7.8%, respectively). The results of these studies suggest newly-weaned pigs prefer temperatures higher than currently recommended. However, keeping pigs at these higher preferred temperatures had no effect on growth performance, but decreased mortality in pigs with light but not heavy weaning weights.

Graduation Semester

2022-08

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Jenny Morris

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