Location: Livestock Behavior ResearchTitle: Evaluation of floor cooling on lactating sows under mild and moderate heat stress Author
|Maskal, Jacob - Purdue University|
|Cabezón, Francisco - Purdue University|
|Schinckel, Alan - Purdue University|
|Stwalley, Robert - Purdue University|
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2017
Publication Date: 2/1/2018
Citation: Maskal, J., Cabezón, F.A., Schinckel, A.P., Marchant Forde, J.N., Johnson, J.S., Stwalley, R. 2018. Evaluation of floor cooling on lactating sows under mild and moderate heat stress. Professional Animal Scientist. 34(1):84-94. doi:org/10.15232/pas.2017-01661.
Interpretive Summary: High environmental temperatures cause lactating sows to reduce their feed intake and milk production to reduce their internal heat production. This results in reduced piglet growth and weaning weights. In addition, heat stress reduces sow fertility as reduced feed intake has negative effects on body condition. The combination of reduced sow productivity, piglet growth, and sow fertility in response to seasonal increases in temperature results in an annual loss of over $360 million for the United States pork industry. Recently, a cooling pad has been designed to remove increased amounts of excess heat produced by modern sows and has been tested in short duration trials of acute heat stress. However, studies have not been undertaken to assess the impact of these new cooling pads throughout an entire farrowing lactation period and to what extent measures of heat stress vary within a day. Therefore, the study objectives were 1) to evaluate the effectiveness of the cooling pads over an entire lactation period, and (2) to evaluate the heat removal capacity of cooling pads within a day. It was determined that cooling pads reduced the negative impact of heat stress on sow thermoregulation and allowed them to maintain a euthermic body temperature.
Technical Abstract: The effectiveness of sow cooling pads during lactation was evaluated under mild and moderate heat stress conditions. The moderate heat stress room was targeted to achieve 32°C from 0800 to 1600 h and 27°C for the rest of the day. The mild heat stress room was targeted to achieve 27°C and 22°C for the same periods, respectively. Sows received either a constant cool water flow of 0.00 (CONTROL, n = 9), 0.25 (LOW, n = 12), or 0.50 (HIGH, n = 10) L/min. Respiration rates (RR), rectal temperatures (RT) and skin temperatures (ST) were recorded everyday (0700 and 1500 h) from the second day in the farrowing room to weaning. The RRs of CONTROL sows increased (P < 0.001) from 23, 56, 41, and 89, LOW sows increased from 21, 24, 29, and 41 and HIGH sows increased from 18, 20, 24, and 27 breaths per minute as heat stress Increased from mild AM (22°C), moderate AM (27°C), mild PM (27°C) and moderate PM (32°C). The STs of LOW sows were 1.1 0.6, 0.8, and 0.4 and STs of the HIGH sows were 1.7, 0.7, 1.1, and 1.0°C lower (P < 0.01) than CONTROL sows for the same heat stress conditions.The RTs of LOW sows were 0.02, 0.20, 0.11, and 0.58°C and HIGH sows were 0.04, 0.22, 0.02 and 0.57°C lower (P < 0.05) for the same four treatments. The sow cooling pads reduced the impact of heat stress.