Department of Animal Science, Iowa State University, Ames, Iowa, United States of America.
PLoS One. 2023 Dec 21;18(12):e0294336. doi: 10.1371/journal.pone.0294336. eCollection 2023.
Piglets are susceptible to hypothermia because they lack hair and energy reserves, have a large surface area to body weight ratio, and have poor body thermostability. Different heat sources are used on farm, but it is not known how long it takes half a litter to locate it and lie down. The objectives of this study were to determine 1) how long it took for ≥ 50% of piglets to locate and lie on- or under the supplemental heat source for ≥ 5 min after the birth of the last-born pig and, 2) how long this cohort of piglets laid on- or under the heat source. A total of 12 sows were enrolled in the study (parity 1 = 4; 3 = 2; 4 = 2; 5 = 2; and 7 = 2). The stall containing one sow and her litter was the experimental unit. Two treatments were compared: 1) Baby Pig Heat Mat-Single 48 (MAT) and 2) Poly Heat Lamp (LAMP). Temperature was 32°C for both heat source treatments. Sow and litter video recordings occurred continually over a 24-h period on the day of farrowing. Two measures were determined 1) how long it took for ≥ 50% of piglets to locate and lie on- or under the supplemental heat source for ≥ 5 min after the birth of the last-born pig (h:min), and 2) how long this cohort of piglets laid on- or under the heat source (min:sec). Lying was defined as either sternal or lateral recumbency with ≥ 75% of the piglet's body touching the heat mat or inside the lamp heat circle. Production records were used to verify farrowing date, total number of piglets born, and born alive. No cross fostering occurred during this study. All data will be presented descriptively. On average, sows assigned to the LAMP treatment took ~2 ½-h to farrow, and for sows assigned to the MAT ~3 ½-h, respectively. Piglets took between ~5-h (LAMP) and ~9-h (MAT) for ≥ 50% of piglets to locate and lie on- or under the supplemental heat source for ≥ 5 min after the birth of the last piglet. Cohort of piglets laid on- or under the heat source as follows, LAMP piglets spent ~29 mins lying and for MAT piglets ~42 mins, respectively. Average pre-weaning mortality was 11% (LAMP) and 18% (MAT). The MAT heat source used less energy than the LAMP (16 vs. 63 kWh) over the study duration. To the authors' knowledge, this is the first published study using a continuous sampling method to precisely examine a new measure (time needed for ≥ 50% of piglets to locate and lie on- or under the supplemental heat source for ≥ 5 min after the birth of the last-born piglet) and to determine how long this cohort of piglets laid on- or under the heat source. Our findings show an immense range in locating and lying under- or on the heat source. Therefore, we suggest that caretakers should assist all piglets to locate the heat source after farrowing is complete to improve piglet livability.
仔猪易患低体温症，因为它们缺乏毛发和能量储备，体表面积与体重比大，且体温稳定性差。农场使用不同的热源，但尚不清楚一半仔猪需要多长时间才能找到并躺在或趴在补充热源上 5 分钟以上。本研究的目的是确定 1）最后一只出生的仔猪出生后，≥ 50%的仔猪需要多长时间才能找到并躺在或趴在补充热源上≥ 5 分钟，以及 2）这群仔猪躺在或趴在热源上的时间有多长。共有 12 头母猪参与了这项研究（产仔 1 = 4；3 = 2；4 = 2；5 = 2；7 = 2）。包含一头母猪及其仔猪的畜栏是实验单位。比较了两种处理方法：1）仔猪保温垫单 48（MAT）和 2）多聚热灯（LAMP）。两种热源处理的温度均为 32°C。分娩当天，母猪和仔猪的视频记录持续进行了 24 小时。确定了两个措施：1）最后一只出生的仔猪出生后，≥ 50%的仔猪需要多长时间才能找到并躺在或趴在补充热源上≥ 5 分钟（h：min），以及 2）这群仔猪躺在或趴在热源上的时间有多长（min：sec）。躺着被定义为胸骨或侧卧位，至少有 75%的仔猪身体接触加热垫或在灯热圈内。使用生产记录来验证分娩日期、出生仔猪总数和出生活仔数。在本研究中没有发生交叉寄养。所有数据将以描述性方式呈现。平均而言，分配到 LAMP 处理的母猪分娩需要2 个半小时，而分配到 MAT 的母猪分娩需要3 个半小时。仔猪需要5 小时（LAMP）到9 小时（MAT），才能使≥ 50%的仔猪在最后一只仔猪出生后≥ 5 分钟内找到并躺在或趴在补充热源上。仔猪躺在或趴在热源上的情况如下，LAMP 仔猪躺卧29 分钟，MAT 仔猪躺卧42 分钟。平均断奶前死亡率为 11%（LAMP）和 18%（MAT）。MAT 热源在研究期间比 LAMP（16 千瓦时对 63 千瓦时）使用的能量更少。据作者所知，这是第一篇使用连续采样方法精确检查新措施（最后一只出生仔猪出生后≥ 50%的仔猪找到并躺在或趴在补充热源上≥ 5 分钟所需的时间）并确定这群仔猪躺在或趴在热源上多长时间的已发表研究。我们的研究结果显示，在找到并躺在或趴在热源下有很大的范围。因此，我们建议饲养员在分娩完成后帮助所有仔猪找到热源，以提高仔猪的存活率。
