Effect of loading density and weather conditions on animal welfare and meat quality of slaughter pigs

Jaewoo An¹, Yongju Kim¹, Minho Song², Jungseok Choi¹, Hanjin Oh¹, Seyeon Chang¹, Youngbin Go¹, Dongcheol Song¹, Hyunah Cho¹, Sanghun Park¹, Yuna Kim¹, Yunhwan Park¹, Gyutae Park¹, Sehyuk Oh¹, Jinho Cho¹^,^*

¹Division of animal science, Chungbuk National University, Cheongju 28644, Korea.

²Department of animal science and biotechnology, Chungnam National University, Daejeon 34134, Korea.

^*Corresponding Author: Jinho Cho, Division of animal science, Chungbuk National University, Cheongju 28644, Korea, Republic of. E-mail: jinhcho@cbnu.ac.kr.

© Copyright 2023 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Nov 28, 2022; Revised: Jan 03, 2023; Accepted: Mar 30, 2023

Published Online: Apr 03, 2023

Abstract

There are several factors that affect the welfare and meat quality of pigs during pre-slaughter transport. Among various factors, the effects of weather conditions and loading density were studied. A total of 3,726 finishing pigs were allotted to one of nine groups arranged in a 3 × 3 factorial design according to the weather conditions (low temperature (LT), under 10°C; normal temperature (NT), 10-24°C; high temperature (HT), upper 24°C), and loading density (low density (LD), upper 0.43 m2/100 kg; normal density (ND), 0.37-0.43 m2/100 kg; high density (HD), under 0.37 m2/100 kg). Each treatment group follow as: LTLD, LTND, LTHD, NTLD, NTND, NTHD, HTLD, HTND, HTHD. In terms of carcass composition, pigs had the highest carcass weight and backfat thickness at LT. Comparing the HD transport to the ND transport, the meat quality indicated a lower pH and more drip loss. The incidence rate of pale, soft, exudative (PSE) pork was high in the order of the HD, LD, and the ND transport (20%, 9%, and 2%, respectively). The HT transport showed the lowest pH and greatest L* value under the given weather conditions. Pigs transported under the HTHD and LTLD conditions had the greatest rates of PSE pork (40% and 20%, respectively). Pigs exposed to HD transport had the shortest laying time and the highest overplap behavior. The LDLT transport pigs had a shorter laying time than the LDNT and LDHT transport pigs. In conclusion, too high or too low density transport is generally not excellent for meat quality or animal welfare, however it is preferable to transport at a slightly low density at high temperature and at a slightly high density at low temperature.

Keywords: Transport; loading density; temperature; welfare; meat quality