Williams Paul D, Paixão Gustavo
MSD Animal Health, Walton Manor, Walton, Milton Keynes, MK7 7AJ, UK.
School of Veterinary Science, University of Bristol, Langford House, Langford, Bristol, BS40 5DU, UK.
BMC Vet Res. 2018 Apr 19;14(1):136. doi: 10.1186/s12917-018-1450-z.
Livestock vaccines (LV) are often stored on-farm, in a refrigerator (fridge), prior to use and little is documented about the storage conditions during this period. As the quality of a vaccine can be impaired by storage at an incorrect temperature, the present study aimed to evaluate the on-farm performance of farm fridges to maintain the correct storage temperature. From January to August 2014, temperature data loggers were placed on selected farms fridges used to store LV (n = 20) in South-West England.
Temperature recording data was available from 17 of the 20 farms. Fifty-nine percent of farm fridges had at least one temperature recording above 8 °C, 53% had at least one recording below 2 °C and 41% at or below 0 °C. Internal fridge temperatures attained 24 °C and dropped to - 12 °C as an absolute maximum and minimum respectively. Fridges tested spent an average of 16% of the total time recorded above 8 °C. Time of the year significantly influenced the percentage of time above 8 °C. External and internal temperatures were found to be positively correlated (p < 0.001). Statistical significant differences in internal and external temperatures were found between March and August.
The majority of fridges in this study would have failed to keep any stored LV within the recommended storage temperature range. If LV are going to be stored on-farm prior to use, then urgent improvements in this part of the cold-chain are required in order to insure vaccine efficacy is not compromised.
家畜疫苗（LV）在使用前通常存放在农场的冰箱中，而关于这一期间的储存条件记录甚少。由于疫苗质量可能会因在不正确的温度下储存而受损，本研究旨在评估农场冰箱维持正确储存温度的性能。2014年1月至8月，温度数据记录器被放置在英格兰西南部用于储存LV的选定农场冰箱上（n = 20）。
20个农场中有17个提供了温度记录数据。59%的农场冰箱至少有一次温度记录高于8°C，53%至少有一次记录低于2°C，41%处于或低于0°C。冰箱内部温度分别达到绝对最高值24°C和绝对最低值-12°C。测试的冰箱在记录的总时间中有16%的时间温度高于8°C。一年中的时间对高于8°C的时间百分比有显著影响。发现外部和内部温度呈正相关（p < 0.001）。3月和8月之间内部和外部温度存在统计学显著差异。
本研究中的大多数冰箱未能将储存的任何LV保持在推荐的储存温度范围内。如果LV在使用前要存放在农场，那么冷链的这一部分需要紧急改进，以确保疫苗效力不受影响。
