Jennett Amy L, Jennett Nigel M, Hopping Joanna, Yates David
Faculty of Medical and Veterinary Sciences, Bristol University, Bristol, UK
Faculty of Engineering and Computing, Coventry University, Coventry, UK.
J Feline Med Surg. 2016 Oct;18(10):804-8. doi: 10.1177/1098612X15595665. Epub 2015 Aug 20.
The aims of this study were to analyse a large body of data obtained by the Royal Society for the Prevention of Cruelty to Animals (RSPCA) Greater Manchester Animal Hospital on the breeding pattern of owned domestic cats in the UK, and to provide clear statistical evidence of whether seasonal variation remains present in temperate climates.
The total number of cats spayed and the number of cats found to be pregnant were recorded on a monthly basis from December 2005 to July 2014 by the RSPCA Greater Manchester Animal Hospital. The percentage of cats found to be pregnant was calculated for each month and the 8.5 years of data were binned into calendar months. The mean and SD of the monthly pregnancy rate was calculated for each calendar month bin, as was the difference between the mean percentage of detected pregnancies and the global mean. The Z score for each month's difference was then calculated.
Data were available for 5414 cats neutered during the 8.5 consecutive years of this study. A global average of 8.9% of cats spayed were found to be pregnant. The mean calendar month pregnancy rate exhibited a very significant variation, with the highest positive deviation being in April (Z score +2.9) and the highest negative deviation being in November/December (Z score -4.5). When aggregated into 3 month averages, an extremely significant difference between 'spring' and 'winter' months of >7 SE (P <<0.01) was found.
This study provides clear statistical evidence, from a large data set, that seasonal breeding patterns are still present under UK temperate conditions. We discuss the impact that this has on charity rescue shelters and propose that a campaign targeted at clients of animal welfare charities encouraging autumn neutering will be the most cost-effective method of cat population control, and help relieve the demand on welfare charity resources.
本研究旨在分析英国皇家防止虐待动物协会（RSPCA）大曼彻斯特动物医院获取的关于英国家养宠物猫繁殖模式的大量数据，并提供明确的统计证据，以证明温带气候下是否仍存在季节性变化。
RSPCA大曼彻斯特动物医院在2005年12月至2014年7月期间每月记录绝育猫的总数和怀孕猫的数量。计算每个月怀孕猫的百分比，并将8.5年的数据按日历月进行分组。计算每个日历月分组的每月怀孕率的均值和标准差，以及检测到的怀孕百分比均值与总体均值之间的差异。然后计算每个月差异的Z分数。
在本研究连续的8.5年中，有5414只猫接受了绝育手术的数据。发现绝育猫的全球平均怀孕率为8.9%。日历月平均怀孕率呈现出非常显著的变化，最大正偏差出现在4月（Z分数+2.9），最大负偏差出现在11月/12月（Z分数-4.5）。当汇总为3个月平均值时，发现“春季”和“冬季”月份之间存在大于7个标准差的极其显著差异（P<<0.01）。
本研究从大量数据集中提供了明确的统计证据，表明在英国温带条件下仍存在季节性繁殖模式。我们讨论了这对慈善救助庇护所的影响，并提出针对动物福利慈善机构客户开展鼓励秋季绝育的活动将是控制猫数量最具成本效益的方法，并有助于减轻对福利慈善资源的需求。
