The statistics on the stock of pigs shows the total number of pigs in Denmark. It aims, among other tings, to form a basis for forecasting future slaughters and future stock of sows. The statistics are also used for different economic and environmental estimations and analyses. The stocks of pigs have been compiled since 1915 but with slightly different methods used over time. The last change was in 01 April 2018. The difference in the number of pigs for new and the old method of analysis is below 1 per cent. The statistics are considered to be comparable from 1998 onwards.
The pig survey are a sample survey published every quarter as the numbers of pigs in thousand. The stock of pigs is further divided into 10 sub-groups, including sows for production, piglets, weaned pigs and pigs for slaughtering. The data series with the total stock of pigs (pigs, total) are published both with and without seasonal adjustment. The statistics are published in the newsletter Nyt fra Danmarks Statistik (in Danish only) and in the Statbank.
Data for the pig survey is collected by means of web questionnaires or by means of the system to system solution ArgoSofts Winsvin. A sample of about 2.000 holdings with pigs according to the The Central Husbandry Register (CHR) is selected. The survey is a sample survey divided into groups (strata) by the size of pigs and types of pigs on the single holding. Farms with many pigs are selected every time. The answers are validated for unrealistic values and next the sample is extrapolated to the total population of all farms with pigs.
The pigs survey is of great interest to EU, the Ministry of Environment and Food, The Danish Association of Slaughterhouses and others farmer´s organizations, but also students and interested people in general. The most important purposes of pig surveys are to provide a basis base for forecasts of pigs for slaughter. The statistics are used in financially and environment studies.
The greatest factor of inaccuracy is updating and matching of the different registers. The relative standard deviation - sampling errors - for pigs is 0.5 per cent to 1.5 per cent. A maximum of 2 per cent has to be observed to meet EU's requirements. As part of a quality assessment statistical errors are calculated for all variables.
The figures are usually published without delay in relation to the scheduled data, however with some exceptions in 2012 and 2013.
The pig surveys have been conducted in their present form since April 1974, but the number of pigs have been conducted at varying points in time and frequency since 1915.
These statistics are published semiannually in a Danish press release and quarterly in the Statbank table SVIN. For further information, see the subject page for Livestock. Data with long timeseries can be find on Livestock (historic) by type of livestock.