Studies on culling rate in gilts by using heat synchronisation.Original Title Untersuchungen zur Ausfallquote von Jungsauen bei Anwendung der Brunstsynchronisation.

摘要

Analysis of the reasons for culling of purchased gilts and 2. check-up studies on the percentage of animals fit for breeding following heat synchronization and artificial insemination over a period of 10 years (1999-2008). Basis: records of veterinary herd management service. Material and methods: The investigation was carried out in a commercial 1200 sow place piglet producing unit that bought in all herd replacements. The herd used a controlled batch farrowing weaner production procedure with a rhythm of 7 days. Following an incorporation period of at last 6 weeks the pubertal gilts were individually set up for biotechnical heat synchronization (HS), and were fed 20 mg of the active substance Altrenogest (5 ml RegumateReg.) on 18 consecutive days. The Altrenogest dose was given in each case in the morning. Every animal received an oestrus inducing injection of 1000IE eCG (5 ml PregmagonReg.) 48 hours after the final Altrenogest dose. Insemination was carried out based on standing heat using semen from boars of the Pietrain breed. Results: Part1: A representative sample of 551 animals came under investigation for the reasons of the culling rates. Of these 58 animals (10.5%) were culled before the first litters: 17.2% before insemination, 29.3% before examination for pregnancy (4th week post insemination), and 53.5% before farrowing. The main reasons for culling were classified into six categories. Most of the animals were removed for extra genital reasons (20.7%), 20.7% for fertility problems, and 12.2% for no oestrus. Part2: On average, 531 gilts per year were provided for piglet production. In the period from 1999 to 2001 the culling rate amounted to 12.9%. In the following years the culling rate steadily declined down to 2.7% (2008). At the same time the gravidity rate was enhanced from 87.1% to 97.8%, and the number of animals removed for health and fertility reasons decreased considerably. Conclusions and clinical relevance: The heat synchronization of gilts by means of tested reproduction biological is an efficient reproduction method in farms with a group-wise farrowing system. The culling rate of purchased gilts could be reduced to less than 3%.