Better animal welfare in the pigsty

In a joint research project, the Institute of Animal Breeding and Husbandry is investigating immunocastration – an animal-friendly alternative to surgical castration of piglets. The goals here are to reduce reservations and develop recommendations for agriculture.

Medical staff gives a piglet an injection
© iStock/dusanpetkovic

Injection instead of castration: To avoid severe boar odor in pork, male animals are castrated. Immunocastration by injection is a much gentler alternative to surgery.

Whether as a steak, roast or cold cuts: the Germans love their pork. According to the Federal Office for Agriculture and Food, in 2020 around 33 kilos of pork were consumed per person during the year, far more than poultry (around 13 kilos) and beef (around 10 kilos). To ensure that the meat of sows and boars tastes equally good, all male animals are castrated shortly after birth – which took place without anaesthetics for a long time. Since January 2021, legislation only allows piglet castration under anaesthetic.

The castration is intended to prevent the pungent smell of boars (known as boar taint), which is formed in the testicles. If meat from uncastrated animals is heated, there is a possibility that it will smell unpleasant. "However, the proportion of animals with a conspicuous odour is relatively low, at around five to eight percent. And in fact, only some people can perceive the smell at all," explained Dr Joachim Krieter, professor at the Faculty of Agricultural and Nutritional Sciences at Kiel University.

However, the boar taint can also be avoided in a different way than through surgery. The animal-friendly alternative is immunocastration. Since 2020, the Kiel team led by Krieter, together with working groups at the University of Göttingen and the Max Rubner-Institut (MRI) in Kulmbach, as well as agricultural businesses, agricultural organisations and slaughterhouses, have been working on this castration by means of vaccination. A very important aspect of the work: "The animals are not given a hormone, but instead a GnRH analogue (bound to a carrier protein)," explained the expert. This is a substance by which "the production of steroids in the testicles is prevented, and thus also the production of boar taint, as well as the dominant behaviour of the often very lively male animals, which can lead to battles for dominance, fights and biting attacks," said Krieter. "For the animals, the method is more humane, and for agriculture it’s more cost-effective compared to surgery, depending on the animal feed costs and the payment arrangements of the slaughterhouses."

"The process has already been used worldwide for 20 years," said the animal husbandry and product quality specialist. The effectiveness of vaccination has been scientifically investigated and proven. There are no residues in the meat due to vaccination. Only in German pigsties has there been scepticism so far. "There is little practical experience with immunocastration – in all areas of the value chain, from agriculture to slaughterhouses, to retail, right through to the consumer."

The quality of the meat is being checked

One of the industry's concerns is that the quality of the meat could suffer due to immunocastration. For example, slaughterhouses fear that the fat of the vaccinated animals – like that of the uncastrated boars – will be too soft for good processing, and that the vaccination will not work for every animal. In order to accurately identify animals in which the vaccination didn’t work, slaughterhouses would have to carry out odour checks – and bear the related costs. That in turn would affect the prices that farmers get for the animals.

In order to eliminate the prejudices and to provide a scientifically sound basis for quality-based payment for agricultural businesses, the meat of immunocastrated animals is being examined for composition, fat content, fat consistency and taste for a period of two years. Around 120 farms in Schleswig-Holstein, Lower Saxony and North Rhine-Westphalia with around 100,000 animals are involved in the large-scale field study on immunocastration, which is being carried out at the initiative of agricultural businesses. The project is funded by the Federal Ministry of Food and Agriculture.

Genetics and animal feed play a major role

"Our goal is to obtain reliable data on the various meat and fat properties that can be obtained with different breeds and different types of animal feed, for immunocastrated animals," said Krieter. Among other things, it is being investigated why the fat content in some animals is significantly higher than the norm. Such peak values are not welcome in pig production. Initial scientific results show that vaccination is not responsible for these variations, but instead genetics – i.e. the breed of pig – and the composition of the animal feed. Further findings are currently being collected and evaluated, with the aim of "deriving recommendations for optimising pig fattening". In autumn 2022, the results will be presented to the public in a workshop.

Author: Jennifer Ruske