Economic Consequences of a Mowing Death

Who Suffers Economic Consequences When a Wild Animal is Killed by a Mower?

First and foremost, farmers suffer economic losses when animals are killed by mowers. In addition to the legal consequences, which can mean fines of several thousand euros for farmers, contaminated feed caused by carcasses can result in far more serious financial losses.

Animal health plays a major role in a farm’s economic performance. A healthy livestock population is a prerequisite for successful production and is reflected in low veterinary costs and high animal performance in the annual balance sheet. Pathogens can seriously endanger the health of individual animals and, beyond that, the health of an entire livestock population. Even years after infection, sequelae and relapses are possible. This applies in particular to highly toxic bacteria that can form under various environmental influences. Clostridium botulinum is particularly hotly debated, researched and considered relevant. It can develop in silage containing parts of wild animal carcasses.

What is Botulism?

C. botulinum is a group of different soil-borne bacteria that are capable of producing neurotoxins, i.e. nerve toxins. These toxins are among the most powerful in nature. The pathogens measure 0.5–2.0 x 1.6–22 μm and can therefore only be seen under a microscope. When magnified, they are characterised by a straight to slightly curved rod shape. There are six different types of C. botulinum toxin (types A–F). Types B, C and D are particularly dangerous for cattle. These strains are known, among other things, for their ability to break down cooked meat, chicken protein, coagulated serum and milk protein. Temperatures of 20–40 °C are particularly conducive to the proliferation of toxin formation by the pathogens, depending on the type. The pathogen can be found almost everywhere, in soil, water and the gastrointestinal tract of mammals, including humans. It is spread through water, dust and plant material. (Agricultural and Veterinary Academy 2010, cf. Rhineland-Palatinate State Investigation Office 2015)

How Does Botulism Occur in Livestock?

A basic distinction must be made between visceral and classic forms of botulism. The classic form of infection with C. botulinum, a bacterium, is a form of poisoning, i.e. toxins produced by C. botulinum in the environment are ingested by the body through the consumption of substances (food, water, etc.). The toxins form in animal carcasses, in protein-rich organic material and in protein-rich decaying plants with a high pH value. (Rhineland-Palatinate State Investigation Office 2015) The Aulendorf Cattle Health Service in Baden-Württemberg describes a case of botulism. On 18 June 2010, two young animals died in the Ravensburg district for reasons that were initially unknown. An investigation revealed that a badger carcass in the basic feed was responsible for the formation of toxins by C. botulinum type C. A total of ten total losses were detected. The Rhineland-Palatinate State Investigation Office also cites mowed animal carcasses in the form of rodents and fawns in silage preparation in the basic feed as the main cause. In visceral botulism (also known as chronic botulism), toxin formation occurs within the gastrointestinal tract. Experts consider this form to be relatively rare. (Albrecht 2010, Rhineland-Palatinate State Investigation Office 2015).

How can Botulism be Recognised in Livestock?

The toxins penetrate the motor end plates of the nerves and prevent the release of acetylcholine, which is necessary for muscle contraction. This leads to flaccid paralysis. In dairy cattle, high-performance animals in particular are considered to be at risk of botulism. The disease manifests itself in movement disorders of the hind limbs, loss of appetite and leads to emaciation. Other signs include salivation, increased heart rate, loss of the calf, metabolic disorders, tendency to oedema, udder diseases and laminitis. A steady sharp increase in the cell count in milk is an early sign of botulism. In addition to cattle, chickens, waterfowl and horses are also affected. (Rhineland-Palatinate State Investigation Office 2015, Albrecht 2010)

What Costs can Botulism Cause?

Based on the causes and effects of C. botulinum contamination described above, it can be concluded that feed hygiene plays a key role in animal husbandry. It can be assumed that even a single carcass in the basic feed, such as that of a fawn, can trigger the formation of highly toxic substances and contaminate several cubic metres of silage. Based on incidents in recent decades, such as those in Baden-Württemberg, it can be deduced from the literature that total loss is to be expected in very few cases (cf. Albrecht, 2010, p. 8). In principle, however, a latent increase in C. botulinum can be assumed, which is difficult to detect. This is also the conclusion reached by veterinarians in the Göttingen Declaration. “These diseases caused by metabolic products (toxins) of certain clostridia […] are demonstrably […] increasing in significance in Germany. Initial reports also confirm contamination with these pathogens in pigs. This process of permanent contamination of the herd with pathogenic Clostridia (via […] green fodder, such as silage) usually takes 2–3 years. The farmer observes very unspecific clinical symptoms. The first thing noticed is a decline in the performance of individual animals or the herd. The incidence of disease fluctuates within the herd. More and more clostridia enter the animals’ bodies, where they can multiply and produce botulinum toxin to a greater or lesser extent. Of course, the concentration of pathogens in the animals’ environment also increases more and more. Once certain thresholds are reached, the clinical picture of chronic botulism with paresis (paralysis) etc. becomes apparent.” (Agricultural and Veterinary Academy, 2010, p. 142 f)

Once present in the livestock population, the percentage of infected animals increases. The pathogens spread through water, air and animal faeces, thereby multiplying continuously. The total loss of an animal, e.g. a heifer or a cow, can quickly result in several thousand pounds in damages. Although not immediately apparent, declining milk yield and poorer milk quality can be a major factor in the long term. The loss of several cubic metres of silage or silage bales generates additional costs of several hundred euros. Veterinary costs of several hundred euros can also be caused by botulism.