Species-appropriate feeding of roe deer

The views of hunters and forest rangers on the feeding of wild roe deer are currently more divergent than ever. Major contributing factors like the calamitous forest situation and climate change have made the necessity of winter feeding a matter of debate. What are the arguments for feeding wild roe deer, and what consequences does it bring? How can proper feeding help to reduce damage from nibbling, and which feeds will help do so? What are the requirements of the sensitive digestive systems of roe deer during times of scarcity? The following article explains the various aspects of feeding deer, based on the findings of prominent wildlife biology experts and scientific studies, followed by a suggested feeding plan for roe deer.
  

Healthy feeds for roe deer

Roe deer don't absolutely need to be given feed. If they are given feed, then it must be at the right time, with locally produced high-quality feed that appropriate to the species and ruminant, and provided continuously" (Deutz, 2020).

There is, then, a high demand for a suitable feed that is appropriate for the species and for ruminants, adapted to the physiology of deer and made of high-quality regional resources. Unlike concentrate feed mixes, it must have a high fibre content. The physiology of the digestive tract of roe deer is optimally adapted to its natural surroundings. Roe deer are game ruminants, meaning that the feed from grazing is chewed, swallowed, and ends up first in the rumen, then in the reticulum, omasum and abomasum. Part of the food will be chewed again (ruminated), depending on particle composition and size. The frequency of the rumination process increases proportionally with the crude fibre content of the feed. The more often a food is ruminated, the more bicarbonate-rich saliva is swallowed and lands in the rumen where, due to its alkaline properties, it is needed for the preservation of the rumen milieu and thus the health of the animal. The saliva serves to buffer the pH value, preventing a significant decrease of the pH value in the rumen. Digestion in ruminants, unlike in monogastric animals, is highly reliant on micro-organisms to break down indigestible carbohydrates, like cellulose, into fatty acids (acetate, propionate, butyrate), which can then be absorbed by the mucosa in the rumen and is an essential source of energy in feed conversion. These properties of the roe deer's digestive tract are vital to a proper diet. At the same time this places great demands on their targeted feeding.
  

Feeding

Feeding is only necessary when food cannot be obtained otherwise. This is only the case during times of scarcity. Times of scarcity (Notzeit) is neither a legally defined term nor a weather-dependent period of time, but rather applies to adverse conditions which make it impossible for wild game to find sufficient food in the wild (Müller-Schallenberg, 2007). The German Federal Hunting Act (Bundesjagdgesetz, or BJagdG) also provides for the protection of game from food shortages (§23 (5) BJagdG); this law is modified by respective hunting laws of the federal states. For Bavaria, this means that the owner of the hunting ground is obliged to provide adequate feed to game in times of scarcity. Feeding game with feed which does not meet the nutritional requirements of the respective game species, as well as feeding outside times of scarcity, is considered a form of animal cruelty (§ 23a (2)(2) AVBayJG). There is therefore no defined time when one may begin to provide feed. A further complicating factor is the distribution of roe deer in diffuse climate zones; they are present both in regions that are mild in the winter and in alpine regions with significantly longer winter periods. There are thus different approaches to determining the time of feeding in line with environmental conditions.
  

Common mistakes: problems with high-energy concentrate feeds

If the feed consists primarily of concentrate feed, the main components of which are cereal products, these short-chain, high-starch carbohydrates are quickly fermented in the rumen to produce a high proportion of fatty acids. This, in combination with less rumination required to break down low-structure concentrate feed, means a significant drop in the rumen's pH value. The alkaline micro-organisms die off, upsetting the sensitive balance in the rumen and leading to what is called rumen acidosis, a hyperacidity in the rumen by which its mucosa is severely damaged. This condition in turn leads to gastrointestinal inflammations and severe diarrhoea, often with fatal consequences due to an immune system already weakened by winter conditions. A study by the University of Veterinary Medicine Vienna, Austria in 2019 (Ricci et al., 2019) examined the microbiotica in the rumen of fed roe deer and its findings confirmed those of previous studies (Deutz et al., 2009): "Easily fermentable supplementary feed promotes the proliferation of the sort of bacterial strains that also lead to acidosis in domestic ruminants – a disorder of the natural acid-base balance." (Ricci et al., 2019). There is thus no doubt of the importance of providing the proper type of feed.
  

The right alternative

What does a species-appropriate feed for roe deer look like? In order to be able to provide safe, high-quality feed, short transport routes and correct storage are absolutely essential. The raw materials in the feed should be ideally from the region and their origins traceable. Otherwise there is a risk of contamination from mycotoxins (mould).  In addition, the supplementary feed must have a high crude fibre content so that rumination is increased and more saliva can be produced.

The feed should have a crude fibre content of at least 14–16% (Bergler et al, 2014). This rules out many feeds found on the market. It should also contain crude fibres with a particle length of at least 1 cm and a maximum protein content of 15% (Deutz, 2014). The aim should never be to deliver an oversupply of nutrients, but rather to provide a feed that covers requirements and is adapted to seasonal food sources.

All these items are met with AGROBS Wildstruktur species-appropriate feed for roe deer, harvested and produced in the Bavarian foothills. 
  
Antonia Triebig, Bsc. Agricultural Science
December 2020, © AGROBS GmbH

  • Dr. Armin DEUTZ, „Rehe: In der Notzeit richtig füttern“, https://www.jagderleben.de/praxis/rehe-notzeit-richtig-fuettern (abgerufen am 03.09.2020)
  • Sara RICCI, Robin SANDFORT, Beate PINIOR, Evelyne MANN, Stefanie U. WETZELS, Gabrielle STALDER, "Impact of supplemental winter feeding on ruminal microbiota of roe deer Capreolus capreolus," Wildlife Biology, 2019(1), 1-11, (18 September 2019)
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  • Dr. Armin DEUTZ, (2014), „Wildfütterung – warum, wann, wie?“, https://www.ooeljv.at/wp-content/uploadsv/2014/05/Wildf%C3%BCtterung-handout-O%C3%96-2014.pdf