There is a debate whether supplemental feeding of deer bears the risk of inducing health problems, in particular acidosis Here, the pH values of forestomach contents of free-ranging roe deer (Capreolus capreolus) shot in areas with and without supplemental winter feeding were compared pH was similar in the dorsal and ventral rumen, but lower at these sites than in the Atrium ruminis, where it was again lower than in the reticulum; this pattern corresponds to expectations based on differences in the presence of saliva at the different sites of the forestomach pH was lower with increasing time that elapsed between death of the animal and measuring pH in unsupplemented animals and was lower in unsupplemented animals in May/June than later in the year Animals with supplemental winter feeding had significantly lower rumen pH (55) than animals without food supplementation (57) These data suggest that supplemental feeding of roe deer has the potential to lower forestomach pH Although pH values measured in supplemented animals in this study would be considered indicative of rumen acidosis in domestic cattle, they are within the range previously measured in various free-ranging Odocoilid species, including roe deer; were of a similar magnitude as the May/June values of unsupplemented roe deer in this study; and must be considered with respect to potentially rapid declines in pH between death of the animal and pH measurement Given methodological problems, analyses of literature data from free-ranging wild ruminants provide little evidence for a systematic variation of rumen pH with feeding type and body mass, but lead to the hypothesis that some New World cervids, including the roe deer, might either naturally have lower pH values than other ruminants or rumen contents whose pH drops rapidly after death

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Forestomach pH in hunted roe deer (Capreolus capreolus) in relation to forestomach region, time of measurement and supplemental feeding and comparison among wild ruminant species

Context In terms of their nutritional physiology, roe deer have been called ‘concentrate selectors’. This implies that they select proteins in their diet and are not able to digest fibre. It is, thus, suggested that in an agricultural landscape, they are unable to digest the high fibre content of arable crops and, thus, suffer and need to be given supplementary feed. Aims Our aim was to determine the nutrient composition and energy content of the roe deer diet in an agricultural habitat compared with that in a natural forest habitat. Methods Rumen contents of 245 roe deer were collected to represent each month of the year for 3 years, weighed, and analysed by standard methods for nutrient and fibre content. Key results Roe deer in the agricultural habitat had rumen contents with significantly higher metabolisable energy (ME) concentrations, with a median of 6.2 MJ ME/kg DM, than did roe deer in the forest habitat, where the median was 5.4 MJ ME/kg DM. The mass of rumen contents in the forest habitat was, on average, 240 g higher than that in the agricultural habitat. Roe deer in the forest habitat compensate for the lower energy concentration in their natural diet by increasing their food intake. The concentration in the agricultural habitat is a result of the higher proportion of easily digestible carbohydrates in the diet. The concentration of crude protein in the rumen contents did not differ statistically between the two areas. In both habitats, the mean crude fibre concentration varied between 24% DM and 34% DM, and was significantly higher in the forest. The concentration of crude fibre selected by the roe deer is similar to the concentration of crude fibre known to be selected by red deer and fallow deer (intermediate feeders) and mouflon (a grazer) (Hofmann 1989). Conclusions The term ‘concentrate selector’ should be replaced by ‘selector’ to avoid misinterpretations. Energy shortfalls were not observed in either of the populations during the study period. Implications Supplemental feeding was not necessary to maintain the population.

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Response of roe deer (Capreolus capreolus) to seasonal and local changes in dietary energy content and quality

Context. The European roe deer owes its ability to digest fibre to its microbiome. This is made up of many different species at different levels of abundance and with different differentiations. In Europe, the roe deer is often classified as a so-called ‘concentrate selector’. This term has often been interpreted by different researchers to mean a selector of either protein- or energy-rich food. According to various studies, this selection behaviour is due to the low abundance of fibre-degrading microorganisms. Aims. The aim of the present study was to determine the concentration of crude nutrients in the rumen of roe deer, with the focus on the fibre fractions, and to show changes among seasons and between habitats. Furthermore, the aim was to find out how far the composition of the ruminal microbiota adapts to these changes. Methods. From 2011 to 2014, we collected the rumens of 245 roe deer in two Bavarian habitat types, a forest and an agricultural habitat. The crude nutrient contents and the size of the total microbiome and the proportions of individual genera were determined in the rumen content. Key results. The average annual concentration of crude fibre in the ingested food is 26–30% and this rises to 38% in certain months. The forest roe deer had the highest proportions of crude fibre in their food and the concentrations of other nutrients were also highly dependent on the season and habitat. Furthermore, the animals also have far less protein in their rumen content than often assumed. The total number of microorganisms in the rumens of the forest deer is significantly higher than in animals living in the agricultural area. The number of microorganisms was highest in the forest roe deer in winter, and in the roe deer from the agricultural area in summer. Clear connections can also be seen between individual groups of microorganisms and particular crude nutrients. The high crude-fibre concentration leads to a high number of fibre-degrading microorganisms, such as, for example, anaerobic fungi or the Ruminococcus flavefaciens. Conclusions. The results showed a high adaptability of the animals to a fibre-rich diet. The microbiome adapts very well to the respective nutrient availabilities. This, in turn, is what allows the roe deer to adapt so readily to diverse habitats and environmental conditions. Implications. Due to the generally high concentrations of fibre, combined with the high numbers of fibre-degraders in the rumen, we suggest that, from now on, we should talk of a roe deer as being a ‘selector’ or ‘browser’ rather than a ‘concentrate selector’.

High fibre selection by roe deer (Capreolus capreolus): evidence of ruminal microbiome adaption to seasonal and geographical differences in nutrient composition

In this study, it was aimed to investigate the effects of formic acid on the in vitro methane production and in vitro ruminal fermentation of alfalfa hay. Effect of 0.0 (control group: YF0), 0.1, 0.2, 0.3, 0.4 and 0.5 ml/L (experimental groups: YF1, YF2, YF3, YF4, and YF5 respectively) formic acid (Amasil85-liquid) addition to rumen fluid on ruminal fermentation parameters of alfalfa hay were determined by using in vitro gas production techniques. Methane production of in vitro incubation increased (to about 20%) with addition of linearly increased formic acid. Linearly increased levels of formic acid addition to rumen fluid has significantly changed the production of in vitro total gas production, metabolic energy (ME) and organic matter digestibility (OMD) at linear, quadratic and cubic. The addition of 0.1 ml/L and 0.2 ml/L formic acid to rumen fluid significantly decreased in vitro total gas production, ME and OMD however addition of 0.3 ml/L and 0.4 ml/L formic acid was not changed in vitro gas production, ME and OMD levels and 0.5 ml/L formic acid was significantly increased all these parameters. Ruminal pH was not changed by addition of formic acid. Formic acid is a safe feed additive because of its properties antibacterial and flavorings and also is used as a fermentation promoter in silage. In this study it has been observed that all doses of formic acid increased in vitro enteric methane production and low doses decreased in vitro total gas production, ME and OMD and high doses have increased all these parameters. High doses have a positive effect on ME and OMD; however formic acid should be used at limited levels in diets due to the negative effect of increasing greenhouse gases. The effect of formic acid addition to the feed raw matter and rations of all livestock would be beneficial to investigate in terms of digestive system parameters and global warming, further in vitro and in vivo studies.

http://agrifoodscience.org/index.php/TURJAF/article/download/491/216

Effect of Formic Acid on In Vitro Ruminal Fermentation and Methane Emission

The objective of this review is to highlight the nutritive value of rumen contents and their potential to use in animal feeds. In most developing countries feeding is the major factor limiting the production of livestock; because it constituents up to seventy percent of the total cost of production. In the last years, researchers look for non-conventional feed ingredients to reduce the feed cost and hence cost of production. One of such non-conventional ingredients is the rumen content, which is readily available in abattoirs and slaughter houses, it’s a good source of energy, protein (feed and microbial protein), minerals and vitamins specially vitamin B complex. The nutritive value of rumen contents varies mainly because the rumen content from different types of ruminants varies dramatically in their composition. The nutritive value of rumen content can be improved by using several methods: adding blood meal, molasses, poultry droppings, urea, enzymes and fermented feed such as silage. Rumen content can be added to diets by different levels according to the types of animals. It can be used as a cheap source of energy and protein with reduced feed cost and environmental pollution. Therefore, some studies concluded that rumen contents could be incorporated in the diets of animals without negative effects on diet acceptability and without any adverse effects on performance.

Rumen Content as Animal Feed: A Review

In the experiment the chemical composition of rumen contents in roe deer (Capreolus capreolus) was investigated in the "Sarajevska Reka" hunting area. The investigations were done on 20 deer shot from May 2005 to January 2006. Experiment was done as random plan, with four treatments (seasons) and uneven distribution of subjects within treatments. The results of chemical analysis confirmed significant influence of season on the amount of total nitrogen and crude protein, ether extract, crude fibre, ash and ammonia nitrogen (P<0.05). Variations in pH values, NFE, calcium and phosphorus in dry matter and total ash of the rumen contents were lower and there was no significant influence of season on those parameters. The obtained results for total protein, calcium and phosphorus in the rumen contents in roe deer shot during the winter show significantly higher presence of those components than the usual recommendations for concentrate mixtures produced for the species. Although those results are not a real indication of the diet's chemical composition, they may be used as potential indicator of the quality of the diet and can be useful when formulating the additional feeding routine for winter months.

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Chemical composition of the rumen contents in roe deer (Capreolus capreolus) as potential quality indicator of their feeding

The influence of formic acid added in three doses (3,5 and 7 g/kg fresh mass) in the intensity of proteolysis and fermentation in Lucerne silages was investigated. On the basis of chemical analyses, it is observed that with the increase of conserving dose the lower pH value, limited proteolysis and increased preservation of proteins was achieved. The amino acid content varied very much due to their degradation and biosynthesis. In treated silages a statistically significant increase of lactic acid was observed while silages with maximum dose of conserving had significantly less free and total acetic acid. Presence of bonded butyric acid only in the control silage had no statistical significance. According to Dulphy and Demarquilly (1981) method, control silage with minimum dose of conserving was estimated as III class and silages with medium and high dose of formic acid were estimated as II quality class.

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Zoran Popovic

Papers

Chemical composition of the rumen contents in roe deer (Capreolus capreolus) as potential quality indicator of their feeding

Effects of the use of formic acid in different doses as the conserving in Lucerne ensiling