A comparison of the effect of forage type and level of feeding on the digestibility and gastrointestinal mean retention time of dry forages given to cattle, sheep, ponies and donkeys

An inventory of grassland use on horse farms

Horses can contribute to the maintenance of grassland. To determine the potential contribution of grassland to horse nutrition, we investigated the seasonal variation of herbage on offer and its nutritional quality in an inventory on six practical horse farms in Central Germany during 2019. On all horse-grazed pastures compressed sward height (CSH) was measured monthly and converted into aboveground herbage (AGH) to allocated short and tall grass sward areas (area-specific) via calibration cuts. In addition, four focus pastures were selected for monthly obtained area-specific herbage quality samples. The farm-specific management was monitored using questionnaires and grazing diaries to determine underlying factors influencing herbage biomass and quality. The proportion of short grass sward areas increased during the grazing season (p=0.0010), which was related to high stocking intensity in terms of livestock unit grazing days (LUGD, p <.0001). On most farms, LUGD were constant throughout the growing season and not adjusted to changing grass growth. Herbage crude protein (CP, p=0.0038), metabolizable energy (ME, p <.0001) concentrations and acid detergent fibre in the organic matter (ADF, p <.0001) differed among the grass sward areas. The results suggest that sufficient ME (4.2 ± 0.32 - 8.4 ± 0.15 MJ ME kg-1 DM) for maintenance and pre-caecal digestible CP (pcdCP) (37.0 ± 3.86 - 77.4 ± 4.44 g kg-1 DM) could be provided during the grazing season. The study highlights the need to incentivise grassland management for herbage provision among horse owners to exploit the potential of grassland during the grazing season.

Fluorescence imaging around the abdomen allows evaluation of gastrointestinal retention of various forms of diet in mice

OBJECTIVES

The aims of this study were to evaluate gastrointestinal (GI) retention of an ingested meal by fluorescence imaging and compare how retention is affected by differences in the physical characteristics of meals.

METHODS

Mice were given an oral fluorescent indocyanine green (ICG) probe enclosed in a liposome. We evaluated the correlation between abdominal and GI fluorescence signals. ICG was administered to mice treated with atropine, and abdominal fluorescence was observed repeatedly. Mice were continuously given a regular chow or a liquid diet containing a low or high methoxyl (LM or HM)-pectin through a catheter placed in the stomach for 2 d, after which the mice were given ICG. In all studies, the mice's abdominal and GI fluorescence signals were observed with in vivo imaging equipment.

RESULTS

The fluorescence intensities (FIs) of the abdomen and the excised GI tract correlated strongly. Attenuation of the abdominal FI was delayed in the atropine-treatment group compared with the non-treated group. The attenuation of abdominal FI 8 to 24 h after ICG administration was significantly weakened in the HM group compared with the regular chow and LM groups.

CONCLUSIONS

Observing FI attenuation around the abdomen allows for the evaluation of GI tract retention of an ingested meal. Compared with a solid meal, a liquid meal stays longer in the digestive tract, whereas a liquid meal in which the viscosity increases in the stomach is retained like a solid meal.

Equid nutritional physiology and behavior: an evolutionary perspective

Like other members of the even-toed ungulates (the perissodactyls), equids once had a higher species diversity in the fossil record than they have today. This is generally explained in comparison to the enormous diversity of bovid ruminants. Theories on putative competitive disadvantages of equids include the use of a single toe as opposed to two toes per leg, the lack of a specific brain cooling (and hence water-saving) mechanism, longer gestation periods that delay reproductive output, and in particular digestive physiology. To date, there is no empirical support for the theory that equids fare better on low-quality forage than ruminants. In contrast to the traditional juxtaposition of hindgut and foregut fermenters, we suggest that it is more insightful to sketch the evolution of equid and ruminant digestive physiology as a case of convergence: both evolved a particularly high chewing efficacy in their respective groups, which facilitates comparatively high feed and hence energy intakes. But because the ruminant system, less based on tooth anatomy but more on a forestomach sorting mechanism, is more effective, equids depend more on high feed intakes than ruminants and may well be more susceptible to feed shortages. Arguably, the most under-emphasized characteristic of equids may be that in contrast to many other herbivores including ruminants and coprophageous hindgut fermenters, equids do not use the microbial biomass growing in their gastrointestinal tract. Equids display behavioral and morphophysiological adaptations to high feed intakes, and their cranial anatomy that facilitates the cropping of forage while performing grinding chewing at the same time might be unique. Rather than looking for explanations how equids are better adapted to their present niches than other organisms, considering them remnants of a different morphophysiological solution may be more appropriate.

Is there a difference in ruminal fermentation control between cattle and sheep? A meta-analytical test of a hypothesis on differential particle and fluid retention

Ruminant species differ in digestive physiology. The species-specific ratio of mean retention time of particles and fluid (MRT_particle/MRT_fluid) in the reticulorumen has been interpreted as controlling ruminal fermentation: a higher ratio indicates of a more distinct 'washing' of particulate digesta by liquid. This should increase the harvest of microbes from the reticulorumen, and keep the microbiome in a state of more intense growth; at the same time, this should increase the metabolic losses of faecal nitrogen of microbial origin, leading to lower values for the apparent digestibility of crude protein (aD CP). A systematic difference has been hypothesized between cattle (higher ratio) and sheep (lower ratio), with a lower MRT_fluid in cattle due to a higher saliva production. Here, we test these hypotheses in a meta-analysis, using only studies that investigated cattle and sheep simultaneously. The datasets included 12 studies on MRT (of which 11 contained information on feed intake), yielding 102 (or 89) individual data; and 26 studies on protein digestibility (of which 18 contained information on intake), yielding 349 individual data. Cattle had a higher MRT_particle/MRT_fluid (2.1) than sheep (1.7), mainly due to longer MRT_particle; only if body mass was included in the model, MRT_fluid was significantly shorter in cattle in the larger MRT dataset (and tended to be shorter in the slightly smaller dataset). Cattle had a significantly lower aD CP than sheep, while there was no such difference in overall (dry or organic matter) digestibility. The dataset confirms a shift in fermentation strategy towards microbial production in cattle. While this has been suggested for ruminants in general, cattle appear particularly far on an evolutionary trajectory of maximizing microbial yield from the forestomach. The application of more specific digestive physiology data (like endogenous losses) gained from sheep to cattle should be done bearing these differences in mind.

Transcutaneous Detection of Intramural Microchips for Tracking the Migration of the Equine Large Colon: A Pilot Study

Colic remains the number one cause of mortality in horses, and large colon displacement including colonic volvulus is one of the leading causes for equine hospitalization and surgery. Currently, there is not an adequate model to study the pathophysiology of this condition. The objective of this proof-of-concept study was to determine if subserosal implantation of bioinert microchips in the large intestine would be detectable by a RFID (radio-frequency identification) receiver when the implanted microchips were adjacent to the body wall, thus identifying the location of the colon within the abdomen. A horse with no history of gastrointestinal disease underwent a ventral midline celiotomy to implant twelve bioinert microchips into the subserosa at predetermined locations within the large colon and cecum. A RFID scanner was used to monitor the location of the colon via transcutaneous identification 1-3 times daily for a one-month period. Following humane euthanasia, a postmortem examination of the horse was performed to assess microchip implantation sites for migration and histologic assessment. Eleven out of the 12 implanted microchips were successfully identified transcutaneously at occurrences as high as 100%. Odds ratios were calculated for the likelihood of identifying each chip in a location different from its most common location. Microchips implanted into the subserosa of the equine large colon can be used as a means of identifying the approximate location of the equine large colon via transcutaneous identification with an RFID scanner.

No size-dependent net particle retention in the hindgut of horses

Sieve analyses of hindgut contents of horses as well as observations in horses where plastic markers had been applied to a caecal cannula suggested that there may be a discrimination by particle size in the passage or retention of digesta. Here, we performed a similar experiment with five caecum-cannulated horses (562 ± 31 kg) fed a constant amount (6.81 kg dry matter/day) of grass hay. Passage markers representing the liquid (Co-EDTA) as well as the particulate digesta phase (Yb-undefined; Cr mordanted fibre 1-2 mm; Ce-mordanted fibre 8 mm) were given as a pulse-dose into the cannula to measure their mean retention times (MRT). The MRTs were compared by repeated-measurements analysis of variance. The MRT in the hindgut was 22.2 ± 2.4 h for Co, 25.0 ± 3.4 h for Yb, 26.2 ± 1.6 h for Cr and 26.3 ± 1.5 h for Ce. Whereas differences between the particle marker MRTs were not significant (p_adj. > 0.05), significant differences were observed between the solute marker Co and each of the particle markers Cr and Ce (p_adj. < 0.009). The results confirm the well-known significant, albeit small, difference in MRT in horses between the fluid and the particle digesta phase, and corroborate another recent study that used a combination of whole, marked hay and individual marker analysis in different particle size fractions of the faeces, which also did not detect a selective retention of any particle size class.

Chemical, mineral composition, in vitro ruminal fermentation and buffering capacity of some rangeland-medicinal plants

A diverse group of rangeland-medicinal plants are being used by ruminant whilst some of them have not been assessed for their nutritional value. This study was aimed to evaluate the chemical and mineral composition, buffering capacity, and in vitro fermentation of some rangeland-medicinal plants including Thymus kotschyanus, Ziziphora persica, Lallemantia royleana, and Scutellaria litwinowii in the family Lamiaceae, and Hypericum scabrum, in the family Hypericaceae. The results indicated that crude protein (CP) content ranged from 8.66% (S. litwinowii) to 12.17% of DM (H. scabrum). It was found that Z. persica had the highest potential gas production, metabolism energy (ME), relative feed value (RFV), and dry matter digestibility (DMD) values of 53.44 (mL 200-1 mg DM), 5.84 (MJ kg-1 DM), 170.66 and 70.88%, respectively. Mineral content differed among plants; Ca ranged from 5.79 to 41.96 g kg-1 DM. The concentrations of Ca, K, Mg, Fe, Zn, and Co were highest for L. royleana. Total volatile fatty acids (TVFA) and propionate concentrations were highest in the culture medium cultured with Z. persica, however, acetate, and butyrate were highest in H. scabrum. Acid-base buffering capacity was lower in T. kotschyanus and H. scabrum compared to other plants, while it was higher in S. litwinowii. Overall, it can be concluded that among plants evaluated in this study, Z. persica had higher nutritional value for sheep feeding.

Effect of incremental proportions of Desmanthus spp. in isonitrogenous forage diets on growth performance, rumen fermentation and plasma metabolites of pen-fed growing Brahman, Charbray and Droughtmaster crossbred beef steers

Desmanthus (Desmanthus spp.), a tropically adapted pasture legume, is highly productive and has the potential to reduce methane emissions in beef cattle. However, liveweight gain response to desmanthus supplementation has been inconclusive in ruminants. This study aimed to evaluate weight gain, rumen fermentation and plasma metabolites of Australian tropical beef cattle in response to supplementation with incremental levels of desmanthus forage legume in isonitrogenous diets. Forty-eight Brahman, Charbray and Droughtmaster crossbred beef steers were pen-housed and fed a basal diet of Rhodes grass (Chloris gayana) hay supplemented with 0, 15, 30 or 45% freshly chopped desmanthus forage on dry matter basis, for 140 days. Varying levels of lucerne (Medicago sativa) hay were added in the 0, 15 and 30% diets to ensure that all diets were isonitrogenous with the 45% desmanthus diet. Data were analyzed using the Mixed Model procedures of SAS software. Results showed that the proportion of desmanthus in the diet had no significant effect on steer liveweight, rumen volatile fatty acids molar proportions and plasma metabolites (P ≥ 0.067). Total bilirubin ranged between 3.0 and 3.6 μmol/L for all the diet treatments (P = 0.67). All plasma metabolites measured were within the expected normal range reported for beef cattle. Rumen ammonia nitrogen content was above the 10 mg/dl threshold required to maintain effective rumen microbial activity and maximize voluntary feed intake in cattle fed low-quality tropical forages. The average daily weight gains averaged 0.5 to 0.6 kg/day (P = 0.13) and were within the range required to meet the target slaughter weight for prime beef markets within 2.5 years of age. These results indicate that desmanthus alone or mixed with other high-quality legume forages can be used to supplement grass-based diets to improve tropical beef cattle production in northern Australia with no adverse effect on cattle health.

Effect of barley straw and Egyptian clover hay on the rumen fermentation and structure and fibrolytic activities of rumen bacteria in dromedary camel

Background and Aim: Understanding the regulations of rumen microbiota and their fibrolytic capabilities under different forages are essential to improve rumen fermentation and animal feed efficiency. This study aimed to evaluate the changes in the rumen fermentation and the structure and fibrolytic activities of rumen bacteria in camels fed barley straw and Egyptian clover hay. Materials and Methods: Three fistulated camels were fed a diet containing barley straw for 30 days; then transitioned to a diet containing Egyptian clover hay for 30 days. In addition, bacterial media enriched with xylan and different cellulose sources, namely, filter paper, wheat straw, and alfalfa hay, were used to evaluate the ability of camel rumen bacteria to produce xylanase and cellulase enzymes. Results: The camel group fed Egyptian clover hay showed higher crude protein intake, rumen ammonia, total volatile fatty acids, and acetic acid. Moreover, the camel group fed barley straw showed higher neutral detergent fiber intake, rumen pH, and propionic and butyric acids. Principal component analysis showed that bacterial communities were separated based on the forage type. Forage type affected the composition of rumen bacteria and most of the bacterial community was assigned to phylum Bacteroidetes and Firmicutes. Egyptian clover hay diet increased the proportions of genus Prevotella and Ruminococcus; while fed barley straw diet increased the Butyrivibrio, RC9_gut_group, and Fibrobacteres. The bacterial culture of the Egyptian clover hay fed group produced the greatest xylanase and the bacterial culture of the barley straw fed group produced the maximum cellulase. Conclusion: Egyptian clover hay is recommended to feed camels in intensive production. Moreover, the bacterial community in the camel rumen is a promising source of lignocellulolytic enzymes.

The Use of Draught Animals in Rural Labour

Simple Summary

Although mechanisation has markedly reduced animal labour demand in agriculture, draught animals are still used in small production units located on terrains that do not favour agriculture mechanisation. Especially in Africa, Latin America, and Asia, they represent one of the main sources of sustenance for thousands of families who utilise animal labour in numerous agricultural tasks, such as ploughing and harvesting, as well as means of transport and hauling. Depending on the geographic area, the species involved are equids (horses, donkeys, and mules) and bovids (buffaloes and cattle). Draught animals proved to be sustainable in terms of global warming and the use of non-renewable energy as compared with agricultural machinery. However, critical points are the quality of human–animal interaction, due to the close contact between animals and humans while working, and the welfare of draught animals when transported and slaughtered, due to the high prevalence of injuries they suffer when subjected to these practices. Therefore, their use should be promoted in rural marginal areas where only low investments are usually feasible, and the energy of the animals can be obtained at a low cost by feeding them harvest residues and by-products.

Abstract

This study discusses scientific findings on the use of draught animals such as equids (i.e., horses, mules, and donkeys) and bovids (i.e., cattle and water buffaloes) in rural labours. Relevant peer-reviewed literature published between 1980 and 2021 was retrieved from CAB Abstracts, PubMed, ISI Web of Knowledge, and Scopus databases. Although animals were used to produce draught power since their domestication and are still being used for this purpose, mechanisation has markedly reduced animal labour demand in agriculture. However, the process was uneven across continents according to economic constraints, and draught animals are currently concentrated in small production units located on terrains that do not favour agriculture mechanisation in Africa, Latin America, and Asia. Generally, equids can work at rates similar to those of bovids or faster but can sustain the work for shorter periods of time. In addition, buffaloes possess tough hooves and resistance to disease that make them suitable for working in wetlands and clay soils. Draught animals allow a marked reduction of both GHG emissions and non-renewable energy consumption as compared with agricultural machinery. In addition, they may allow obtaining profits from otherwise non-usable lands. Therefore, their use should be promoted in rural areas where low investments are usually the only ones feasible, and the energy of the animals can be obtained at a low cost by feeding them harvest residues and by-products. However, more attention should be paid to the quality of human–animal interactions—due to the close contact between animals and humans while working—and to the welfare of draught animals when transported and slaughtered—due to the high prevalence of injuries they suffer when subjected to these practices.

Seasonal Variation in the Faecal Microbiota of Mature Adult Horses Maintained on Pasture in New Zealand

Simple Summary

Ten horses were kept on pasture for one year, with hay provided from June to October. Each month we measured how much pasture was present and collected pasture and hay samples to assess their nutrient content, and faecal samples from all horses to investigate the diversity of the bacterial species present using next-generation sequencing technology. The population of faecal bacteria was more diverse during the months when the horses were kept exclusively on pasture compared to the months when pasture was supplemented with hay. The diet offered, and the season and the month we sampled the paddock all had a major influence on the diversity of the species of bacteria in the faeces. While there were some differences between the horses, generally the bacterial populations could be grouped together in samples obtained during May, June, and July (late-autumn to winter period), and January, February, and March (a period of drought). More specifically we were able to show an association between specific bacterial species, nutrients (dry matter, protein, and structural carbohydrates), and climatic conditions (rainfall and temperature). Our study showed that the diversity and composition of the bacterial population of horses kept on pasture changes over a 12-month period, and this reflects changes in the nutrient composition of the pasture, which in turn is influenced by climate. The findings of this study may have implications for managing horses on pasture and the use of forages for horses susceptible to digestive problems.

Abstract

Seasonal variation in the faecal microbiota of forage-fed horses was investigated over a 12-month period to determine whether the bacterial diversity fluctuated over time. Horses (n = 10) were maintained on pasture for one year, with hay supplemented from June to October. At monthly intervals, data were recorded on pasture availability and climate (collected continuously and averaged on monthly basis), pasture and hay samples were collected for nutrient analysis, and faecal samples were collected from all horses to investigate the diversity of faecal microbiota using next-generation sequencing on the Illumina MiSeq platform. The alpha diversity of bacterial genera was high in all samples (n = 118), with significantly higher Simpson’s (p < 0.001) and Shannon-Wiener (p < 0.001) diversity indices observed during the months when horses were kept exclusively on pasture compared to the months when pasture was supplemented with hay. There were significant effects of diet, season, and month (ANOSIM, p < 0.01 for each comparison) on the beta diversity of bacterial genera identified in the faeces. While there was some inter-horse variation, hierarchical clustering of beta diversity indices showed separate clades originating for samples obtained during May, June, and July (late-autumn to winter period), and January, February, and March (a period of drought), with a strong association between bacterial taxa and specific nutrients (dry matter, protein, and structural carbohydrates) and climate variables (rainfall and temperature). Our study supports the hypothesis that the diversity and community structure of the faecal microbiota of horses kept on pasture varied over a 12-month period, and this variation reflects changes in the nutrient composition of the pasture, which in turn is influenced by climatic conditions. The findings of this study may have implications for grazing management and the preparation of conserved forages for those horses susceptible to perturbations of the hindgut microbiota.

Comparison of In Vivo and In Vitro Digestibility in Donkeys

We compared in vivo and in vitro dry matter (DM) and neutral detergent fiber (NDF) digestibility in donkeys using feces as microbial inoculum. Four donkeys were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The animals were fed two types of hay, with or without flaked barley. For the in vivo procedure, total feces were collected for 6 days from each donkey; digestibility was calculated as the difference between ingested and excreted DM and NDF. For the in vitro procedure, donkey feces were buffered and used as microbial inoculum in an Ankom DaisyII Incubator; digestibility was estimated after 60 h of incubation. In vivo results showed that the addition of barley to hays did not change the digestibility values. In vivo estimates were higher than in vitro ones. The equations used to predict in vivo estimates from in vitro data were not reliable (R2 = 0.47 and 0.21; P = 0.003 and 0.078 for NDF and DM digestibility, respectively). Further studies need to evaluate different sample size and digestion times.

Donkey Feeding During Maintenance, Pregnancy, and Lactation: Effects on Body Weight, Milk Production, and Foal Growth

We evaluated the daily intake in donkeys during maintenance, late pregnancy, and early lactation. The growth curves of the foals in the first eight weeks of life and the milk production in lactating jennies were also investigated. Donkeys were separated into two groups: seven pregnant jennies (group 1: pregnant/lactating) and seven nonpregnant, nonlactating jennies (group 2). The groups were fed two different diets each. The feeding period for group 1 covered eight weeks before parturition and eight weeks postpartum. Group 2 was managed during the same time period (16 weeks). Diet 1 consisted of ad libitum hay, which was fed to group 1 during late pregnancy and to group 2 from weeks 1-8. Diet 2 consisted of the same ad libitum hay supplemented with 2 kg/head/day of concentrate, which was fed to group 1 during lactation and to group 2 from weeks 9-16. The daily dry matter intake (diet 1) was 2.56 kg/100 kg of body weight (BW) for nonpregnant jennies and 31% lower in the pregnant donkeys. In the lactating jennies, the total dry matter intake was similar to the nonpregnant group fed diet 2. The nonpregnant jennies lost 1.9% of their initial BW when fed diet 1, whereas they gained 8.4% of their initial BW when fed with diet 2. A weight loss was also found in the lactating donkeys. The foals more than doubled in their birth weight within two months.

Are dietary strategies to mitigate enteric methane emission equally effective across dairy cattle, beef cattle, and sheep?

The digestive physiology of ruminants is sufficiently different (e.g., with respect to mean retention time of digesta, digestibility of the feed offered, digestion, and fermentation characteristics) that caution is needed before extrapolating results from one type of ruminant to another. The objectives of the present study were (1) to provide an overview of some essential differences in rumen physiology between dairy cattle, beef cattle, and sheep that are related to methane (CH₄) emission; and (2) to evaluate whether dietary strategies to mitigate CH₄ emission with various modes of action are equally effective in dairy cattle, beef cattle, and sheep. A literature search was performed using Web of Science and Scopus, and 94 studies were selected from the literature. Per study, the effect size of the dietary strategies was expressed as a proportion (%) of the control level of CH₄ emission, as this enabled a comparison across ruminant types. Evaluation of the literature indicated that the effectiveness of forage-related CH₄ mitigation strategies, including feeding more highly digestible grass (herbage or silage) or replacing different forage types with corn silage, differs across ruminant types. These strategies are most effective for dairy cattle, are effective for beef cattle to a certain extent, but seem to have minor or no effects in sheep. In general, the effectiveness of other dietary mitigation strategies, including increased concentrate feeding and feed additives (e.g., nitrate), appeared to be similar for dairy cattle, beef cattle, and sheep. We concluded that if the mode of action of a dietary CH₄ mitigation strategy is related to ruminant-specific factors, such as feed intake or rumen physiology, the effectiveness of the strategy differs across ruminant types, whereas if the mode of action is associated with methanogenesis-related fermentation pathways, the strategy is effective across ruminant types. Hence, caution is needed when translating effectiveness of dietary CH₄ mitigation strategies across different ruminant types or production systems.

Biomass yield and feeding value of rye, triticale, and wheat straw produced under a dual-purpose management system

Dual-purpose management of winter cereals for grazing and grain production provides highly nutritive forage for ruminants in the spring and may positively affect straw feeding value. A 2-yr study investigated the effect of spring defoliation of triticale, wheat, and rye at the tillering and stem elongation stages on total biomass, grain yields, and straw quality. Furthermore, straws of spring-defoliated and undefoliated (control) cereal crops were evaluated for nutritional value and voluntary intake as a means of assessing the efficiency of dual-purpose management systems from the winter feeding context as well. The feeding study consisted of 9 total mixed rations (TMR), each containing 35% triticale, rye, or wheat straw obtained under 3 spring-defoliation regimens. The TMR were individually fed to fifty-four 1-yr-old Anatolian Merino ewes for 28 d. Defoliation of the crops at tillering did not affect the total biomass production or grain yields. However, biomass and grain yields were reduced ( < 0.01) by 55 and 52%, respectively, in crops defoliated at stem elongation. Straw of spring-defoliated cereals had less NDF and ADF concentrations ( < 0.01) but greater CP ( < 0.01), nonfiber carbohydrates ( < 0.01), and ME concentrations ( < 0.01) compared with straw from undefoliated crops. The increase in the nutritive value of straw led to greater nutrient digestion ( < 0.01) and intake of DM and OM of ewes ( < 0.01). However, sheep live weight gain did not differ among treatments ( > 0.77). This study indicated that straw feeding value and digestibility can be increased through spring defoliation.

Comparison of feed intake, digestion and rumen function among domestic ruminant species grazing in upland vegetation communities

This study aimed to compare feed intake, digestion, rumen fermentation parameters and bacterial community of 5 beef cows, 12 crossed ewes and 12 goats grazing together in spring-early summer on heather-gorse vegetation communities with an adjacent area of improved pasture. Organic matter intake (OMI) and digestibility (OMD) were estimated using alkane markers. Ruminal fluid samples were collected for measuring fermentation parameters, and studying the bacterial community using terminal restriction fragment length polymorphism (T-RFLP). Spot samples of urine were taken to determine purine derivative (PD) and creatinine concentrations to estimate microbial protein synthesis in the rumen. Herbaceous species were the main dietary component in all animal species. Cattle had higher (p < 0.05) daily OMI (g/kg LW^0.75 ) and OMD, whereas sheep and goats showed similar values. The highest ammonia concentration was observed in sheep. Total VFA, acetate and butyrate concentrations were not influenced by animal species, while propionate concentrations in goats were 1.8 times lower (p < 0.05) than in sheep. Acetate:propionate ratio was greater (p < 0.05) in goats, whereas cattle excreted more allantoin (p < 0.05). Estimated supply of microbial N was higher in cows (p < 0.01), whereas the efficiency of microbial protein synthesis was lower (p < 0.01) in this animal species. Hierarchical clustering analysis indicated a clear effect of animal species on rumen bacterial structure. Differences among animal species were also observed in the relative frequency of several T-RFs. Certain T-RFs compatible with Lachnospiraceae, Proteobacteria and Clostridiales species were not found in goats, while these animals showed high relative frequencies of some fragments compatible with the Ruminococcaceae family that were not detected in sheep and cattle. Results suggest a close relationship between animals' grazing behaviour and rumen bacterial structure and its function. Goats seem to show a greater specialization of their microbial populations to deal with the greater fibrous and tannin content of their diet.

Content of nutrients and energy in pasture vegetation and their apparent digestibility in Old Kladruber horses

This study focuses on the determination of apparent digestibility of pasture vegetation nutrients in horses of the Old Kladruber breed through a balance indicator method (determination of acid insoluble ash). When evaluating the nitrogenous substances, their determination was based on the content of pure protein (sum of amino acids) which is more accurate than crude protein. There were differences in the chemical composition of dry matter from pasture vegetation and horse excrements. Regarding crude fat, crude fibre, acid detergent fibre, neutral detergent fibre, acid detergent lignin, ash, P and Mg, the average values in dry matter of horse excrements were significantly (P≤ 0.01) higher; on the contrary, we found significantly (P≤ 0.01) lower mean values of nitrogen-free extract, organic matter and Ca ​​in the dry mass of pasture grass. The highest coefficient of apparent digestibility for organic nutrients was determined in the nitrogen-free extract (73%) followed with organic matter (71%), pure protein (68%), crude protein (65%) and crude fat (61%). In case of fibre and its fractions, the apparent digestibility coefficients decreased as follows: crude fibre (66%), neutral detergent fibre (66%), acid detergent fibre (63%) and acid detergent lignin (42%). Significantly lower values were determined for coefficients of apparent digestibility for minerals P (16%) and Mg (50%), which highlights the need for their regular supplementation in horses on pasture. This study extends the current state of knowledge regarding the apparent digestibility of pasture vegetation which is a prerequisite for optimal nutrition of horses.

Ecology and characteristics of methanogenic archaea in animals and humans

In this review, the molecular techniques used in animal-based-methanogen studies will be discussed along with how methanogens interact not only with other microorganisms but with their animal hosts as well. These methods not only indicate the diversity and levels of methanogens, but also provide insight on their ecological functions. Most molecular techniques have been based on either 16S rRNA genes or methyl-coenzyme M reductase, a ubiquitous enzyme in methanogens. The most predominant methanogens in animals belong to the genus Methanobrevibacter. Besides methanogens contributing to overall H2 balance, methanogens also have mutual interactions with other bacteria. In addition to shared metabolic synergism, the host animal retrieves additional energy from the diet when methanogens are co-colonized with other normal flora. By comparing genes in methanogens with other bacteria, possible gene transfer between methanogens and other bacteria in the same environments appears to occur. Finally, diets in conjunction with the genetics of methanogens and hosts may represent the biological framework that dictate the extent of methanogen prevalence in these ecosystems. In addition, host evolution including the immune system could serve as an additional selective pressure for methanogen colonization.

Digestion characteristics of two forms of preserved lucerne forage fed to mature horses

A trial was conducted, using 12 mature thoroughbred horses as a cross-over design, to compare the water and energy intake and the digestibility of dry lucerne chaff (LC) against a controlled fermented lucerne (CFL) product (HNF Fiber®; Fiber Fresh Feeds Ltd, Reporoa, New Zealand). Significant (P < 0.05) increases in dry matter intake (20%), energy intake (20%), retained energy (32%) and digestible energy (22%) were observed for the CFL compared to the LC. In a concurrent small scale study within the trial, numeric improvements in water intake (18%) for the CFL were recorded. The results demonstrated that the standard reference values underestimate the digestibility and nutritional contribution made by CFL when fed to horses, and that this type of forage has increased nutritional benefits.

Population trends of grassland birds in North America are linked to the prevalence of an agricultural epizootic in Europe

Globalization of trade has dramatic socioeconomic effects, and, intuitively, significant ecological effects should follow. However, few quantitative examples exist of the interrelationship of globalization, socioeconomics, and ecological patterns. We present a striking illustration of a cascade in which bovine spongiform encephalopathy (BSE; "mad cow disease") outbreaks in Europe exerted pressure on global beef markets, subsequently affecting North American hayfields and grassland bird populations. We examined competing models, which linked the prevalence of BSE in five focal countries, volume of beef exports to those countries from North America, and the amount of hayfield harvested and the abundance of grassland birds in North America. We found that (i) imports from North America increased 1 y after BSE outbreaks; (ii) probably because fewer cattle remained, the hay harvest in North America was reduced 2 y after the outbreak; (iii) the reduced hay harvest yielded a positive response in grassland bird populations 3 y after the outbreak.