Arjan Jonker

Rumen microbial community composition varies with diet and host, but a core microbiome is found across a wide geographical range.

Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.

Nutrient composition and degradation profiles of anthocyanidin-accumulating Lc-alfalfa populations.

Alfalfa (Medicago sativa L.) is one of the most used forages in the world but suffers the disadvantage of having poor protein utilization by the animal. The poor protein utilization is the result of excessive ruminal protein degradation, which might be reduced by the protein precipitating capacity of anthocyanidin (AC) and condensed tannins (CT). The objective of this study was to determine the effects of the Lc-transgene on survival, anthocyanidin, condensed tannin and chemical profiles in crossed populations of western Canadian-adapted Lc-alfalfa. These were compared with their non-transgenic (NT) parental varieties, Rangelander, Rambler, and Beaver. Lc-alfalfa forage accumulated enhanced amounts of anthocyanidin, with an average concentration of 197.4 µg g-1 DM, while condensed tannins were not detected. Both of these metabolites were absent in the NT parental varieties. Lc-alfalfa had a lower (24.8 vs. 27.3% DM; P < 0.02) crude protein (CP) and higher (58.3 vs. 55.5% DM; P < 0.01) carbohydrate (CHO) c...

Measuring methane from grazing dairy cows using GreenFeed

The GreenFeed (GF; C-lock Inc.) system for estimating methane (CH4) and carbon dioxide emissions from cows enables data to be acquired from a grazing herd, where individuals are unencumbered by equipment associated with sampling respired breath. Cows choose when or if they want to visit a GF. Confidence in CH4 measurements from this system requires information on individual cow use, patterns of visits and data need to be accumulated over several days or weeks. The effect of stocking rate (SR) on CH4 and carbon dioxide emissions was examined in herds of 28 and 40 dairy cows, each grazing an 11-ha self-contained farmlet (Low SR and High SR), in four measurement periods over a lactation. Emissions were measured for up to 3 weeks in each period; CH4 averaged 331 and 305 g/cow.day, with 19.6 and 16.5 kg milk/cow.day during the measurements for the Low and High SR, respectively. Values for CH4 were similar to estimates derived from calculated feed intakes, and daily carbon dioxide emissions averaged 10.8 and 10.0 kg/day for cows in Low and High SR treatments, respectively. Data from the GF system distinguished effects of SR, but only ~20 cows from each farmlet were regular (daily) users, despite feed restrictions for the High SR cows. Visits by ‘users’ averaged 1.6 and 1.1 cows/h for Low and High SR herds, respectively, and were spread over 24 h with a small circadian variation in emission rates. The GF can be integrated into intensive pasture-based dairying and estimates of CH4 emissions are in line with expectations associated with feed availability and stage of lactation, however the variation between cows in number of visits to the GF has not been explained.

Buccal Swabbing as a Noninvasive Method To Determine Bacterial, Archaeal, and Eukaryotic Microbial Community Structures in the Rumen

ABSTRACT Analysis of rumen microbial community structure based on small-subunit rRNA marker genes in metagenomic DNA samples provides important insights into the dominant taxa present in the rumen and allows assessment of community differences between individuals or in response to treatments applied to ruminants. However, natural animal-to-animal variation in rumen microbial community composition can limit the power of a study considerably, especially when only subtle differences are expected between treatment groups. Thus, trials with large numbers of animals may be necessary to overcome this variation. Because ruminants pass large amounts of rumen material to their oral cavities when they chew their cud, oral samples may contain good representations of the rumen microbiota and be useful in lieu of rumen samples to study rumen microbial communities. We compared bacterial, archaeal, and eukaryotic community structures in DNAs extracted from buccal swabs to those in DNAs from samples collected directly from the rumen by use of a stomach tube for sheep on four different diets. After bioinformatic depletion of potential oral taxa from libraries of samples collected via buccal swabs, bacterial communities showed significant clustering by diet (R = 0.37; analysis of similarity [ANOSIM]) rather than by sampling method (R = 0.07). Archaeal, ciliate protozoal, and anaerobic fungal communities also showed significant clustering by diet rather than by sampling method, even without adjustment for potentially orally associated microorganisms. These findings indicate that buccal swabs may in future allow quick and noninvasive sampling for analysis of rumen microbial communities in large numbers of ruminants.

Effect of fresh pasture forage quality, feeding level and supplementation on methane emissions from growing beef cattle

The objectives of this study were to determine the effect of fresh pasture forage quality (vegetative and mature pasture in different seasons), feeding level and supplementation with maize silage or palm kernel expeller on methane (CH4) production (g/day) and yield (g/kg dry matter intake; DMI) in growing beef cattle. The null hypothesis was that pasture quality, DMI level and supplementation have no effect on the CH4 yield (g/kg DM) in beef cattle. Four experiments were conducted and in three experiments (Exp. 1–3) freshly cut vegetative or mature pasture was fed to 14 growing beef animals in two consecutive periods, respectively, at intake levels of 1.5, 1.8 and 1.1 × maintenance metabolisable energy requirements (MEm) in Exp. 1–3, respectively. For Exp. 3, 100% maize silage was fed in a third consecutive period to the same cattle used in Periods 1 and 2. In Exp. 4, 4 animals were fed one of three treatments at 1.6 × MEm of 100% fresh pasture, fresh pasture supplemented with 35% DM maize silage or fresh pasture supplemented with 35% DM palm kernel expeller. After acclimatisation to respective diets, DMI and CH4 were measured for 12 animals in individual open circuit respiration chambers for two consecutive days in each experiment. Methane yield (g/kg DMI) was similar when animals were fed vegetative or mature pasture in Exp. 1 (20.0) and 2 (25.8), whereas in Exp. 3 feeding vegetative pasture resulted in a higher CH4 yield (25.7; P < 0.05) compared with feeding mature pasture (23.3), with feeding 100% maize silage intermediate (23.8). Methane yield of cattle fed pasture supplemented with maize silage in Exp. 4 was 10% higher (P < 0.05) compared with cattle fed mature pasture only or supplemented with palm kernel expeller (25.9, 23.3, 23.4 g/kg DMI, respectively). The regression between DMI and CH4 yield was similar for vegetative and mature pasture and pasture composition could explain up to 26% of variation in CH4 yield (P < 0.05). The CH4 yield in cattle fed 100% pasture (Exp. 1–3) was not affected by DMI and averaged 24.1 ± 2.78 g/kg DMI. In conclusion, fresh pasture forage quality, feeding level and supplementation had only minor, but some significant, effects on CH4 yield in beef cattle.

Enteric methane and carbon dioxide emissions measured using respiration chambers, the sulfur hexafluoride tracer technique, and a GreenFeed head-chamber system from beef heifers fed alfalfa silage at three allowances and four feeding frequencies

The objective of this study was to determine methane (CH) and carbon dioxide (CO) emissions from 8 beef heifers (approximately 20 mo of age and 382 ± 24.3 kg BW) measured by respiration chambers and the sulfur hexafluoride (SF) tracer technique and a mobile head-chamber, spot-sampling system (GreenFeed; C-Lock Inc., Rapid City, SD) when fed alfalfa silage at 3 feeding levels and 4 feeding frequencies. Feeding frequency may affect CH yield (g/kg DMI), and measurement systems (such as GreenFeed or SF) are needed to obtain accurate estimates of CH emissions from individual cattle under grazing where new pasture is provided once or twice daily. The Hereford × Friesian heifers were used in 5 consecutive periods (P1 to P5) of 14 d with CH and CO emissions measured with the SF technique in wk 1 (5-6 d), with chambers in wk 2 (2 d), and with the GreenFeed system when not in chambers (8 d) of each period. Alfalfa silage was restricted to 6, 8, 8, and 8 kg DM/d in P1, P2, P3, and P4, respectively, and provided ad libitum (10.9-12.2 kg DM/d) in P5. Silage was fed in 2, 2, 3, and 4 meals per day in P1, P2, P3, and P4, respectively, and was continuously available (refilled twice daily) in P5. Methane production increased from 141 to 265 g/d as DMI doubled ( < 0.001), but average CH yields measured in respiration chambers (24.5 g/kg DMI) and by the SF technique (22.8 g CH/kg DMI) and the GreenFeed system (26.2 g/kg DMI) were unaffected by feeding management ( = 0.6 for chambers and SF and = 0.06 for GreenFeed). The CH yields estimated by the GreenFeed system did not differ from CH yields estimated by the chambers in P1, P2, P3, and P5 but were greater ( < 0.02) than CH yields estimated by the SF technique in P2, P3, P4, and P5. Yields of CO (g/kg DMI) decreased with increasing DMI ( < 0.04) and CO production (g/d) increased from 5,293 to 9,167 g/d as DMI increased ( < 0.001). In general, the SF technique and the GreenFeed system provided means for CH yield that were not different from those of respiration chambers, and CH yields (g/kg DMI) were unaffected by DMI level or feeding frequency.

The Role of Proanthocyanidins Complex in Structure and Nutrition Interaction in Alfalfa Forage.

Alfalfa (Medicago sativa L.) is one of the main forages grown in the world. Alfalfa is a winter hardy, drought tolerant, N-fixing legume with a good longevity, high yield, high nutrient levels, high digestibility, unique structural to non-structural components ratio, high dry matter intake, and high animal productivity per hectare. However, its main limitation is its excessively rapid initial rate of protein degradation in the rumen, which results in pasture bloat and inefficient use of protein with consequent excessive excretions of nitrogen into the environment. Proanthocyanidins are secondary plant metabolites that can bind with protein and thereby reduce the rate and extent of ruminal protein degradation. However, these secondary metabolites do not accumulate in alfalfa. This review aims to firstly describe the events involved in the rapid release of protein from alfalfa and its effect on ruminant nutrition, environmental pollution, and pasture bloat; secondly, to describe occurrence, structure, functions and benefits of moderate amounts of proanthocyanidin; and finally, to describe the development of alfalfa which accumulates moderate amounts of proanthocyanidins. The emphasis of this review focuses on the role of proanthocyanidins compounds in structure and nutrition interaction in ruminant livestock systems.

Methane emissions from lactating and non-lactating dairy cows and growing cattle fed fresh pasture

Currently, a fixed methane (CH4) emission factor is used for calculating total CH4 emissions from cattle in the national greenhouse gas inventory of New Zealand, independent of diet composition, cattle class (beef, dairy) or physiological state (growing, lactating, non-lactating). The objectives of this study were to determine CH4 emissions from lactating and non-lactating dairy cows (118 dairy cows; 81 lactating and 37 non-lactating, over 10 periods) and growing dairy heifers (12 measured twice) fed 100% fresh pasture forage in respiration chambers, which in combination with the published data of beef cattle (36 measured twice) fed fresh pasture were used to determine the relationship between CH4 emissions and dry matter intake (DMI), feed quality, cattle class (dairy vs beef) and physiological state (lactating, non-lactating and growing). Before regression analysis the dominant variables (DMI, CH4) needed to be transformed using natural logarithms (Ln) to make the variation in CH4 emissions more homogeneous across the range of data (i.e. stabilise the variance). Over all periods, average DMI ranged from 3.1 to 13.9 kg/day, average CH4 production from 64 to 325 g/day and average CH4 yield from 21.4 to 26.5 g/kg DMI. The DMI alone explained 90.8% of the variation in CH4 production (LnCH4 (g/day) = 3.250 + 0.9487 × LnDMI). Regression was improved to a minor extent (<3%, with associated increased prediction error) by including physiological status, cattle class or dietary composition in the model, in addition to LnDMI, on LnCH4 production. In conclusion, DMI alone was the strongest predictor for CH4 emissions from cattle fed fresh pasture with minor but irrelevant improvements in the prediction when considering pasture quality, cattle class or physiological status.

Evaluation of the Feed Value for Ruminants of Blends of Corn and Wheat Distillers Dried Grains

Recently, biofuel processing has produced a large amount of biofuel coproducts. However, to date, there is little information on the metabolic characteristics of proteins and energy in biofuel coproduct-based rations. The objective of this study was to study the metabolic characteristics of proteins and energy in biofuel coproduct-based rations in terms of (1) chemical and nutrient profiles, (2) protein and carbohydrate subfraction associated with various degradation rate, (3) rumen and intestinal degradation and digestion kinetics, and (4) metabolic characteristics of proteins. Two sources of grain corn were mixed with two sources of biofuel coproducts (wheat-based dried distillers grains with solubles, wDDGS) in ratios of 100:0, 75:25, 50:50, and 25:75%. The study revealed that increasing the biofuel coproduct inclusion level increased most of the nutritional components linearly (P < 0.05) except starch, which linearly decreased. With increasing biofuel coproduct inclusion level, the rumen degradation rate and the effective degradability of organic matter were not affected (P > 0.05), but the effective degradability of starch was decreased (P < 0.05). Effective degradation of crude protein and neutral detergent fiber as well as predicted truly absorbed protein supply in the small intestine and degraded protein balance were increased (P < 0.05). In conclusion, the inclusion of the biofuel coproduct up to 25-50% in rations improved potential nitrogen and energy synchronization for microbial growth and improved truly absorbable protein supply to the small intestine, without altering energy value.

The Occurrence, Biosynthesis, and Molecular Structure of Proanthocyanidins and Their Effects on Legume Forage Protein Precipitation, Digestion and Absorption in the Ruminant Digestive Tract

Forages grown in temperate regions, such as alfalfa (Medicago sativa L.) and white clover (Trefolium repens L.), typically have a high nutritional value when fed to ruminants. Their high protein content and degradation rate result, however, in poor utilization of protein from the forage resulting in excessive excretion of nitrogen into the environment by the animal. Proanthocyanindins (also known as condensed tannins) found in some forage legumes such as birdsfoot trefoil (Lotus corniculatus L.), bind to dietary protein and can improve protein utilization in the animal. This review will focus on (1) the occurrence of proanthocyanidins; (2) biosynthesis and structure of proanthocyanidins; (3) effects of proanthocyanidins on protein metabolism; (4) protein precipitating capacity of proanthocyanidins and their effects on true intestinal protein adsorption by ruminants; and (5) effect on animal health, animal performance and environmental emissions.