Lucerne Chaff Research Articles

Effects of Sugarcane-Derived Polyphenol Supplementation on Methane Production and Rumen Microbial Diversity of Second-Cross Lambs.

The objective of this study was to evaluate the effects of feeding sugarcane-derived polyphenolic supplement (Polygain, The Product Makers Australia, Keysborough, VIC, Australia) on enteric methane (CH4) emission, rumen microbiota, and performance of second-cross lambs. For this purpose, 24 Poll Dorset × (Border Leicester × Merino) lambs were allocated to 3 different treatments: Control (C), 0.25% Polygain (0.25 PG), and 1% Polygain (1 PG) diets with a uniform basal feed (25% cracked wheat grain, 25% cracked barley grain, 25% oaten chaff, 25% lucerne chaff). Both doses of Polygain reduced the total CH4 production (g/day; p = 0.006), CH4 yield (CH4, g/kg of dry matter intake; p = 0.003) and CH4 intensity (CH4, g/kg of BW; p = 0.003). Dry matter intake tended to be greater (p = 0.08) in sheep fed 1 PG compared to the C group, with the 0.25 PG group being intermediate. The average daily gain of the lambs was improved (p = 0.03) with 1% Polygain supplementation. The relative abundance of genera Methanobrevibacter_unidentified, Methanomethylophilaceae_uncultured, Methanogenic archaeon mixed culture ISO4-G1, Methanosphaera uncultured rumen methanogen, Methanogenic archaeon ISO4-H5, and Methanobrevibacter boviskoreani JH1 were reduced with Polygain supplementation. In conclusion, feeding Polygain reduced lambs' enteric CH4 emissions, altered the rumen microbiome, and improved the growth performance of lambs.

Provision of lucerne in the diet or as a manipulable enrichment material enhances feed efficiency and welfare status for growing-finishing pigs

This research investigated the effects of including lucerne in a diet and as manipulable enrichment material on growing-finishing pig growth performance and behaviour. Forty-eight intact male Duroc × (Large White × Landrace) pigs with an initial live weight (LW) of 26.4 ± 2.32 kg (mean ± SD) were blocked by LW and randomly assigned to two dietary treatments (control vs lucerne), and two manipulable material treatments (without and with lucerne chaff for manipulable material). The barley and soybean meal-based control diet was formulated according to a commercial standard, while the lucerne diet replaced 100 g/kg of the barley and soybean oil in the control diet with lucerne chaff. The diets were formulated to have the same amount of digestible energy and apparent ileal digestible lysine. Manipulable material (lucerne chaff) was provided daily at 100 g/pig. Pigs had ad libitum access to diets via electronic feeders until they reached approximately 90 kg LW, at which time they were slaughtered. There were no interactions between dietary treatment and provision of manipulable material on pig production and behaviour. Feeding the lucerne diet reduced average daily feed intake, LW gain, feed intake per feeder visit, and feeding rate, but increased feed efficiency (P < 0.05). Access to manipulable material did not affect any growth traits, but the number of feeder visits per day was greater and the duration of visits to the feeder was lower in pigs that had access to lucerne chaff (P < 0.001). Compared to the other groups, pigs that consumed the lucerne diet or had access to manipulable material rested for a shorter duration but engaged in more social interactions and exploration behaviour. In conclusion, including 10% lucerne in growing-finishing diets improved feed efficiency and lucerne chaff appears to be an attractive enrichment source to pigs.

Feeding Sows Lucerne, or Diets with Similar Energy and Nutritional Profiles to Lucerne, Improves the Pre-Weaning Performance of Piglets

Feeding fibre and branched-chain amino acids (BCAA) to sows during late gestation and lactation, respectively, have been shown to improve litter weights at weaning. Therefore, supplementing primiparous sow diets with lucerne chaff, a feedstuff high in fibre, BCAA and tryptophan, may improve the performance of their progeny. Experiment 1 investigated the effects of feeding primiparous sows (n = 118) either (i) a control diet (CON); (ii) CON with 1 kg of lucerne chaff (LUC); or (iii) a diet formulated to have a similar digestible energy and BCAA content as CON + LUC (SIMLUC 1) until farrowing. The LUC and SIMLUC 1 diets improved day 21 litter weight (p = 0.055). In Experiment 2 primiparous (n = 111) and multiparous sows (parities 2–5, n = 112) were fed either the CON or SIMLUC diet (SIMLUC 2) from day 110 of gestation to farrowing (PreF), or to day 10 post-farrowing (PreF + PostF). The SIMLUC 2 diet tended to be more beneficial to primiparous compared to multiparous sows when fed PreF, as indicated by an interaction between diet and parity on day 21 average piglet weights (p = 0.078). Overall, SIMLUC is most effective in improving primiparous progeny performance as evidenced by their D21 weights.

Digestion, faecal grain loss and energy requirements of Huacaya alpacas fed lucerne chaff, oat chaff and whole grain barley diets

This study determined the digestibility of three common supplementary feeds, faecal whole grain loss and the energy requirements of adult Huacaya alpacas (live weight 62 kg) using individual pens and feeding at a range of initial notional energy levels approximating maintenance (M) to 1.6 × M. The diets were lucerne (Medicago sativa) chaff (LC), oaten (Avena sativa) chaff (OC) and whole barley grain (Hordeum vulgare) plus oaten chaff (BOC) (40:60 ratio). After 2 weeks introduction, DMI, faecal output and live weight were measured for 7 days. Samples were analysed for DM, organic matter (OM), GE and N content. Feed composition was respectively for diets LC, BOC, OC: OM 89.1, 96.4, 95.8 %; DE 12.8, 11.9, 12.2 MJ/kg DM; CP 21.7, 9.6, 7.3 %. OC included 25 % oat grain, of which 55 % was whole grain. Two alpaca showed signs of subclinical acidosis. DMI averaged 1014 g/d (range 579−1576 g/d) during digestibility measurements. Whole grain loss as % of grain fed was 16.3 % for BOC significantly greater than 5.2 % for OC. For LC and BOC, DMI required for alpacas at maintenance was 41 g/kg W0.75/d, equivalent to 1.48 % of live weight, and the MEm requirement was 399 kJ ME/kg W0.75/d. Energy retained in fibre averaged 180 (s.e. 6.6) kJ/day and was 0.0146 of ME intake, equivalent to 8.2 ± 0.30 kJ/kg0.75/d. While it was possible to feed up to 435 g DM/d of cereal grain to alpaca, whole barley grain excretion was associated with a 27 % decline in the ME value of barley. Alpaca fed whole grain barley adapted to the diet whereas adaptation to a diet of oaten chaff with cracked oat grain resulted in depressed DMI and live weight loss, probably from mild acidosis.

Fermentation Characteristics and In Vitro Digestibility of Fibers and Fiber-Rich Byproducts Used for the Feeding of Pigs.

Simple SummaryInclusion of dietary fibers into the diet may have positive impact on health and wellbeing of pigs. The objective of the study was to examine physicochemical properties of fiber preparations and fiber-rich byproducts in relation to fermentability and digestibility using in vitro batch-culture incubation. Powdered cellulose, Aspergillus niger mycelium, which is a byproduct of citric acid production, lucerne chaff, soybean shells, wheat bran, and sugar beet pulp were notably fermented and contributed to the digestible dry matter and organic matter when used as diet constituents. The tested lignocelluloses were not fermented and are rather useful as bulk materials.Dietary fibers may have positive impact on health and wellbeing of pigs. The study examined physicochemical properties of two lignocelluloses (including and excluding bark), powdered cellulose, Aspergillus niger mycelium, lucerne chaff, soybean shells, wheat bran, and sugar beet pulp in relation to fermentability and digestibility using in vitro batch-culture incubation. Maize starch and a purified cellulose were used as standardized substrates for classification of the test substrates. The substrates covered a wide range regarding their physicochemical properties. Swelling capacity (SC) was 9–411%, water binding capacity (WBC) was 4.4–14.3 g/g dry matter (DM), and water holding capacity (WHC) was 4.1–10.6 g/g DM. Gas production and other fermentation parameters—namely post-incubation pH, CH4, NH3, and short chain fatty acids (SCFA) concentrations—revealed a significant fermentation of sugar beet pulp, soybean shells, lucerne chaff, wheat bran, A. niger mycelium, and powdered cellulose, whereas the lignocelluloses were not fermented. Significant correlations were found between the physicochemical properties and the fermentation parameters (p < 0.05). Enzymatic pre-digestion mostly reduced gas, NH3, and SCFA production. In vitro digestibility of DM (IVDMD) and organic matter (IVOMD) was mostly negligible after enzymatic pre-digestion. Fermentation alone led to only 0.10–0.15 IVDMD and 0.14–0.15 IVOMD in lignocelluloses and powdered cellulose, respectively, but 0.44–0.37 IVDMD and 0.46–0.38 IVOMD in the remainder of substrates (p < 0.05). In vitro digestibility was again correlated with the physicochemical properties of the substrates and the fermentation parameters (p < 0.05). The fiber preparations and fiber-rich byproducts were fermented to a relevant extent. In contrast, lignocelluloses were not fermented and can be used rather as bulk material.

Diet and irradiation effects on the bacterial community composition and structure in the gut of domesticated teneral and mature Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae)

BackgroundMass-rearing, domestication and gamma irradiation of tephritid fruit flies used in sterile insect technique (SIT) programmes can negatively impact fly quality and performance. Symbiotic bacteria supplied as probiotics to mass-reared fruit flies may help to overcome some of these issues. However, the effects of tephritid ontogeny, sex, diet and irradiation on their microbiota are not well known.ResultsWe have used next-generation sequencing to characterise the bacterial community composition and structure within Queensland fruit fly, Bactrocera tryoni (Froggatt), by generating 16S rRNA gene amplicon libraries derived from the guts of 58 individual teneral and mature, female and male, sterile and fertile adult flies reared on artificial larval diets in a laboratory or mass-rearing environment, and fed either a full adult diet (i.e. sugar and yeast hydrolysate) or a sugar only adult diet. Overall, the amplicon sequence read volume in tenerals was low and smaller than in mature adult flies. Operational taxonomic units (OTUs), belonging to the families Enterobacteriaceae (8 OTUs) and Acetobacteraceae (1 OTU) were most prevalent. Enterobacteriaceae dominated laboratory-reared tenerals from a colony fed a carrot-based larval diet, while Acetobacteraceae dominated mass-reared tenerals from a production facility colony fed a lucerne chaff based larval diet. As adult flies matured, Enterobacteriaceae became dominant irrespective of larval origin. The inclusion of yeast in the adult diet strengthened this shift away from Acetobacteraceae towards Enterobacteriaceae. Interestingly, irradiation increased 16S rRNA gene sequence read volume.ConclusionsOur findings suggest that bacterial populations in fruit flies experience significant bottlenecks during metamorphosis. Gut bacteria in teneral flies were less abundant and less diverse, and impacted by colony origin. In contrast, mature adult flies had selectively increased abundances for some gut bacteria, or acquired these bacteria from the adult diet and environment. Furthermore, irradiation augmented bacterial abundance in mature flies. This implies that either some gut bacteria were compensating for damage caused by irradiation or irradiated flies had lost their ability to regulate bacterial load. Our findings suggest that the adult stage prior to sexual maturity may be ideal to target for probiotic manipulation of fly microbiota to increase fly performance in SIT programmes.

The effect of dietary nitrate and canola oil alone or in combination on fermentation, digesta kinetics and methane emissions from cattle

Nitrate and lipids have been recognized as effective dietary additives to reduce enteric methane (CH4) production. The objective of this experiment was to evaluate the effects of nitrate (NO3¯) and canola oil, alone or in combination, on enteric CH4, volatile fatty acid (VFA) concentrations, digesta kinetics and outflow of DM and microbial non-ammonia nitrogen (MicNAN) from the rumen of cattle. Four rumen-cannulated steers were used in the experiment which was designed as 4 × 4 Latin Square with four 21-d periods and four treatments. Dietary treatments consisted of a control diet (CON: 400 g/kg lucerne chaff and 600 g/kg barley grain), NO3¯ (CON + 20 g NO3¯/kg), O (CON + 50 g canola oil/kg), and NO3¯+O (CON + 20 g NO3¯/kg + 50 g canola oil/kg) with all inclusions expressed as g/kg as-fed. Exogenous markers (Co-EDTA, Yb-acetate and 15NH4Cl) were continuously infused into the rumen over 4 d to estimate digesta flow and rumen N outflow while whole tract digestibility (DMD) was determined using chromic oxide. Compared with the CON diet, feeding the NO3¯+O diet reduced (P < 0.01) methane yield (MY, g CH4/kg DMI) by 25%, daily methane production (DMP, g CH4/d) by 26% (P < 0.01) and the rumen mean retention time (MRT; P < 0.05). Nitrate containing diets reduced DMD (P < 0.01). Total VFA did not differ between treatments (P > 0.05) but NO3¯-containing diets increased acetate proportion (P < 0.01) whereas feeding the O diet increased propionate proportion (P < 0.01). Oil-containing diets reduced rumen volume (P < 0.01). The rumen protozoa concentration was reduced by including NO3¯ and canola oil alone or in combination in the diet of cattle (P < 0.05). This experiment demonstrates that feeding NO3¯+O has a synergistic effect on reducing methanogenesis from beef cattle which is consistent with NO3¯ and canola oil having complementary mechanisms for suppressing enteric CH4 production. Reducing methanogenesis by feeding NO3¯+O in this experiment did not improve the flow of MicNAN from the rumen (g MicNAN/d), microbial growth efficiency (g MicNAN/digestible organic matter intake, DOMI) or the proportion of microbial N derived from rumen NH3.

Treatment with potassium bromide mitigates ataxia and reduces tremor in lambs with perennial ryegrass toxicosis

ABSTRACTAims: To assess the use of potassium bromide (KBr) as a therapeutic intervention for perennial ryegrass toxicosis (PRGT) in lambs fed ryegrass seed containing lolitrem B.Methods: Male lambs aged 10–12 months (n = 43) were assigned to receive ryegrass seed containing lolitrem B, at a dose of 0.16 mg/kg/day (Groups 2, 3 and 4), or lucerne chaff and molasses (Groups 1 and 5). Lambs in Groups 2 and 3 were observed for clinical signs and gait changes until defined signs of PGRT were observed, when they were transferred, with lambs in Group 1, to the Testing phase of the trial. Lambs in Group 3 were then treated with a single oral dose of 300 mg/kg bromide. Lambs in Groups 4 and 5 received KBr daily from the start of the trial (540 mg/kg bromide over 3 days then 20 mg/kg daily) and were transferred to the Testing phase after 18 days. Clinical examination and gait assessment, and surface electromyography of the triceps muscle, measuring root-mean-square (RMS) voltages, were carried out on Days 0, 1 and 2 of the Testing phase followed by necropsy, histopathology, measurement of concentrations of bromide in serum and CSF and faecal cortisol metabolites (FCM).Results: In Group 3 lambs, mean composite gait scores decreased between Testing phase Day 0 and Days 1 and 2 (p < 0.001), but increased in lambs in Group 2 between Day 0 and Day 2 (p = 0.015). Scores for lambs in Group 3 on Day 2 were lower than for lambs in Group 2 (p < 0.001). Mean RMS voltages on Day 2 were higher in lambs in Group 2 than Group 3 (p = 0.045). Mean concentrations of bromide in serum were >800 µg/mL in lambs in Groups 3 and 4 on Day 2. Concentrations of FCM were higher in lambs from Group 2 than in Groups 1 or 5, but were similar in Groups 2, 3 and 4. Histopathological findings in the cerebellum of lambs from Groups 2, 3 and 4 were similar, showing pyknosis of neurons within the granular layer of the cerebellum and Purkinje neuron proximal axonal spheroid formation.Conclusions and clinical relevance: A single oral dose of 300 mg/kg bromide in lambs with neurological signs of PRGT resulted in reduced composite gait scores and reduced RMS voltages, indicating a significant improvement in clinical signs of ataxia, movement disorder and muscle tremor associated with the neurotoxic effects of lolitrem B.

Comparison of Gel Larval Diet With Traditional Lucerne Chaff and Carrot Solid Diets for Rearing of Queensland Fruit Fly (Diptera: Tephritidae).

Sterile insect technique (SIT) for Queensland fruit fly, Bactrocera tryoni Froggatt, Australia's most economically damaging fruit fly species, is currently undergoing a major renewal and expansion. SIT relies on efficient and economical mass-rearing procedures that produce high-quality flies. Two solid larval diets, carrot and lucerne chaff, have traditionally been used to rear Queensland fruit fly. Recently, a gel larval diet has been developed to eliminate biological bulking agents from the mass-rearing process, but to date, there has been no direct comparison of gel larval diet with traditional solid diets. In the present study, the performance of flies reared on gel larval diet was compared with the performance of flies reared on carrot and lucerne chaff diets. In addition, to investigate whether the performance of reared flies depends on ancestral diet as well as tested diet, we sourced eggs from a colony maintained on carrot diet and from a colony maintained on a lucerne chaff diet. Overall, the gel diet was as good or better than the solid diets in all quality control parameters, including, egg-larval duration, pupal number, pupal recovery, adult emergence, percentage of fliers, and rate of fliers. Of note, larvae developed faster and pupated more synchronously on the gel diet than on either of the solid diets. At the loading densities used, gel and carrot diets produced less waste than lucerne chaff diet. Gel diets offer a rearing solution for Queensland fruit fly that eliminates biological bulking agents and yields faster and more synchronous larval development without compromising productivity or quality.

Effect of Dietary Grape Pomace and Seed on Ewe Milk and Meat Quality of Their Suckling Lambs

The effect of wine by-products in the feeding of ewes on fatty acid composition of milk and meat of their suckling lambs and the sensory quality of the meat was investigated. Forty-two ewes were fed during the second half of gestation and lactation one out of three treatments: a control diet based on a commercial concentrate and two concentrates supplemented with either 10% grape pomace or 5% grape seed. In addition, all animals had ad libitum access of Lucerne chaff. The control group showed lower concentration of saturated fatty acids (mainly in short and medium chain) and higher monounsaturated fatty acids (mainly oleic acid) in the milk fat, being the total polyunsaturated fatty acids unchanged. However, this variation was not reflected in the meat of the suckling lambs, where only few differences in individual fatty acids were found, such as linoleic acid being highest in the pomace treatment. Spicy and metallic flavours were increased in the wine by-products groups, but overall liking was not affected. The by-products added to the diets may be a good way to reduce costs on feeding and waste, but they were not able to provide a healthier fatty acid profile, neither in milk nor in the meat of the suckling lambs.

Accumulation, Persistence, and Effects of Indospicine Residues in Camels Fed Indigofera Plant.

Indospicine (l-2-amino-6-amidinohexanoic acid) is a natural hepatotoxin found in all parts of some Indigofera plants such as Indigofera linnaei and Indigofera spicata. Several studies have documented a susceptibility to this hepatotoxin in different species of animals, including cattle, sheep, dogs, and rats, which are associated with mild to severe liver disease after prolonged ingestion. However, there is little published data on the effects of this hepatotoxin in camels, even though Indigofera plants are known to be palatable to camels in central Australia. The secondary poisoning of dogs after prolonged dietary exposure to residual indospicine in camel muscle has raised additional food safety concerns. In this study, a feeding experiment was conducted to investigate the in vivo accumulation, excretion, distribution, and histopathological effects of dietary indospicine on camels. Six young camels (2-4 years old), weighing 270-390 kg, were fed daily a roughage diet consisting of Rhodes grass hay and lucerne chaff, supplemented with Indigofera and steam-flaked barley. Indigofera (I. spicata) was offered at 597 mg DM/kg body weight (bw)/day, designed to deliver 337 μg indospicine/kg bw/day, and fed for a period of 32 days. Blood and muscle biopsies were collected over the period of the study. Concentrations of indospicine in the plasma and muscle biopsy samples were quantitated by validated ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The highest concentrations in plasma (1.01 mg/L) and muscle (2.63 mg/kg fresh weight (fw)) were found at necropsy (day 33). Other tissues were also collected at necropsy, and analysis showed ubiquitous distribution of indospicine, with the highest indospicine accumulation detected in the pancreas (4.86 ± 0.56 mg/kg fw) and liver (3.60 ± 1.34 mg/kg fw), followed by the muscle, heart, and kidney. Histopathological examination of liver tissue showed multiple small foci of predominantly mononuclear inflammatory cells. After cessation of Indigofera intake, indospicine present in plasma in the remaining three camels had a longer terminal elimination half-life (18.6 days) than muscle (15.9 days), and both demonstrated monoexponential decreases.

Does energy intake influence diet selection of novel forages by horses?

While it has been shown that diet selection by equids can be influenced by nutritional factors, it is presently unclear how diet choices by horses are modulated when animals are faced with a familiar-novel dichotomy. Therefore, this study aimed to investigate the effect of energy intake on foraging behaviour in horses and the selection of familiar (FF) and nutritious novel (NF) forages. Twelve adult mares were maintained in yards during feeding and were housed in two groups in barren paddocks when not feeding. The experiment lasted for 8 weeks; in weeks 0, 4 and 8 horses received a maintenance diet and in weeks 1–3 and 5–7 horses were switched to a low energy (LE; 80% RDI) or high energy (HE; 120% RDI) diet. In weeks 3 and 7 a two-choice test was presented in a split-plot design, with 12 horses being the main-plot units. The LE and HE diets were applied at the main-plot level (n=6) while the subplots were the 10min feeding intervals (combined over 3 consecutive days) where horses (one at a time) were introduced to a forage preference test (1 to 4). The tests were made up as pairs, based on the nutritional profile, with one being FF (oaten or lucerne chaff) and the other feed was NF (bamboo, tagasaste, willow or saltbush leaf chaff) and presented in a checkerboard design. In wk 8 the preference of all forages together was examined. Forage intake, the number of visits to each zone/bucket and time spent foraging or moving toward each zone/bucket were recorded. Horses demonstrated a greater preference for FF, but there were no differences between the LE and HE diet groups in the proportions of intake of NF. There was a higher acceptance of NF on Day 1, which declined on Day 2 and 3 for both diet groups (P<0.001). The LE group had a marginally higher proportion of zones visits to the NF compared to the HE group (P=0.009). In the final preference test, horses showed a greater acceptance of NF willow, bamboo and saltbush compared with tagasaste (P=0.01). Some possible explanations for the neophobic response seen in this study are discussed.

Postprandial glucose, insulin, and glucagon-like peptide-1 responses of different equine breeds adapted to meals containing micronized maize.

The enteroinsular axis is a complex system that includes the release of incretin hormones from the gut to promote the absorption and utilization of glucose after a meal. The insulinogenic effect of incretin hormones such as glucagon-like peptide-1 (GLP-1) remains poorly characterized in the horse. The aim of this study was to compare postprandial glucose, insulin, and GLP-1 responses of different equine breeds adapted to twice-daily meals containing micronized maize. Four Standardbred horses, 4 mixed-breed ponies, and 4 Andalusian cross horses in moderate BCS (5.5 ± 0.2 out of 9) were fed meals at 0800 and 1600 h each day. The meals contained micronized maize (mixed with soaked soybean hulls and lucerne chaff), with the amount of maize gradually increased over 12 wk to reach a final quantity of 1.7 g/kg BW (1.1 g/kg BW starch) in each meal. Animals had ad libitum access to the same hay throughout. After 12 wk of acclimation, serial blood samples were collected from all animals over a 14-h period to measure concentrations of glucose, insulin, and GLP-1, with meals fed immediately after the 0 and 8 h samples. Glucose area under the curve (AUC) values were similar between breed groups (P = 0.41); however, ponies and Andalusian horses exhibited significantly higher insulin AUC values after both meals compared with Standardbred horses (both P < 0.005). Postprandial GLP-1 AUC values were also significantly higher in ponies and Andalusian horses compared with Standardbred horses (breed × time interaction; P < 0.001). Correlation analysis demonstrated a strong positive association between concentrations of insulin and GLP-1 over time (rs = 0.752; P < 0.001). The increased insulin concentrations in ponies and Andalusian horses may partly reflect lower insulin sensitivity but could also be attributed to increased GLP-1 release. Given that hyperinsulinemia is a recognized risk factor for the development of laminitis in domestic equids, this study provides evidence that the enteroinsular axis warrants further investigation.

Production attributes of Merino sheep genetically divergent for wool growth are reflected in differing rumen microbiotas

Divergent genetic selection for wool growth as a single trait has led to major changes in sheep physiology and metabolism, including variations in rumen microbial protein production and uptake of α-amino nitrogen in portal blood. This study was conducted to determine if sheep with different genetic merit for wool growth exhibit distinct rumen bacterial diversity. Eighteen Merino wethers were separated into groups of contrasting genetic merit for clean fleece weight (CFW; low: WG− and high: WG+) and fed a blend of oaten and lucerne chaff diet at two levels of intake (LOI; 1 or 1.5 times maintenance energy requirements) for two seven-week periods in a crossover design. Bacterial diversity in rumen fluid collected by esophageal intubation was characterized using 454 amplicon pyrosequencing of the V3/V4 regions of the 16S rRNA gene. Bacterial diversity estimated by Phylogenetic distance, Chao1 and observed species did not differ significantly with CFW or LOI; however, the Shannon diversity index differed (P=0.04) between WG+ (7.67) and WG− sheep (8.02). WG+ animals had a higher (P=0.03) proportion of Bacteroidetes (71.9% vs 66.5%) and a lower (P=0.04) proportion of Firmicutes (26.6% vs 31.6%) than WG− animals. Twenty-four specific operational taxonomic units (OTUs), belonging to the Firmicutes and Bacteroidetes phyla, were shared among all the samples, whereas specific OTUs varied significantly in presence/abundance (P<0.05) between wool genotypes and 50 varied (P<0.05) with LOI. It appears that genetic selection for fleece weight is associated with differences in rumen bacterial diversity that persist across different feeding levels. Moderate correlations between seven continuous traits, such as methane production or microbial protein production, and the presence and abundance of 17 OTUs were found, indicating scope for targeted modification of the microbiome to improve the energetic efficiency of rumen microbial synthesis and reduce the greenhouse gas footprint of ruminants.

Molybdenum deprivation, purine ingestion and an astrocyte-associated motor neurone syndrome in sheep: assumed clinical effects of inosine.

An astrocyte-associated motor neurone syndrome was produced in molybdenum-deprived sheep fed xanthosine. Mo-deprived sheep fed inosine, adenosine or guanosine would be also expected to develop astrocyte-associated motor neurone syndromes, because all these purine nucleosides can act as neuromodulators and all depend on the Mo-associated enzyme xanthine oxidase-dehydrogenase for their catabolism. To investigate the relationship between inosine ingestion and low Mo concentration, eight sheep were fed lucerne chaff with a Mo value <0.10 ppm and the Mo antagonist, sodium tungstate, for 21 weeks, with inosine (35 mg/kg/day) fed for the last 18 of these weeks. This clinical study was uncontrolled. An astrocyte-associated motor neurone syndrome was produced in three sheep 18-27 months later. It was characterised by diaphragmatic, laryngeal, lingual and pharyngeal muscle weakness. The diaphragmatic muscle weakness was the most severe and potentially lethal. These findings suggest that purinergic neuromodulation of respiration, vocalisation and swallowing is different to that of limb movement. The syndrome produced, and assumed to be caused by the treatment given, has not been reported in livestock. A similar syndrome is seen in human motor neurone disease, but not in equine motor neurone disease, and this is consistent with it being an upper, not a lower, motor neurone effect.

Repeatability of an In‐Feed Sugar Test in Ponies

Reasons for performing studyInsulin resistance (IR) can be difficult to diagnose from basal insulin and glucose concentrations, so a field‐based oral sugar test (OST) is preferred. However, the repeatability of this test has not been reported.ObjectivesTo determine the repeatability of an in‐feed OST in ponies.Study designA repeated measures, longitudinal study.MethodsEight mixed‐breed ponies received an in‐feed OST at 08.00 h, after an overnight fast, once weekly for 3 weeks. D‐glucose powder (0.75 g/kg bwt), wheat bran (200 g) and water (500 ml) were combined, and mixed with lucerne chaff (0.3% bwt). Blood samples were taken before, and 90 and 180 min after, feeding. All meals were consumed. Blood glucose concentration was determined immediately and serum was obtained for insulin determination by equine‐specific ELISA. Fasting glucose, insulin and glucose:insulin ratios were used to classify ponies as IR, compensated IR or normal on each occasion and the results were compared to the OST.ResultsDiagnosis of IR from basal values was consistent in only 3/8 ponies, with a large mean coefficient of variation (CV) of 51% for baseline insulin, across tests. The OST results were repeatable in 7/8 ponies, with mean CV at 25% for the 90 min insulin sample (CV for 7 ponies: 19%). The OST was repeatable on 2/3 occasions in the eighth pony, however, resting hyperinsulinaemia meant that IR was diagnosed on 3/3 occasions using basal values in this pony. There was significant (P&lt;0.05) variability in insulin concentration at 180 min, but not 90 min, across tests.ConclusionsAn OST is more repeatable when assessing IR in ponies than basal values/ratios. Both resting hyperinsulinaemia and insulin responses to oral sugar can be assessed with the OST, which increases the likelihood of accurately diagnosing IR. Blood sampling at 90 min post feeding is recommended for more consistent results.Ethical animal research: The experimental protocol was approved by the Animal Ethics Committee of the University of Queensland (SVS/QUT/109/13/QUT). Sources of funding: This study was funded by Queensland University of Technology. Competing interests: None.

An animal house study on utilisation of fresh tedera (Bituminaria bituminosa var. albomarginata and crassiuscula) by Merino wethers

Bituminaria bituminosa is a drought-tolerant, perennial legume that has been used for centuries as a part of the mixed sward in grazing systems around the Mediterranean sea and ‘cut and carried’ to feed as hay to dairy goats in the Canary Islands; varieties albomarginata and crassiuscula, commonly known as tedera, are native only to the Canary Islands. In south-western Australia, tedera will likely be directly grazed as green plants to help fill the feed gap in summer–autumn, due to its drought tolerance and capacity to retain green leaves. There are no reports of ill-effects of grazing tedera in its native environment; however, tedera is never the sole diet there. Hence, before proceeding to grazing trials it was important to conduct pen feeding studies with a sole diet of tedera. Sheep fed fresh tedera exclusively for 34 days readily consumed the forage and remained in good health, as reflected by a standard set of blood chemistry parameters. Furthermore, while the intake of the sheep fed tedera may not have been ad libitum (~1.0 kg DM/head.day), they maintained their liveweight (42.5 kg) and body condition (condition score 3) throughout the experiment. This is the first experiment to measure the in vivo digestibility and nitrogen balance of sheep fed ‘fresh’ tedera forage. During the metabolism study, the in vivo digestibility of organic matter in the dry matter of the fresh tedera was similar to that of lucerne chaff (59% vs 55%) when the sheep fed lucerne chaff had their intake restricted to that of those fed tedera.

Effect of dietary potassium supplementation on the calcium absorption capacity in the rumen and abomasum and fractional excretion of urinary minerals in sheep

The aim of this study was to determine the effect of potassium (K) supplementation on the calcium (Ca) absorption capacity from the rumen and abomasum of sheep. The Ca absorption capacity from the rumen and abomasum of sheep was measured using stable strontium (Sr) as a Ca-analogue tracer method. The sheep, cannulated at either the rumen or abomasum, were randomly allocated to one of two groups (control or K-supplemented) and fed in individual metabolism pens twice daily with a diet comprising oaten hay, lucerne chaff and barley fortified with or without potassium carbonate (K2CO3). The K content of the diet of the K-supplemented animals was 3.1% of dry matter compared with 1.4% for the control animals. The animals were fed their respective diets for a period of 2 weeks. The fractional absorption capacity (FC) of Ca was estimated before, during and after the treatment period. Supplementation with K decreased the FC of Ca in both the rumen and abomasum during treatment and increased the FC of Ca in the abomasum post-treatment. Supplementation with K also increased the fractional excretion of K in the urine, but decreased the fractional excretion of Ca and magnesium (Mg) (P &lt; 0.05), showing that K supplementation significantly affected Ca and Mg metabolism. Results suggest that renal conservation of Ca and Mg is an important mechanism controlling the Ca and Mg pool for vital functions of the body. In times of high demand for these minerals during lactation and pregnancy, high K in the diets may predispose sheep to hypomagnesaemia and hypocalcaemia, which in turn will have a negative impact on productivity and economic returns.

The β3-adrenergic agonist (BRL35135A) improves feed efficiency and decreases visceral but not subcutaneous fat in lambs

There is evidence that an atypical adrenoreceptor subtype is involved in mediating some of the physiological effects of catecholamines, particularly in some adipose tissue sites. Therefore, a study was conducted to determine the effect of the β3-agonist BRL35135A on growth performance and body composition in ruminant lambs. Twenty-two second cross wether lambs (32.5±0.7kg) were individually-housed in pens and randomly allocated on the basis of stratified live weights to two treatments (n=11 per treatment). The control group were offered barley (20%) and lucerne chaff (80%) ad libitum and the treated group were given the BRL35135A (1mg/30kg live weight) with the feed. Feed refusals were recorded daily and lambs weighed weekly. After 42days all lambs were slaughtered commercially and carcass, visceral organ and fat depots recorded. Chilled carcasses were scanned by dual-energy X-ray absorptiometry to measure body composition. Dietary β3-agonist treatment had no effect on average daily gain, final live weight or carcass weight but reduced residual feed intake (0.41 vs −0.41, P=0.061). There were no effects of dietary β3-agonist treatment on carcass chemical composition but β3-agonist treatment increased the weight of the feet (0.89 vs 0.94kg, P<0.05) and the skin (4.22 vs 4.56kg, P<0.05). Dietary β3-agonist treatment decreased the weight of the omental (0.64 vs 0.51kg, P<0.05) and perirenal (0.30 vs 0.23kg, P<0.05) fat depots. In conclusion, these data confirm that BRL35135A was active in sheep when given with feed, as indicated by a partitioning of nutrients from visceral fat mass and an improvement in feed efficiency. The effects on adipose tissue were specific to omental and perirenal fat as there was no change in carcass fat and these data are consistent with β3-receptors being the predominant β-receptor subtype in internal fat tissues.

Motor neurone disease in molybdenum‐deficient sheep fed the endogenous purine xanthosine: possible mechanism for Tribulus staggers

The occurrence of Tribulus terrestris motor neurone disease (MND) in sheep is linked with grazing Tribulus growing on cultivation paddocks. A previous survey found that the molybdenum (Mo) content of Tribulus growing on uncultivated soils in the Coonabarabran district of New South Wales was 3.03 ppm, but on cultivated soils it was <0.04 ppm. Tribulus contains the purine, xanthosine, which functions as a neuromodulator, and the catabolism of xanthosine is Mo-dependent. To investigate the relationship between xanthosine ingestion and low Mo concentration, eight sheep were fed Mo-deficient lucerne chaff (<0.10 ppm), the Mo antagonist, sodium tungstate, and xanthosine (25 mg/kg/day) over 18 weeks and then returned to pasture. Signs of MND developed in two sheep 30 months later and astrocyte degeneration occurred in all sheep. The findings were similar to those observed in sheep with T. terrestris MND, suggesting that the combination of xanthosine ingestion and Mo deficiency may be the cause of this disorder.