Increasing the proportion of Leucaena leucocephala in hay-fed beef steers reduces methane yield

peer reviewedContext: Leucaena leucocephala (leucaena) is a leguminous shrub adapted to higher rainfall (>600 mm) in frost-free areas of Australia. It can be a source of high-quality forage for cattle grazing tropical grass-based pastures that are seasonally deficient in the nitrogen content required for adequate levels of performance. Leucaena contains bioactive compounds that may reduce methanogenesis in the rumen, helping to achieve Australia's goal to make red meat production carbon neutral by 2030. Aim: A study was undertaken to evaluate the response in animal performance and methane production to increasing percentages of leucaena in a hay-based diet. Methods: Growing steers were fed diets containing 0%, 18%, 36% and 48% leucaena. Intake, liveweight gain, methane production and yield were measured in a cross-over trial with two modern cultivars of leucaena (Redlands and Wondergraze). Methane was measured in open-circuit respiration chambers. Key results: There were no effects of cultivar on most parameters. Increasing leucaena percentage in the diet increased dry matter intake, animal performance and methane production (g/day) but reduced methane yield (g/kg dry matter intake) according to the equation: methane yield = 19.8-0.09 × leucaena percentage in the diet. The inclusion of polyethylene glycol to nullify potential antimethanogenic activity of tannins restored methane yield by 67%, indicating that tannins were responsible for most of the observed reduction in methane yield. Conclusion: The results demonstrate that leucaena can improve animal performance and reduce methane yield in steers fed low-quality grasses. Implications: Leucaena can be included in diets of grazing cattle in areas agronomically suited to its production, as a means to reduce enteric methane emissions

Effects of Na intake on Na conservation, digestion and mineral metabolism in growing ruminants fed Stylosanthes hamata cv. Verano

Effects of adequate (2 g NaHCO/l drinking water) or low Na intake on Na conservation, live-weight gain, roughage digestion and mineral metabolism were studied in nine young goats and six cattle for 3-6 months fed a diet of Stylosanthes hamata cv. Verano containing 7 %;

Treatment of experimentally induced Lantana poisoning in sheep

Lantana poisoning was induced in sheep by giving 4 g kg−1 Lantana camara orally. When the contents of the rumen were removed from sheep three or six days after giving them lantana and placed into the empty rumens of normal sheep, the recipient sheep became intoxicated. Administration of purgatives such as raw linseed oil or Glauber's salts orally, or administration of bethanechol subcutaneously failed to stimulate rumen motility in lantana poisoned sheep and are therefore unlikely to be effective in eliminating residual toxin from the rumen. Intravenous administration of a multiple electrolyte solution to lantana poisoned sheep improved rumen motility, and motility was increased even more when 2–3 1 of freshly collected rumen liquid was given orally to rehydrated animals. However, these treatments did not restore motility to normal and animals treated by these methods did not survive the intoxications. The effect of manually removing the rumen contents from sheep with lantana poisoning was studied in sheep with chronically‐implanted rumen cannulae. When the rumen contents were removed from sheep three days after lantana was given and replaced with fresh rumen contents or a multiple electrolyte solution, there was a significant increase in survival compared with untreated sheep. Removal of rumen contents at six days and replacement with fresh rumen contents or simulated rumen contents containing a buffered mixture (pH 6.7, ‐ 330 mV) of lucerne and rumen liquid, also significantly increased survival, but replacement with a multiple electrolyte solution did not. It is concluded that lantana poisoning can be treated by removing the residual toxin from the rumen and re‐establishing rumen fermentation. Copyrigh