Intake and digestibility in cattle grazing temperate grass associated with legume and/or energetic supplementation

The intercrop between grasses and legumes is an alternative to maintain and increase animal production. The study was conducted to evaluate the effect of grass-legume mixtures with or without supplementations on rumen fermentation, nutrient intake, and microbial protein synthesis. Six Holstein steers fitted with ruminal cannula were kept in a double 3 × 3 Latin square design. The treatments were: 1) oat, annual ryegrass, and supplement (GS), 2) oat, annual ryegrass, and vetch (GL), 3) oat, annual ryegrass, vetch, and supplement (GLS). Supplementation of ground maize was given daily at 11 h at 1% of body weight. Total digestible nutrient intake was higher in steers fed GS and GLS. Animals on GL ingested higher concentrations of nitrogen (N) compared to animals on GS and GLS diets. Ruminal pH and ammonia concentration were higher in GL. Grass-legume mixtures and supplements showed higher concentrations of sugar, α-amino acids, and peptides. The ruminal fermentative parameters, ruminal pH, ammonia, and sugars ranged cubically across the day. Microbial protein synthesis was similar amongst the treatments. Animals exclusively consuming temperate grass produce higher ruminal pH and ammonia concentrations. Therefore, using temperate legumes in pasture systems can be included in the cattle diet in lieu of utilizing energy supplements.

The Proximate Compositions And Rumen Degradabilities Of Some Tropical And Temperate Legumes

The proximate compositions and degradabilities in the rumen of tropical legumes (peas and beans) and temperate peas were studied with the aim of comparatively evaluating their nutritive potential for ruminants. The mean crude fibre content of temperat peas (11.3%) was higher than for tropical peas and beans. The mean gross energy contents of tropical peas (18.2 MJ/kg) and beans (18.6 MJ.kg) were higher than for temperate peas (17.0 MJ/kg) despite a higher mean ash value for the tropical types. Other proximate components were very similar for both tropical and temperate legumes although lima bean had a higher crude protein content. Generally the individual compositions of both the temperate peas and were within the range of published values for tropical legumes. The degradabilities of the dry matter and crude protein in the rumen of hay-fed cows were comparable for both tropical and temperate type legumes.

Infection and Invasion of Roots by Symbiotic, Nitrogen-Fixing Rhizobia during Nodulation of Temperate Legumes

SUMMARY Bacteria belonging to the genera Rhizobium, Mesorhizobium, Sinorhizobium, Bradyrhizobium, and Azorhizobium (collectively referred to as rhizobia) grow in the soil as free-living organisms but can also live as nitrogen-fixing symbionts inside root nodule cells of legume plants. The interactions between several rhizobial species and their host plants have become models for this type of nitrogen-fixing symbiosis. Temperate legumes such as alfalfa, pea, and vetch form indeterminate nodules that arise from root inner and middle cortical cells and grow out from the root via a persistent meristem. During the formation of functional indeterminate nodules, symbiotic bacteria must gain access to the interior of the host root. To get from the outside to the inside, rhizobia grow and divide in tubules called infection threads, which are composite structures derived from the two symbiotic partners. This review focuses on symbiotic infection and invasion during the formation of indeterminate nodules. It summarizes root hair growth, how root hair growth is influenced by rhizobial signaling molecules, infection of root hairs, infection thread extension down root hairs, infection thread growth into root tissue, and the plant and bacterial contributions necessary for infection thread formation and growth. The review also summarizes recent advances concerning the growth dynamics of rhizobial populations in infection threads.