Utilisation de l'azote des fourrages verts par le mouton en croissance : influence du stade de végétation, de l'espèce fourragère, de la fertilisation azotée et de l'addition d'orge

Grenet, Élisabeth; Demarquilly, C.; Boissau, J.-M.; Bousquet, H.; Dudilieu, Madeleine; Jailler, Marie; Jamot, Jacquelme; L'hôtelier, L.

doi:10.1051/animres:19770402

Cited by 4 publications

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“…The digestibility of the organic matter also affects nitrogen retention: the higher the digestibility the greater the nitrogen retention. This relationship has already been observed for fresh fodder material (Grenet & Demarquilly, 1977). In addition, the quality of the silage preservation as judged by its fermentation characteristics greatly influences the nitrogen retention.…”

Section: Discussionsupporting

confidence: 64%

“…The nitrogen retention, which was quite similar for lucerne and grass silages, varied from 1-3 to 6-8 g/day, whilst the differences between fresh lucerne (12-9 g of nitrogen retained per day) and fresh grasses ( -0'2 to 6-1 g of nitrogen retained per day) were greater (Grenet & Demarquilly, 1977).…”

Section: Comparison Of Different Additives and Speciesmentioning

confidence: 85%

“…With cocksfoot silages the nitrogen retentions were higher with the silages than with the fresh forages, unlike the other Gramineae; this arose essentially because the urine losses were lower. It is true that with cocksfoots the nitrogen balances tend to be only slightly positive: nevertheless it has already been shown (Grenet & Demarquilly, 1977) for the fresh forages that sheep fed with cocksfoot retained less nitrogen at the same nitrogen intake and the same digestible organicmatter intake than the ryegrass-fed animals. It was supposed that cocksfoots, poorer in soluble carbohydrates (2-7-10-4 % of dry matter depending on the maturity against 8-7-21-6% for the ryegrasses) contained less rapidly available energy for microbial synthesis.…”

Section: Discussionmentioning

confidence: 98%

“…Table 6 shows the influence of the principal factors that affect nitrogen retention for the 87 grass silages and the 21 lucerne silages. Nitrogen retention increases with nitrogen intake (either as total nitrogen or as insoluble nitrogen) and with the amount of digestible organic matter consumed, although the correlations are poorer than with the fresh forages (Grenet & Demarquilly, 1977). The digestibility of the organic matter also affects nitrogen retention: the higher the digestibility the greater the nitrogen retention.…”

Section: Discussionmentioning

confidence: 99%

“…The nitrogen retention of sheep fed the standing parent crops and the direct-cut silages with or without additive was measured to assess the effect of additives on nitrogen retention, and to see whether the nitrogen retention could be predicted from the silage characteristics. Results on nitrogen retention in sheep given fresh forages have been published previously (Grenet & Demarquilly, 1977).…”

Section: Introductionmentioning

confidence: 99%

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Utilization of grass-silage nitrogen by growing sheep

Grenet¹

1983

J. Agric. Sci.

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The digestibility, the voluntary intake and the nitrogen balance of 108 diets corresponding to 94 silages prepared from 20 fresh crops were measured in growing sheep. Series of silages were made from the same fresh forage. Each series included two "controls: a direct-cut silage without additive and a direct-cut silage with formic acid, with a variable number of experimental silages with different additives.Rumen ammonia concentration, measured on rumen-fistulated sheep, decreased when an additive was used. It increased with nitrogen intake and was inversely related to the organic-matter digestibility and the crude-fibre digestibility. It varied with the silage composition.The crude-protein digestibility of direct-cut silages without additives was similar to or slightly higher than the crude-protein digestibility of the fresh crops. The addition of formic acid depressed the digestibility, but the addition of formaldehyde decreased it even more. The urinary nitrogen loss was higher for silages without additive than for the fresh crops and was decreased by the addition of formic acid. The addition of formaldehyde to formic acid had an additive effect.Retained nitrogen was lower in silages without additives (12% of nitrogen intake) than in parent crops (15-7%). It increased when formic acid (15-8%) was added. The addition of formaldehyde at a low rate (1-5 1/t green fodder) to the formic acid did not increase the nitrogen retention whether expressed in g/day or as percentage of nitrogen intake, but the addition of formaldehyde at a high rate (3-5 1/t green fodder) to formic acid decreased nitrogen retention. The other additives based on cereals or whey did not improve the nitrogen balance compared with formic acid. Nitrogen retention differed according to plant species.Retained nitrogen increased with digestible organic-matter intake and nitrogen intake. It increased with the silage water-soluble carbohydrate content. The higher the silage fermentation product content (ammonia, lactic acid, propionic acid), the lower the retained nitrogen. It appears that the nitrogen value of silages can be high provided that the silages are well preserved and that excessive protein breakdown is avoided. INTRODUCTIONammonia nitrogen). At the same time, a great decrease in water-soluble carbohydrates, which The nutritive value of silages depends first on are broken down into organic acids and alcohols, the nutritive value of the fresh herbage but is takes place. Consequently, more nitrogen is lower on average, particularly with respect to the degraded in the rumen where excessive ammonia is nitrogen value. The proteins of the forages are produced, and higher urinary nitrogen losses occur hydrolysed by the plant proteases (soon after while the amount of amino acids at the animal's ensiling): the slower the decline in pH, the greater disposal is reduced and the amount of nitrogen the proteolysis. Afterwards partial deamination retained is decreased (Conrad et al. 1961;Durand, and decarboxylation of amino acids take place Zelter & Tisse...

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Section: Discussionsupporting

confidence: 64%

Section: Comparison Of Different Additives and Speciesmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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