EFFECT OF QUALITY OF FORAGE ON AVAILABILITY OF TRACE ELEMENTS AND SOME MAJOR ELEMENTS

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1 EFFECT OF QUALITY OF FORAGE ON AVAILABILITY OF TRACE ELEMENTS AND SOME MAJOR ELEMENTS M. Lamand, Non Renseigné, Y. Rayssiguier, J.C. Tressol, Claudine Lab, Annie Bellanger To cite this version: M. Lamand, Non Renseigné, Y. Rayssiguier, J.C. Tressol, Claudine Lab, et al.. EFFECT OF QUALITY OF FORAGE ON AVAILABILITY OF TRACE ELEMENTS AND SOME MAJOR ELEMENTS. Annales de Recherches Vétérinaires, INRA Editions, 1977, 8 (3), pp <hal > HAL Id: hal Submitted on 1 Jan 1977 HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

2 EFFECT OF QUALITY OF FORAGE ON AVAILABILITY OF TRACE ELEMENTS AND SOME MAJOR ELEMENTS M. LAMAND D.AMBOULOU Y. RAYSSIGUIER J.C. TRESSOL Claudine LAB Annie BELLANGER &dquo; Laboratoire des Maladies Nutritionnelles ** Laboratoire des Maladies Métaboliques I.N.R.A., C.R.Z.V. de Theix, BEAUMONT, France Résumé EFFET DE LA QUALITE DU FOURRAGE SUR LA DIGESTIBILITE DES OLIGO-ELEMENTS ET DE QUELQUES ELEMENTS MAJEURS. &horbar; L influence de la qualité du fourrage sur la digestibilité du cuivre, zinc, manganèse, calcium et magnésium a été étudiée au cours des deux périodes de bilan sur agneaux en croissance (25 kg). Les animaux ont reçu successivement un ray-grass italien, premier cycle stade épiaison, distribué sous forme d herbe congelée ou sous forme de foin séché au sol dans de très mauvaises conditions météorologiques. Le cuivre et le zinc ont été nettement moins digestibles et moins bien retenus dans le foin que dans l herbe. La digestibilité du manganèse n a pas été affectée par la qualité du fourrage mais par sa teneur en cet élément. Les digestibilités du calcium et du magnésium n ont pas été modifiées. La rétention du calcium a évolué parallèlement à l ingestibilité de la ration. Introduction Poor quality forages have been shown to produce mineral deficiencies in ruminants. Several factors are involved but an insolved question is the role played by the low level of minerals in the diet and the influence of poor quality forage which is ingested less and poorly digestible. For instance, we observed (Lamand, unpublished results) clinical and biochemical copper and zinc deficiencies in sheep receiving poor hay. It was therefore of interest to examine the availability of some minerals in hay dried in poor weather conditions. Experimental procedures Italian Rye Grass (first cycle) at the earing stage was cut and a part was immediately frozen, while the second part was dried in the field for five weeks. The hay was dampened by rainfall about every three days. The frozen grass (allowed to thaw at room temperature) and the hay were given succes-

3 sively to six growing lambs (Limousin x Romanov) weighing on the average 25 kg body weight in two balance trials of 5 days. The pre-experimental period before each balance lasted three weeks. Care was taken to avoid contaminations in order to insure an optimum accuracy. Digestibility and retention of the elements were computed without taking the urinary excretion into account. The trace elements were determined by atomic absorption spectrophotometry and the experimental conditions were those already described (Lamand, 1974). Calcium and magnesium were determined by atomic absorption spectrometry with lantanum (avoiding interferences) after dry ashing, and phosphorus by a colorimetric method. Results The hay looked strawy but not very mouldy. It was less ingested than the grass (table 1) and its dry matter was poorly digestible (ten points lower than the corresponding grass). The poor weather conditions did not leach out analysed minerals but on the. contrary enhanced the content of some major (P and Mg) and trace elements (Cu, Zn and mainly Mn). (Tables 1, 2.) However the ash content, from 11 % in the grass, decreased to 9 % in the hay. The availability of copper and zinc dropped significantly in the hay compared to the grass. In contrast, manganese digestibility and retention rose like the manganese content. There was a drop in Ca and P retention and no change in Mg digestibility when lambs were fed with hay (Table 3).

4 Discussion The rainfall did not leach out the analysed minerals ; on the contrary there was an increase in some minerals especially for manganese. Contamination by the soil was possible, but certainly limited because the ash content was low. Leaching induced losses of dry matter, mainly cellular contents, thus modifying the hay mineral pattern in comparison with the grass. The beneficial influence of hay quality is a commonly admitted idea but it has never been demonstrated as far as trace element s availability is concerned. The influence of quality is important for copper and zinc digestibility and retention. Miller and Cragle (1965) already noticed a positive correlation between the dry matter digestibility of a diet and zinc retention. We succeeded in lowering plasma zinc below 70 pg/100 ml, within three weeks in ten ewes receiving exclusively a poor hay containing 28 mg zinc/kg D.M. The influence of a diet s digestibility characteristics on zinc availability probably explains the differences between different author s work on ruminant requirements for zinc. In contrast, manganese availability does not seem to be influenced by the forage quality : its manganese content seems to be the most important factor modifying manganese retention. Our results agree with the conclusions of Lomba, Chauvaux and Bienfet (1975) who found that manganese intake is the main factor influencing manganese retention in cattle. Poor quality forage was less ingested than grass which induced a significant drop in the calcium intake quantity. The increase in phosphorus and magnesium level explained the constancy of ingested quantities of these two elements with poor hay. Poor quality forage induced a lower intake which could not cover the requirements for growing lambs. Growth retardation could explain the decrease of Ca, which could also be related to the effect of decreased ingested amount, since young ruminants absorb and retain Ca in direct relation to intake (Braithwaite, 1976). Mineral availability might be affected by the quality of forage. Leibholz (1974) has shown that P availability is reduced in sheep given

5 a low energy diet, and rough forage increases salivary secretion and phosphorus excretion (Tomas, 1974). The influence of the stage of herbage growth on mineral availability has already been shown (Gueguen and Demarquilly, 1975). This effect might also be related to the forage quality. Changing to the poor hay, modifies fermentations in the forestomachs which are the main site of Mg absorption (Tomas and Potter, 1976). Many factors might affect Mg availability : carbohydrates in the diet (Madsen et al., 1976), volatile fatty acids (Rayssiguier and Remesy, 1976) and the diet s physical form (Amboulou, Lamand and Rayssiguier, 1977). However, the good Mg digestibility with poor hay is not surprising since consumption of straw or rough hay has been shown to increase magnesemia when ruminants are fed with grass (Larvor, Brochart and Ladrat, 1960). There was no drop in Mg absorbed with poor hay but urinary loss of Mg has not been investigated and Mg retained is unknown. In conclusion, with the use of poorly digestible diets such as poor hay or straw, the copper and zinc should be given according to recommandations of the Agricultural Research Council, if not in greater quantities, and the retention of calcium and phosphorus might be affected by the poor quality and lower intake of these diets. Accepted for publication, June Summary The effect of forage quality on copper, zinc, manganese, calcium, phosphorus and magnesium availability were studied. Six growing lambs (25 kg) received successively frozen grass (Italian Rye Grass, first cycle at earing stage) and the same plant as hay dried after a very wet period in two balance trials. Copper and zinc digestibility and retention dropped more significantly with poor hay than with grass, Manganese availability was not modified by forage quality but by its content. There was a drop in calcium and phosphorus retention and no change in Mg digestibility when lambs were fed with hay. References AMBOULOU L., LAMAND M., RAYSSIGUIER Y., Chopping versus grinding and pelleting of hay : effect on availability of trace elements and major elements. Ann. Rech. Vet., 8, 1-6. BRAITHWAITE G.D., Calcium and phosphorus metabolism in ruminants with special reference to parturient paresis. J. Dairy Res., 43, GUEGUEN L., DEMARQUILLY C., influence of the vegetative cycle and the growth stage on the mineral value of some herbage plants for adult sheep. In International Grassland Congress., C.LP. Edit., Sao Paulo Brasil, LARVOR P., BROCHART M., LADRAT J., Influence d un supplement fibreux sur la magnesemie des bovins a I herbe. Ann. Zootech., 9, LEIBHOLZ J., The flow of calcium and phosphorus in the digestive tract of the sheep. Austr. J. Agric. Res., 25, LOMBA F., CHAUVAUX G., BIENFET V., Recherches statistiques sur la digestibilit6 du manganese alimentaire chez les bovins, precisions sur leurs besoins en cet 616ment. Ann. Nutr. Alim., 29, MADSEN F.C., LENTZ D.E., MILLER J.K., LOWREY-HARNDEN D.. HANSARD S.L., Dietary carbohydrate effects upon magnesium metabolism in sheep. J. Anim. Sci., MILLER J.K., CRAGLE R.G., Gastrointestinal sites of absorption and endogenous excretion of zinc in dairy cattle. J. Dairy Sci., 48, RAYSSIGUIER Y., REMESY C., Magnesium absorption in the caecum of rats related to volatile fatty acids production. Ann. Rech. Vet., TOMAS F.M Phosphorus homeostasis in sheep. Ill. Relationship between the amount of salivary phosphorus secreted and the quantities of phosphorus excreted via the urine and faeces. Austr. J. Agric. Res., 25, TOMAS F.M., POTTER B.J., The site of magnesium absorption from the ruminant stomach. Br. J. Nutr., 36,