The effect of feeding animals ad libitum vs. at maintenance level on the in vivo digestibility of mown herbage from two permanent grasslands of different botanical composition

The aim of this experiment was to study the effect of feeding level (FL) on the digestibility of unconserved forage obtained from two permanent grasslands cut at three different dates during the first cycle of growth. Forage was offered to Texel sheep (wethers), at maintenance level and at ad libitum level. Differences in voluntary intake (VI) between grasslands were also tested. Organic matter digestibility (OMD) measured at ad libitum level and at VI was 13% higher on harvested forage from grassland rich in forbs (GRF) than grassland rich in grasses (GRG) at early herbage growth stages, but these differences were no longer found at later maturity stages. In GRF, there were no differences for OMD, at either FL at the young growth stages, but at the end of the cycle the OMD obtained at ad libitum level (0·56) was higher than that at maintenance level (0·50). However, in GRG, at an early stage of forage maturity, OMD at ad libitum level (0·67) was lower than that at maintenance level (0·70), but this difference was no longer found at the end of the growth cycle. In conclusion, the effect of FL on the digestibility of unconserved forage from permanent grasslands depends on the type of grassland. These differences are mainly explained by the different botanical composition of the grassland types.

[1]  J. Andrieu,et al.  NIRS prediction of the feed value of temperate forages: efficacy of four calibration strategies. , 2011, Animal : an international journal of animal bioscience.

[2]  P. Cruz,et al.  Nutritive value of two meadows and relationships with some vegetation traits , 2010 .

[3]  P. Huhtanen,et al.  A meta-analysis of feed digestion in dairy cows. 1. The effects of forage and concentrate factors on total diet digestibility. , 2009, Journal of dairy science.

[4]  P. Huhtanen,et al.  A meta-analysis of feed digestion in dairy cows. 2. The effects of feeding level and diet composition on digestibility. , 2009, Journal of dairy science.

[5]  M. Duru,et al.  Relevance of Plant Functional Types based on Leaf Dry Matter Content for Assessing Digestibility of Native Grass Species and Species‐Rich Grassland Communities in Spring , 2008 .

[6]  M. Bruinenberg,et al.  Dairy cow performance on silage from semi-natural grassland , 2006 .

[7]  L. Fiems,et al.  Agri-environmental grass hay: nutritive value and intake in comparison with hay from intensively managed grassland , 2004, Archives of animal nutrition.

[8]  M. Bruinenberg,et al.  Factors affecting digestibility of temperate forages from seminatural grasslands: a review , 2002 .

[9]  A. Nianogo,et al.  Effect of selective consumption on voluntary intake and digestibility of sorghum (Sorghum bicolor L. Moench) stover, cowpea (Vigna unguiculata L. Walp.) and groundnut (Arachis hypogaea L.) haulms by sheep , 2000 .

[10]  A. M. Vuuren,et al.  Effect of reducing nitrogen fertilizer on grassland on grass intake, digestibility and milk production of dairy cows , 2000 .

[11]  D. Wilman,et al.  Physical breakdown of chickweed, dandelion, dock, ribwort, spurrey and perennial ryegrass when eaten by sheep and when macerated , 1997, The Journal of Agricultural Science.

[12]  P. Udén,et al.  The effect of feeding level on intake and digestibility of Rhodes grass (Chloris gayana, cv Kunth) by dairy cows , 1997 .

[13]  P. V. Soest,et al.  Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. , 1991, Journal of dairy science.

[14]  D. Mertens,et al.  Intake and digestibility by wethers as influenced by forage morphology at three levels of forage offering. , 1990, Journal of animal science.

[15]  E. Owen,et al.  Feeding straw to small ruminants: effect of amount offered on intake and selection of barley straw by goats and sheep , 1990 .

[16]  G. Fahey,et al.  Effects of intake and forage level on site and extent of digestion of plant cell wall monomeric components by sheep. , 1990, Journal of animal science.

[17]  R. H. Armstrong,et al.  The voluntary intake and in vivo digestibility of herbage harvested from indigenous hill plant communities , 1986 .

[18]  L. Raab,et al.  The estimation of the digestibility and metabolizable energy content of ruminant feedingstuffs from the gas production when they are incubated with rumen liquor in vitro , 1979, The Journal of Agricultural Science.

[19]  J. M. A. Tilley,et al.  A TWO-STAGE TECHNIQUE FOR THE IN VITRO DIGESTION OF FORAGE CROPS , 1963 .

[20]  W. F. Raymond,et al.  Studies in the digestibility of herbage. 7. Further evidence on the effect of level of intake on the digestive efficiency of sheep. , 1959 .

[21]  K. Blaxter,et al.  Some observations on the digestibility of food by sheep, and on related problems , 1956, British Journal of Nutrition.

[22]  G. Lemaire,et al.  Changes in the permanent grassland composition and feeding value during the growing season. , 2002 .

[23]  P. Udén,et al.  Promising tropical grasses and legumes as feed resources in Central Tanzania IV. Effect of feeding level on digestibility and voluntary intake of four herbaceous legumes by sheep , 1998 .

[24]  C. Demarquilly,et al.  Digestibilité et ingestibilité des fourrages verts chez le mouton : effets respectifs du niveau d'alimentation et de l'âge ou du poids des animaux , 1987 .

[25]  N. Bartiaux-Thill,et al.  Influence du niveau d'alimentation, de la supplémentation et de la qualité de l'herbe sur la digestibilité en vue de la mesure de l'ingestion au pâturage , 1987 .