Composition, Intake, Digestibility, and Prediction of Digestibility of Coastal Bermudagrass Hays

Hawkins, George; Paar, Gary E.; Little, Joe A.

doi:10.3168/jds.s0022-0302(64)88791-9

Cited by 7 publications

(1 citation statement)

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“…Simpler methods were later developed for breeding higher ingestible forages [19], but seemingly without significant further use. According to Minson and Wilson [142], Blaxter et al [44] first reported that voluntary intake was positively correlated with digestibility, and Hawkins et al [115] reported that voluntary intake was negatively correlated with lignin content. The rate of NDF degradation, measured in situ in fistulated animals, varied very significantly among genotypes [38,124].…”

Section: Devising a Breeding Criterion For Genetic Improvement Of Ingmentioning

confidence: 99%

Genetic variation and breeding strategies for improved cell wall digestibility in annual forage crops. A review

et al. 2003

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-Forage plants are the basis of ruminant nutrition, and cell wall digestibility is the limiting factor of their feeding value. Cell wall digestibility is therefore "the" target for improving the feeding value of forage crops. Among annual forages, maize cropped for silage making is the most widely used, and much research in genetics, physiology and molecular biology of annual forages is devoted to maize. Sorghum, immature small grain cereals and straws of small grain cereals are also given to cattle. Some dicotyledons are or were also used, such as forage beets, kales, canola in temperate areas and amaranths in tropical and subtropical areas. Large genetic variation for cell wall digestibility was proved from both in vivo and in vitro experiments in numerous species. Among the regular maize hybrids (excluding brown-midrib ones), the NDF in vivo digestibility nearly doubled from 32.9 to 60.1%. Correlations between in vivo and in vitro estimates of cell wall digestibility were often close to 0.75, but in vitro estimates of cell wall digestibility significantly reduced the range of variation between genotypes. Despite lignin content is well known as the major factor making cell wall undigestible, breeding for a higher digestibility of plant only from a lignin content trait appeared impossible. Correlations between lignin content and cell wall digestibility were indeed greatly variable according to the genetic background. Moreover, enzymatic solubilities were excessively dependent on lignin, and correlation between in vivo estimates of cell wall digestibility and lignin content were always lower than correlation between in vitro estimates of cell wall digestibility and lignin content. Among brown-midrib genes, the bm3 mutant in maize, and the bmr12 (and possibly bmr18) mutant in sorghum, which are both altered in the COMT activity, appeared as the most efficient in cell wall digestibility improvement. Moreover, a great genetic variation in the efficiency of the maize bm3 gene for cell wall digestibility improvement was observed according to the genetic background, with a lower efficiency when the normal germplasm was of better cell wall digestibility. Efficient breeding maize and others annual forage plants demands a renewing of genetic resources. Because resources of interest in cell wall digestibility improvement could be of poor agronomic value, the best is likely to cell wall digestibility / ingestibility / annual forage / maize / genetic variation / breeding / lignin Résumé -Amélioration de la digestibilité des parois des fourrages annuels. Les plantes fourragères sont à la base de l'alimentation des ruminants, mais leur valeur nutritive est limitée par la digestibilité variable des parois végétales, dont l'amélioration est alors la cible essentielle des programmes de sé-lection. Parmi les fourrages annuels, le maïs est la plante la plus cultivée, et c'est sur cette espèce que porte l'essentiel de la recherche en génétique, physiologie et biologie moléculaire. Toutefois, le sorgho, les céréales à paill...

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