scholarly journals Bidirectional selection for dry-matter digestibility in orchardgrass

1989 ◽  
Author(s):  
Mohammad Jurial Rind Baloch
Keyword(s):  
Dry Matter ◽  
Dry Matter Digestibility ◽  
Selection For ◽  
Bidirectional Selection

Divergent Selection for In Vitro Dry Matter Digestibility in Smooth Bromegrass 1

Crop Science ◽  
1986 ◽  
Vol 26 (6) ◽  
pp. 1123-1126 ◽  
Author(s):  
N. J. Ehlke ◽  
M. D. Casler ◽  
P. N. Drolsom ◽  
J. S. Shenk
Keyword(s):  
Dry Matter ◽  
Divergent Selection ◽  
Smooth Bromegrass ◽  
Dry Matter Digestibility ◽  
Selection For

The genetic relationship between the digestibility of leaf, stem and whole plant in Setaria

1974 ◽  
Vol 25 (3) ◽  
pp. 401 ◽  
Author(s):  
JB Hacker
Keyword(s):  
Ploidy Level ◽  
Genetic Relationship ◽  
Dry Matter ◽  
Genetic Correlations ◽  
Dry Matter Digestibility ◽  
Whole Plant ◽  
Genotypic And Phenotypic Correlations ◽  
Selection For ◽  
Positive Correlations

The genetic interrelationships of in vitro dry matter digestibility of whole plant (DMDWP), leaf (DMDL), stem (DMDS) and terminal two leaf (DMD2L) fractions were investigated in 4-week regrowth of 21 tetraploid clones of Setaria anceps and 14 hexaploid clones of Setaria trinervia. There were significant differences between genotypes of more than eight digestibility units for all fractions, and for all fractions significant positive correlations were obtained between genotype performance at successive harvests. Genotypic and phenotypic correlations between leaf and stem digestibility were mainly positive, but generally low. Genetic correlations for DMDL–DMDWP and DMDS–DMDWP mostly exceeded 0.7 and for DMD2L–DMDL 0.6. Markedly lower values were obtained for the DMD2L–DMDWP comparison. Genotypic correlations for DMDWP-percentage leaf were greater than 0.4 at one harvest. It is concluded that selection for high DMDWP should result in improvement for both leaf and stem digestibility, providing selection was within populations at the same ploidy level. There appears to be little justification for basing selection on the terminal two-leaf fraction, in view of the relatively inconsistent ranking of genotypes in the two successive harvests, and the relatively low genetic correlations between digestibility of this fraction and that of the whole plant.

The effect of tiller length and age on herbage quality of hybrid Pennisetum canopies.

1987 ◽  
Vol 35 (1) ◽  
pp. 21-28
Author(s):  
M. Warndorff ◽  
A. Dovrat ◽  
T. Kipnis
Keyword(s):  
Dry Matter ◽  
Low Light ◽  
Growing Period ◽  
Dry Matter Digestibility ◽  
Herbage Quality ◽  
Selection For ◽  
Hybrid Pennisetum ◽  
Whole Plants

Whole plants were sampled every 10 or 11 days from field-grown P. americanum X P. purpureum canopies which were cut at intervals of 3 or 6 weeks. Tillers of varying lengths were analysed for in vitro dry matter digestibility (IVDMD). During the growing period, average whole tiller digestibility decreased, as did differences between tillers of different lengths. In 42-day-old herbage, no difference in IVDMD was found between 10 and 70 cm tillers. The decline in digestibility with time was attributed to (1) the appearance of tall tillers and (2) the detrimental effects of low light intensities on tillers growing deep in the canopy. Results suggested that it is doubtful whether tiller length or other morphological or physiological traits can be used to predict herbage digestibility, and that in breeding for better digestibility selection for stem digestibility per se should be more promising than selection for reduced stem growth. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Dry matter intake and nutrient selection by lactating cows grazing irrigated pastures at different pasture allowances in summer and autumn

1998 ◽  
Vol 38 (5) ◽  
pp. 451 ◽  
Author(s):  
W. J. Wales ◽  
P. T. Doyle ◽  
D. W. Dellow
Keyword(s):  
Milk Production ◽  
Perennial Ryegrass ◽  
Crude Protein ◽  
Dry Matter ◽  
Fibre Content ◽  
Lactating Cows ◽  
Dry Matter Digestibility ◽  
Herbage Intake ◽  
Selection For

Summary. Three experiments investigating the effects of herbage allowance on the consumption of nutrients by lactating cows were conducted on irrigated perennial pastures in northern Victoria during summer and autumn. Experiment 1 was conducted in mid lactation (autumn–early winter) with perennial ryegrass [54% of dry matter (DM)]–white clover (22% of DM) pasture offered at allowances of 15, 20, 30 and 40 kg DM/cow.day. Herbage intake increased (P<0.001) from 8.0 to 14.6 kg DM/cow.day as allowance increased and this was associated with a decrease (P<0.001) in utilisation from 54 to 37%. The cows consistently selected a diet 11% higher in in vitro dry matter digestibility than that in the pasture on offer, but selection for crude protein increased (P<0.001) from 21 to 41% above that in herbage on offer as herbage allowance increased. Neutral detergent fibre content of the diet selected was lower (P<0.001) than that in herbage on offer. Along with these changes, milk production increased (P<0.001) from 9.0 to 15.5 kg/day as herbage allowance increased at a marginal response of 0.99 kg milk/kg extra DM consumed. Experiments 2 and 3 were conducted in mid lactation (summer) on pasture containing 28% paspalum, 26% weeds, 17% perennial ryegrass or 36% paspalum, 19% weeds and 24% ryegrass respectively. Pasture allowances were between 20 and 70 kg DM/cow.day. Herbage intake increased (P<0.001) from about 8 to 17 kg DM/cow.day as allowance increased in both experiments and was accompanied by a decrease (P<0.001) in utilisation from about 40 to less than 25%. In experiment 2, the cows consistently selected a diet with a similar in vitro dry matter digestibility to that of the herbage pregrazing, regardless of allowance, but selection for crude protein increased (P<0.05) from 25 to 45% above that in herbage on offer, as allowance increased. In experiment 3, the diet selected was 13% greater (P<0.001) in in vitro dry matter digestibility and 42% greater (P<0.001) in crude protein than the herbage on offer. Neutral detergent fibre content of the diet selected was lower (P<0.001) than that in herbage on offer in experiment 3, while the difference was small in experiment 2. Along with these changes, milk production increased (P<0.001) (in experiment 2, 12.3–15.0 kg/cow.day; experiment 3, 10.0–15.8 kg/cow.day) as herbage allowance increased, but the marginal responses were lower (0.28 kg milk/kg extra DM consumed in experiment 2, 0.64 kg milk/kg extra DM consumed in experiment 3) than observed in experiment 1 reflecting the differences in pasture quality.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

ACCEPTABILITY AND UTILIZATION OF GRADED LEVELS OF GMELINA ARBOREA AND CASSAVA PEELS CONCENTRATES IN WEST AFRICAN DWARF SHEEP

2015 ◽  
Vol 4 (2) ◽  
pp. 415-422
Author(s):  
Amoka Pius ◽  
Tawose O M
Keyword(s):  
Dry Matter ◽  
Nutritive Value ◽  
Control Diet ◽  
Nutrient Digestibility ◽  
Dry Matter Intake ◽  
Gmelina Arborea ◽  
Leaf Meal ◽  
Dry Matter Digestibility ◽  
Inclusion Level ◽  
Cassava Peels

The nutritive value ,voluntary dry matter intake, and the nutrient digestibility of graded levels of Gmelina arborea and cassava peels concentrates in WAD sheep was investigated. Twelve WAD sheep aged 1-2 years old and weighting 14.00± 0.45 kg were used in a complete randomized design. Diets were formulated such that cassava peels was replaced with Gmelina arborea leaf meal at 0, 33.33, 66.67, 100% levels, designated as diets A, B, C, and D respectively. Diet without Gmelina arborea leaf meal was tagged the control diet. The concentrate feed was compounded to contain 16% CP. Diets with 33.33% inclusion level of Gmelina arborea had significantly (P<0.05) higher dry matter intake (DMI) 598.80g day-1, while the lowest DMI 425.00g day-1 was obtained in animals fed 100% inclusion level of Gmelina arborea. Crude protein intake (CPI) of animals fed diets with 33.33% inclusion levels of Gmelina arborea were significantly (P<0.05) highest, followed by 66.67% inclusion level and the least was observed in 0% inclusion level of Gmelina arborea. Dry matter digestibility (DMD) was significantly (P<0.05) different across the dietary treatments, animals placed on diets with 33.33% inclusion level had the highest DMD, followed by animals on diets with 66.67, 100 and 0% inclusion levels. CP digestibility (P<0.05) increased from 33.33% to 100% inclusion levels of Gmelina arborea leaf meal, the lowest CP digestibility was observed at 0% inclusion level. CF digestibility (P<0.05) increased from 33.33% to 100% inclusion levels of Gmelina arborea leaf meal, while the lowest CF digestibility was observed at 0% inclusion level. N intake increased significantly (P<0.05) with increase in the level of Gmelina arborea inclusion from 33.33% to 100%. N retention was significantly (P<0.05) different, diets with 33.33% Gmelina arborea inclusion had the highest value (64.36g day-1) followed by 66.67%, 100% and the least (52.64g day-1) was at 0% inclusion level of Gmelina arborea.  N balance values also followed the same trend. From the results of this study, it can be concluded that the inclusion of Gmelina arborea leaf meal in WAD rams diet was well tolerated without adverse effect on acceptability, intake and nutrient digestibility, and inclusion level of 33.33% is hereby recommended in ruminants diet for optimum performance and productivity.

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