Leaf and stem nutritive value of timothy cultivars differing in maturity

1997 ◽  
Vol 77 (2) ◽  
pp. 237-249 ◽  
Author(s):  
G. Bélanger ◽  
R. E. McQueen
Keyword(s):  
Cell Wall ◽  
Dry Matter ◽  
Nutritive Value ◽  
Weight Ratio ◽  
Phleum Pratense ◽  
Cultivar Differences ◽  
Early Maturing ◽  
True Digestibility ◽  
Phleum Pratense L

The nutritive value of herbage is a function of the nutritive value of its component leaves and stems and their proportion in the herbage. A previous study indicated that the proportion of leaves in the herbage did not explain entirely the differences in in vitro true digestibility and NDF concentrations between early and late-maturing timothy (Phleum pratense L.) cultivars. It was therefore hypothesized that the leaves and stems of early and late-maturing cultivars differ in nutritive value. The evolution of leaf and stem nutritive value of field-grown timothy cultivars differing in maturity, and the relationships between parameters of leaf and stem nutritive value, and the leaf to weight ratio (LWR) were studied during primary growth in two experiments. On a given date, stems of early-maturing cultivars had in vitro true digestibilities of dry matter and cell wall up to 61 g kg−1 DM and 71 g kg−1 DM lower that those of late-maturing cultivars, respectively. The NDF concentration of stems of early-maturing cultivars was up to 32 g kg−1 DM greater than that of late-maturing cultivars. There were no cultivar differences in leaf in vitro true digestibilities of dry matter and cell wall, and NDF concentration on a given date. At a given LWR, however, the leaves and stems of early-maturing cultivars had greater in vitro true digestibilities of dry matter and cell wall, and a lower NDF concentration than those of late-maturing cultivars. Our results indicate that differences in herbage nutritive value at a given stage of maturity between early- and late-maturing timothy cultivars is explained by a greater nutritive value of leaves and stems of the early-maturing cultivars. Key words: Phleum pratense L., timothy, cultivar, digestibility, cell wall, leaf, stem

Digestibility and cell wall concentration of early- and late-maturing timothy (Phleum pratense L.) cultivars

1996 ◽  
Vol 76 (1) ◽  
pp. 107-112 ◽  
Author(s):  
G. Bélanger ◽  
R. E. McQueen
Keyword(s):  
Cell Wall ◽  
Nutritive Value ◽  
Field Experiments ◽  
Weight Ratio ◽  
Phleum Pratense ◽  
Early Maturing ◽  
Mathematical Relationships ◽  
The Relationship ◽  
Phleum Pratense L

Ear emergence or heading of early- and late-maturing cultivars of timothy (Phleum pratense L.) in the spring varies by as much as 3 wk. Two field experiments were conducted to describe the evolution of digestibility and cell-wall concentration of early- and late-maturing timothy cultivars during primary growth and to analyze the relationship between parameters of nutritive value and the leaf blade to biomass weight ratio (LWR). Compared with late-maturing cultivars of timothy on a given date, early-maturing cultivars had lower in vitro true digestibilities of DM and cell wall and a greater NDF concentration. Differences in in vitro true DM digestibility and NDF concentration between early- and late-maturing cultivars were not only related to the proportion of leaf blades in the biomass. Different parameters are, therefore, required to describe the mathematical relationships between digestibility and NDF concentration and LWR of early- and late-maturing cultivars. Key words:Phleum pratense, timothy, cultivars, digestibility, cell wall

Leaf and stem nutritive value of timothy genotypes under varying N fertilization

2004 ◽  
Vol 84 (4) ◽  
pp. 1101-1104 ◽  
Author(s):  
G. Bélanger ◽  
A. Brégard ◽  
R. Michaud ◽  
G. F. Tremblay
Keyword(s):  
Cell Wall ◽  
Nutritive Value ◽  
N Fertilization ◽  
Phleum Pratense ◽  
Neutral Detergent Fiber ◽  
Acid Detergent Fiber ◽  
True Digestibility ◽  
Sib Families ◽  
Phleum Pratense L

Populations and half-sib families of timothy (Phleum pratense L.), contrasting in forage N concentration, were studied in two experiments conducted in growth rooms with varying N applications. They differed in leaf and stem in vitro true digestibility (IVTD) of DM and in vitro cell wall digestibility (IVCWD), and in stem neutral detergent fiber (NDF) concentration; this confirms the presence of genetic variability for leaf and stem nutritive value in timothy under both limiting and non-limiting N conditions. Key words: Digestibility, grasses, Phleum pratense, neutral detergent fiber, acid detergent fiber

Leaf and stem nutritive value of timothy grown with varying N nutrition in spring and summer

1999 ◽  
Vol 79 (2) ◽  
pp. 223-229 ◽  
Author(s):  
G. Bélanger ◽  
R. E. McQueen
Keyword(s):  
Cell Wall ◽  
Nutritive Value ◽  
Nitrogen Deficiency ◽  
Phleum Pratense ◽  
Shoot Biomass ◽  
Negative Effect ◽  
N Deficiency ◽  
Rate Of Decline ◽  
Phleum Pratense L

Nitrogen fertilization is known to have a limited effect on the digestibility of grasses. In a previous paper, however, we reported that N deficiency increased the proportion of leaves in the shoot biomass, and hence, indirectly increased the digestibility of timothy (Phleum pratense L). This was mitigated by the direct negative effect of N deficiency on the digestibility of leaves or stems or both early in the regrowth. The objective of this study was to determine the direct effect of N deficiency on three parameters of nutritive value of leaves and stems of timothy cv. Champ. The evolution of leaf and stem in vitro true digestibility (IVTD), in vitro cell wall digestibility (IVCWD), and neutral detergent fiber (NDF) concentration of field-grown timothy fertilized with four rates of N was studied during a spring and summer regrowth cycle by sampling at weekly intervals. The rate of decline in leaf nutritive value in spring was greater than that in summer, and was less than the rate of decline in stem nutritive value during spring. Nitrogen deficiency consistently increased the NDF concentration of leaves but had a lesser effect on the NDF concentration of stems. Nitrogen deficiency decreased leaf IVCWD when the leaf-to-weight ratio (LWR) was high early in the spring and summer regrowth cycles. At the end of regrowth when LWR values were low, leaf IVCWD was greatest when no N was applied. As a result, the negative effect of N deficiency on the leaf IVTD during the early part of the spring and summer regrowth cycles diminished as the regrowth cycles progressed. Nitrogen deficiency had a limited effect on stem IVCWD. We concluded that the direct negative effect of N deficiency on the digestibility of the timothy shoot biomass can be attributed primarily to its effect on the NDF concentration and cell wall digestibility of leaves. Key words: Phleum pratense L., grasses, digestibility, cell wall, nitrogen

Delayed harvest affects mineral and NDF concentrations, and digestibility of timothy

2008 ◽  
Vol 88 (2) ◽  
pp. 325-329 ◽  
Author(s):  
S. Pelletier ◽  
G. F. Tremblay ◽  
G. Bélanger ◽  
P. Seguin ◽  
R. Drapeau ◽  
...  
Keyword(s):  
Key Words ◽  
Dry Matter ◽  
Metabolic Disorders ◽  
Nutritive Value ◽  
Phleum Pratense ◽  
Neutral Detergent Fiber ◽  
Fiber Concentration ◽  
Harvest Delay ◽  
Phleum Pratense L

A 1-wk delay after late heading in the harvest of timothy spring growth reduced dietary cation-anion difference (-17%), in vitro digestibilities of dry matter (-7%) and neutral detergent fiber (-10%), and increased neutral detergent fiber concentration (+5%). In summer regrowth, the harvest delay tended to have similar effects, but variations (1-6%) were smaller. Key words: Nutritive value, stages of development, Phleum pratense L., metabolic disorders

Leaf and stem dry matter digestibility and ruminal undegradable proteins of alfalfa cultivars

2002 ◽  
Vol 82 (2) ◽  
pp. 383-393 ◽  
Author(s):  
G. F. Tremblay ◽  
G. Bélanger ◽  
K. B. McRae ◽  
R. Michaud
Keyword(s):  
Dry Matter ◽  
Nutritive Value ◽  
Weight Ratio ◽  
Cultivar Differences ◽  
Eastern Canada ◽  
Alfalfa Plant ◽  
Dry Matter Digestibility ◽  
Whole Plant ◽  
Whole Plants

Increased dry matter digestibility and ruminal undegradable protein (RUP) concentration are traits highly ranked to improve the nutritive value of forage legumes. Whole-plant, leaf, and stem samples of 27 alfalfa cultivars grown in eastern Canada were analysed for total nitrogen (TN), in vitro RUP, and in vitro dry matter digestibility (IVDMD). The objectives were to determine if significant variation exists among these cultivars, and to establish the relationship between nutritive value parameters of leaves and stems, and those of whole plants. Cultivars were seeded in triplicate on 2 consecutive years and evaluated during the 2 subsequent production years with two harvests per year. There were significant differences among cultivars in IVDMD of stems and plants in spring growth and summer regrowth. Cultivar differences in leaf IVDMD were significant only in spring growth, but this variation was negligible in practical terms. Cultivars with high forage IVDMD also had high stem IVDMD and this relationship was stronger in summer regrowth. Alfalfa plant IVDMD is a function of stem digestibility and the leaf weight ratio (LWR). Cultivar differences were significant for plant TN in spring growth and summer regrowth, and for stem TN in spring growth only. Leaf (270 to 306 g kg-1 TN) and stem (242 to 287 g kg-1 TN) RUP concentrations varied among cultivars in spring growth. Cultivars with high stem RUP also had high leaf RUP concentration but differences in plant RUP were not always attributed to leaf and stem RUP. The RUP concentration was on average 10% higher in leaves than in stems in spring growth, and this difference reached 15% in summer regrowth. The LWR varied among cultivars in spring growth and summer regrowth, and it was positively related to plant RUP in spring growth. Improved whole-plant RUP concentration is unlikely to be achieved by simply selecting for high RUP in leaves or stems; LWR has a principal role in determining alfalfa plant RUP concentration. Key words: Dry matter digestibility, ruminal undegradable proteins, alfalfa, genetic variation, stems, leaves

EFFECT OF STRUCTURAL AND CHEMICAL FACTORS OF FORAGES ON POTENTIALLY DIGESTIBLE FIBER, INTAKE, AND TRUE DIGESTIBILITY BY RUMINANTS

1988 ◽  
Vol 68 (3) ◽  
pp. 787-799 ◽  
Author(s):  
V. GIRARD ◽  
G. DUPUIS
Keyword(s):  
Cell Wall ◽  
Dry Matter ◽  
Plant Cell Wall ◽  
Neutral Detergent Fiber ◽  
Optimum Number ◽  
Apparent Digestibility ◽  
Cool Season ◽  
Dry Matter Digestibility ◽  
True Digestibility

In view of the large variation found in plant cell wall digestibilities with ruminants, an attempt was made to group 124 feeds into different lignification classes (clusters) on the basis of chemical characteristics. Each feed cluster was described using a structural coefficient [Formula: see text] that related the potentially digestible fiber (PDF, %) to the ratio between lignin and cell wall volume. The optimum number of clusters was determined iteratively by performing a regression of the apparent digestibility of dry matter at maintenance level (DDM1, %) against the PDF and cell soluble (SOL, %) contents of feeds. The [Formula: see text] coefficients varied from 0.05 (grains, N = 13) to 1.85 (corn silage, N = 3) and increased with the maturity of the grasses from 0.88 (legumes, vegetative cool season grasses, N = 26) to 1.33 (mature, cool season grasses, N = 19). Predicted PDF were closely correlated (r > 0.9, P < 0.01) to in vitro cell wall disappearances (IVCWD). Apparently digestible cell wall in four grasses and four legumes increased linearly with 96-h IVCWD and standard error (SE) was similar to the SE of predicted apparent digestible SOL from SOL concentrations. Assuming that similarity between SE could be also observed in larger samples, PDF and SOL were used in summative equations to predict apparent dry matter digestibility. DDM1 discounted for intake (DDM1 – 4, %) was regressed against SOL and PDF concentrations of 87 feeds:[Formula: see text]with ds and df, the true digestibilities of SOL and PDF. Estimates of ds and df were 0.98 and 0.95 for a zero-production (maintenance) level of intake, and 0.91 and 0.79 for an intake level four times maintenance. Since the true digestibility of the PDF component was only 4% – 13% lower than that of the cell soluble component, the concentration of PDF in cell wall was the major determinant in the variation in apparent digestibility of forages. Key words: lignin, neutral detergent fiber, true digestibility, cluster analysis, feeds

The effect of temperature on quality characteristics in timothy (Phleum pratense L.) genotypes

1993 ◽  
Vol 73 (4) ◽  
pp. 1017-1026 ◽  
Author(s):  
N. Ames ◽  
A. R. McElroy ◽  
J. Erfle
Keyword(s):  
Dry Matter ◽  
Nutritive Value ◽  
Genetic Factors ◽  
Lignin Content ◽  
Rumen Fluid ◽  
Phleum Pratense ◽  
Effect Of Temperature ◽  
Genotypic Differences ◽  
Genetic Traits ◽  
Phleum Pratense L

Improving the nutritive value of timothy (Phleum pratense L.) through breeding is dependent on selecting for genetic traits which directly contribute to ruminant digestibility. The identification of these traits is the goal of many forage researchers. The objectives of this research were to evaluate the leaf and stem digestibility of six timothy genotypes under different temperature conditions using two methods of estimating digestibility. Correlations between leaf and stem digestibility were not significant, suggesting that separation of these components is nessessary to clearly evaluate genotypic differences. Temperature had an important effect on digestibility, particularly for the stem fraction. Isolating leaf from stem and evaluating genotypes individually across temperatures may permit the identification of more simple genetic factors which control digestibility in timothy. Genotypic differences were observed at all temperatures. The rumen fluid digestion resulted in a much greater range within and among genotypes for both stem and leaf fractions. Genotypes tended to follow the same trends with respect to temperature using both techniques suggesting that only a portion of the dry matter digested by rumen fluid is available to the cellulases used in these experiments. Lignin content was measured for two of the most variable genotypes and the results showed that while levels increased with higher growth temperature, differences between genotypes are more pronounced at 10 °C for both leaf and stem. Key words: Digestibility, forage quality, lignin, temperature, timothy, Phleum pratense L.

In vitro ruminal undegradable proteins of alfalfa cultivars

2000 ◽  
Vol 80 (2) ◽  
pp. 315-325 ◽  
Author(s):  
G. F. Tremblay ◽  
R. Michaud ◽  
G. Bélanger ◽  
K. B. McRae ◽  
H. V. Petit
Keyword(s):  
Protein Degradation ◽  
Dry Matter ◽  
Degradation Rate ◽  
Weight Ratio ◽  
Principal Component ◽  
Neutral Detergent Fiber ◽  
Cultivar Differences ◽  
Dry Matter Digestibility ◽  
Protein Degradation Rate

The quality of alfalfa would be greatly improved by an increase in its ruminal undegradable protein (RUP) concentration. Protein degradation rate (PDR), in vitro dry matter digestibility (IVDMD), leaf weight ratio (LWR), dry matter yield (DMY), total nitrogen (TN), in vitro RUP (expressed on both TN, RUP-TN, and dry matter basis, RUP-DM), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were determined in 27 alfalfa cultivars. Cultivars were seeded in triplicate on 2 consecutive years and evaluated during the 2 subsequent production years with two harvests per year. Protein degradation rate and RUP-TN were determined using a ruminal inhibitor in vitro system. Data were averaged for spring growth, summer regrowth, and both harvests across 2 production years. Each of the three data sets was analyzed by ANOVA followed by a principal component analysis (PCA) on the ANOVA means. For the four-harvest data, cultivar differences were highly significant (P < 0.001) for all variates except for PDR (P = 0.07) and RUP-TN concentration (P = 0.10). The first PCA axis was largely defined positively by RUP-DM, IVDMD, TN, LWR, and RUP-TN, but negatively with ADF, NDF, PDR, and DMY. The second PCA axis defined a contrast between PDR versus RUP-TN, DMY, ADF, and NDF. Five cultivars were distinctive with high or low PCA scores in all three PCA. Rangelander and Heinrichs, along with Ultra, had low PDR; the first two cultivars had low DMY whereas Ultra was a medium-yielding cultivar. In contrast, Algonquin and Oneida VR had high PDR and medium DMY. While the first principal component (PC) indicated a general trend that low PDR and high RUP were associated with low-yielding cultivars, the second PC identified specific cultivars with both low PDR and high DMY. Therefore, selection for low PDR and high DMY is feasible. Key words: ruminal protein escape, dry matter digestibility, alfalfa

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