GENETIC VARIABILITY IN THE PHYSICAL PROPERTIES AND OTHER QUALITY TRAITS OF TIMOTHY

1988 ◽  
Vol 68 (3) ◽  
pp. 713-720 ◽  
Author(s):  
J. SURPRENANT ◽  
R. MICHAUD
Keyword(s):  
Genetic Variation ◽  
Physical Properties ◽  
Water Retention ◽  
Nutritive Value ◽  
Water Solubility ◽  
Phleum Pratense ◽  
Selection Strategies ◽  
Packed Volume ◽  
Two Populations ◽  
Phleum Pratense L

The breeding of timothy (Phleum pratense L.) is mainly targetted at improving the nutritive value of the crop. Three physical properties, packed volume (PV), water retention (WR) and water solubility (WS) have been suggested as indirect measurements of voluntary intake. Variation for these three traits was estimated at the early heading and the flowering stages for 2 consecutive years within four timothy populations (Itasca, Labelle, Pronto and Richmond). Significant genetic variation was observed for PV, WR, WS, plant height (PH), dry matter yield (DMY), crude protein (CP), and digestibility (IVDMD) but the magnitude of the variation was inconsistent among populations. Curiously, PV, WR and WS seemed to improve from early heading to flowering. Significant variation was observed in all four populations for PV, in three populations for WS and in only two populations for WR. The different interactions between genotypes, years and maturities indicated that different selection strategies might be needed according to the base population used. The correlations within and between maturity stages among PV, WR, WS, PH, DMY, CP and IVDMD were inconsistent among populations. The presence of genetic variation in timothy for the three physical properties under study suggests that improvement of these traits may be possible through breeding. However, further information is needed on the heritability and the evolution of these traits with advancing maturity.Key words: Timothy, Phleum pratense L., packed volume, water retention, water solubiliy, forage quality

HERITABILITY OF PHYSICAL PROPERTIES AND OTHER QUALITY TRAITS IN TIMOTHY

1990 ◽  
Vol 70 (3) ◽  
pp. 683-689 ◽  
Author(s):  
J. SURPRENANT ◽  
R. MICHAUD ◽  
G. ALLARD ◽  
C. A. ST-PIERRE
Keyword(s):  
Genetic Variability ◽  
Physical Properties ◽  
Water Retention ◽  
Water Solubility ◽  
Phleum Pratense ◽  
Neutral Detergent Fiber ◽  
Quality Traits ◽  
Narrow Sense Heritability ◽  
Selection For ◽  
Packed Volume

An important aspect in breeding for improved quality is to identify and evaluate new selection criteria. The purposes of this work were (1) to evaluate genetic variability for three physical properties in timothy (Phleum pratense L.): packed volume (PV), water retention (WR) and water solubility (WS); these traits being potential indicators of voluntary intake, (2) to estimate their heritability, and (3) to determine the genetic relationship between these physical properties and some other quality traits. In this study, 25 clones and their half-sib families were evaluated over a 3-yr period for dry matter yield (DMY), crude protein (CP), digestibility (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF) and three physical properties. The genetic analysis revealed that most genetic variability was additive for these traits. Narrow sense heritability estimates for PV (0.77–0.93), WR (0.70–0.96) and WS (0.33–0.67) suggest that genetic gains could be expected from selection. The phenotypic correlations indicated that PV, WR and WS were positively correlated with CP and IVDMD but negatively correlated with NDF and ADF. The exception was WS, which was not correlated with CP. According to these results, selection for either lower PV or lower WR would have a detrimental effect on CP, IVDMD, NDF and ADF while selection for WS would have little if any effect on these traits.Key words: Digestibility, packed volume, water retention, water solubility, fiber

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.

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

scholarly journals Assessment of genetic variation in timothy (Phleum pratense L.) using RAPD and UP-PCR

Hereditas ◽  
2003 ◽  
Vol 138 (2) ◽  
pp. 101-113 ◽  
Author(s):  
YANG-DONG GUO ◽  
TAPANI YLI-MATTILA ◽  
SEPPO PULLI
Keyword(s):  
Genetic Variation ◽  
Phleum Pratense ◽  
Phleum Pratense L

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

Timothy mineral concentration and derived indices related to cattle metabolic disorders: A review

2008 ◽  
Vol 88 (6) ◽  
pp. 1043-1055 ◽  
Author(s):  
Sophie Pelletier ◽  
Gilles Bélanger ◽  
Gaëtan F Tremblay ◽  
Perttu Virkajärvi ◽  
Guy Allard
Keyword(s):  
Metabolic Disorders ◽  
Nutritive Value ◽  
Phleum Pratense ◽  
Soil Mineral ◽  
Cool Season ◽  
Mineral Concentration ◽  
Factors Affecting ◽  
Milk Fever ◽  
Mineral Concentrations ◽  
Phleum Pratense L

Timothy (Phleum pratense L.) is grown in several countries, mainly for livestock forage. The nutritive value and dry matter (DM) yield of timothy is well established but less information is available on mineral concentration and related indices, like the dietary cation-anion difference (DCAD) and the grass tetany (GT) index. These indices predict the risk of a forage diet to cause metabolic disorders, i.e., milk fever for DCAD and grass tetany for the GT index. Improving our knowledge of factors affecting timothy mineral concentration is important for livestock production. This review paper compares timothy with other common cool-season grasses for mineral concentrations, DCAD, and GT index. Also assessed are variations in timothy mineral concentration affected by harvest and fertilization management, soil mineral availability, and environmental conditions. These results demonstrate the high potential for improvement and use of timothy forage to decrease the incidence of metabolic disorders within the dairy industry. Key words: Milk fever, grass tetany, dietary cation-anion difference, grass tetany index, forage, cool-season grasses

Leaf and stem nutritive value of timothy cultivars of different maturity at an irrigated site in southwestern Saskatchewan

2005 ◽  
Vol 85 (2) ◽  
pp. 377-383 ◽  
Author(s):  
Paul G. Jefferson
Keyword(s):  
Nutritive Value ◽  
P Uptake ◽  
Phleum Pratense ◽  
Forage Yield ◽  
Neutral Detergent Fiber ◽  
Acid Detergent Fiber ◽  
Days To Maturity ◽  
Fertilizer Rates ◽  
Phleum Pratense L ◽  
Or Modelling

Leaf and stem structural components contribute to variation in nutritive value among timothy (Phleum pratense L.) cultivars. Modelling timothy growth and nutritive value requires a better understanding of this variation. A trial of 11 timothy cultivars was conducted on irrigation at Swift Current, Saskatchewan from 1995 to 1997. Leaf:stem ratio, forage yield, days to maturity, N, P, acid detergent fiber (ADF) and neutral detergent fiber (NDF) concentrations, N/P ratio and P uptake of leaf and stem components were determined for spring growth forage. Two N fertilizer rates (100 and 150 kg N ha-1) did not consistently affect leaf and stem nutritive value. Cultivars differed in maturity, stem P, stem N, stem NDF, leaf NDF and leaf ADF in all 3 yr. Days to maturity was correlated to stem P concentration (r = 0.59, P < 0.05, to 0.77, P < 0.01) and leaf ADF concentration (r = 0.59, P < 0.05, to 0.82, P < 0.01) in all 3 yr but not to stem NDF concentration. Days to maturity was correlated to stem N concentration and leaf NDF concentration in 1995 and 1997 but not in 1996. However, days to maturity did not explain the observed variation among cultivars for stem NDF concentration and several other variables. While maturity differences among timothy cultivars must be taken into account when selecting for improved nutritive value or modelling growth and quality, additional variation for these traits was evident. Key words: Forage quality, Phleum pratense L., maturity, forage yield

ESTIMATION OF THE NUTRITIVE VALUE OF SILAGES

1986 ◽  
Vol 66 (1) ◽  
pp. 117-127 ◽  
Author(s):  
J. P. LAFOREST ◽  
J. R. SEOANE ◽  
G. DUPUIS ◽  
L. PHILLIP ◽  
PAUL M. FLIPOT
Keyword(s):  
Cell Walls ◽  
Crude Protein ◽  
Dry Matter ◽  
Nutritive Value ◽  
Water Solubility ◽  
Protein Digestibility ◽  
Physical Characteristics ◽  
Dry Matter Digestibility ◽  
Close Relationship ◽  
Packed Volume

Forty-eight wethers were used to determine voluntary intake and digestibility of eight silages made from pure swards of legumes and grasses. Chemical and physical characteristics of silages were measured and related to dry matter intake, digestibility coefficients and digestible nutrient intakes by means of simple correlation and linear regression analyses. Intakes of dry matter (DM), digestible energy, digestible protein and total digestible nutrients were correlated negatively with percentage cell walls (r = −0.87) and positively with crude protein (r = 0.92). Lignin and the logarithm of (lignin × 100/acid detergent fiber) were highly correlated to cell walls digestibility (r = 0.98). There was a close relationship between protein digestibility and crude protein content (r = 0.99). Dry matter digestibility was accurately estimated by a summative equation (r = 0.74). The physical characteristics (packed volume and water solubility) of the silages were not well correlated to either digestibility coefficients or intake. The nutritive value of good quality, well-preserved grass and legume silages was satisfactorily predicted from laboratory analyses of crude protein and cell wall components. The applicability of the equations developed in this study should be tested using a larger number of silages. Key words: Nutritive value, forages, silages, sheep

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