Effect of variety and maturity stage on chemical composition, carbohydrate and protein subfractions, in vitro rumen degradability and energy values of timothy and alfalfa

Abstract

[279][280][281][282][283][284][285][286][287][288][289][290]. The objective of this study was to investigate the effects of forage variety and stage of maturity on chemical composition, protein and carbohydrate subfractions, in vitro rumen degradability and energy content under the climatic conditions of western Canada. Two varieties of alfalfa (Medicago sativa L. cvs. Pioneer and Beaver) and timothy (Phleum pratense L. cvs. Climax and Joliette), grown at three locations in Saskatchewan (Canada), were cut at three stages [1 = 1 wk before commercial cut (early bud for alfalfa; joint for timothy); 2 = at commercial cut (late bud for alfalfa; pre-bloom head for timothy); and 3 = one week after commercial cut (early bloom for alfalfa; full head for timothy)]. The results showed that: (1) the varieties had minimal effects on nutritional value; however, (2) stage of cutting had a large impact on chemical composition, protein and carbohydrate fractions, in vitro rumen degradability and energy value. As plant maturity advanced from stage 1 to 3, the following changes were noticed: (a) CP was decreased [alfalfa: 20.2 to 17.6; timothy: 11.1 to 7.9% dry matter (DM)]; fibre was affected very little in alfalfa but increased in timothy [acid detergent fibre (ADF): 38.0 to 40.7; neutral detergent fibre (NDF): 68.7 to 72.8% DM]; lignin and neutral detergent insoluble protein (NDIP) were not affected in either forage; acid detergent insoluble protein (ADIP) was increased in alfalfa (3.5 to 17.1% CP), but no effect was seen in timothy; (b) the rapidly degradable protein fraction (PA) was reduced in alfalfa (51.2 to 34.8% CP) but increased in timothy (9.2 to 27.5% CP); the rapidly degradable fraction (PB1) increased in alfalfa (0.0 to 25.2% CP), but decreased in timothy (31.6 to 16.7%); the intermediate degradable fraction (PB2) decreased in both forages (alfalfa: 14.1 to 5.2; timothy: 37.8 to 29.4% CP); the slowly degradable fraction (PB3) declined in alfalfa (33.1 to 17.7% CP), but was not affected in timothy (averaging 21.3% CP); the unavailable fraction (PC) associated with the cell wall increased in alfalfa (3.5 to 17.1% CP), but did not change in timothy (averaging 5.2% CP); (c) in vitro rumen degradabilities of DM (IVDMD) and NDF (IVNDFD) increased at stage 2 and then declined at stage 3. The highest IVDMD and IVNDFD after a 48-h incubation were at cutting stage 2 (50.5 and 37.3%; 42.8 and 37.3% for alfalfa and timothy, respectively); (d) the energy content behaved in a quadratic fashion; it increased initially and then decreased with the highest energy contents at stage 2 for both forages (TDN 1x , DE 1x , DE p , ME p , NE Lp : 63.8% DM, 2.92, 2.68, 2.26, 1.40 Mcal kg -1 DM for alfalfa; 45.3% DM, 2.03, 1.86, 1.43, 0.82 Mcal kg -1 DM for timothy, respectively). In general, the best cutting was found at stage 2, which was latebud for alfalfa varieties and pre-bloom head for timothy. , à trois stades (1 = une semaine avant la récolte commerciale (début du bourgeonnement pour la luzerne; début de la montaison pour la fléole);...

Investigation of feed value of alfalfa (Medicago sativa L.) harvested at different maturity stages

“…ADF content increased with maturation (P<0.05). The findings in this experiment are in agreement with those reported by Yu et al (2003), Sayan et al (2004), Dolezal and Skladanka (2008), Homolko et al (2008), Canbolat and Karaman (2009), Aksoy and Nursoy (2010), Pop et al (2010). ADF is composed of cellulose and lignin, and there is an inverse relationship between ADF and digestibility.…”

“…ME content decreased with maturation due to an increase in CS, ADF and NDF (P<0.05). Our findings support some researcher's reports Yu et al (2003), Polat et al (2007), Aksoy and Nursoy (2010) reported that hemicellulose, cellulose and lignin, which are important cell wall components of forage fiber, have a negative effect on digestibility and related with this on energy values. The highest value of average NEL was determined Weir et al (1960), Manga (1978), Yolcu et al (2000), Yu et al (2003), Sayan et al (2004), Cozzi et al (2005), Özyigit and Bilen (2006), Dolezal andSkladanka (2008) Homolko et al (2008), Canbolat and Karaman (2009), Aksoy and Nursoy (2010), Pop et al (2010) in some legumes.…”

“…ME content decreased with maturation due to an increase in CS, ADF and NDF if evaluation is made in terms of maturity (P<0.05). Our findings support some researcher's reports Yu et al (2003), Polat et al (2007), Aksoy and Nursoy (2010) reported that hemicellulose, cellulose and lignin, which are important cell wall components of forage fiber, have a negative effect on digestibility and related with this on energy values. The lowest and highest values of average NEL were determined in the seed-setting period as 1135.25 K.cal/kg and in the budding period as 1396.72 K.cal/kg.…”

“…When averages of maturity stage evaluated DM and NFE were shown significant (P<0.05) differences in terms of harvests. As can be seen from Manga (1978), Yolcu et al (2000), Yu et al (2003), Geren et al (2003), Dinic et al (2004), and Özyigit and Bilgen (2006) et al (2010) in some legumes. NDF is composed of hemicellulose, cellulose and lignin.…”

Nutritive value of Trifolium pratense L. for ruminants estimated from in situ ruminal degradation of neutral detergent fibre and in vivo digestibility of organic matter and energy

“…The above results are in agreement with Koukolová et al (2004), whereas the effects of maturity on degradability characteristics were comparable with those found in forage by elizalde et al (1999) and Yu et al (2004). Differences in phenophases are related to cell wall structures, complexity and components such as phenolic acid and lignin concentrations (Yu et al, 2003(Yu et al, , 2004, which are of vital importance for the cell wall carbohydrate degradability (Jung and Allen, 1995). Significant differences (P < The effect of declining feed digestibility with increasing maturity, as demonstrated by Rinne et al (2002) and Jančík et al (2008), was clearly illustrated in the present study.…”