Validation of the n-alkane and NIRS techniques to estimate intake, digestibility and diet composition in sheep fed mixed lucerne: ryegrass diets

Keli, A.; Andueza, Donato; Vega, A. de; Guada, J.A.

doi:10.1016/j.livsci.2008.02.011

Cited by 26 publications

(38 citation statements)

References 38 publications

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“…Next, 0.5 g of the samples was weighed into 200 × 20-mm-thick-walled screw-topped Pyrex test-tubes containing 100 mg of internal standard (a solution of heptane containing 1 mg/g of C 22 and C 34 ). Then, an extraction of the n-alkanes was performed by following the technique described by Mayes et al (1986) and using the modifications suggested by Keli et al (2008). An alkane analysis was performed through in Agilent 6890 gas chromatography instrument fitted with an automatic injector and a flame ionization detector.…”

Section: Methodsmentioning

confidence: 99%

Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures

et al. 2014

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-The objective of this study was to evaluate the characteristics of ruminal fermentation and enteric methane production in beef cattle subjected to different supplementation frequencies while grazing on Brachiaria brizantha cv. Marandu pastures. Nine cattle (325±65.7 kg BW) fitted with ruminal and duodenal cannulas were used in the ruminal fermentation study, and 12 cattle (399±32.6 kg BW) were used in the enteric methane production study. The treatments included supplementation once daily, supplementation once daily except Saturdays and Sundays, or supplementation on alternate days. The supplementation was equivalent to 10 g kg −1 BW day −1 for all treatments. The design employed was completely randomized with three treatments and three replications. When all supplements were provided (day 1), no effects of supplementation frequency were observed on ruminal pH; concentration of NH 3 -N; concentration of acetic, propionic, or butyric acids; or total volatile fatty acids (VFA), but there were month effects. During the day on which only daily supplements were provided (day 2), significant differences were observed only on the molar concentration of acetic acid and total VFA; and month effects were noted on all variables. No significant differences were observed in ruminal fluid volume, dilution rate, N intake, bacterial N synthesis and enteric methane production among the studied supplementation frequencies. Differences were observed in the enteric methane production in the different months, with 85 g kg −1 of gross energy intake observed in September and 123 g kg −1 of gross energy intake observed in November. Lower supplementation frequency is a good option to lower labor costs with little or no consequences on ruminal fermentation characteristics and enteric methane production.

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Section: Methodsmentioning

confidence: 99%

Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures

et al. 2014

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“…After this, 0.5 g was weighed and placed into 200 × 20 mm thick-walled screw-topped Pyrex test-tubes, adding 100 mg of internal standard (solution of heptane containing 1 mg g -1 of C 22 and C 34 ). Then n-alkanes were extracted following the technique described by Mayes et al (1986), with the modifi cations suggested by Keli et al (2008).…”

Section: Data Collection and Analytical Proceduresmentioning

confidence: 99%

Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

Canesin

Berchielli

Vega

et al. 2014

Sci. agric. (Piracicaba, Braz.)

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Reduced supplementation frequency is a broadly applied management practice.Ruminants consuming low quality forages/pastures, supplemented less than once daily are able to maintain body weight gain (BWG), effi ciency of use of dry matter, nitrogen and other nutrients, as compared with animals supplemented once daily. We evaluated the feeding behavior, dry matter intake (DMI), dry matter and organic matter digestibility (DMD and OMD), BWG, Longissimus muscle area and backfat depth of Nellore steers raised on Brachiaria brizantha cv. Marandu pastures during the dry season, with different supplementation patterns. Thirty six animals (338 ± 40.7 kg) were distributed over nine paddocks according to a completely randomized design.Treatments were based on supplementation frequency: once daily (OD), once daily except Saturdays and Sundays (SS), or on alternate days (AD), at 1.0 %, 1.4 % and 2.0 % BW, respectively Average total DMI accounted for 1.6 % BW day -1 , with no effect of supplementation frequency.Supplementation frequency had no effect on BWG or grazing time during the day. There was no difference in Longissimus muscle area animals supplemented daily, SS and AD. The backfat depth was thinner in animals supplemented AD, but even in this case, it was within the standards considered satisfactory for a fi nishing steer. Reducing supplementation frequency seems a good option to lower labor costs without affecting feed effi ciency or carcass quality in beef cattle grazing tropical pastures.

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“…Among them, a major consideration is the need to adjust the faecal alkane concentration for incomplete recovery (Dove and Mayes, 2005), even for intake estimates (Keli et al, 2008). Incomplete recovery can be modified by a series of factors including diet type (Dove et al, 1989;Robaina et al, 1993;Ferreira et al, 2005;Charmley and Dove, 2007) and level of intake (Stakelum and Dillon, 1990;Olivá n et al, 2007), and seems to be due mainly to losses in post-ruminal compartments (Mayes et al, 1988;Kafilzadeh and Parker, 1990;Ohajuruka and Palmquist, 1991).…”

Section: Introductionmentioning

confidence: 99%

In vitro studies of the metabolism of [14C]-n-alkanes using ruminal fluid of sheep as substrate

Keli

Mayes²,

Vega

2008

Animal

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Whether the rumen microbes are able to synthesize and/or degrade long-chain alkanes in anaerobic conditions remains a question to be answered before these hydrocarbons can be confidently used as duodenal flow or rumen transit markers. In this context, an experiment in vitro was carried out to establish whether within a rumen liquor fermentation system, n-alkanes can be derived from de-waxed structures of the plant or from non-alkane wax components (long-chain fatty alcohols, long-chain fatty acids and esters), or may be metabolized by bacteria to other components or to shorter-chain hydrocarbons. Ryegrass was labelled with 14 C in growth chambers under controlled conditions in order to use it as a substrate. The labelled material obtained was separated in three fractions: labelled alkanes, labelled de-waxed plant and labelled wax components without the alkanes. These fractions were used for three different incubations in vitro, which objectives were as follows: 1. To check whether rumen bacteria can synthesize alkanes from carbon structures other than waxes (e.g. sugars). 2. To verify whether rumen bacteria can metabolize the n-alkanes to other compounds. 3. To check whether rumen bacteria can synthesize n-alkanes from other carbon compounds from waxes. The results showed that there was neither bacterial synthesis nor metabolism of the n-alkanes in in vitro conditions.

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Validation of the n-alkane and NIRS techniques to estimate intake, digestibility and diet composition in sheep fed mixed lucerne: ryegrass diets

Cited by 26 publications

References 38 publications

Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures

Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures

Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

In vitro studies of the metabolism of [14C]-n-alkanes using ruminal fluid of sheep as substrate

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