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South African Journal of Animal Science

On-line version ISSN 2221-4062
Print version ISSN 0375-1589

S. Afr. j. anim. sci. vol.46 n.4 Pretoria  2016 

Effects of types and doses of yeast on gas production and in vitro digestibility of diets containing maize (Zea mays) and lucerne (Medicago sativa) or oat hay



A.M.A. ElmasryI, II; G.D. MendozaI; L.A. MirandaIII; G. VázquezI, #; A.Z.M. SalemIV; P.A.HernándezV

IDoctorado en Ciencias Agropecuarias, Universidad Autónoma Metropolitana Unidad Xochimilco, 04960 México, D.F., México
IIBotany Department, Faculty of Agriculture, Menoufia University, Po 32511, Shebin El-Kom, Egypt
IIIUniversidad Autónoma Chapingo, Departamento de Zootecnia, 56230, México
IVFacultad de Medicina Veterinaria, Universidad Autónoma del Estado de México, Toluca 50000, México
VCentro Universitario UAEM-Amecameca, Universidad Autónoma del Estado de México, 56900, México




Two yeast products formulated with Saccharomyces cerevisiae were evaluated at the same colony-forming units (CFUs) per gram of substrate. Samples of maize, lucerne and oat hays were mixed (0.5 kg) to a proportion of 80% forage (lucerne or oat) with 20% maize (DM basis) and combined with each yeast to obtain 1.5 x 107 or 3.0 x 107 CFU/g DM. There was also a control without yeast. In vitro gas production was measured at 0, 2, 4, 6, 8, 10, 14, 18, 24, 30, 36, 42, 48, 60, and 72 h incubation. There was no forage/yeast interaction. Both yeast products tended to reduce the maximum volume produced quadratically and lag time linearly, while in vitro dry matter digestibility (IVDMD) increased linearly. Ruminal ammonia N and lactic acid were not affected, whereas methane and carbon dioxide tended to be reduced with the intermediate dose of yeast. When the mixture included oat hay, the total volume of gas increased, the lag time decreased, and there was higher IVDMD than in the lucerne-based mixtures, which were associated with lower methane production. Ammonia and lactic acid remained unchanged. The two yeast products showed the same effects on the dynamics of gas production and in vitro digestibility when dosed at the same number of viable cells or CFUs, and there was no interaction with forage quality.

Keywords: forages, ruminal fermentation in vitro, Saccharomyces cerevisiae




Yeast products for ruminants based on Saccharomyces cerevisiae increase the number of cellulolytic bacteria (Wallace & Newbold, 1993; Alzahal et al., 2014), and are associated with a higher rumen pH promoted by the yeast, which favours the growth of fibrolytic bacteria (Fibrobacter and Ruminococcus) and lactate-utilising bacteria (Megasphaera and Selenomonas; Pinloche et al., 2013). They have thus been regarded as rumen pH stabilisers (Chaucheyras-Durand et al., 2008; Desnoyers et al., 2009). In most in vivo evaluations of commercial products that contain Saccharomyces cerevisiae, researchers confirmed that the amounts of live cells were described by the commercial manufactures (Crosby et al., 2004; Pinloche et al., 2013; Ahmed et al., 2015; Pienaar et al., 2012).

In a few experiments, the colony-forming units (CFUs) were corroborated (Bitencourt et al., 2011; Vyas et al., 2014; Emmanuel et al., 2007). In contrast, data from Arcos-García et al. (2000) showed that the CFU value determined in the laboratory differed from that reported on the yeast product packaging. Opsi et al. (2012) demonstrated that live yeast affects ruminal fermentation slightly more than inactivated yeast.

Several studies have been conducted to evaluate neutral detergent fibre (NDF) levels with yeast (Plata et al., 1994; Miranda et al., 1996; Wang et al., 2001), but information that compares forage sources is scarce. Roa et al. (1997) compared lucerne and coffee hull and cornstalk with or without Saccharomyces cerevisiae on in situ digestion and rumen fermentation, and did not find forage/yeast interactions with differences among forages. However, a legume and a lignocellulosic residue differ greatly in nutritional value and the response to yeast addition in digestibility can be different. Therefore, the objective of this study was to evaluate the effects of two commercial yeast products on in vitro fermentation kinetic parameters, as determined by gas production, of lucerne- and oat-based diets, dosed at the same CFU levels of Saccharomyces cerevisiae.


Materials and Methods

The products that were evaluated were Procreatin 7 (7.53 x 109 CFU/g) and Biosaf SC 47 (1.18 x 109 CFU/g) (Safmex S.A. de C.V Mexico), both of which are formulated with Saccharomyces cerevisiae. They were dosed at the same CFUs per gram of substrate, based on the viable yeast concentration determined in the laboratory (Camacho et al., 2009).

Composite representative samples (n = 3) of maize, lucerne and oat hay were obtained from the experimental dairy farm at the University of Chapingo, oven dried at 55 °C, and ground to 1 mm. After this, 0.5 kg each of forage and maize grain were mixed in a proportion of 80% forage (lucerne or oat) with 20% maize (DM basis), and combined with each yeast product to obtain 1.5 x 107 or 3.0 x 107 CFU/g DM. There was also a control without yeast. The treatments were allotted in a completely randomized design with a 2 x 3 factorial arrangement, in which the factors were forage source (lucerne and oat) and yeast product (Procreatin 7 and Biosaf SC 47), evaluated at three concentrations (0.0, 1.5 x 107 and 3.0 x 107 CFU/g). Forage and maize samples were analysed for dry matter (DM), organic matter (OM) and ether extract (EE), according to AOAC (1990), and neutral detergent fibre (NDF) and acid detergent fibre (ADF), according to Van Soest et al. (1991). Starch in the maize was measured enzymatically from the glucose that was released, as described by MacRae & Armstrong (1968) and modified by Wester et al. (1992). The compositions of the forages and maize are shown in Table 1.

Amber flasks (100 ml) were prepared with 500 mg DM from each treatment, with four tubes per treatment. The inoculums consisted of rumen liquor obtained as described by Mendoza-Martínez et al. (2015) using an oesophageal probe from two sheep (34 ± 1.6 kg bodyweight) fed a 50:50 forage : concentrate ratio. The inoculum was obtained before the morning feeding, and was mixed and strained through eight layers of cheesecloth into a flask flushed with carbon dioxide (CO2). Then 10 ml strained ruminal fluid was added to each bottle, and 80 ml of the buffer solution described by Goering & Van Soest (1970) was added under a continuous flow of carbon dioxide to maintain anaerobic conditions. Each flask was closed tightly with a rubber stopper and aluminium crimp. The flasks were incubated in a water bath at 38 °C. Gas pressure was measured with a pressure gauge (Metron, Mode: 63100, Mexico) at 0, 2, 4, 6, 8, 10, 14, 18, 24, 30, 36, 42, 48, 60 and 72 h of incubation (Blümmel & Lebzien, 2001). Head space pressure values were transformed to gas volumes by a linear regression equation:

V= (P+0.0186) (0.0237)-1

At each time fraction, three parameters of the kinetics of gas production were estimated: lag phase (h); maximal volume (Vm; mL g-1 DM of substrate); and rate (S; h-1) of gas production, using the model proposed by Menke & Steingass (1988), Vo= Vm /(1+e(2-4*s*(t-L))). At the end of incubation, the residuals from each bottle were filtered using a flask Buchner with a sintered filter (filter paper F/ fast MOD.617 Code P.V.NO.1034) to estimate DM digestibility. The fermentation residues were dried at 65 °C overnight before being weighed.

Lactate and N-NH3 were determined by spectrophotometry using samples of residual fluid collected at 36 h incubation. Fluid samples were centrifuged (25,200 x g for 10 min) and subsamples of supernatant were used to analyse lactate (Taylor, 1996) and ammonia N (McCullough, 1967).

The results were analysed according to a completely randomized design in which treatments were regarded as fixed effects, testing linear and quadratic effects for grain level (Steel et al. 1997). Means were compared using a Tukey's test. Differences among treatments were declared at P <0.05 and a tendency at P <0.10. Data were analysed with JMP7 software (Sall et al. 2012).



There was no forage/yeast interaction. Therefore, the main effects of yeast and forage are presented separately in Tables 2 and 3. Both yeast products tended to reduce the maximum volume of gas produced quadratically, while Procreatin 7 reduced lag time linearly, but they increased in vitro DM digestibility linearly (P <0.001). Ruminal ammonia N and lactic acid were not affected, whereas methane tended to be reduced (P <0.11) at the intermediate dose of yeast for Procreatin 7, while the carbon dioxide (CO2) was increased (P <0.05). Biosaf had no effect on either gas (Table 2). In Table 3 shows that oats increased the total volume of gas produced, decreased lag time, and increased in vitro digestibility (P <0.0001), compared with the lucerne based mixtures. It is postulated that these effects could be associated with lower methane production (P <0.05) for oats, as ammonia and lactic acid remained unchanged.



The results from this experiment indicated that the use of Saccharomyces cerevisiae, dosed at similar CFU levels, had the same effect on the dynamics of fermentation in two diets based on oat or lucerne. Therefore, some of the variability in the results reported in the literature, described as a yeast/diet interaction (Patra 2012; Lascano & Heinrichs, 2007), may be explained by differences in the number of viable cells that were used. Different substrate combinations, however, cannot be disregarded. Elghandour et al. (2016) for instance compared three commercial yeast products and observed that one strain was more effective in the stimulation of gas production. They suggested that the difference could be related to the number of active cells and other factors, such as nutrients and carrier materials. The variation in viability is then a concern. Wallace & Newbold (1995) reported that the viability of preparations can vary from 109 - 1010 live cells/g to 2 x 107 live cells/g. Opsi et al. (2012) showed higher gas production with live yeast than with inactivated yeast, and concluded that live yeast affects ruminal fermentation slightly more than inactivated yeast. Since one of the mechanisms of action of yeast is oxygen consumption, related to the yeast high respiratory rate (Newbold et al., 1996), the numbers of viable cells tested should be reported in yeast evaluations, so that various strains that differ in oxygen consumption ability and metabolic activity can be identified (Kutasi et al., 2004).

Although it has been reported that yeast produces metabolites, such as malate, which stimulate lactate-using bacteria (Nisbet & Martin, 1991; Martin & Nisbet, 1992; Nisbet & Martin, 1993), no changes were detected in this metabolite, possibly because grain levels were low in the current substrate mix. Other studies with 62% forage found no yeast effect in ruminal lactate, even when the average ruminal pH in the control diet was significantly higher (Křížová et al., 2011).

The positive effects on digestibility have been confirmed in meta-analyses (Desnoyers et al., 2009; Poppy et al., 2012) and other studies that showed dose responses with increasing levels of CFUs in straw-based diets (Ganai et al., 2015). The higher digestibility values could be explained by a higher population of cellulolytic bacteria, which is one of the most consistent effects of yeast (Martin & Nisbet, 1992; Wallace & Newbold, 1993). However, the positive effects are not consistent, even in experiments with increasing doses of yeast (Crosby et al., 2004) where cell viability was not certified.

In terms of the comparison of diets based on grasses (oat) and legumes (lucerne), Doran et al. (2007) observed lower digestibilities with lucerne diets compared with oats, which were associated with a higher lignin cellulose ratio in the lucerne legume than in the oats. Ghasemi et al. (2012) compared 0 or 5 g SC 47 (8 x 109 CFU/g) with lucerne hay or maize silage and detected only an improvement in the NDF in situ digestion measured after three hours' incubation. In another study, which compared several straws with increasing doses of Saccharomyces cerevisiae, Tang et al. (2008) observed that supplementation with yeast cultures increased cumulative gas production, but digestibility was not affected. This may be explained by the lignocellulosic characteristic of the substrates, because the doses used by Tang et al (2008) were higher than in the current experiment. Several studies have confirmed that substrates with low digestibility do not respond to yeast supplementation in vivo (Roa et al., 1997; Arcos-García et al., 2000; Crosby et al., 2004). It is possible that the variability in response to yeast supplementation in terms of forage quality is a function of the potentially digestible fraction, as has been suggested for the response to fibrolytic enzymes (Mendoza et al., 2014), which is another factor that needs to be considered in yeast evaluation assays.



The results indicate that in order to conduct a proper comparison of yeast products, it is necessary to evaluate the number of CFUs to incubate products with the same number of viable cells. This will allow to elucidate the effects among forage quality x yeast source x dose in in vitro evaluations. These results show the importance of checking the CFUs of Saccharomyces cerevisiae in products used as feed additives for ruminants.


Authors' Contributions

AMAE, LAM, GV and GDM conceived and designed the experiment. AMAE conducted the experiment. PAH and AZMS participated in statistical analyses and all authors participated in interpretation of results and writing and integration of the manuscript.


Conflict of Interest Declaration

The authors declare that they have no conflict of interest between the authors and other people or organizations that could inappropriately bias their results.



Ahmed, M.H., Elghandour, M.M.Y., Salem, A.Z.M., Klieve, A.V. & Abdelrassol, A.M.A., 2015. Influence of Trichoderma reesei or Saccharomyces cerevisiae on performance, ruminal fermentation, carcass characteristics and blood biochemistry of lambs fed Atriplex nummularia and Acacia saligna mixture. Livest. Sci. 180, 90-97.         [ Links ]

Alzahal, O., Dionissopoulos, L., Laarman, A.H., Walker, N. & McBride, B.W., 2014. Active dry Saccharomyces cerevisiae can alleviate the effect of subacute ruminal acidosis in lactating dairy cows. J. Dairy Sci. 97, 7751-7763.         [ Links ]

AOAC, 1990. Official methods of analysis (15th ed.), Association of Official Analytical Chemists, Arlington, Virginia, USA.         [ Links ]

Arcos-García, J.L., Castrejón, F.P., Mendoza, G.D. & Pérez, E.P.G., 2000. Effect of two commercial yeast cultures with Saccharomyces cerevisiae on ruminal fermentation and digestion in sheep fed sugar cane tops. Livest. Prod. Sci. 63, 153-157.         [ Links ]

Bitencourt, L.L., Silva, J.R.M., Oliveira, B.M.L., Júnior, G.S.D., Lopes, F., Júnior, S.S., Zacaroni, O.F. & Pereira, M.N., 2011. Diet digestibility and performance of dairy cows supplemented with live yeast. Sci. Agric. (Piracicaba, Braz.), 68, 301-307.         [ Links ]

Blümmel, M. & Lebzien, P. 2001. Predicting ruminal microbial efficiencies of dairy rations by in vitro techniques. Livest. Prod. Sci. 68, 107-117.         [ Links ]

Camacho, A., Giles M., Ortegón A., Palao, M., Serrano, B. & Velázquez, O., 2009. Técnicas para el Análisis Microbiológico de Alimentos. 2a ed. Facultad de Química, UNAM. México.         [ Links ]

Chaucheyras-Durand, F., Walker N.D. & Bach A., 2008. Effects of active dry yeasts on the rumen microbial ecosystem: Past, present, and future. Anim. Feed Sci. and Technol. 145, 5-26.         [ Links ]

Crosby, M.M., Mendoza, G.D., Bárcena, R., González, S. & Aranda, E., 2004. Influence of Saccharomyces cerevisiae dose on ruminal fermentation and digestion in sheep fed a corn stover diet. J. Appl. Anim. Res. 25, 9-12.         [ Links ]

Desnoyers, M., Giger-Reverdin, S., Bertin, G., Duvaux-Ponter, C. & Sauvant, D., 2009. Meta-analysis of the influence of Saccharomyces cerevisiae supplementation on ruminal parameters and milk production of ruminants. J. Dairy Sci. 92, 1620-1632.         [ Links ]

Doran, M.P., Laca, E.A. & Sainz R.D., 2007. Total tract and rumen digestibility of mulberry foliage (Morus alba), alfalfa hay and oat hay in sheep. Anim. Feed Sci. and Technol. 138, 239-253.         [ Links ]

Elghandour, M.M.Y., Kholif, A.E., Lopez, S., Mendoza, G.D., Odongo, N.E. & Salem, A.Z.M., 2016. In vitro gas, methane and carbon dioxide productions of high fibrous diets incubates with fecal inocula from horses fed live yeasts in response to the supplementation with different yeasty additives. J. Equine Vet. Sci. 38, 64-71.         [ Links ]

Emmanuel, D.G.V., Jafari, A., Beauchemin, K.A., Leedle, J. A. Z. & Ametaj, B. N., 2007. Feeding live cultures of Enterococcus faecium and Saccharomyces cerevisiae induces an inflammatory response in feedlot steers. J. Anim. Sci. 85, 233-239.         [ Links ]

Ganai, A.M., Sharma, T. & Dhuria, R.K., 2015. Effect of yeast (Saccharomyces cerevisiae) supplementation on ruminal digestion of bajra (Pennisetum glaucum) straw and bajra straw-based complete feed in vitro. Anim. Nutr. Feed Technol. 15, 145-153.         [ Links ]

Ghasemi, E., Khorvash, M. & Nikkhah, A., 2012. Effect of forage sources and Saccharomyces cerevisiae (Sc47) on ruminal fermentation parameters. S. Afr. J. for Anim. Sci. 42, 164-168.         [ Links ]

Goering, H.K. & Van Soest, P.J., 1970. Forage Fiber Analysis (Apparatus, Reagents, Procedures, and Some Applications), Agric. Handbook No. 379. Agricultural Research Service, United States Department of Agriculture. Washington, DC.         [ Links ]

Kfizova, L., Richter, M., Tfinacty, J., Riha, J. & Kumprechtova, D., 2011. The effect of feeding live yeast cultures on ruminal pH and redox potential in dry cows as continuously measured by a new wireless device. Czech J. Anim. Sci. 56, 37-45.         [ Links ]

Kutasi, J., Jurkovich, V., Brydl, E., Könyves, L., Tirián, A.E. & Bata, Á., 2004. Influence of different Saccharomyces cerevisiae strains on the oxygen concentration in the rumen fluid. J. Anim. Feed Sci. 13, 131 -134.         [ Links ]

Lascano, G.J., & Heinrichs A.J., 2007. Yeast culture (Saccharomyces cerevisiae) supplementation in growing animals in the dairy industry. CAB Reviews. 2, 1-13.         [ Links ]

MacRae, J.C. & Armstrong D.G., 1968. Enzyme method for determination of α-linked glucose polymers in biological materials. J. Sci. Food Agric. 19, 578-581.         [ Links ]

Martin, S.A. & Nisbet, D.J., 1992. Effect of direct fed microbial on rumen microbial fermentation. J. Dairy Sci. 75, 1736-1744.         [ Links ]

McCullough, H., 1967. The determination of ammonia in whole blood by direct colorimetric method. Clin. Chem. Acta 17, 297-304.         [ Links ]

Mendoza, G.D., Loera-Corral, O., Plata-Pérez, F.X., Hernández-García, P.A. & Ramírez-Mella, M., 2014. Considerations on the use of exogenous fibrolytic enzymes to improve forage utilization. The Scientific World Journal Volume 2014, Article ID 247437, 9 pages         [ Links ]

Mendoza-Martínez, G.D., Pinos-Rodríguez, J.M., Lee-Rangel, H.A., Hernández-García, P.A., Rojo-Rubio, R. & Relling, A., 2015. Effects of dietary calcium propionate on growth performance and carcass characteristics of finishing lambs. Anim. Prod. Sci. 56, 1194-1198.         [ Links ]

Menke, K. & Steingass, H., 1988. Estimation of the energetic feed value obtained from chemical analysis and in Vitro gas production using rumen fluid. Anim. Res. Dev. 28, 7-55.         [ Links ]

Miranda, R.L.A., Mendoza, M.G.D., Bárcena-Gama, J.R. González, M.S.S. Ferrara, R., Ortega, C.M.E. & Cobos, P.M.A., 1996. Effect of Saccharomyces cerevisiae or Aspergillus oryzae cultures and NDF level on parameters of ruminal fermentation. Anim. Feed Sci. Technol. 63, 289-296.         [ Links ]

Newbold, B.C.J., Wallace, R.J. & McIntosh, M., 1996. Mode of action of the yeast Saccharomyces cerevisiae as a feed additive for ruminants. Br. J. Nutr. 76, 249-261.         [ Links ]

Nisbet, D.J. & Martin, S.A., 1991. Effect of a Saccharomyces cerevisiae culture on lactate utilization by the ruminal bacterium Selenomonas ruminantium. J. Anim. Sci. 69, 4628-4633.         [ Links ]

Nisbet, D.J. & Martin, S.A., 1993. Effects of fumarate, L-malate, and an Aspergillus oryzae fermentation extract on D-lactate utilization by the ruminal bacterium Selenomonas ruminantium. Curr. Microbiol. 26, 133-136.         [ Links ]

Opsi, F., Fortina, R., Tassone, S., Bodas, R. & López, S., 2012. Effects of inactivated and live cells of Saccharomyces cerevisiae on in vitro ruminal fermentation of diets with different forage: concentrate ratio. J. Agric. Sci. 150, 271-283.         [ Links ]

Patra, A.K. 2012.The use of live yeast products as microbial feed additives in ruminant nutrition. Asian J. Anim. Vet. Adv. 7, 366-375.         [ Links ]

Pienaar, G.H., Einkamerer, O.B., Van der Merwe, H.J., Hugo, A. & Fair, M.D., 2012. The effect of an active live yeast product on the digestibility of finishing diets for lambs. Small Ruminant Res., 123, 8-12.         [ Links ]

Pinloche, E., McEwan, N., Marden, J., Bayourthe, C., Auclair, E. & Newbold, C.J., 2013. The effects of a probiotic yeast on the bacterial diversity and population structure in the rumen of cattle. PLoS ONE 8, e67824.         [ Links ]

Plata, P.F., Mendoza, G.D., Bárcena-Gama, J.R. & González S.M., 1994. Effect of a yeast culture (Saccharomyces cerevisiae) on neutral detergent fiber digestion in steers fed oat straw diets. Anim. Feed Sci. Technol. 49, 203-210.         [ Links ]

Poppy, G.D., Rabiee, A.R., Lean, I.J., Sanchez, W.K., Dorton, K.L., Morley, P.S., 2012. A meta-analysis of the effects of feeding yeast culture produced by anaerobic fermentation of Saccharomyces cerevisiae on milk production of lactating dairy cows. J Dairy Sci. 95, 6027-6041.         [ Links ]

Roa, M.L., Bárcena-Gama, J.R., González, S.M., Mendoza, G.M., Ortega, M.E. & García, C.B., 1997. Effect of fiber source and a yeast culture (Saccharomyces cerevisiae1026) on digestion and the environment in the rumen of cattle. Anim. Feed Sci. Technol. 64, 327-336.         [ Links ]

Sall, J., Lehman, A., Stephens, M. & Creighton, L., 2012. JMP® Start Statistics: A guide to statistics and data analysis, 5th edn. SAS Institute Inc: Cary, NC, USA.         [ Links ]

Steel, G.D.R., Torrie, J.H. & Dickey, D.A., 1997. Principles and procedures of statistics: a biometrical approach, 3rd edn. McGraw-Hill, New York, NY.         [ Links ]

Tang, S.X., Tayo, G.O., Tan, Z.L., Sun, Z.H., Shen, L.X., Zhou, C.S., Xiao. W.J., Ren, G.P., Han, X.F. & Shen, S.B., 2008. Effects of yeast culture and fibrolytic enzyme supplementation on in vitro fermentation characteristics of low-quality cereal straws. J. Anim. Sci. 86, 1164-1172.         [ Links ]

Taylor, K. A. C. C. 1996. A simple colorimetric assay for muramic acid and lactic acid. Applied Biochemistry and Biotechnology 56:49-58.         [ Links ]

Van Soest, P.J., Robertson, J.B. & Lewis, B.A., 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. J. Dairy Sci., 74, 3583-3597.         [ Links ]

Vyas, D., Uwizeye, A., Mohammed, R., Yang, W.Z., Walker, N.D. & Beauchemin K.A., 2014. The effects of active dried and killed dried yeast on subacute ruminal acidosis, ruminal fermentation, and nutrient digestibility in beef heifers. J. Anim. Sci., 92, 724-732.         [ Links ]

Wallace, R.J. & Newbold, C.J., 1993. Rumen fermentation and its manipulation: the development of yeast cultures as feed additives. In: Biotechnology in the Feed Industry. Ed: Lyous, T.P., Alltech Technical Publications, Nicholasville, Kentucky. pp. 173-192.         [ Links ]

Wallace, R.J. & Newbold, C.J., 1995. Microbial feed additives for ruminants. In: Probiotics: Prospects of Use in Opportunistic Infections. Ed: Fuller, R., Heidt, P., Rusch, V. and van der Waaij, D., Institute for Microbiology and Biochemistry, Herborn-Dill, Germany, 101-125 <> (accessed 30.07.07).         [ Links ]

Wang, Z., Eastridge, M.L. & Qiu, X., 2001. Effects of forage neutral detergent fiber and yeast culture on performance of cows during early lactation. J. Dairy Sci. 84, 204-212.         [ Links ]

Wester, T.J., Gramlich, S.M., Britton, R.A. & Stock, R.A., 1992. Effect of grain sorghum hybrid on in vitro rate of starch disappearance and finishing performance of ruminants. J. Anim. Sci. 70, 2866-2876.         [ Links ]



Received 23 March 2016
Accepted 30 September 2016
First published online 12 November 2016



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