Skip to main content
NCBI home page
Iranian Journal of Veterinary Research logoLink to Iranian Journal of Veterinary Research
. 2018 Spring;19(2):96–100.

Effects of yeast (Saccharomyces cerevisiae) supplementation on intake, digestibility, rumen fermentation and milk yield in Nili-Ravi buffaloes

M I Anjum 1,*, S Javaid 2, M S Ansar 3, A Ghaffar 1
PMCID: PMC6056139  PMID: 30046319

Abstract

Rumen Yeast® (RY; Saccharomyces cerevisiae), a live yeast strain, improves milk yield and composition and nutrients digestibility through balancing rumen ecosystem and increasing ruminal cellulolytic bacteria numbers in cattle. To examine the effects of dietary supplementation of RY in Nili-Ravi buffaloes, 16 buffaloes with 8 L average daily milk production were randomly divided into two groups, and investigated for a 60-day period. Group I (control) was offered maize silage ad libitum as sole forage plus 3 kg of concentrate/head per day (16% crude protein (CP) and 72% total digestible nutrients (TDN)), while group II was given the same diet as control supplemented with RY (14 g/head per day). Feed intake, nutrient digestibility, rumen fermentation and milk production of each animal were recorded. Average dry matter (DM) intake was not affected (P>0.05) in buffaloes with or without RY (14.7 and 14.3 kg/day, respectively). Digestibility of DM, CP, and ruminal pH were similar (P>0.05) between the groups, but the digestibility coefficients of neutral detergent fiber and acid detergent fiber were greater (P<0.05) for the animals that received RY. Milk production (9.60 vs. 9.15 L/day) and 4% fat corrected milk (FCM) (11.32 vs. 11.85 L/day) were significantly (P<0.05) greater in the buffaloes fed with RY than the control group. Milk composition was similar between the experimental groups, however, milk somatic cell count (SCC) was significantly (P<0.01) lower in RY supplemented buffaloes than the control animals. In conclusion, feeding RY had positive effects on milk production, fibre digestibility and SCC in buffaloes fed maize silage-concentrate based diet.

Key Words: Digestibility, Intake, Lactating buffaloes, Milk production, Yeast (Saccharomyces cerevisiae)

Introduction

Buffalo has been the mainstay of the rural economy of small farmers in many of the developing countries of South Asia including Pakistan (Khan, 2009 ▶). Buffalo is normally kept as a dual-purpose animal i.e., both for milk and meat. Feeding cost contributes 60-70% of total animal production cost (Sindhu et al., 2002 ▶; Anjum and Afzal, 2015 ▶). Buffalo has better digestive ability than cattle to utilize poor quality roughages (Agarwal et al., 2008 ▶). Normally buffaloes are kept on green forages/roughages during maintenance, and offered concentrates (supplemented feeds) only during milking stage that may sometimes causes unstable rumen environment, poor digestion and absorption of costly nutrient and thus increases production cost (Sarwer et al., 2009 ▶). In this scenario, there is a dire need to introduce biotechnological tools and methods to stablize rumen ecosystem and enhance utilization efficiency of available feed resources (i.e., forages, crop residues and agro-industrial by-products) to reduce feeding cost of buffalo production.

Yeast supplementation in diets of ruminants is one option to increase utilization of poor quality roughages, grains and by-product based diets (Shriver-Munsch, 2011 ▶). Previous researchers (Moallem et al., 2009 ▶; Degirmencioglu et al., 2013 ▶; Meller et al., 2014) outlined some benefits of live yeast supplementation as increase in milk yield, milk protein, fibre digestion and stabilization of rumen pH in dairy cattle. The others reported that live yeast addition may balance rumen ecosystem and increase cellulolytic bacteria numbers in cattle (Wadhwa and Bakshi, 2013 ▶) and sheep (Mosoni et al., 2007 ▶). However, some researchers proposed that the effect of yeast supplementation is more pronounced in animals under stress conditions (Schingoethe et al., 2004 ▶; Moallem et al., 2009 ▶). Jouany and Morgavi (2007 ▶) reported that live yeast increases fibre digestion by stimulating cellulolytic bacteria and increases flow of microbial protein from the rumen. Furthermore, Bakr et al. (2015) noticed the decreased rumen ammonia nitrogen (N) concentration and increased ruminal pH, total volatile fatty acids (VFAs) and cellulose digestion in cattle that received the diet supplemented with yeast. Although good information on the effect of yeast supplementation is available in cattle, data on the effect of feeding live yeast in dairy buffaloes is scarce. Therefore, this study was planned to evaluate the effects of Rumen Yeast® (RY; Saccharomyces cerevisiae) supplementation on nutrients digestibility, feed intake, milk yield, milk composition, rumen fermentation parameters and economic viability in Nili-Ravi buffaloes fed maize silage-concentrate based total mixed ration.

Materials and Methods

Dairy buffaloes, feeding and management

Sixteen Nili-Ravi buffaloes, about 35 to 50 days in milk (2nd and 3rd production cycle), with average milk production of 8 ± 0.40 L/day were taken from Livestock Research Station, National Agricultural Research Centre (Islamabad, Pakistan). These buffaloes were kept in individual tie stalls. After acclimatization for 7 days, the animals were randomly allocated into two groups of 8 buffaloes each, and investigated for a 60-day period. Group I (control) was offered maize silage as sole forage ad libitum plus 3 kg of concentrates/head per day (16% CP and 72% TDN). Group II received the same diet as of control plus 14 g of RY/head. The RY consisted of 15 billion S. cerevisiae cells per g which released a considerable amount of metabolites (mannans and beta glucans) to improve microbial activity in the rumen. Concentrate was formulated as 25% rice polishing, 25% wheat bran, 15% maize gluten feed, 15% cane-molasses, 8% maize grains, 7% rapeseed cake, 3% cottonseed cake, 0.5% common salt, 0.5% di-calcium phosphate, 0.5% mineral premix and 0.5% urea, on a dry matter (DM) basis. This concentrate contained 90.20% DM, 16.08% CP, analyzed by method of AOAC (1990), and 33.59% neutral detergent fibre (NDF), 20.87% acid detergent fibre (ADF), determined by Van Soest et al. (1991), and 72.00% TDN. The TDN was calculated by regression equation based on proximate composition as described by Wardeh (1981). Maize silage was prepared mechanically in bales at Livestock Research Station during September which contained 33.00% DM, 8.90% CP, 48.50% NDF, 25.90% ADF (on a DM basis), and pH = 3.82. Feeding the animals was done twice daily at approximately 0830 and 1600 h. Total quantity of feed offered and refused by each animal was recorded daily to get feed intake. Fresh water was offered 3-4 times per day to all buffaloes. The buffaloes were milked twice a day, at approximately 0200 and 1400 h. Daily milk production was recorded and milk samples were collected fortnightly for chemical analyses. The trial lasted for 60 days (October to December, 2016) including the last 5 days for total collection of faeces for determination of nutrients digestibility. For that, feeds and orts samples (one sample/animal per day) were obtained, and composited by each buffalo for chemical analysis. Faeces were weighed daily and 10% of total faeces were composited by each buffalo, dried first at 60°C and then at 100°C in air forced oven, grinded, and analyzed for proximate composition according to AOAC (1990 ▶), and NDF and ADF by Van Soest et al. (1991 ▶). Hygienic environment was maintained by cleaning of floor with water. Milk fat, protein, total solids and somatic cell counts (SCC) were measured using MilkoScan analyser (FOSS ANA MilkoScan FT 120, GERBER INSTRUMENTS, Switzerland) according to the methods of Zecconi et al. (2002 ▶). Estimation of 4% fat corrected milk (FCM) was done by method described in NRC (2001 ▶) as:

4% FCM = 0.4 × milk yield (kg/day) + 15 × fat yield (kg/day)

while solids non fat (SNF) were calculated as total solids minus fat.

During the last week, rumen fluid was collected from all buffaloes using a stomach tube, 3 h after morning feeding. Approximately 100 ml of rumen fluid was collected from each animal into a clean, dry flask as described by Shen et al. (2012 ▶) and ruminal pH was immediately measured using a portable digital pH meter (350-JANWAY, UK). Concentration of VFAs was assayed using gas chromatography (GC-Auto-system, Perkin Elmer, USA) according to the method of Hu et al. (2005 ▶). Rumen ammonia-N concentration was determined according to the method described by Conway (1974 ▶).

Economic benefit

The economic returns, expressed as the ratio of output to input, was calculated as:

Output/input = (MP × MPM) / (DMI × MPF)

Where,

MP: The average milk produced (L/head)

MPM: The average market price of milk ($/L)

DMI: The daily DM intake (DMI; kg/head per day)

MPF: The market price of feeds (Xie et al., 2012)

Statistical analysis

The data collected on different parameters were subjected to statistical analysis using t-test for means comparison between control group versus RY supplemented group at P<0.05 and P<0.01 levels of probability (Steel et al., 1997 ▶).

Results

Results of present study on body weight (BW) changes, DMI, milk production, FCM and milk composition (protein, fat, SNF, total solids and SCC) are given in Table 1. Rumen yeast supplementation had positive effect on the BW changes of the lactating buffaloes (P<0.05). Total DMI was 2.8% greater in buffaloes fed with RY compared to the control animals (14.7 and 14.3 kg, respectively), however, this increase was not statistically significant (P>0.05).

Table 1.

Effect of rumen yeast (Saccharomyces cerevisiae) on dry matter intake, milk production and milk composition in Nili-Ravi lactating buffaloes

Parameters Without RY (control, n=8) With RY (treated, n=8) P-value
Average body weight (kg/head)
Initial weight (kg) 541.50 ± 12.33 514.60 ± 15.49 0.252
Final weight (kg) 558.25 ± 10.09 545.50 ± 11.45 0.361
Total weight gain (kg) 16.75 ± 8.09 30.90 ± 10.75 0.039
Total DM intake (kg/head per day)
Concentrate 2.70 ± 0.00 2.70 ± 0.00 0.471
Maize silage* 11.60 ± 0.50 12.00 ± 0.46 0.353
Total 14.30 ± 0.50 14.70 ± 0.46 0.372
Milk production (L/day)
Milk yield 9.15 ± 0.26b 9.60 ± 0.22a 0.041
4% Fat corrected milk 11.32 ± 5.00b 11.85 ± 5.00a 0.037
Milk composition (%)
Protein 4.42 ± 0.24 4.58 ± 0.18 0.293
Fat 6.35 ± 0.19 6.55 ± 0.15 0.257
Solids non fat 9.99 ± 0.29 9.91 ± 0.22 0.187
Total solids 16.34 ± 0.27 16.46 ± 0.30 0.328
Initial somatic cell count (no per ml) 13165 ± 87.5 12950 ± 98.7 0.401
Final somatic cell count (no per ml) 10750 ± 113.2b 8500 ± 137.4a 0.007
Open in a new tab

Mean±SE with different superscripts in the same row differ significantly (P<0.05).

*

Maize silage was offered ad libitum as a sole forage source plus 3 kg concentrate (16% CP and 72% TDN) daily without RY serves as control and with RY (14 g/head per day) as treated. n=8 Nili-Ravi lactating buffaloes per treatment

Average daily milk production and 4% FCM increased by 4.3% (9.60 vs. 9.15 L) and 4.7% (11.85 vs. 11.32 L) in RY supplemented buffaloes compared to control group, respectively (P<0.05). Milk protein, fat, SNF and total solids were similar (P>0.05) between the groups, whereas, SCC was lower (P<0.01) in the buffaloes that received RY compared to those animals which received the control diet (8500 vs. 10750 numbers/ml).

Feeding RY to lactating buffaloes did not affect (P>0.05) total tract DM and CP digestibility (Table 2). However, NDF and ADF digestibility was significantly (P<0.05) higher in buffaloes fed the diet with RY compared to the control group.

Table 2.

Effect of rumen yeast (Saccharomyces cerevisiae) on nutrients intake and digestibility in Nili-Ravi lactating buffaloes

Description Without RY (control, n=8) With RY (treated, n=8) P-values
Average daily intake (kg/day)
Dry matter 14.60 ± 0.50 14.70 ± 0.46 0.117
Crude protein 1.38 ± 0.06 1.40 ± 0.04 0.251
Neutral detergent fibre 2.83 ± 0.11 2.89 ± 0.10 0.368
Acid detergent fibre 2.13 ± 0.11 2.16 ± 0.10 0.303
Nutrients digestibility (%)
Dry matter 70.98 ± 1.31 69.88 ± 0.64 0.265
Crude protein 68.25 ± 1.17 67.99 ± 0.34 0.419
Neutral detergent fibre 59.91 ± 0.78b 62.72 ± 0.97a 0.041
Acid detergent fibre 54.23 ± 0.56b 56.87 ± 0.67a 0.036
Open in a new tab

Mean±SE with different superscripts in the same row differ significantly (P<0.05)

Results regarding rumen fluid parameters are shown in Table 3. The level of rumen ammonia-N was lower (P<0.05) while total VFAs concentration was higher (P<0.05) in buffaloes receiving RY supplemented diet compared to the control group.

Table 3.

Effect of rumen yeast (Saccharomyces cerevisiae) on rumen fermentation parameters in Nili-Ravi lactating buffaloes

Description Without RY (control, n=8) With RY (treated, n=8) P-values
pH 7.32 ± 0.50 7.04 ± 0.46 0.141
Ammonia nitrogen (mg/ml) 14.87 ± 0.06 11.63 ± 0.04 0.037
Total VFAs (mg/ml) 2.13 ± 0.11 2.65 ± 0.10 0.031
Open in a new tab

Mean±SE with different superscripts in the same row differ significantly (P<0.05)

The economic benefit from feeding RY supplement to lactating buffaloes is shown in Table 4. On DM basis, the price of one kg maize silage was $ 0.23, whereas the cost of concentrate was $ 0.32. The market price of each litre of milk was considered as $ 0.72. Therefore, total feed cost with RY was $ 3.69 per buffalo per day and control feed cost was $ 3.61. Market price of daily milk produced per buffalo with RY was $ 6.91, and for the control buffalo was $ 6.59. Therefore, economic benefit (ratio of output/input) with RY had a slightly higher effect compared to control (1.88 vs. 1.83).

Table 4.

Economic analysis of rumen yeast (Saccharomyces cerevisiae) supplementation to Nili-Ravi lactating buffaloes

Description Without RY (control, n=8) With RY (treated, n=8)
Cost of feed ($/day)
Concentrate 0.87 0.87
Maize silage 2.74 2.77
Rumen yeast - 0.05
Total feed cost ($/head per day) 3.61 3.69
Average milk yield (L/head per day) 9.15 9.60
Market price of milk produced ($/head per day) 6.59 6.91
Economic benefits (output/input) 1.83 1.88
Open in a new tab

Discussion

The positive effect of RY supplementation on post-partum (35 to 50 days) BW changes of Nili-Ravi lactating buffaloes compared to the control group might be due to the greater availability of energy that might had resulted in body restoration. The RY supplementation might have stimulated the growth of cellulolytic bacteria which resulted in higher NDF digestibility and more production of VFAs for energy (Ayad et al., 2013 ▶) which were also recorded in this study. Degirmencioglu et al. (2013 ▶) also observed a decrease in mobilization of body reserves in yeast supplemented buffaloes than control group, however the effect was not significant.

No effect of RY on DMI of buffaloes, in present study, was in accordance with the findings of previous researchers who reported that live yeast supplementation has no effect on DMI in dairy cattle (Rossow et al., 2017 ▶) and heifers (Ghazanfar et al., 2015 ▶). But, others found the higher (P<0.05) DMI in dairy cattle (Desnoyers et al., 2009 ▶), Anatolian buffalo (Degirmencioglu et al., 2013 ▶) and sheep (Payandeh and Kafilzadeh, 2007 ▶) receiving yeast supplementation. The inconsistency in the results may be due to the difference in feed type, feed intake, age, health and stress status of animals which may affect yeast efficacy (Moallem et al., 2009 ▶).

The positive effect of RY on milk production in present study was in line with the findings of previous researchers (Stein et al., 2006 ▶; Moallem et al., 2009 ▶; Degirmencioglu et al., 2013 ▶) for cows, and may be attributed to an increase in NDF digestibility and more VFA production thus allowing higher energy availability for milk yield. The lower SCC in the buffaloes fed with supplemented-RY diet compared to the control group was in agreement with other studies (Stein et al., 2006 ▶; Sretenović et al., 2008 ▶). The researchers noted that the reduction of SCC in yeast supplemented cows may be attributed to a better health status of udder (Stein et al., 2008 ▶) or the improved immune status of these cows (Bakr et al., 2015 ▶). But the probable mechanisms involved are not yet clear.

The increase in NDF and ADF digestibility with RY supplementation in present study might be due to enhanced cellulolytic bacteria population, which resulted in higher utilization of cellulose and more production of VFAs for energy. Moallem et al. (2009 ▶) also observed improvement in fibre digestion with addition of yeast to the diet because of the increase in the number of cellulolytic bacteria. Mosoni et al. (2007 ▶) reported higher cellulolytic bacteria population in the rumen of sheep fed a diet supplemented with live yeast culture. Guedes et al. (2008 ▶) concluded that live yeast supplementation has improved fibre digestibility up to 4.3% in cows fed corn silage based diets that supports our NDF and ADF digestibility results in buffaloes. However, no increase in DMD was observed with RY in buffaloes. Increase in NDF digestibility without any increase in DMD in RY fed cows compared to control was also observed by Bitencourt et al. (2011 ▶) and Pinloche et al. (2013 ▶) however, the reason was not clearly known.

The higher total ruminal VFAs concentration in RY fed group than the control animals, in our study, was in line with the findings of Abd el-Tawab (2007) and Bakr et al. (2015 ▶). The increase of total VFAs concentration in RY fed buffaloes might be due to more NDF digestibility. More VFA (especially propionate) production results in reduced availability of H2 and C, required for methane production, and consequently reduces energy loss (Bakr et al., 2015 ▶). In our study, rumen ammonia-N concentration was significantly lower in RY treated buffaloes than the control animals which is in agreement with previous findings (Abd el-Tawab, 2007; Moallem et al., 2009 ▶; Bakr et al., 2015 ▶). The decrease in rumen ammonia-N of RY fed buffaloes appear to be the result of incorporation of ammonia into microbial protein (Bakr et al., 2015 ▶), or it may be due to inhibitory effect of RY on proteolysis (Khattab et al., 2003 ▶).

In conclusion, dietary supplementation of lactating buffaloes with RY had positive effects on milk production, milk SCC, NDF digestibility and VFAs concentration in Nili-Ravi buffaloes fed on maize silage-concentrate based diet.

Acknowledgment

The authors thank Ms. Elko Organization Pvt. for financial assistance and providing Rumen Yeast® (a product of ICC, Brazil) to conduct this research under public private partnership at Animal Nutrition Program, Animal Sciences Institute, National Agricultural Research Centre, Islamabad, Pakistan.

Conflict of interest

There is no potential conflict of interest by the authors for this research paper.

References

  1. Agarwal, N , Kamra, DN , Chatterjee, PN , Kumar, R , Chaudery, LC In vitro methanogenesis, microbial profile and fermentation of green forages with buffalo rumen liquor as influenced by 2-Bromoethanesulphuric acid. Asian-Aust. J. Anim. Sci. 2008;21:818–823. [Google Scholar]
  2. Anjum, MI , Afzal, M Influence of substituting wheat straw with corncobs in fattening rations for growth rate and nutrient digestibility in buffalo calves. J. Anim. P. Sci. 2015;25:1216–1221. [Google Scholar]
  3. AOAC . Official methods of analysis. 15th Edn. Association of Official Analytical Chemists; 1990. [Google Scholar]
  4. Ayad, MA , Benallou, B , Saim, MS , Smadi, MA , Meziane, T Impact of feeding yeast culture on milk yield, milk components, and blood components in Algerian dairy herds. J. Vet. Sci. Technol. 2013;4:135–139. [Google Scholar]
  5. Bakr, HA , Hassan, MS , Giadinis, ND , Panousis, N , Ostojic, D , Abd El-Tawab, MM , Bojkovski, J Effect of Saccharomyces cerevisiae supplementation on health and performance of dairy cows during transition and early lactation period. Biotechnol. Anim. Husb. 2015;31:349–364. [Google Scholar]
  6. Bitencourt, LL , Silva, M , Menezes, B , Oliveira, L , Junior, D , Lopes, F , Zacaroni, OF , Pereira, MN Diet digestibility and performance of dairy cows supplemented with live yeast. Sci. Agric. 2011;66:301–307. [Google Scholar]
  7. Conway, EJ . Micro-diffusion analysis and volumetric errors. 9th Edn. London, UK: London Crosby-Cock Wood and Son Ltd; 1974. pp. 175–177. [Google Scholar]
  8. Degirmencioglu, T , Ozcan, T , Ozbilgin, S , Senlurklu, L Effects of yeast culture addition (Saccharomyces cerevisiae) to Anatolian water buffalo diets on milk composition and somatic cell count. 2013;Mljekartro:42–48. [Google Scholar]
  9. Desnoyers, M , Giger-Reverdin, S , Bertin, G , Duvaux-Ponter, C , Sauvant, D Meta-analysis of the influence of Saccharomyces cerevisiae supplementation on ruminal parameters and milk production of ruminants. J. Dairy Sci. 2009;92:1620–1632. doi: 10.3168/jds.2008-1414. [DOI] [PubMed] [Google Scholar]
  10. Ghazanfar, S , Anjum, MI , Azim, A , Ahmed, I Effects of dietary supplementation of yeast (Saccharomyces cerevisiae) culture on growth performance, blood parameters, nutrient digestibility and fecal flora of dairy heifers. J. Anim. P. Sci. 2015;25:53–59. [Google Scholar]
  11. Guedes, CM , Gonçalves, D , Rodrigues, MAM , Dias-Da-Silva, A Effects of a Saccharomyces cerevisiae yeast on ruminal fermentation and fiber degradation of maize silages in cows. Anim. Feed Sci. Technol. 2008;145:27–40. [Google Scholar]
  12. Hu, WL , Liu, JX , Ye, JA , Wu, YM , Guo, YQ Effect of tea saponin on rumen fermentation in vitro. Anim. Feed Sci. Technol. 2005;120:333–339. [Google Scholar]
  13. Jouany, JP , Morgavi, DP Use of ‘natural’ products as alternatives to antibiotic feed additives in ruminant production. Animal. 2007;1:1443–1466. doi: 10.1017/S1751731107000742. [DOI] [PubMed] [Google Scholar]
  14. Khan, MA . Buffalo the animal of future. 1st Edn. Lahore, Pakistan: Idara Matbuaat; 2009. p. 78. [Google Scholar]
  15. Khattab, HM , Salem, FA , Sayeda, MM , Nagh, HM Effect of Yea-Sacc, Lacto-Sacc supplementation and energy level on performance, rumen activity, some blood constituents and carcass traits in growing sheep. Egypt. J. Nutr. Feed. 2003;4:981–989. [Google Scholar]
  16. Moallem, UH , Lehrer, L , Livshitz, M , Zachut-Yakoby, S The effect of live yeast supplementation to dairy cows during the hot season on production, feed efficiency and digestibility. J. Dairy Sci. 2009;92:343–351. doi: 10.3168/jds.2007-0839. [DOI] [PubMed] [Google Scholar]
  17. Mosoni, P , Chaucheyras-Durand, F , Bera-Maillet, C , Forano, E Quantification by real-time PCR of cellulolytic bacteria in the rumen of sheep after supplementation of a forage diet with readily fermentable carbohydrates: effect of a yeast additive. J. Appl. Microbiol. 2007;103:2676–2685. doi: 10.1111/j.1365-2672.2007.03517.x. [DOI] [PubMed] [Google Scholar]
  18. NRC . Nutrient requirements of dairy cattle. Washington D: National Academy Press; 2001. [Google Scholar]
  19. Payandeh, S , Kafilzadeh, F The effect of yeast (Saccharomyces cerevisiae) on nutrient intake, digestibility and finishing performance of lambs fed a diet based on dried molasses sugar beet pulp. Pak. J. Biol. Sci. 2007;10:4426–4431. doi: 10.3923/pjbs.2007.4426.4431. [DOI] [PubMed] [Google Scholar]
  20. Pinloche, E , McEwan, N , Marden, JP , Bayourthe, C , Auclair, E , Newbold, CJ The effects of a probiotic yeast on the bacterial diversity and population structure in the rumen of cattle. PLOS One. 2013;8:67824. doi: 10.1371/journal.pone.0067824. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Rossow, HA , Riordan, T , Riordan, A Effects of addition of a live yeast product on dairy cattle performance. J. Appl. Anim. Res. 2017;46:1–5. [Google Scholar]
  22. Sarwer, M , Khan, MA , Nisa, M , Bhatti, SA , Shahzad, MA Nutritional management for buffalo production. Asian-Aust. J. Anim. Sci. 2009;22:1060–1068. [Google Scholar]
  23. Schingoethe, DJ , Linke, KN , Kalscheur, KF , Hippen, AR , Rennich, DR Feed efficiency of mid-lactation dairy cows fed yeast culture during summer. J. Dairy Sci. 2004;87:4178–4181. doi: 10.3168/jds.S0022-0302(04)73561-4. [DOI] [PubMed] [Google Scholar]
  24. Shen, JS , Chai, Z , Song, LJ , Liu, JX , Wu, YM Insertion depth of oral stomach tubes may affect the fermentation parameters of ruminal fluid collection in dairy cows. J. Dairy Sci. 2012;95:5978–5984. doi: 10.3168/jds.2012-5499. [DOI] [PubMed] [Google Scholar]
  25. Shriver-Munsch, CM. Effect of feeding various dosages of Saccharomyces cerevisiae fermentation product on health, reproduction and costs in multiparous dairy cows. MVSc Thesis. USA.: Oregon State University; 2011. p. 17. [Google Scholar]
  26. Sindhu, AA , Khan, MA , Nisa, M , Sarwar, M Agro-industrial by-products as a potential source of livestock feed. A review. Int. J. Agric. Biol. 2002;4:307–310. [Google Scholar]
  27. Sretenović, LJ , Petrovic, MP , Aleksic, S , Pantelic, V , Katic, V , Bogdanovic, V , Beskorovajni, R Influence of yeast, probiotics and enzymes in rations of dairy cows performance in transition. Biotechnol. Anim. Husb. 2008;24:33–43. [Google Scholar]
  28. Steel, RGR , Torrie, JH , Dickey, DA . Principles and procedures of statistics A biochemical approach. 3rd Edn. NY, USA: McGraw Hill Book Co. Inc.; 1997. pp. 113–115. [Google Scholar]
  29. Stein, DR , Allen, DT , Perry, EB , Bruner, JC , Gates, KW , Renberger, TG , Mertz, K , Jones, D , Spicer, LJ Effects of feeding propionibacteria to dairy cows on milk yield, milk components and reproduction. J. Dairy Sci. 2006;89:111–125. doi: 10.3168/jds.S0022-0302(06)72074-4. [DOI] [PubMed] [Google Scholar]
  30. Van Soest, PJ , Robertson, HB , Lewis, BA Methods of dietary fibre, NDF and non-starch polysaccharides in relation to animal material. J. Dairy Sci. 1991;74:3583–3595. doi: 10.3168/jds.S0022-0302(91)78551-2. [DOI] [PubMed] [Google Scholar]
  31. Wadhwa, M, Bakhshi, MPS. Utilization of fruit and vegetable wastes as livestock feed and as substrate for generation of other value-added products. FAO. Rome. 2013. http://fao.org/docrep/018/i3273e/i3273e.pdf.
  32. Wardeh, MF. Models for estimating energy and protein utilization for feed. PhD Dissertation. Logan, USA: Utah State University; 1981. p. 87. [Google Scholar]
  33. Xie, XX , Meng, QX , Ren, LP , Shi, FH , Zhou, B Effect of cattle breed on finishing performance, carcass characteristics and economic benefits under typical beef production system in China. Ital. J. Anim. Sci. 2012;58:312–316. [Google Scholar]
  34. Zecconi, A , Casirani, G , Binda, E , Piccinini, R The importance to assess the effect of voluntary milking system on teat tissues, intramammary infections and somatic cell counts. Dept. Anim. Path. Univ. of Milan, Italy. 2002;11:119–124. [Google Scholar]

Articles from Iranian Journal of Veterinary Research are provided here courtesy of Shiraz University

RESOURCES