Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania

Maiko Tresphory Mwanibanza; Germana Henry Laswai; Ismail Saidi Selemani; Eliamon Titus Lyatuu; Raphael Mrode; Daniel Komwihangilo

doi:doi:10.11648/j.ijast.20261001.13

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| Peer-Reviewed

Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania

Maiko Tresphory Mwanibanza^*

, Germana Henry Laswai

, Ismail Saidi Selemani

, Eliamon Titus Lyatuu

, Raphael Mrode

, Daniel Komwihangilo

Published in International Journal of Animal Science and Technology (Volume 10, Issue 1)

Received: 2 January 2026 Accepted: 27 January 2026 Published: 11 February 2026

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Abstract

An on-farm monitoring experiment was conducted to assess the effect of supplementing lactating dairy cows with wet spent grain by-products (WSGB) on milk production, methane emissions, and economic profitability in smallholder dairy systems in Northern Tanzania. Forty (40) lactating cross-bred dairy cows, with equal numbers selected from two locations: Arusha City Council (ARCC) and Hai District Council (HDC) were subjected to two dietary supplements, wet spent grain by-products (S1) and common concentrates (S2) in a 2x2 factorial arrangement. Data on feed intake, milk yield, milk composition and methane emissions were recorded for a period of 30 days, including 7 days of adaptation. An economic analysis was performed to evaluate the profitability of the two supplements in the study areas. Body weights (BW) were estimated using heart girth width measured using weighing bands. Near-Infrared spectroscopy (NIRS), lactoscope 300^MT, and laser methane detector (LMD) were employed to determine the chemical composition of the feedstuffs, milk quality and methane (CH₄) emissions from the cows, respectively. The results showed that the average values (%) of crude protein (CP) and neutral detergent fibre (NDF) of supplement S1(21.93 and 53.35, respectively) were higher (P<0.05) than those of S2(12.63 and 29.12, respectively). The mean values of intake (g/kg BW) of CP and supplement NDF were higher (P<0.05) in cows supplemented with S1(3.23 and 3.06, respectively) than those on S2(2.48 and 1.04, respectively). Similarly, cows supplemented with S1 had higher (P<0.05) average yields of milk (39.7 g/kgBW), milk fat (308 g/kg of milk) and milk protein (449 g/kg of milk) than those on S2(33.64, 201.96, and 358.25, respectively). The gross margin (TZSH, per litre of milk) was higher (P<0.05) for cows fed on supplement S1 (777.38) than those on S2(622.48). In terms of location, cows in ARCC had a greater gross margin (701.08) than those in the HDC (698.8). The amount of methane (g/litre of milk) emitted from the cows on S1(11.7) was lower (P<0.05) than their counterparts in S2 (17.2), and the intensity was more pronounced in ARCC (17.27) compared to HDC (11.54). It is concluded that wet spent grain byproduct is a valuable supplement for dairy cows, effectively enhancing milk yield, gross margin from milk sales and lowering methane emissions. Further investigation is recommended into the optimal level of combination of brewery by-products with common concentrates to optimize nutrition and production potential of the cows.

Published in	International Journal of Animal Science and Technology (Volume 10, Issue 1)
DOI	10.11648/j.ijast.20261001.13
Page(s)	31-44
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2026. Published by Science Publishing Group

Keywords

Wet Spent Grain By-products, Dairy Cows, Milk Production, Methane emission, Smallholder Dairy Farmers, Economic Profitability

References

[1]	Maleko, D., Msalya, G., Mwilawa, A., Pasape, L., Mtei, K. (2018) Smallholder dairy cattle feeding technologies and practices in Tanzania: failures, successes, challenges and prospects for sustainability. International Journal of Agricultural Sustainability. 16(2), 201-213.
[2]	Lao, E. J. (2021). Big Data in Agriculture (BDA) Scrutinising the opportunities, challenges and sustainability of brewers’ spent grain as a feed source for dairy cattle. IGCSE Biology, 3(2), 56-64.
[3]	Knapp, J. R., Laur, G. L., Vadas, P. A., Weiss, W. P., & Tricarico, J. M. (2014). Invited review: Enteric methane in dairy cattle production: Quantifying the opportunities and impact of reducing emissions. Journal of Dairy Science, 97(6), 3231-3261. https://doi.org/10.26480/bda.02.2021.56.64
[4]	Kajeguka, D. C., Kaaya, R. D., Desrochers, R., Iranpour, M., Kavishe, R. A., Mwakalinga, S., Schioler, Alifrangis, M., Lindsay, Dibernardo, A. and Kulkarni, M. A. (2017). Mapping clusters of chikungunya and dengue transmission in northern Tanzania using disease exposure and vector data. Tanzania Journal of Health Research, 19(4). Arusha-Tanzania (Doctoral Dissertation, Mount Meru University).
[5]	Dida, M. F., Garcia, S. C., & Gonzalez, L. A. (2024). Dietary concentrate supplementation increases milk production and reduces predicted greenhouse gas emission intensity in pasture-based commercial dairy farms. Journal of Dairy Science, 107(8), 5639-5652.
[6]	Kerby, C., & Vriesekoop, F. (2017). An overview of the utilisation of brewery by-products as generated by british craft breweries. Beverages, 3(2), 24.
[7]	Zanton, G. I., & Heinrichs, A. J. (2016). Efficiency and rumen responses in younger and older Holstein heifers limit-fed diets of differing energy density. Journal of Dairy Science, 99(4), 2825-2836. Hatungimana, E., & Erickson, P. S. (2019). Effects of storage of wet brewers' grains treated with salt or a commercially available preservative on the prevention of spoilage, in vitro and in situ dry matter digestibility, and intestinal protein digestibility. Applied Animal Science, 35(5), 464-475.
[8]	Malik, P. K., Trivedi, S., Mohapatra, A., Kolte, A. P., Mech, A., Victor, T., Elena, A., and Bhatta, R. (2024). Oat Brewery Waste Decreases Methane Production and Alters Rumen Fermentation, Microbiota Composition, and CAZymes Profiles. Microorganisms, 12(7), 1475.
[9]	Ge, T., Yang, C., Li, B., Huang, X., Zhao, L., Zhang, X., and Zhang, E. (2023). A high-energy diet modifies rumen microbial composition and microbial energy metabolism patterns in fattening sheep. BMC Veterinary Research, 19(1), 32.
[10]	Mwanibanza, M. T., Laswai, G. H., Selemani, I. S., Lyatuu, E., & Mrode, R. (2025). An Assessment of the Status and Factors Influencing Utilization of Brewery By-products as Feed to Dairy Cows Under Smallholder System in Northern Tanzania. Animal and Veterinary Sciences, 13(3), 52-65. https://doi.org/10.11648/j.avs.20251303.11
[11]	Gross, J. J. (2022). Limiting factors for milk production in dairy cows: perspectives from physiology and nutrition. Journal of animal science, 100(3), skac044.
[12]	Trupa, A., Aplocina, E., & Degola, L. (2015). Forage quality and feed intake effect on methane emissions from dairy farming. Engineering for Rural Development, 14, 601-605.
[13]	Hawkins, J. W., Komarek, A. M., Kihoro, E. M., Nicholson, C. F., Omore, A. O., Yesuf, G. U., and Rufino, M. C. (2022). High-yield dairy cattle breeds improve farmer incomes, curtail greenhouse gas emissions and reduce dairy import dependency in Tanzania. Nature Food, 3(11), 957-967.
[14]	Feyissa, A. A., Senbeta, F., Tolera, A., Diriba, D., & Boonyanuwat, K. (2023). Enteric methane emission factors of smallholder dairy farming systems across intensification gradients in the central highlands of Ethiopia. Carbon Balance and Management, 18(1), 23.
[15]	Ruban, S. Y., Perekrestova, A. V., Shablia, V. P., & Bochkov, V. M. (2018). Feed conversion efficiency in different groups of dairy cows. Ukrainian journal of Ecology, 8(1), 124-129.
[16]	Macdonald Campus of McGill University. (2003). Feeding the dairy cow during lactation. Dairy Cattle Production 342-450A, 1-8.
[17]	Lukuyu, M. N., Gibson, J. P., Savage, D. B., Duncan, A. J., Mujibi, F. D. N., & Okeyo, A. M. (2016). Use of body linear measurements to estimate liveweight of crossbred dairy cattle in smallholder farms in Kenya. SpringerPlus, 5, 1-14.
[18]	Chagunda, M. G. G., Ross, D., & Roberts, D. J. (2009). On the use of a laser methane detector in dairy cows. Computers and Electronics in Agriculture, 68(2), 157-160.
[19]	AOAC 2000. Association of Official Analytical Chemists. Official method of analysis. 15th edition, AOAC, Washington DC, 1298 pp.
[20]	Corson, D., Waghorn, G. C., Ulyatt, M. J., & Lee, J. (1999). NIRS: Forage analysis and livestock feeding (pp. 127-132). Proceedings of the New Zealand Grassland Association. Retrieved from https://pdfs.semanticscholar.org/3ece/7a7d0cb4444135eefd71793f1bbc7999d84f77.pd
[21]	Kaylegian, K. E., Lynch, J. M., Fleming, J. R., & Barbano, D. M. (2009). Influence of fatty acid chain length and unsaturation on mid-infrared milk analysis. Journal of dairy science, 92(6), 2485-2501.
[22]	Kaylegian, K. E., Lynch, J. M., Fleming, J. R., & Barbano, D. M. (2009). Influence of fatty acid chain length and unsaturation on mid-infrared milk analysis. Journal of dairy science, 92(6), 2485-2501.
[23]	Scholkmann, F., J. Boss, and M. Wolf. (2012). An efficient algorithm for automatic peak detection in noisy periodic and quasi-periodic signals. Algorithms 5: 588-603. https://doi.org/10.3390/a5040588
[24]	Wu, L., Koerkamp, P. W. G., & Ogink, N. (2018). Uncertainty assessment of the breath methane concentration method to determine methane production of dairy cows. Journal of Dairy Science, 101(2), 1554-1564.
[25]	Gołaś, Z. (2017). Determinants of Milk Production Profitability. Problems of Agricultural Economics, 3(352), 19-40. https://doi.org/10.5604/00441600.1245843
[26]	Klimberg, R. (2023). Fundamentals of predictive analytics with JMP. SAS Institute.
[27]	Laswai, G. H., Mghen, D. M., Mtenga, A. L., Ndikumana, J., & Zziwa, E. (2013). Chemical composition and nutritional values of feed resources for ruminants. Eastern and Central Africa (ECA) feedstuff table for ruminants.
[28]	Magori, N. K. (2016). Effect of feeding practice on performance of dairy cattle under zero grazing system in Turiani division, /Master's dissertation, Sokoine University of Agriculture).
[29]	Ngesi, A. C., Laswai, G. H., Msalya, G. M., Lyatuu, E. T., Komwihangilo, D. M., & Mrode, R. (2025). An Assessment on the Feeding Practices and other Factors Influencing Dairy Production Under Smallholder Systems of Kilimanjaro Region in Tanzania. International Journal of Animal Science and Technology, 9(2), 87-99.
[30]	Van Saun, R. J. (2022). Feeding and nutrition. Medicine and Surgery of Camelids, 55-107.
[31]	Rashid, M., Aboshady, H. M., Agamy, R., & Archimede, H. (2024). Milk production and composition in warm-climate regions: a systematic review and meta-analysis. Tropical Animal Health and Production, 56(8), 382.
[32]	NRC (2001). National Research Council, Committee on Animal Nutrition, & Subcommittee on Dairy Cattle Nutrition. Nutrient requirements of dairy cattle: National Academies Press.
[33]	Mirzaei AA, NM Sis 2008. Nutritive Values of Some Agro‒Industrial By‒products for Ruminants‒ A Review. World Journal of Zoology. 3(2): 40‒46.
[34]	Niu, M., Kebreab, E., Hristov, A. N., Oh, J., Arndt, C., Bannink, Bayat, A. R., Brito, A. F., Boland, T., Casper, D. and Crompton, L. A. (2018). Prediction of enteric methane production, yield, and intensity in dairy cattle using an intercontinental database. Global change biology, 24(8), 3368-3389.
[35]	Moran, J. (2005). Nutrient requirements of dairy cows. Tropical Dairy Farming: Feeding Management for Small Gholder Dairy Farmers in the Humid Tropics., 312.
[36]	Muñoz, C., Herrera, D., Hube, S., Morales, J., & Ungerfeld, E. M. (2018). Effects of dietary concentrate supplementation on enteric methane emissions and performance of late lactation dairy cows. 78(September), 429-437. https://doi.org/10.4067/S0718-58392018000300429
[37]	Boland, T, M., Pierce, K. M., Kelly, A. K., Kenny, D. A., Lynch, M. B., Waters, S. M., Whelan, S. J., & McKay, Z. C. (2020) Feed Intake, Methane Emissions, Milk Production and Rumen Methanogen Populations of Grazing Dairy Cows Supplemented with Various C 18 Fatty Acid Sources. Animals (Basel). 10(12): 2380. https://doi.org/10.3390/ani10122380
[38]	Kamboh, A. A. (Ed.). (2017). Review on preservation and utilization of wet brewery spent grain as concentrate replacement feed for lactating dairy cows. J. Anim. Health Prod, 5(1), 10-13.
[39]	Hoffmann, A., Cardoso, A. S., Fonseca, N. V. B., Romanzini, E. P., Siniscalchi, D., Berndt, A. C, and Reis, R. A. (2021). Effects of supplementation with corn distillers’ dried grains on animal performance, nitrogen balance, and enteric CH4 emissions of young Nellore bulls fed a high-tropical forage diet. Animal, 15(3), 100155.
[40]	Morshidy, S. (2025). Modern nutritional approaches to mitigating enteric methane emissions in ruminants: A review. Animal Reports, 1(1), 41-59.
[41]	Chalchissa, G., Mekasha, Y., & Urge, M. (2014). Feed resources quality and feeding practices in urban and peri-urban dairy production of southern Ethiopia. Tropical and subtropical Agroecosystems, 17(3), 539-546.

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Mwanibanza, M. T., Laswai, G. H., Selemani, I. S., Lyatuu, E. T., Mrode, R., et al. (2026). Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania. International Journal of Animal Science and Technology, 10(1), 31-44. https://doi.org/10.11648/j.ijast.20261001.13

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ACS Style

Mwanibanza, M. T.; Laswai, G. H.; Selemani, I. S.; Lyatuu, E. T.; Mrode, R., et al. Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania. Int. J. Anim. Sci. Technol. 2026, 10(1), 31-44. doi: 10.11648/j.ijast.20261001.13

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AMA Style

Mwanibanza MT, Laswai GH, Selemani IS, Lyatuu ET, Mrode R, et al. Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania. Int J Anim Sci Technol. 2026;10(1):31-44. doi: 10.11648/j.ijast.20261001.13

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@article{10.11648/j.ijast.20261001.13,
  author = {Maiko Tresphory Mwanibanza and Germana Henry Laswai and Ismail Saidi Selemani and Eliamon Titus Lyatuu and Raphael Mrode and Daniel Komwihangilo},
  title = {Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania},
  journal = {International Journal of Animal Science and Technology},
  volume = {10},
  number = {1},
  pages = {31-44},
  doi = {10.11648/j.ijast.20261001.13},
  url = {https://doi.org/10.11648/j.ijast.20261001.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijast.20261001.13},
  abstract = {An on-farm monitoring experiment was conducted to assess the effect of supplementing lactating dairy cows with wet spent grain by-products (WSGB) on milk production, methane emissions, and economic profitability in smallholder dairy systems in Northern Tanzania. Forty (40) lactating cross-bred dairy cows, with equal numbers selected from two locations: Arusha City Council (ARCC) and Hai District Council (HDC) were subjected to two dietary supplements, wet spent grain by-products (S1) and common concentrates (S2) in a 2x2 factorial arrangement. Data on feed intake, milk yield, milk composition and methane emissions were recorded for a period of 30 days, including 7 days of adaptation. An economic analysis was performed to evaluate the profitability of the two supplements in the study areas. Body weights (BW) were estimated using heart girth width measured using weighing bands. Near-Infrared spectroscopy (NIRS), lactoscope 300MT, and laser methane detector (LMD) were employed to determine the chemical composition of the feedstuffs, milk quality and methane (CH4) emissions from the cows, respectively. The results showed that the average values (%) of crude protein (CP) and neutral detergent fibre (NDF) of supplement S1(21.93 and 53.35, respectively) were higher (P<0.05) than those of S2(12.63 and 29.12, respectively). The mean values of intake (g/kg BW) of CP and supplement NDF were higher (P<0.05) in cows supplemented with S1(3.23 and 3.06, respectively) than those on S2(2.48 and 1.04, respectively). Similarly, cows supplemented with S1 had higher (P<0.05) average yields of milk (39.7 g/kgBW), milk fat (308 g/kg of milk) and milk protein (449 g/kg of milk) than those on S2(33.64, 201.96, and 358.25, respectively). The gross margin (TZSH, per litre of milk) was higher (P<0.05) for cows fed on supplement S1 (777.38) than those on S2(622.48). In terms of location, cows in ARCC had a greater gross margin (701.08) than those in the HDC (698.8). The amount of methane (g/litre of milk) emitted from the cows on S1(11.7) was lower (P<0.05) than their counterparts in S2 (17.2), and the intensity was more pronounced in ARCC (17.27) compared to HDC (11.54). It is concluded that wet spent grain byproduct is a valuable supplement for dairy cows, effectively enhancing milk yield, gross margin from milk sales and lowering methane emissions. Further investigation is recommended into the optimal level of combination of brewery by-products with common concentrates to optimize nutrition and production potential of the cows.},
 year = {2026}
}

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TY  - JOUR
T1  - Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania
AU  - Maiko Tresphory Mwanibanza
AU  - Germana Henry Laswai
AU  - Ismail Saidi Selemani
AU  - Eliamon Titus Lyatuu
AU  - Raphael Mrode
AU  - Daniel Komwihangilo
Y1  - 2026/02/11
PY  - 2026
N1  - https://doi.org/10.11648/j.ijast.20261001.13
DO  - 10.11648/j.ijast.20261001.13
T2  - International Journal of Animal Science and Technology
JF  - International Journal of Animal Science and Technology
JO  - International Journal of Animal Science and Technology
SP  - 31
EP  - 44
PB  - Science Publishing Group
SN  - 2640-1312
UR  - https://doi.org/10.11648/j.ijast.20261001.13
AB  - An on-farm monitoring experiment was conducted to assess the effect of supplementing lactating dairy cows with wet spent grain by-products (WSGB) on milk production, methane emissions, and economic profitability in smallholder dairy systems in Northern Tanzania. Forty (40) lactating cross-bred dairy cows, with equal numbers selected from two locations: Arusha City Council (ARCC) and Hai District Council (HDC) were subjected to two dietary supplements, wet spent grain by-products (S1) and common concentrates (S2) in a 2x2 factorial arrangement. Data on feed intake, milk yield, milk composition and methane emissions were recorded for a period of 30 days, including 7 days of adaptation. An economic analysis was performed to evaluate the profitability of the two supplements in the study areas. Body weights (BW) were estimated using heart girth width measured using weighing bands. Near-Infrared spectroscopy (NIRS), lactoscope 300MT, and laser methane detector (LMD) were employed to determine the chemical composition of the feedstuffs, milk quality and methane (CH4) emissions from the cows, respectively. The results showed that the average values (%) of crude protein (CP) and neutral detergent fibre (NDF) of supplement S1(21.93 and 53.35, respectively) were higher (P<0.05) than those of S2(12.63 and 29.12, respectively). The mean values of intake (g/kg BW) of CP and supplement NDF were higher (P<0.05) in cows supplemented with S1(3.23 and 3.06, respectively) than those on S2(2.48 and 1.04, respectively). Similarly, cows supplemented with S1 had higher (P<0.05) average yields of milk (39.7 g/kgBW), milk fat (308 g/kg of milk) and milk protein (449 g/kg of milk) than those on S2(33.64, 201.96, and 358.25, respectively). The gross margin (TZSH, per litre of milk) was higher (P<0.05) for cows fed on supplement S1 (777.38) than those on S2(622.48). In terms of location, cows in ARCC had a greater gross margin (701.08) than those in the HDC (698.8). The amount of methane (g/litre of milk) emitted from the cows on S1(11.7) was lower (P<0.05) than their counterparts in S2 (17.2), and the intensity was more pronounced in ARCC (17.27) compared to HDC (11.54). It is concluded that wet spent grain byproduct is a valuable supplement for dairy cows, effectively enhancing milk yield, gross margin from milk sales and lowering methane emissions. Further investigation is recommended into the optimal level of combination of brewery by-products with common concentrates to optimize nutrition and production potential of the cows.
VL  - 10
IS  - 1
ER  -

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Author Information

Maiko Tresphory Mwanibanza

Department of Animal, Aquaculture and Range Sciences (DAARS), Sokoine University of Agriculture, Morogoro, Tanzania;Tanzania Livestock Research Institute (TALIRI), Dodoma, Tanzania

Contact Email

http://orcid.org/0009-0007-8705-2178
Germana Henry Laswai

Department of Animal, Aquaculture and Range Sciences (DAARS), Sokoine University of Agriculture, Morogoro, Tanzania

http://orcid.org/0000-0003-4782-7286
Ismail Saidi Selemani

Department of Animal, Aquaculture and Range Sciences (DAARS), Sokoine University of Agriculture, Morogoro, Tanzania

http://orcid.org/0000-0003-0388-0069
Eliamon Titus Lyatuu

International Livestock Research Institute (ILRI), Dar es Salaam, Tanzania

http://orcid.org/0000-0001-9909-2117
Raphael Mrode

International Livestock Research Institute (ILRI), Nairobi, Kenya

http://orcid.org/0000-0003-1964-5653
Daniel Komwihangilo

Tanzania Livestock Research Institute (TALIRI), Dodoma, Tanzania

http://orcid.org/0000-0002-3291-9869

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APA Style

Mwanibanza, M. T., Laswai, G. H., Selemani, I. S., Lyatuu, E. T., Mrode, R., et al. (2026). Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania. International Journal of Animal Science and Technology, 10(1), 31-44. https://doi.org/10.11648/j.ijast.20261001.13

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ACS Style

Mwanibanza, M. T.; Laswai, G. H.; Selemani, I. S.; Lyatuu, E. T.; Mrode, R., et al. Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania. Int. J. Anim. Sci. Technol. 2026, 10(1), 31-44. doi: 10.11648/j.ijast.20261001.13

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AMA Style

Mwanibanza MT, Laswai GH, Selemani IS, Lyatuu ET, Mrode R, et al. Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania. Int J Anim Sci Technol. 2026;10(1):31-44. doi: 10.11648/j.ijast.20261001.13

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@article{10.11648/j.ijast.20261001.13,
  author = {Maiko Tresphory Mwanibanza and Germana Henry Laswai and Ismail Saidi Selemani and Eliamon Titus Lyatuu and Raphael Mrode and Daniel Komwihangilo},
  title = {Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania},
  journal = {International Journal of Animal Science and Technology},
  volume = {10},
  number = {1},
  pages = {31-44},
  doi = {10.11648/j.ijast.20261001.13},
  url = {https://doi.org/10.11648/j.ijast.20261001.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijast.20261001.13},
  abstract = {An on-farm monitoring experiment was conducted to assess the effect of supplementing lactating dairy cows with wet spent grain by-products (WSGB) on milk production, methane emissions, and economic profitability in smallholder dairy systems in Northern Tanzania. Forty (40) lactating cross-bred dairy cows, with equal numbers selected from two locations: Arusha City Council (ARCC) and Hai District Council (HDC) were subjected to two dietary supplements, wet spent grain by-products (S1) and common concentrates (S2) in a 2x2 factorial arrangement. Data on feed intake, milk yield, milk composition and methane emissions were recorded for a period of 30 days, including 7 days of adaptation. An economic analysis was performed to evaluate the profitability of the two supplements in the study areas. Body weights (BW) were estimated using heart girth width measured using weighing bands. Near-Infrared spectroscopy (NIRS), lactoscope 300MT, and laser methane detector (LMD) were employed to determine the chemical composition of the feedstuffs, milk quality and methane (CH4) emissions from the cows, respectively. The results showed that the average values (%) of crude protein (CP) and neutral detergent fibre (NDF) of supplement S1(21.93 and 53.35, respectively) were higher (P<0.05) than those of S2(12.63 and 29.12, respectively). The mean values of intake (g/kg BW) of CP and supplement NDF were higher (P<0.05) in cows supplemented with S1(3.23 and 3.06, respectively) than those on S2(2.48 and 1.04, respectively). Similarly, cows supplemented with S1 had higher (P<0.05) average yields of milk (39.7 g/kgBW), milk fat (308 g/kg of milk) and milk protein (449 g/kg of milk) than those on S2(33.64, 201.96, and 358.25, respectively). The gross margin (TZSH, per litre of milk) was higher (P<0.05) for cows fed on supplement S1 (777.38) than those on S2(622.48). In terms of location, cows in ARCC had a greater gross margin (701.08) than those in the HDC (698.8). The amount of methane (g/litre of milk) emitted from the cows on S1(11.7) was lower (P<0.05) than their counterparts in S2 (17.2), and the intensity was more pronounced in ARCC (17.27) compared to HDC (11.54). It is concluded that wet spent grain byproduct is a valuable supplement for dairy cows, effectively enhancing milk yield, gross margin from milk sales and lowering methane emissions. Further investigation is recommended into the optimal level of combination of brewery by-products with common concentrates to optimize nutrition and production potential of the cows.},
 year = {2026}
}

Copy | Download

TY  - JOUR
T1  - Effects of Brewery Byproducts on Dairy Cows in Northern Tanzania
AU  - Maiko Tresphory Mwanibanza
AU  - Germana Henry Laswai
AU  - Ismail Saidi Selemani
AU  - Eliamon Titus Lyatuu
AU  - Raphael Mrode
AU  - Daniel Komwihangilo
Y1  - 2026/02/11
PY  - 2026
N1  - https://doi.org/10.11648/j.ijast.20261001.13
DO  - 10.11648/j.ijast.20261001.13
T2  - International Journal of Animal Science and Technology
JF  - International Journal of Animal Science and Technology
JO  - International Journal of Animal Science and Technology
SP  - 31
EP  - 44
PB  - Science Publishing Group
SN  - 2640-1312
UR  - https://doi.org/10.11648/j.ijast.20261001.13
AB  - An on-farm monitoring experiment was conducted to assess the effect of supplementing lactating dairy cows with wet spent grain by-products (WSGB) on milk production, methane emissions, and economic profitability in smallholder dairy systems in Northern Tanzania. Forty (40) lactating cross-bred dairy cows, with equal numbers selected from two locations: Arusha City Council (ARCC) and Hai District Council (HDC) were subjected to two dietary supplements, wet spent grain by-products (S1) and common concentrates (S2) in a 2x2 factorial arrangement. Data on feed intake, milk yield, milk composition and methane emissions were recorded for a period of 30 days, including 7 days of adaptation. An economic analysis was performed to evaluate the profitability of the two supplements in the study areas. Body weights (BW) were estimated using heart girth width measured using weighing bands. Near-Infrared spectroscopy (NIRS), lactoscope 300MT, and laser methane detector (LMD) were employed to determine the chemical composition of the feedstuffs, milk quality and methane (CH4) emissions from the cows, respectively. The results showed that the average values (%) of crude protein (CP) and neutral detergent fibre (NDF) of supplement S1(21.93 and 53.35, respectively) were higher (P<0.05) than those of S2(12.63 and 29.12, respectively). The mean values of intake (g/kg BW) of CP and supplement NDF were higher (P<0.05) in cows supplemented with S1(3.23 and 3.06, respectively) than those on S2(2.48 and 1.04, respectively). Similarly, cows supplemented with S1 had higher (P<0.05) average yields of milk (39.7 g/kgBW), milk fat (308 g/kg of milk) and milk protein (449 g/kg of milk) than those on S2(33.64, 201.96, and 358.25, respectively). The gross margin (TZSH, per litre of milk) was higher (P<0.05) for cows fed on supplement S1 (777.38) than those on S2(622.48). In terms of location, cows in ARCC had a greater gross margin (701.08) than those in the HDC (698.8). The amount of methane (g/litre of milk) emitted from the cows on S1(11.7) was lower (P<0.05) than their counterparts in S2 (17.2), and the intensity was more pronounced in ARCC (17.27) compared to HDC (11.54). It is concluded that wet spent grain byproduct is a valuable supplement for dairy cows, effectively enhancing milk yield, gross margin from milk sales and lowering methane emissions. Further investigation is recommended into the optimal level of combination of brewery by-products with common concentrates to optimize nutrition and production potential of the cows.
VL  - 10
IS  - 1
ER  -

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