Ammonia-N concentration in alfalfa silage and its effects on dairy cow performance: a meta-analysis


  • Juan I. Sánchez-Duarte South Dakota State University
  • Álvaro García South Dakota State University



dairy cattle, Medicago sativa L., milk fat, milk protein, milk yield, regression model


Background: Ammonia nitrogen (N) in alfalfa silage is used to evaluate silage quality, but its effect on dairy cows production is unknown. Objective: A meta-analysis was conducted to assess the effects of ammonia-N concentration in alfalfa silage on dairy cow performance. Methods: Thirty-four comparisons from 10 studies were analyzed with linear and quadratic models by the mixed-effect models of the R program using study as a random effect. The variance explained by the models was evaluated calculating marginal R2 (m) and conditional R2 (c). Results: Dry matter intake declined (DMI; p = 0.007), and milk production and milk fat yield tended to decrease linearly in response to increasing ammonia-N concentration (p = 0.08). Milk fat and milk protein percentages were unaffected. Milk protein yield, however, showed a positive linear trend effect (p = 0.07) along with a significant quadratic effect (p = 0.01) in response to increasing ammonia-N concentration. Values of R2 (m) and R2 (c) indicated less variation for significant models. Conclusion: Increased ammonia-N in alfalfa silage reduced DMI, negatively impacting milk production and milk fat yield. The quadratic response in milk protein yield might be explained by the initial reduction in milk production, and the subsequent utilization of ammonia-N to produce more rumen microbial protein, which results in more milk protein.

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Author Biographies

Juan I. Sánchez-Duarte, South Dakota State University

PhD(c), Dairy and Food Science Department, South Dakota State University, USA.

Álvaro García, South Dakota State University

DVM, PhD., Dairy and Food Science Department, South Dakota State University, USA.


Akaike H. A new look at the statistical model identifi cation. IEEE Trans Autom Control 1974; 19:716-723.Altman N, Krzywinsky M. Points of signifi cance: Regression diagnostic. Nature Met 2016; 13:385-386.

Bartley EE, Avery TB, Nagaraja TG, Watt BR, Davidovich A, Galitzer S, Lassman BL. Ammonia toxicity in cattle. V. Ammonia concentration of lymph and portal, carotid, and jugularblood after the ingestion of urea. J Anim Sci 1981; 53:494-498.

Broderick GA, Brito AF, Olmos Colmenero JJ. Eff ects of feeding formate-treated alfalfa silage or red clover silage on the production of lactating dairy cows. J Dairy Sci 2007; 90:1378-1391.

Broderick GA, Muck RE. Eff ect of alfalfa silage storage structure and rumen-protected methionine on production in lactating dairycows. J Dairy Sci 2009; 92:1281-1289.

Broderick GA. Performance of lactating dairy cows fed either alfalfa silage or alfalfa hay as the sole forage. J Dairy Sci 1995; 78:320-329.

Buchanan-Smith JG, Yao YT. Non-protein nitrogen in corn silage:a partial characterization, its utilization in the rumen and eff ect upon digestibility and retention of nitrogen in lambs. Can J Anim Sci 1978; 58:681-690.

Colombari G, Borreani G, Crovetto GM. Eff ect of ensiling alfalfa at low and high dry matter on production of milk used to make grana cheese. J Dairy Sci 2001; 84:2494-2502.

Conrad HR, Baile CA, Mayer J. Changing meal patterns and suppression of feed intake with increasing amounts of dietary nonprotein nitrogen in ruminants. J Dairy Sci 1977; 60:1725-1733.

Doepel L, Pacheco D, Kennelly JJ, Hanigan MD, Lopez IF, Lapierre H. Milk protein synthesis as a function of amino acid supply. J Dairy Sci 2002; 87:1279-1297.

Douglas B, Maechler M, Bolker B, Walker S. Fitting linear mixed-eff ects models using lme4. J Stat Software 2015; 67:1-48.

Fredeen HA, McQueen RE, Browning DA. Eff ects of enzymes and nutrients in a bacterial inoculant on quality of timothy oralfalfa silage and dairy cow performance. Can J Anim Sci 1991; 71:781-791.

Givens DI, Rulquin H. Utilisation by ruminants of nitrogen compounds in silage-based diets. Anim Feed Sci Tech 2004;114:1-18.

Huhtanen P, Nousiainen JI, Khalili H, Jaakkola S, Heikkila T. Relationships between silage fermentation characteristics and milk production parameters: Analyses of literature data. LivestProd Sci 2003; 81:57-73.

Johnson PCD. Extension of Nakagawa & Schielzeth’s R2GLMMto random slope models. Met Ecology Evol 2014; 5:944-946.

Kent BA, Arambel MJ, Walters JL. Eff ect of bacterial inoculant on alfalfa haylage: Ensiling characteristics and milk production response when fed to dairy cows in early lactation. J Dairy Sci1988; 71:2457-2561.

Krizsan SJ, Broderick GA, Muck RE, Promkot C, Colombini S, Randby AT. Eff ect of alfalfa silage storage structure and roasting corn on production and ruminal metabolism of lactating dairy cows. J Dairy Sci 2007; 90:4793-4804.

Kung LJr, Craig WM, Satter LD. Ammonia-treated alfalfa silage for lactating dairy cows. J Dairy Sci 1989; 72:2565-2572.

Kung LJr, Satter LD, Jones BA, Genin KW, Sudoma AL, Enders GLJr, Kim HS. Microbial inoculation of low moisture alfalfa silage. J Dairy Sci 1987; 70:2069-2077.

Kung LJr, Shaver R. Interpretation and use of silage fermentation analysis reports. Focus on forage, 2001; Vol. 3, No. 13. University of Wisconsin Extension.

Kung LJr, Taylor CC, Lynch MP, Neylon JM. The eff ect of treating alfalfa with lactobacillus buchneri 40788 on silage fermentation, aerobic stability, and nutritive value for lactating dairy cows. J Dairy Sci 2003; 86:336-343.

Muck RE, Walgenbach RP. Variations in alfalfa buff ering capacity. Am Soc Agric Eng 1985: ASAE Paper No. 85-1535.

Muck RE. Factors infl uencing silage quality and their implications for management. J Dairy Sci 1988; 71:2992-3002.

Muck RE. The art and science of making silage. Proceeding, Western Alfalfa & Forage Conference; 2011 Dec 11-13; Las Vegas, NV. Davis, CA.

Nagel SA, Broderick GA. Eff ect of formic acid or formaldehyde treatment of alfalfa silage on nutrient utilization by dairy cows. J Dairy Sci 1992; 75:140-154.

Nakagawa S, Schielzeth H. A general and simple method for obtaining R2 from generalized linear mixed-eff ects models. Met Ecology Evol 2013; 4:133-142.

Ohshimaa M, McDonald P. A review of the changes in nitrogenous compounds of herbage during ensilage. J Sci Food Agric 1978; 29:491-505.

Owens VN, Albrecht KA, Muck RE, Duke SH. Protein degradation and fermentation characteristics of red clover and alfalfa silage harvested with varying levels of total nonstructural carbohydrates. Crop Sci 1999; 39:1873-1880.

Pan Z, Lin DY. Goodness-of-fi t methods for generalized linear mixed models. Biometrics 2005; 61:1000-1009.

Pinheiro J, Bates D, DebRoy S, Sarkar D, R Core Team. _nlme: Linear and Nonlinear Mixed Eff ects Models_2016; R package version 3.1-128.

R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. 2015.

Russelle M. The environmental impact of N2 fi xation by alfalfa. Proceedings, National Alfalfa Symposium; 2004 Dec 13-15; San Diego, CA. UC, Davis 2004.

St-Pierre NR. Invited review: Integrating quantitative fi ndings from multiple studies using mixed model methodology. J Dairy Sci 2001; 84:741-755.

Van Os M, Dulphy JP, Baumont R, Jailler M, Ballet JM. The infl uence of ammonia and amines on grass silage intake and intake behavior in dairy cows. Ann Zootech 1995; 44:73-85.

Van Soest PJ. Nutritional ecology of the ruminant. 2nd ed. Cornell University Press; 1994. p.463.

Volden H, Mydland LT, Olaisen V. Apparent ruminal degradation and rumen escape of soluble nitrogen fractions in grass and grass silage administered intraruminally to lactating dairy cows. J Anim Sci 2002; 80:2704-2716.

Weiss B. Optimizing and evaluating dry matter intake of dairy cows. WCDS Adv Dairy Tech 2015; 27:189-200.

Wright DA, Gordon FG, Steen RWJ, Patterson DC. Factors influencing the response in intake of silage and animal performance after wilting of grass before ensiling: A review. Grass Forage Sci 2000; 55:1-13.




How to Cite

Sánchez-Duarte, J. I., & García, Álvaro. (2017). Ammonia-N concentration in alfalfa silage and its effects on dairy cow performance: a meta-analysis. Revista Colombiana De Ciencias Pecuarias, 30(3), 175–184.



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