The effect of trace mineral source on NDF digestibility has been studied by several authors[1,2,3,4,5,6] in dairy cows and beef on a low forage diets and high forage diets. A meta-analysis of 11 studies[7] showed that the effect on NDF digestibility varied depending on the method chosen. Studies using total collection methods showed an increase of + 2.80 + 0.44 units (P<0.01), studies using uNDF240 as a marker tended to result in an increase of +1.70 + 0.67 units (p=0.06) whereas studies using an in-situ incubation method did not show a difference.

A study carried out by Oba et al[9] has shown that each one-point difference in NDF digestibility can represent 0.25 to 0.3 kg of daily Energy Corrected milk production.

In a trial carried out by Cornell University[10], milk production was increased in early lactation cows fed hydroxy trace minerals compared to cows fed sulphates or cows fed a mixture of organic trace minerals and sulphates. NDF digestibility was however not tested in this study.

It should be noted that since milk yield response to energy supply is not linear and decreases with increasing energy supply, it would be expected that greater NDF digestibility would increase milk yield mainly when energy supply is below requirement. Indeed, if a diet already provides energy in excess of requirement, additional energy from increased NDF digestibility would not be expected to increase milk yield.

The effect of the different sources of trace minerals on NDF digestibility are presented in Figure 2. NDF digestibility was the highest in the hydroxy trace mineral group.

Energy Corrected Milk yield in the primiparous cows was not different between the groups, whereas there were differences between the Energy Corrected Milk Yield of the multiparous cows with the animals fed a mixture of 70% hydroxy trace minerals and 30% organic trace minerals having the highest milk production (see Figure 5).

1. Faulkner, M.J. and W.P. Weiss (2017). Effect of source of trace minerals in either forage- or by-product-based diets fed to dairy cows: 1. Production and macronutrient digestibility, Journal of Dairy Science 100:5358-53-67.
2. Miller, M.D, Lanier, J.S, Kvidera, S.K, Dann, H.M, Ballard, C.S. and R.J. Grant (2020). Evaluation of source of corn silage and trace minerals on lactational performance and total-tract nutrient digestibility in Holstein cows. J. Dairy Sci., 103:3147-3160.
3. Guimaraes, O, Jalali, S, Wagner, T, Spears, J and T. Engle (2019). The influence of trace mineral source on fiber digestion, rumen fermentation characteristics, and mineral solubility in beef cattle fed a low-quality forage diet. J. An. Science. 97, Issue Supp. 3: 167.
4. Guimaraes, O, Wagner, T, Spears, J and T. Engle (2020). Influence of trace mineral source on digestion, ruminal volatile fatty acid and soluble mineral on steers fed a dairy type diet balanced to meet requirements for a high producing lactating dairy cow. J. An. Science. 98, Issue Supp. 3: 133–134.
5. Caldera, C.E, Weigel, B, Kucharczyk, V.N, Sellins, K.S, Archibeque, S.L, Wagner, J.J, Han, H, Spears, J.B. and T.E. Engle (2019). Trace mineral source influences ruminal distribution of copper and zinc and their binding strength to ruminal digesta. J. Anim. Sci., 97:1852-1864.
6. Guimaraes, O, Jalali, S, Wagner, J.J, Spears, J.W, and T.E. Engle (2021). Trace mineral source impacts rumen trace mineral metabolism and fiber digestion in steers fed a medium-quality grass hay diet. J. An. Science, 99(9): 1–7.
7. Ibraheem, M, Kvidera, S, and B. Bradford (2021). Meta-analysis to determine the impact of the trace mineral source on nutrient digestibility in dairy and beef animals. J. Dairy Sci. 104, suppl. 1: 244.
8. Guimaraes, O, Jalali, S, Wagner, J.J, Spears, J.W, and T.E. Engle (2021). Trace mineral source impacts rumen trace mineral metabolism and fiber digestion in steers fed a medium-quality grass hay diet. J. An. Science, 99(9): 1–7.
9. Oba, M. and M.S. Allen (1999). Evaluation of the Importance of the Digestibility of Neutral Detergent Fiber from Forage: Effects on Dry Matter Intake and Milk Yield of Dairy Cows. J. Dairy Sci., 99:589-596.
10. Yasui, T, Ryan, C.M, Gilbert, R.O, Perryman, K.R. and T. R. Overton (2014). Effects of hydroxy trace minerals on oxidative metabolism, cytological endometritis, and performance of transition dairy cows. J. Dairy Sci. 97: 3728-3738.
11. Daniel, J.B, Kvidera, S.K. and J. Martín-Tereso (2020). Total-tract digestibility and milk productivity of dairy cows as affected by trace mineral sources. J. Dairy Sci. 103 (10).