Nutritive Value of Corn Silages Treated with Chemical Additives for Lactation1,2

Abstract

Corn silage of 27 to 29% dry matter was ensiled alone and with additions of limestone, urea, diammonium phosphate, as well as with limestone combined with either urea or diammonium phosphate. There was a slight increase in pH over control values with single chemical additives and any combination increased pH more than a single chemical additive (P<0.01).Addition of urea and diammonium phosphate significantly increased the crude protein equivalent of the treated silage. All added compounds produced an increase in the concentration of organic acids in the treated silage compared to the control silage.Intake of silage dry matter by milking cows was 1.7 to 1.9% of body weight for silages preserved alone or with additions of 0.5% urea, 0.5% limestone, both urea and limestone, or 1.0% diammonium phosphate plus limestone, but intake was less for those with additions of diammonium phosphate alone (1.3%), 0.75% urea alone, or with limestone (1.5%). Differences in fat-corrected milk production due to silages fed were small, but cows fed diammonium phosphate and 0.75% urea-treated silages produced 1.0 and 2.2kg less than those treated with 0.5% urea, which averaged 17.1 kg/cow/day.