Publication Date


Advisor(s) - Committee Chair

L.D. Brown, Frank Toman

Degree Program

Department of Agriculture

Degree Type

Master of Science


The effects of chemical additives on the fermentation pattern and subsequent feeding value of corn silage was investigated over a two year period. Corn plants harvested in August 1967 (Experiment I) were ensiled with no additive, 3.50 per cent area, or urea-mineral mix supplying an equal amount of urea. Those harvested in August 1968 (Experiment II) were ensiled with no additive, 0.50 per cent urea, or 0.75 per cent urea. The nutritive value of these silages was evaluated chemically and by lactation trials.

:he addition of urea alone, or in combination with minerals elevated the initial pH and buffered against reduction of pH during fermentation. Urea-mineral combination exhibited a stronger buffering action than urea alone.

Data obtained during the first 25 days of fermentation in Experiment II indicated that acetic acid essentially completed after 5 days. Lactic production was acid production continued throughout the 25-day period. The production of propionic, butyric, and lactic acids was significantly increased by increased amounts c: urea (P<.01). Acetic acid production was significantly increased (P<.01) by the addition of 0.75 per cent urea but was slightly, although not significantly, depressed by the addition of 0.50 per cent urea.

In both experiments the treated silages tended to have less crude fiber, ether extract, and nitrogen-free-extract, but more ash and crude protein than the control silages. The crude protein content appeared to be elevated in an amount corresponding to the amount of urea added.

The effects of fermentation on urea were studied in Experiment II. Approximately 72.7, 65.3, and 66.6 per cent of the initial nitrogen as urea in the control, 0.50 per cent urea, and 0.75 per cent urea silages, respectively, was converted to other forms. The increase in NH 3 -N accounted for 22.8, 44.4, and 24.8 per cent of this decrease in urea-N in the control, 0.50 per cent urea, and 0.75 per cent urea silages, respectively.

In the lactation trials, 24 Holstein cows were arranged In a 3 x 3 Latin Square design. Experimental silages were fed ad libitum. The diets were isonitrogenous and isccaloric. No significant difference was noted in milk production, silage consumption, and body weight change between COWS fed the control and 0.50 per cent urea silages in both experiments. Cows fed the urea--ineral silage in Experiment I, produced significantly less milk, consumed significantly less silage, and gained significantly less body weight than did cows fed the control and 0.50 per cent urea silages (P<.01, P<.01, P<.05, respectively). In Experiment II, cows fed the control and 0.50 per cent urea silages consumed significantly more silage dry matter than cows fed the 0.75 per cent urea silage (P<.01). Cows fed the control silage gained significantly more weight than did those fed the 0.75 per cent urea silage (P<.05), whereas, cows fed 0.50 per cent urea silage were not different from either the control or 0.75 per cent urea group in this respect. No significant differences in FCM production were noted among treatment groups.


Agriculture | Agronomy and Crop Sciences | Animal Sciences | Life Sciences | Plant Sciences