Drought-stressed , Irrigated , and Additive-treated Corn Silages for Growing Cattle

Cattle fed drought-stressed corn silage gained about 10% slower but were just as efficient as cattle fed irrigated corn silage. Because the irrigated corn out yielded the drought corn (17.4 VS. 8.2 tons per acre), the irrigated silage gave a much higher cattle gain per acre (1928 VS. 940 1b). Silo Guard II® -treated silage had an advantage in DM recovery and feed conversion over its control and produced 4.6 more pounds of cattle gain per ton of crop ensiled. Cattle fed H/M Inoculant®treated silage gained significantly faster than cattle fed the control, however, the treated silage gave only slight improvements in DM recovery and gain per ton of crop ensiled.

August 16 for the drought-stressed and August 31 for the The dought-stressed corn had a grain yield of 20.5 bu per acre; the irrigated corn, 128.One silo of irrigated and one of drought-stressed corn served as controls.One silo of drought-stressed corn was treated with Silo Guard II ® and one silo of irrigated with H/M Inoculant ® .Ensiling temperatures were monitored for the first 42 days in all four silos and nylon bags (nine per silo) were buried for additional observations of silage DM recoveries.The silos were opened on February 8, 1984. of four cattle per silage.
The silages were fed to light weight yearling steers and heifers in six pens Silages were full-fed and all cattle received 2.0 lb of supplement daily (as-fed basis).Rations were formulated to provide 12% crude protein (DM basis), 200 mg of Rumensin ® per animal daily, and equal amounts of calcium, phosphorus, and vitamins A, D, and E.
The silos were emptied at a uniform rate and samples taken twice weekly.Feed offered was recorded daily for each of the 24 pens and the quantity of silage was adjusted daily to assure that fresh feed was always in the bunks.Feed not consumed was removed, weighed, and discarded every 7 days.
All calves were weighed individually on two consecutive days at the start (February 8 and 9, 1984) and at the end of the 84-day trial (May 2 and 3).Intermediate weights were taken before the A.M. feeding on days 28 and 56.
Three aerobic stability (bunk life) measurements were made on each silage.Approximately 60 lb of fresh silage was obtained from 3 ft below the surface in the center of each silo, while feeding out the top, middle, and bottom thirds of the silos.These were divided into 4.0 lb lots and each lot was placed in an expanded polystyrene container lined with plastic.A thermocouple wire was placed in the center of each container and cheesecloth stretched across the top.Containers were stored at 18 to 20 C and the silage temperature was recorded twice daily.After a designated number of days of air exposure, replicated containers of each silage were weighed, mixed, and sampled and dry matter loss was determined.

Results and Discussion
Visual appraisal indicated that all four silages were well preserved.Chemical analyses are shown in Table 20.1.The drought silages, which were much wetter at harvest than the irrigated silages, had more extensive fermentations with higher lactic and acetic acids and lower insoluble nitrogen and pH values.Neither additive significantly affected chemical composition.
Adjusted ensiling temperatures are shown in Figure 20.1.The maximum ambient temperature on the day of harvest was 108 F for the drought silages and 91 F for irrigated.As a result, initial temperature of the forage entering the silos was 7.7 degrees higher for the drought silages (99.4 VS 91.7).
Silage DM recovery and loss results are shown in Table 20.2.In the concrete stave silos, DM lost during fermentation, storage, and feedout was 36% higher for the drought silages (8.25%) than for the irrigated silages (5.25%).The buried nylon bags gave results similar to the silos, with irrigated silages having lower losses than drought silages.Feedable DM recoveries for the treated silages were slightly higher than their controls: 90.9 VS. 89.0% for Silo Guard II and 93.0 VS. 92.2% for H/M Inoculant.
Aerobic stabilities of silage from the top, middle, and bottom thirds of each silo are shown in Table 20.3.In general, stability increased as feeding progressed and the additives had little influence on stability.
Performance by cattle fed the control and treated silages is shown in Table 20.4.Cattle fed Silo Guard II -treated silage gained slightly faster and more efficiently than those fed its control.Cattle fed H/M Inoculant-treated silage gained faster (P<.05) and consumed 4.7% more feed than those fed its control.Also shown in Table 20.4 are cattle gains per ton of corn ensiled.These data combine silage recoveries (Table 20.2) and cattle performance.Silo Guard II silage produced 4.6 extra pounds of gain and H/M Inoculant, 2.3 extra pounds when compared with their control silages.
Performance by cattle fed the drought and irrigated silages is shown in Table 20.5.Cattle fed irrigated silage consumed more (P<.05)feed and gained faster (P<.05) than those fed drought silage.However, drought silage was utilized just as efficiently as irrigated silage.Also shown in Table 20.5 are cattle gains per ton of corn ensiled and per acre.The nutritive value of irrigated and drought silages was similar and a ton of each produced about the same amount of cattle gain.However, irrigated silage had double the yield per acre of drought silage (17.4 VS. 8.2 tons) and gave double the cattle gain per acre (1928 VS. 940 lb).

Table 20 .
1. Chemical Analyses of the Four Corn Silages Made in the Concrete Stave SilosTable 20.2.Dry Matter Recoveries and Losses From the Concrete Stave Silos and Buried Bags for the Four Corn Silages

Table 20 .
4. Performance by Cattle Fed the Four Corn Silages and Cattle Gain per Ton of Corn Ensiled ab P<.05 for irrigated control VS.H/M Inoculant.1 100% dry matter basis.2All values are adjusted to the same silage DM content, 35 percent.

Table 20 .
5. Performance by Cattle Fed the Drought and Irrigated Corn Silages, Cattle Gain per Ton of Corn Ensiled, and Cattle Gain per Acre