Lactation Trial Propels Interest in Shredlage
By Bill Mahanna
The looming high price of corn grain combined with the variability in the level of kernel damage in corn silage has led to much interest in alternative approaches to processing such as that being offered by Shredlage LLC.
The results of a University of Wisconsin lactation study (Ferraretto and Shaver, 2012) comparing shredlage to conventionally-processed corn silage was presented at the recent American Dairy Science Assn. meetings and is stimulating even more interest in this unique approach to chopping and processing corn silage.
Corn silage from the same hybrid was harvested at the University of Wisconsin Arlington Research Dairy at approximately 35% dry matter and stored in 10-ft. bags. The conventional kernel-processed silage (KP) was harvested with a John Deere 6910 at a theoretical chop length of 19 mm (0.74 in.) and processed with conventional rolls set at a 3-mm gap (Figure 1).
The shredlage treatment (SHRD) was harvested with a Claas Jaguar with half of the knives removed to achieve a 30-mm (1.18-in.) chop length with novel cross-grooved rolls set at a 2.5-mm gap (Ferraretto and Shaver, 2012).
The Shredlage processor (www.shredlage.com) was designed to allow a longer length of chop for more effective fiber in high corn silage diets (Figure 2) while delivering aggressive kernel damage not typically possible with conventional rolls in longer-cut silage (Olson, 2012).
The kernel processing score (percent of starch passing a 4.75-mm sieve) was 75% for the SHRD treatment compared to 60% for the KP silage, suggesting the developers were achieving their desired kernel damage effect.
However, what makes a difference is the resulting animal performance because the developers suggest that there will not be a significant fuel savings with SHRD even though the cutter head requires less power when set at 30 mm (Olson, 2012).
The silages were allowed to ferment for 30 days before 112 cows were stratified by breed, parity and days in milk and then assigned to pens (14 pens of eight cows each), and after a two-week adjustment period, randomly assigned to eight-week treatment periods fed assigned diets consisting of 50% corn silage (SHRD or KP), 10% alfalfa silage, 10.3% dry ground corn, 7.4% corn gluten feed, protein, fat and mineral/vitamins (Ferraretto and Shaver, 2012b).
One of the first questions producers ask about longer-chopped corn silage is if sorting is an issue given the SHRD diets had 15.5% on the top screen of the Penn State separator box compared to only 3.5% of the top screen with the KP diet. However, screening of refusals with the Penn State box indicated very minimal sorting, which did not differ statistically between treatments.
The cows fed the SHRD diet tended (P < 0.08) to consume 1.4 lb. per day more dry matter than the KP treatment cows. Milk yield averaged 96.0 lb. for the SHRD cows and 94.2 lb. for the KP cows but was not statistically different (P < 0.14) between treatments. Fat percentage, protein percentage and milk urea nitrogen did not differ between treatments.
The researchers concluded that feeding shredlage corn silage tended to increase dry matter intake and that fat- (P < 0.07) and energy-corrected milk (P < 0.10) yields also tended to be 2.2 lb. per day greater for cows fed shredlage compared to traditionally harvested and processed corn silage.
The researchers depleted the shredlage corn silage earlier than planned but detected a treatment-by-week interaction (P < 0.04; Figure 3) with the fat-corrected milk advantage for the SHRD treatment group increasing as the feeding period lengthened (Ferraretto and Shaver, 2012).
Perhaps the most important finding was that with the longer-chop, both ruminal and total-tract starch digestibilities were increased with the SHRD treatment (Ferraretto and Shaver, 2012b).
This implies a positive economic effect in this high corn-price environment, but also suggests ration-balancing implications. While the kernel damage may be more extensive and consistent in shredlage, until dairy producers and nutritionists become more accustomed to superior processing, it will require close attention to ruminal starch digestion, especially as starch digestibility increases over time in fermented storage.
The Bottom Line
There are plans by Wisconsin researchers to conduct a second trial this coming year to include investigating the effect that the increased fiber surface area in shredlage may exert on fiber digestibility.
There also needs to be more quantitative data on how shredlage affects silage bunker and drive-over pile densities (field reports indicate excellent density values) and the fuel consumption and efficiency of choppers outfitted with shredlage processors.
However, given that all the shredlage processors produced this first commercial year were very quickly sold, it appears the industry is welcoming technologies allowing for increased effective fiber in corn silage while reducing the time and hassle of monitoring kernel damage of silage delivered to the storage structure.
Ferraretto, L.F., and R.D. Shaver. 2012. Effects of corn shredlage on lactation performance by dairy cows. J. Dairy Sci. Vol. 95, Suppl. 2.
Ferraretto, L.F., and R.D. Shaver. 2012b. Results of UW-Madison corn shredlage feeding trial. Proceedings Four-State Dairy Nutrition & Management Conference. June 13-14, 2012. Dubuque, Iowa.
Olson, R. 2012. Personal communications. www.shredlage.com.
This article was originally published in September 2012 Feedstuffs issue, and is reproduced with their permission.