Over the past few years, sustainability has earned its status as a dairy industry buzzword. It's become rare to attend a meeting where the concept of producing milk and meat sustainably isn't mentioned or alluded to. In much the same vein, shrink has become the nutrition community's focus for sustainability.
Corn silage shrink, or the loss of weight between ensiling and feedout, is economically important, yet hard to quantify. And, unless there is buy-in on-farm, practices that minimize or mitigate these losses are less likely to be adopted.
For a number of reasons, including the potential to degrade air and water quality, federal and state agencies in California have become concerned with defining and minimizing silage shrink, noted Peter Robinson, University of California-Davis cooperative extension specialist, at the Western Large Herd Conference. Yet, virtually no research had been conducted to document the extent of silage shrink in the large-scale silage piles typical of the southwestern U.S.
Using eight corn silage piles, ranging in size from 1,052 tons to 13,470 tons in California's San Joaquin Valley, Robinson's team measured total shrink losses as well as the phase of the process where those losses occurred. All piles were covered within 48 hours with an oxygen barrier film and black/white outer plastic and weighted with tire chains.
The loses were evaluated based on wet weight, oven dry weight, and oven dry weight corrected for volatile compounds lost in the oven. Total losses were 8.4 percent, 6.8 percent and 2.8 percent, respectively, suggesting that most of what is measured as wet weight shrink is water.
To a great degree, the most significant shrink occurred in the silage mass prior to face exposure. Losses from the exposed face, as well as those occurring between face removal and the mixer, were much smaller.
While the number of piles was insufficient to examine many mitigation strategies, pile bunk density, face management, rate of face use and face orientation did not have obvious impacts on shrink, noted Robinson. The only factor that seemed to impact shrink was the average temperature during feedout, as higher temperatures were related to greater water weight shrink losses.
According to Robinson's research, true shrink losses in well-managed piles, measured as oven dry weight corrected for volatile compounds lost in the oven, are much lower than has generally been assumed (less than 3 percent in the corn silage piles studied). The exposed face is a small portion of those losses, and mitigations proposed within the state may not be as effective in reducing shrink as it was once thought.
The author is an associate editor and an animal science graduate of Cornell University. Smith covers feeding, milk quality and heads up the World Dairy Expo Supplement. She grew up on a Medina, N.Y., dairy, and interned at a 1,700-cow western New York dairy, a large New York calf and heifer farm, and studied in New Zealand for one semester.
Corn silage shrink, or the loss of weight between ensiling and feedout, is economically important, yet hard to quantify. And, unless there is buy-in on-farm, practices that minimize or mitigate these losses are less likely to be adopted.
For a number of reasons, including the potential to degrade air and water quality, federal and state agencies in California have become concerned with defining and minimizing silage shrink, noted Peter Robinson, University of California-Davis cooperative extension specialist, at the Western Large Herd Conference. Yet, virtually no research had been conducted to document the extent of silage shrink in the large-scale silage piles typical of the southwestern U.S.
Using eight corn silage piles, ranging in size from 1,052 tons to 13,470 tons in California's San Joaquin Valley, Robinson's team measured total shrink losses as well as the phase of the process where those losses occurred. All piles were covered within 48 hours with an oxygen barrier film and black/white outer plastic and weighted with tire chains.
The loses were evaluated based on wet weight, oven dry weight, and oven dry weight corrected for volatile compounds lost in the oven. Total losses were 8.4 percent, 6.8 percent and 2.8 percent, respectively, suggesting that most of what is measured as wet weight shrink is water.
To a great degree, the most significant shrink occurred in the silage mass prior to face exposure. Losses from the exposed face, as well as those occurring between face removal and the mixer, were much smaller.
While the number of piles was insufficient to examine many mitigation strategies, pile bunk density, face management, rate of face use and face orientation did not have obvious impacts on shrink, noted Robinson. The only factor that seemed to impact shrink was the average temperature during feedout, as higher temperatures were related to greater water weight shrink losses.
According to Robinson's research, true shrink losses in well-managed piles, measured as oven dry weight corrected for volatile compounds lost in the oven, are much lower than has generally been assumed (less than 3 percent in the corn silage piles studied). The exposed face is a small portion of those losses, and mitigations proposed within the state may not be as effective in reducing shrink as it was once thought.
The author is an associate editor and an animal science graduate of Cornell University. Smith covers feeding, milk quality and heads up the World Dairy Expo Supplement. She grew up on a Medina, N.Y., dairy, and interned at a 1,700-cow western New York dairy, a large New York calf and heifer farm, and studied in New Zealand for one semester.
