There are a number of benefits to merging hay as opposed to raking. We will go over a few of those benefits to help you understand how an Oxbo merger can help boost productivity as well as improve the feed quality.
There are a few different rake types that perform better or worse, depending on crops and field conditions. What they all have in common is that they roll, sweep or drag hay across the ground to make a windrow. As the crop is moved across the ground, dirt, rocks and other foreign material is rolled into the windrow with the forage, which raises ash content, reduces feed quality and creates the potential for more wear and tear on machinery.
Mergers have proven to produce better quality feed as a result of hay being lifted and conveyed off the ground. This lifting action helps reduce the amount of foreign material in the hay helping lower ash content. Windrow quality also improves by eliminating roping resulting in faster drying times. Mergers also provide a number of improvements in productivity and versatility.
Higher nutritional quality of merged forage, due in part to lower ash content, produces a "home-grown milk-maker" and lessens the amount spent on uncontrolled costs of purchased commodities. Below are a couple articles that help highlight the benefits of merging when it comes to feed quality and ash content.
Hoard's DairymanDan Undersander, University of Wisconsin Extension Agronomist, May 25, 2007
Merging windrows rather than raking will result in hay or silage with less ash content since the windrow is picked up and moved horizontally by a conveyer rather than being rolled across the ground. Merging can result in 1 to 2 percent less ash in the hay or silage. Mergers are expensive and may not be economical on many farms though this could be an advantage of using a custom harvester.
ADVANCED AG SYSTEMS'Crop Soil NewsTomas Kilcer, Certified Crop Advisor, May 2016
So, what is a little dirt in the tons of forage? For starters you have just inoculated a highly digestible, high sugar forage with a range of wild and not so beneficial bacteria and molds. They are not good for your cows or for making silage. Second, Dr. Sniffen of Fencrest LLC found that going from 9% to 11% ash will knock 1.9 pounds of milk off per cow per day. On a 100 cow dairy this is los of over $11, 590 in a 205 day lactation of high forage diet of 50% legume. I calculated for two mid west farms this year that simple ash levels were costing them $65,000 on one, and $75,000 on the other from lost milk production by feeding 2% more ash. Adjusting cutting height, and/or putting on extended skid plates will leave taller stubble to allow for tedding plus raking/merging without skyrocketing ash levels.