Since beginning grazing in 1992 we have experimented with many systems of supplemental feeding our cows on pasture. Each season we have tried to maintain an experiment to see how the cows react at different times during the grazing season.
Our first project was using a complete pelleted feed, fed in the fence line bunks either before or after milking. Because our milking system was slow, feeding after milking caused the entire herd to be off pasture for up to eight hours a day. While feeding before milking caused slow throughput in the parlor. Before our first season was over we had installed a feeding system in the parlor which allowed us to regulate the amount of feed provided to each individual cow. Protein content of the early ration was at 16% or more and the cows were constantly on the verge of diarrhea. As we decreased the protein content of the ration the cows manure firmed up slightly.
Several nutritional consultants felt we were starving our cows as the milk production dropped and body condition scores dropped respectively. Our next experiment was to increase the supplemental portion of the pasture ration by feeding up to 24# of concentrate to each cow. It became necessary to feed some of the concentrate in the pasture, as there wasn’t time for the cows to consume half of the daily dry matter intake during the short time they were being milked. We also had concerns about slugging the rumen with high levels of grain and causing concerns with acidosis. A simple system of delivering the grain mix to pasture was found and grain was processed into range cubes to reduce the waste issue. All this caused an increase in the cost of supplementation as well as an increase in time spent delivering this to the herd. When high grain prices hit us in 1995 we decided to reduce the amount of grain fed to the herd.
In early 1996, David Iles, a fellow grazier in North Carolina, suggested that removing all the additional protein, and reducing the supplementation to 1% of the cows body weight per day had improved production and greatly reduce the cost of producing an pound of milk for him. We followed his suggestion and immediately saw an improvement in body condition and reproductive performance. Due to our seasonal status we continued to refine our feeding program. We felt that energy was the limiting factor in the cows diet early in the grazing season. Rapid digestion of the high quality forages caused much of the grain to be only partially digested before exiting the digestive system. Particle size was reduced and that seem to improve the efficiency. We have experimented with several by-products as well as other grain sources to improve rapid response to energy sources in the digestive system. Our current analysis is that during early pasture growth additional energy can be beneficial but as the season progresses, if pasture quality is maintained then supplemental energy may have little benefit in increasing milk production and can be a detriment to reproductive efficiency.
The most important issue in this progression has been that the pasture quality has improved considerably since we began grazing the milking herd in 1992. Since high quality pasture is the lowest cost feed in our operation it just makes sense to use as much of it as the cows will consume.
Balancing a ration was one of the most important aspects of our old conventional dairy system, but with a sound pasture system the cows receive an adequately balanced ration with little input from us. I think this should be the point in a low cost pasture based system. Nature provides an adequate system for our livestock, we may mess it up slightly through our fertility management systems, but through minor manipulations we can provide a balance diet for our animals from the forages we produce. Ruminant livestock will be healthier if most of the feed they consume is forage based.
Our pasture system has led to a healthier herd of dairy cows and a more profitable system for us here at River-View Farm.