Pigs on pasture: An assessment of pasture health, pork quality, and ecosystem rebound after rotational grazing
Our research project aims to assist farmers in obtaining information about whether the increased labor costs associated with rotational grazing of hogs is offset by decreased grain costs and increased pasture and soil quality.
In our first year, we successfully raised a total of 24 pigs in two management styles: rotationally grazed, and continually grazed. The experimental layout was designed by Professor Brian Schultz. The carcasses were evaluated in partnership with the Arion Thiboumery and his staff at Vermont Packinghouse. A preliminary look at the data indicate that the management style has little perceptible effect on the carcass quality of the pigs.
Throughout the season, two student interns handled most of the daily pig chores, including feeding, watering, rotating the pigs to new pastures if applicable, and maintaining the fences. They also assisted in soil sampling and loading the pigs onto trailers for transport to the slaughterhouse.
In conversation with other local pig farmers, we discovered that there is significant interest in the results of this experiment. Some farmers were keenly interested in the value of rotational grazing versus continuous grazing.
Due to this year’s severe drought, we were unable to re-seed the pasture, but will commence with this phase of the research in the spring.
There were three main experiment treatments: pigs in a rotational grazing system, pigs in a similar-sized continuous grazing system, and a control without pigs for plant and soil comparisons. The control paddocks were mown periodically to prevent brush infiltration and to mimic general pasture care. To prevent massive destruction at feeding, watering, and loafing sites, the pigs were fed at different locations daily and water and shade structures were moved weekly.
24 pigs were successfully raised on pasture. Three groups of fours pigs each were rotated on smaller paddocks weekly, while the remaining three groups of four pigs were given complete access to their pastures.
The grazing action of the pigs varied a great deal. Some groups rooted extensively while others rooted very little. This did not appear to have any relation to the management style (rotationally grazed versus continuous).
Sampling and Analysis
We examined three areas of interest:
1) pasture and soil quality;
2) carcass quality;
3) average daily gain
Pasture and soil quality: Soil samples were taken before, during, and after their grazing. We will be taking more soil samples in the spring. Soils were analyzed for the standard suite of agronomic parameters plus organic matter content. Data analysis will be conducted during the winter months, augmented by spring sampling.
We used square meter quadrat sampling to determine pasture composition before the pigs were given access to the pasture.
In 2017, we will continue with more soil sampling and quadrat sampling after the reseeding.
Carcass quality: We worked with Arion Thiboumery of Vermont Packinghouse to assess carcass quality of the 24 pigs in the study. We measured backfat depth, meat firmness, and loin eye area.
Data analysis will include comparing these measures between the rotationally grazed groups, the continuously grazed groups, and industry norms for confinement-raised pigs.
Average daily gain:
All grain given to the pigs was weighed and tracked. This information will be analyzed with the hanging weight information from the slaughterhouse.
Regrowth of pasture and assessment of pasture improvements: Unfortunately, due to the extensive drought, we were unable to re-seed the pastures as described in our proposal. We will do this work in early spring 2017, with sampling of soils and pasture taking place in spring and summer of 2017.
A preliminary look at the carcass quality data doesn’t appear to show any substantial differences between pigs raised in a rotational grazing system and those raised without one. In 2017, we will perform data analysis to compare these measures between the rotationally grazed groups, the continuously grazed groups, and industry norms for confinement-raised pigs.
In 2017, we will continue with our soil sampling and will perform data analysis to help determine pasture health with regard to reseeding and pig management styles.
We were unable to reseed the pastures as described in the grant proposal due to the extraordinary drought. We are planning to seed as described in the proposal in the spring.
We hosted a workshop titled “What Pigs Do to Pasture and What Pasture Does to Pigs” at the 2016 NOFA Summer Conference. Due to bad weather and logistics, no one from the conference travelled to Hampshire Farm for the workshop. In 2017, the NOFA Summer Conference will be held at Hampshire College, and we will offer the workshop again with modifications reflecting our continued work.
Over the winter of 2016, we are planning a visit to the Rodale Institute to learn about their pastured pig operation.
In April 2017, we will reseed to pasture and resume taking soil samples and quadrat samples. In the summer of 2017, we plan to present our findings at the NOFA Summer Conference. During the summer and fall, we will submit articles about our research to OnPasture.com and Cornell Small Farms Quarterly.
In the winter of 2017, we are looking forward to presenting our findings at the annual Pennsylvania Association for Sustainable Agriculture conference.