Pigs on pasture: An assessment of pasture health, pork quality, and ecosystem rebound after rotational grazing

Pig Procurement and Care: We will purchase a group of weaned piglets from the same farm. The males, if intact, will be castrated, and all piglets will receive an ear tag for individual identification. The piglets will be trained to electric fence for one week. Any medication given or other medical interventions will be documented.

Experimental Layout: We will use a large pasture at Hampshire College farm, with uniform soil types. Fence lines will be maintained with mowing and string trimming. There will be three main experiment treatments: pigs in a rotational grazing system, pigs in a similar sized paddock with no rotational grazing, and a control without pigs for plant and soil comparisons. The control paddock with no pigs will be mowed periodically to prevent brush infiltration and to mimic general pasture care. To prevent massive pasture destruction at feeding and watering sites, feeders and drinkers will be moved frequently (see FNE16-859 Solis Appendix for experimental design images.)

FNE16-859_Solis Appendix

We are interested in using this field as a temporary pig pasture. Farmers may wish to use a field for pigs one year, cattle the next, or for hay, or for crops. With New England farmland at a premium, it is helpful that certain types of infrastructure are temporary.

A schematic description of the experimental layout (for full details and map, see Appendix A). There are three systems: 1) four pigs in a field section rotated among three paddocks within the section; 2) four pigs ins a field section of comparable size with no paddocks or rotations; 3) a small section with no pigs at all (area comparable to a paddock) as a control for comparing plants and soil. In each section we will choose one half randomly to be re-seeded after pigs are removed (shaded), and the other half to leave as is. We currently plan three replicates of each system section (so 3 x (4+4) = 24 pigs total), randomly located in a two acre field (thus if we actually use 90% of the field, the section sizes with pigs will have them at a total density of ca. 16 pigs per acre).

Sampling and analysis: We will examine four areas of interest, which are described below: 1) pasture and soil quality
2) carcass quality
3) average daily gain

4) regrowth of pasture and soil quality in the following season

1. Pasture and Soil Quality: We will collect samples for soil quality and pasture composition three times—prior to animals on pasture, at 3 months and after animals have been removed (approximately April, August, and October 2016). Composite soil samples (8 cores/sample) and pasture composition samples will be taken along the paddock lengths at 2 locations per paddock (Figure 1, Appendix A. Total=7 paddocks or sites in the non-paddock areas x 2 samples x 3 replicates x 3 dates=126 samples). Soils will be analyzed for the standard suite of agronomic parameters plus organic matter content. Pasture composition will be measured using square meter quadrats to assess plant diversity.

2. Carcass Quality: We will work with Arion Thiboumery of Vermont Packinghouse to assess carcass quality of the 24 hogs in the study. He will look at depth of backfat at the 10th rib and the last rib, marbling, meat color, loin pH, and loin eye area. These measures will be compared between the rotationally grazed groups, the non- rotationally grazed groups, and industry norms for confinement raised pigs

3. Average Daily Gain: All grain given to the pigs will be weighed and tracked. We will receive hanging weight information from the slaughterhouse. Using their ear tags, we will be able to cross reference each hanging weight with each ear tag number.

4. Regrowth of Pasture and Assessment of Pasture Improvements: In each section, we will choose one half randomly to be disked and re-seeded after the pigs are removed. During the following spring of 2017, soils and pasture will be sampled monthly from April to July in all of the plots. (Total=7 paddocks x 2 samples x 3 replicates x 3 dates=126 samples)

Statistical Design and Analysis: This design allows clear separation of the effects being studied for graphing and also statistical analysis, such as analysis of variance for randomized treatments or randomized blocks with split plots for effects of rotation, reseeding and their interactions (Anderson et al. 202, Gomez and Gomez 1984, Little and Hills 1978). This design allows clear separation of the effects being studied for graphing and also statistical analysis, such as analysis of variance for randomized treatments or randomized blocks with split plots for effects of rotation, reseeding and their interactions (Anderson et al. 202, Gomez and Gomez 1984, Little and Hills 1978). Such statistical analyses will be conducted under the guidance of our technical advisor.

Timetable