The objective is to determine how the nutritional value in a pasture is converted into meat for pastured pork. This information will translate into improved farm efficiency through a better use of feed, the primary cost in livestock operations. A more detailed understanding of pasture nutritional value, allows the farmer to be more planned in the amount of concentrated feed, with a consequent benefit in animal performance, economic costs and environmental cost related to grain production. We expect that pigs raised in the barn on a concentrated mix alone will be outperformed in growth rate from the pigs raised on pasture and concentrated mix.
A second objective is to maximize pig performance by increasing the amount of food the pigs harvest from our land. To this end, we will improve a pasture, adding crops. We will determine if such improvement can further cut costs and energy related to harvest. Pigs rotated on the improved pasture will be fed 80% of the concentrated feed provided to the pigs raised in the barn and pigs raised on pasture. We expect that pigs on the improved pasture will outperform the pigs on a regular pasture and pigs raised in the barn.
The interaction between pastures and pigs have been studied very little in the past, mainly because pigs are not ruminants and therefore are not considered herbivores. By what we observed, pigs have the ability to utilize forage and convert it into meat, especially in case of adults animals.
The purpose of the project is to determine how much feed can be provided by forage and what are the effect on the animals in terms of growth and quality of the meat. There are many aspect of this way to manage pigs that can have an effect on sustainability of northeast farms: financially, since part of the daily energy and amino acids requirement is satisfied by grazing, there’s a potential reduction in feed costs. From an environmental perspective, using pastures as a nutritional source means a lower reliance on external inputs and so a lower carbon footprint. In addition, the rotational plans can lead to healthier and more productive soil and a lower concentration of nitrates in manure pits or piles, and therefore a reduction in the potential for water pollution and carbon costs related to manure spreading. From the perspective of animal welfare, raising pigs on pastures promotes a stronger immune system and therefore less need for medications. Pastured pigs also can engage in greater exercise, leading to leaner meat, and have the ability to express natural animal behavior.
The project is important to our farm because can highlight the benefits of raising pigs on pasture and allow us to increase our knowledge on forage production specific for pigs. The goal of Agricola farm is to raise 100% of the pigs (120/140) outside using the practices applied in this project. For us, this means more time spent with the animals and more time dedicated to rotations, but less time spent on manure handling and spreading, less need for medication, happier and healthier animals. Moreover, a reduction in feed cost and potentially an improvement in the quality of our meat. These practices can be used by other farmers without the need of big additional costs and can approachable by any farmer who wants to produce meat sustainably.
In order to evaluate the effect of pastures on pigs growth we separated an homogeneous group of animals in 3 subgroups, exposed to different nutritional regimes: 1) grain concentrate feed only, confined in the barn (Barn group), 2) grain concentrate feed with integration of pasture (Pasture group). Pictures below shows the two different groups.
The Barn group was raised in a confined area with no grass (500Sq feet per pig) and administered with our custom non-GMO grain mix twice a day; the Pasture group was splitted in 2 and rotated on paddocks in a pasture field. Each group was administered with the same amount and type of grain we used for the Barn group.
Every day we weighted the amount of feed given to each group using a portable hanging scale and 5 gallon buckets.
Each group included 5 pigs, counterbalanced for gender and initial weight, for a total of 15 pigs.
The experimental research lasted for the 90 days prior to the day of slaughtering.
The total area grazed by the animals was 5 acres each and each group grazed 5 different paddocks ranging from 2700 to 10000 square feet, depending on the vegetation and time of the year. On average pigs were rotated every 11 days. Rotations were deter
mined based on the amount of biomass available in the paddocks and growth pattern. Once pigs were moved a cover crop was planted were soil was left bare. Each paddocks was delineated by a two strand electrified wire fence. Pigs in each paddock had access to shade, natural shelter (trees), and a water trough.
Samples of forage were collected the day pigs were introduced in the paddocks, using a one square foot quadrat. Each of them was weighted and labelled with the number of corrisponding sq ft that were collected; then each sample was frozen until the day of shipping to the lab (Dairy One Forage Lab).
Every week/10 days we took measures of lenght (from in between the ears and the start of the tail) and girth to determine the weight of the animals using the formula (length2 X girth) / 400.
At the end of the 90 days, 2 pigs from each group was sent to the slaughterhouse to determine the exact weight.
Thickness of back fat was measured on the carcasses of the animals in correspondence to the last rib and 7 cm from the back bone.
The study aimed to compare pig size in two groups, pasture vs non pasture group. Weekly measures of length and girth size were taken for 15 pigs using a measure tape. Other measurement included size of the paddocks and weight of grains, using a 5 gallon bucket and a hanging portable scale. Grains were weighted every day, twice a day. Paddocks were made of polywire and connected to an electric fencer in the barn. Everytime pigs were rotated in a new paddock a sample of the grass in order to determine forage energy, proteins and yield for the whole paddock.
2 additional crops (turnips and alfalfa) were established in a pasture that was originally planned to be an “improved” pasture. Alfalfa was seeded the last week of april and turnips the at the beginning of june. They were both broadcasted by hand and they had a great emergency in the beginning. However, they didn’t grow as hoped for different reasons. Turnips suffered of a heavy insect pressure (flea beetle) during the first couple weeks of growth and the were outcompeted by weeds over the next couple weeks. Turnips seeded on other areas of the farms didn’t suffer so badly the presence of the beetle. Alfalfa grew up well in the first couple month but it suffered the extreme hot weather in june/lack of water and didn’t produce a great yield. The effect of weather affected greatly the experimental design of the study but not the outcome of the project.
For these reasons the “improved pasture” was considered as normal pasture, since the nutrient content wasn’t different compared to the “non improved” pasture.
The main advantage of having pigs on pasture was the reduction of costs associated with manure spreading and time spent on cleaning pens in the barn. This allowed the farmers to spent more time on other projects. Also, pasture productivity increased due to rotational grazing. Some of the paddocks were grazed again with sheep later in the season.
Areas that were digged by pigs offered a optimal environment for growing cover crops and other perennial grass, thank to the ideal soil preparation performed by the animals.
The size of the pigs were monitored throughout the whole duration of the experiment. Pigs raised on pasture gained on average more weight compared to pigs raised confined, according to the measure taken with the tape. However, the measured weight doesn’t catch precisely enough the actual weight of the animals measured at slaughtering.
Forage tests gave a great indication of the amount of nutrient supplemented by the pasture, including elements essential to pig growth such as phosphorus, calcium, lysin, proteins and energy content. Another parameter essential for meat quality is the % of oil in the forage which will be accounted for pasture rotations next year and will be fundamental in the production of cured meat.
Education & Outreach Activities and Participation Summary
We provided tours to more than 100 people over the course of 4 months, showing them how we manage pigs on pasture and the importance of good farming practices that affect animal and soil health.
We trained 2 people at the farm on how to manage pig rotations and how to establish cover crops.
The project highlighted several positive aspects of raising pigs outdoor. First, we notice a change in behaviour of animals raised on pasture compared animals raised inside. Outdoor pigs showed a more active behaviour due to foraging, digging and interacting. This resulted in a better body condition and better health. For these reasons, farmers gained more awareness on the importance of raising pigs on pasture and also improved their ability to manage pasture properly, especially timing of rotations which is a key element in this kind of practice.
Farmers gained awereness on the positive and negative impacts that pigs can have on soil health which is highly dependent on speed of rotations, season of the year and weather.
Farmers gained knowledge on cover crop and specifically on crop establishment, importance of seeding techniques and the choice of right cover crop for the right purpose.
The project brought greater awareness on the importance of raising pigs on pasture and increased our skills in terms of drove management. Timing of rotations and response of the soil to animal grazing were the two keys components of this project and were both investigated more in depth thank to the project. Other benefits derived from the experiment were related to manure management. We spent less time in cleaning and spreading manure with our tractor, which lead to less money used for gas, maintenance and more time spent with the animals. We achieved better growth rates without additional feed and our pastures were cut without the need of any machinery.
We felt accomplished with our management of the pigs cause we were aware that what we were doing was positive for us, for the animal, for the environment and finally on the community.
Overall, the study’s approach was good. The only thing we could have changed is the way pig weight was measured because the method was too rough and imprecise. We would benefit greatly from the purchase of a livestock scale that would give more accurate results and a better understanding of the effects pasture have on pigs. We found trends that can be useful to answer our question but we could produce more accurate results in the future. We are going to keep studying this topic next year since the project showed a benefit in raising pigs outdoor and we would like to quantify more precisely the advantage of including pasture in the diet.
Another issue we had with our study was related to the weather. We planned at the beginning to have an improved pasture in the study, with additional crops (alfalfa and turnips) in the pasture stand. Unfortunately, the scorching hot we had in july didn’t allow a good growth of the plants and by time the pigs were in the pasture these plants were to small to be considered as an additional source of energy. Alfalfa proved to be not the best choice for grazing pigs since it’s too sensitive to pigs and doesn’t seem to be liked so much. Turnips can still be incorporated in the mix next year, since we had good results in other pastures at the farm where they were seeded as cover crop.
Other pig farmers will benefit from this study. More and more farms are trying to raise pigs on pasture and there is the need to explore more the effect of this management on the soil and the possible solutions that can be adopted to succeed. We made good connections over the course of the past summer with several farmers in Vermont that are raising pigs outdoor and they showed a great interest in knowing more about rotations and crops that can be used to improve the energy content of the forage. In the next months, the farm is planning to create a coalition of Vermont farmers that use these practices to raise pigs on pasture and we will discuss more in depth the results that this study highlighted.