By Ulla Skovsbøl

Hundreds of black goats swarm around the visitors as the agricultural scientists of the SOLID project approach the Pérez Family Farm in the Andalusian countryside outside Granada on for a farm visit.

José Luis Perez Peula and his brother Antonio Perez Peula  run the farm with two milkers and a an elderly goat herd, while his daughter Belén is in charge of the farm dairy producing a delicious goat cheese using 20 percent of the milk produced on farm  by his daughter Belen Peréz Peula  – the rest is delivered to the local dairy.

The Pereéz Family farm has been involved in the project as a case farm and the owners have tested new low-input feeding strategies based on by-products in cooperation with scientists from the Animal Nutrition Institute at the research institution CSIC in Granada.

Started as a teenager

The two brothers grew up on the farm, and José Luis Pérez Peula is happy to be able to continue working the family farm.

“When I was fourteen years old I started working with my father.  We were sitting in the shade of the olive trees and milking the goats by hand. I had to milk 200 goats once a day by hand,” he remembers.

It was hard work, but he liked it and he has never regretted following in his father´s foot steps. Yet, the farm has changed a lot since he was a teenager.

The family now cultivates 400 hectares of land with  grain, cauliflower, a mixture of oats and barley meant for hay and and also with more extensive pastures for 1200 Murciano Granacina goats.

Benefit from feeding by-products

The farm has benefitted from being involved in the SOLID project. The Pérez were already using by-products before being involved in cooperation with the animal nutritionists from Granada, but the experts have helped improve their feeding strategy. They now use waste from the cauliflower fields in a more efficient way than before.

“Cauliflower is rich in protein – 25 per cent in the fruit and 12 per cent in the leaves,”  David R. Yañez-Ruiz,  animal nutritionist  at CSIC and involved in the SOLID project.

“Based on estimation of daily intake of the by-product the farmer was advised to reduce concentrate supply to animals by 25 per cent during the period that animals had access to the by-product. This represented a significant reduction in feeding costs without compromising milk production at all,” he says.

Facts about the farm

• Area: 400 ha
• Crops: Grain, cauliflower, oats and barley for hay, grass, extensive pastures
• Goats: 1200 Murciano Granacina
• Lactation: Eight month (250 days).
• Milking frequency: Twice a day
• Yield: 2.5 kg per goat per day on average
• Milk composition: 5 % fat, 3 % protein
• Cheese: 20 % of the milk used for on farm cheese production

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SOLID visit to the Peréz Family Farm – May 2015

Based on research from the SOLID project Spanish nutritionists recommend Mediterranean  farmers to apply a low input strategy using by-products from the olive- and greenhouse industry as feed for dairy goats.

By Ulla Skovsbøl

Tomato salad with rich olive oil is a simple but delicious dish on the Mediterranean dining table. But tomatoes and olives are not only suited for the human diet  – silages made out of waste from the olive and tomato industries have also proved to be an attractive feed for dairy goats.

Within the SOLID project the scientists at the Animal Nutrition Institute at the research institution CSIC in Granada have tested a broad range of by-products fit for husbandry production on low input farms.

In particular, leaves and pulp from the olive oil industry and wasted fruits from the intensive greenhouse production – primarily tomatoes – appeared to be promising as goat feed.

Both types of products were fed as silage and tested in vitro as well as in vivo at the institute and also on case study farms. Silage made out of tomato waste mixed with straw and barley appears to be very well suited for feeding ruminants, although the challenge is the high moisture of the tomatoes.

Olives in tomatoes for dinner

The tomato and barley silage has a moderate content of protein and provides good energy for dairy goats. However, Spanish goats are not used to silage, and thus often reluctant to eat it – contrary to what is popularly believed, goats are quite conservative when it comes to new types of feed, David R. Yáñez-Ruiz, nutritionist at CSIC, explains.

Also olive leaves mixed with both barley and olive pulp turned out to suit the small ruminant very well. The pulp cannot be fed separately as it is too wet, but the dry leaves can balance the silage, and olive silage proved to be a valid replacement for medium quality hay. The energy content (from the remaining olive oil in the pulp)  is higher, but the olive silage contains less protein compared to hay.

The project has tried to identify the ideal composition of the silage made out of by-products and has developed specific recommendations for the farmers:

The ideal Mediterranean by-product silage

• Olive-silage: 50 % olive pulp, 25 % olive leaves, 25 % barley.
• Tomato-silage: 85 % tomatoes, 15 % straw

Although, silage made out of by-products proved to suit the small ruminants well, the farmers turned out to be as skeptical as the goats when it came to using it, as silage is not commonly used in the region.

However, when the goat farmers saw the positive results, they changed their minds, and even more so when it appeared that they could save money using the by-product silage.

Low-input a promising strategy in the South

In general David R. Yáñez-Ruiz is very satisfied with the out-come of the research conducted within the SOLID project in Spain.

“In my opinion, the low input aspects are the most important, in particular in Southern Spain,” he says.

“Organic systems are quite well-defined, whereas low-input farming is more vaguely defined and therefore in general complicated to address. But in particular, in Southern Spain the perspectives of using by-products to much larger extent are quite promising.”

“In Spain, we have to differentiate between North and South. In the North they have sufficient pastures and grass available, and farmers can “afford” to run low-input farming, whereas it is more difficult to run a farm with less input in the dry Southern part of the country,” he explains.

However, during the last years, the interest in low-input farming has increased even in the South:

“During the last years, prices have been going up on feed, fertilizers and all other farm input. Therefore, more farmers are going back to less intensive farming strategies with lower inputs to reduce the costs of production. And under these circumstances, our research appears to be even more useful,” David R. Yáñez-Ruiz concludes.

The SOLID activities at CSIC, Granada

• Developed sustainability assessment tool based on data from various farms.
• Held meetings with farmers in order to identify their needs for advisory services.
• Conducted a number of experiments with different by-products and analysed the sustainability of these products as animal feed

The farm has been involved in the participatory research conducted by the Animal Nutrition Institute at CSIC in Granada aimed at finding the means to reduce livestock feeding costs as part of the SOLID project.

Apparently, the goats also enjoyed being involved in SOLID, in particular as it implied new and interesting diets such as self-service dinner in the cauliflower field, humorously documented on the video.  They also tested silage made with waste from the tomato and olive industries but self-service cauliflowers was the winner!

Read more about the tomato and olive silage

…. and watch a video about feeding goats with byproducts.

SOLID-partners are developing software intended to optimise feeding management within organic and conventional low input dairy systems. First part of the model – a simulation of feed demand – is ready. It works as a useful library or starting point for other users and developers.

Jan Vaillant and Lisa Baldinger, WP3

SOLID partners in WP3 are in the midst of developing a decision support system (DSS) – a software – that supports farmers and consultants to evaluate measures in terms of their ability to reduce risks of feed shortages on low input dairy farms – both orga­nic and conventional. The system has three major parts: A simulation of feed demand, feed supply and a diet optimization. The first part has just been published as an open-source JavaScript library. Apart from being used within SOLID-DSS we believe it might be a useful library or starting point for other users and developers.

The library called dairy.js covers several routines to simulate dairy cow herds for both productive cows and (still under development) young stock, for instance herd structure, intake, requirements and milk yields.

The source code is available at https://github.com/jvail/dairy.js and some illustrative examples can be found at this website. Potential use cases range from simulation, web-based decision support, rapid model prototyping, education or scientific modeling. We tried to keep the code structure as simple as possible to make it easy to re-use, modify only parts and use them in any environment (web, web-worker, node.js) and we welcome any contribution to the library. Additionally utility tools for curve fitting and MILP/LP solving have been ported to JavaScript and are available in a public repository. Details of the implementation and relevant references to scientific publications can be found inside the source code files.

Here we describe the different aspects of the library:

Herd structure
The structure of the herd and demographics is calculated with a simple, deterministic model to estimate the percentage of cows per parities 1 to 3 (>2) within the herd. The simulation adjusts heifer availability (either “sell or buy”) if there are too many or not enough heifers available to achieve the target herd size. An adjustment for different calving patterns, a seasonal distribution is still under development.

Milk & milk solids
In order to simulate milk yield on arbitrary time steps we apply a Wood lactation curve. If parameters for the Wood curve are not available it is possible to fit the equation to milk yield data to obtain the three parameters of the Wood curve. A best fit is achieved with a Levenberg-Marquardt least-squares minimization implemented in lmfit.js. The obtained Wood parameters are used to calculate milk yield and solids. Both are then adjusted for parity.

Requirements & intake
Both energy and protein requirements for each cow may be calculated and expressed in units for different systems (Germany, France, Finland and the Great Britain). Since SOLID-DSS requires the estimation of a cow’s intake from grazing we have implemented parts of the GrazeIn model and thus intake is calculated using a fill value based system from INRA. Therefore the units of intake capacity are fill values. Requirements include energy and protein for maintenance, production, gestation, body weight change and grazing activity.

Grouping
If necessary and applicable on a target farm the cows may be separated into several groups. Within dairy.js this is done by minimizing the sum of variance of the cow’s requirements divided by their intake capacity within groups i.e. cows within groups require a “similar” energy and protein density in their diet. This is achieved by applying the k-means algorithm.

Diet
Means to calculate diets are included here but since this is probably the most important and difficult part, the design has not yet been fixed. Diets are calculated with a linear program using glpk.js and are optimized as such that the total sum of relative (to the cow’s requirements) violations (nutrients in diet / nutrients required) is minimized (Nutrients are energy and protein) subject to the following constraints: feed intake equals intake capacity, the Ruminal Nitrogen Balance (RNB) of the diet is within or equals the recommended upper and lower bound of the RNB and concentrate by matter in diet is below or equals a user defined maximum. The violations of energy requirements should be weighted higher compared to protein since the underlying intake equations with respect to concentrate substitution requires a non-mobilizing cow to have a zero energy balance. Although the system specific protein requirements can be calculate with dairy.js the diet optimization used in SOLID-DSS will always use only the German protein system (uCP, RNB). This is due to the complexity of other, probably more advanced though not necessarily better protein systems, requiring input parameters that are not provided by the crop models used to estimate feed supply. However energy is always expressed in system specific units.

Limitations
Apart from missing functionality, parts of the library still require additional testing and evaluation. In particular the implementation of concentrate substitution rates in a linear program is challenging. However our tests seem to suggest that the error in intake estimation will be acceptable especially in a low-input system when concentrate feeding will be substantially below 40% of total dry matter intake.

AUTHORS

Jan Vaillant, Leibniz Centre for Agricultural Landscape Research, Germany & Lisa Baldinger, University of Natural Resources and Life Sciences, Austria, WP3

By Jo Smith, Organic Research Centre, UK

Agroforestry (combining trees and agriculture) has the potential to help to meet these conflicting demands by integrating energy production from short rotation coppice, and livestock production, without compromising the delivery of ecosystem services. Although the potential of agroforestrybased agricultural systems has been demonstrated in principle, evidence on the performance of such systems in the context of European low-input production systems is lacking.

This task in the SOLID project therefore aims to evaluate the economic and environmental impact of agroforestry on lowinput and organic dairy systems in the UK.

The agroforestry system at Wakelyns Agroforestry (eastern England 52.4ºN, 1.4ºE) consists of twin rows of willow (Salix viminalis) with 10-12m wide crop alleys between (Fig. 1). An organic arable rotation in the alleys includes cereals, potatoes and a fertility-building ley. Coppicing for bioenergy takes place in December or January on a two year rotation.

Within the crop alleys, a fertility-building ley was sown in late May 2011 as a mixture of white clovers, red clovers, lucerne, yellow trefoil and chicory. While this system does not contain livestock, the mature SRC agroforestry system provides an opportunity to address questions regarding productivity and environmental impacts.

As a comparison, a neighbouring field with the same ley mix sown at the same time, has been used as a control. Managed as part of the organic arable rotation, this area has no trees within the field.

Silvopastoral systems that combine livestock and trees offer two main advantages for the animals, which may have positive impacts on productivity. First, trees modify microclimatic conditions including temperature, water vapour content or partial pressure, and wind speed, which can have beneficial effects on pasture growth and animal welfare. The research at Wakelyns showed that wind speeds were lower in the agroforestry alleys in comparison with the no-tree control.

Measured monthly, wind speeds were on average 2.7mph and up to 6.5mph stronger in the control than in the agroforestry. Combined with point measurements of air temperature at 1.5m, the resulting wind chill was significantly colder in the control plots during the winter months witha noticeable difference of 1 to 4°C during the cooler months.

Second, trees also provide alternative feed resources during periods of low forage availability, particularly in climates with seasonal droughts such as the Mediterranean. With SOLID partners MTT and CSIC, the feed value of the willow was assessed in 2011.
Crude protein concentrations ranged from 99 to 167 g/kg DM and organic matter digestibility varied between 0.38 and 0.41 depending on the age of the willow and the season of harvest. While it is apparent that the willow is limited as a feed resource for dairy cows in terms of feed values and actual amounts, the greatest potential is as a source of roughage for dry cows or heifers, or for other ruminant species such as goats which are better able to digest the woody material.

In addition to the agricultural production, the output from the tree component, in this case as woodchip for bioenergy, can increase overall productivity from the system. Assessments of the productivity in the ley and from the willow harvested for biomass in 2012 and 2013 recorded higher biomass production in the agroforestry (Fig. 3). Woodchip from the willow SRC at Wakelyns feeds into the biomass boiler that heats the farmhouse – this saves an estimated £1200/yr on heating oil.

The research in this task suggests that agroforestry can provide a sustainable approach to ruminant production by increasing overall productivity, and modifying the microclimate to improve animal welfare. A second part of this deliverable, due in 2015, will report on the establishment and management of an SRC willow/alder silvopastoral system at Elm Farm, Berkshire, where animals from a dairy unit will be integrated into the system.