Organic growing pigs in pasture systems – effect of feeding strategy and cropping system on foraging activity, nutrient intake from the range area and pig performance

Titre

Organic growing pigs in pasture systems – effect of feeding strategy and cropping system on foraging activity, nutrient intake from the range area and pig performance

Créateur

Malene Jakobsen

Sujet

Foraging

Master Thesis

Organic farming

Pastures

Pigs

Date

March 2014

Type

Master of Science Thesis

uri

https://orgprints.org/id/eprint/26677/7/26677.pdf

Résumé

Production of organic growing pigs is characterized by indoor housing with access to outdoor
concrete yards and feeding high amounts of supplementary feed based on grain and imported
protein feed. However, this is not in accordence with the organic principles, which insist on
optimization of nutrient recirculation, use of local renewable resources and animals being able
to perform normal behaviour.
The overall aim of the project was to contribute to development of an eco-efficent and
trustworthy organic production system based on free-range growing pigs in pasture systems.
The point of departure was to integrate the unique innate ability of pigs to forage above and
below ground as a resource in the farming system. It was hypothesised that foraging in the
range area could pose an important contribution to nutrient supply of growing pigs.
Foraging activity, nutrient intake from the range area and pig performance were investigated
in 36 growing pigs foraging on alfalfa or grass and fed either a standard organic feed mixture
(HP: high protein) or a grain mixture with 52% of crude protein recommendations (LP: low
protein) from an average live weight of 58 kg to 90 kg in three replicates. Pigs were fed 80%
of energy recommendations and had access to a total of 154 m2 pig-1 during the 40-days
experimental period from September to October 2013.
Rooting activity was significantly affected by feed and forage crop interactions but the effect
of protein level was more pronounced in grass paddocks with LP pigs rooting 44% of all
observations and HP pigs 19% compared to 28 vs. 16% for pigs foraging on alfalfa. Protein
level did not have a significant effect on grazing activity but pigs on alfalfa grazed
significantly more than pigs on grass (10 vs. 4% of all observations).
Based on crop samples alfalfa intake tended to be significantly affected by protein level with
a daily dry matter intake in LP and HP pigs of 470 and 330 g pig-1

, corresponding to an
energy intake of 0.35 vs. 0.32 Danish Feed Units. Alfalfa crude protein and lysine intake was
higher in LP pigs compared to HP pigs but the difference was not significant. Compared to
grass paddocks available earthworm crude protein was higher in alfalfa paddocks (84 vs. 55 g
pig-1 day-1
) indicating the potential of contributing to protein requirements of organic growing
pigs.
Daily weight gain and feed conversion ratio were significantly affected by feed and forage
crop interactions. LP treated pigs had 33% lower daily weight gain compared to HP pigs (589
vs. 878 g) and 31% poorer feed conversion ratio (3.75 vs. 2.59 kg feed kg-1 weight gain) in
grass paddocks, whereas in alfalfa paddocks LP pigs only had 18% lower daily weight gain
compared to HP pigs (741 vs. 900 g) and 14% lower feed conversion ratio (2.95 vs. 2.54 kg
feed kg-1 weight gain). LP pigs foraging on alfalfa used 169 g less feed crude protein
compared to HP pigs, whereas in grass paddocks it was 109 g less, indicating the nitrogen
efficiency of the systems.
Regarding development of eco-efficient forage based system for organic growing pigs, further
investigations are needed, in particular on suitable forage crops, energy requirements for
activity and social interactions and effect of group size on foraging behaviour.

Editeur

Aarhus, Denmark

Langue

en