Intake of grass-clover when sows are kept on pastur

Background and Objective

Offering roughage to gestating sows improves their health, but can also be interesting from an economic point of view. When sows are kept on pasture, they consume fresh grass-clover as roughage without the need for harvest, storage and feeding. A part of the nutrient demand of the sows can therefore be supplied by fresh grass-clover.

Knowledge about the actual amounts of grass-clover that are consumed by the sows is necessary to adapt the amount and nutrient concentration of the concentrate feed that is offered to the sows. Therefore we document edthe grass-clover consumption of sows on pasture.

Approach

The experiment was repeated over several years, and each year the experimental period was  6 weeks within the grazing period of the gestating sows.

Once a week, fresh matter and dry matter of the grass-clover were determined by taking samples for randomly selected spots of 1 m² each on the pasture.

Nutrient concentration of grass-clover was analysed according to Weende.

Body weight of the sows was documented once a week.

The composition of the grass-clover ley and its growth rate was determined.

Results

In the exceptionally dry and hot year 2018, clover grass growth was rather sparse and the leaf mass in the growth was low. On average, the sows consumed 2.4 kg of forage dry matter per animal per day during the experimental period in 2018 trial. With 8.1 MJ ME per kg dry matter, the sows were able to meet half of their energy maintenance requirements via the ingested clover grass, at least at the beginning of the grazing period. In 2019, the sward developed significantly better than in 2018. The clover grass developed more leaf mass and thus had a higher protein content than in the previous year. On average, sows consumed 1.8 kg of forage dry matter with an average of 6.7 MJ ME during this trial period. These results show that even during the hot and dry summer of 2018, sows were able to meet some of their maintenance requirements for energy from roughage via clover grass intake.
The cutting method proved to be an easy-to-implement method that provided a good estimate of the forage quantities and qualities available on clover-grass pasture for pregnant sows.