How do we feed the gilts?
What do we need to focus on, and why? At Vilomix we have had the pleasure of a visit from scientist Thomas Sønderby Bruun from SEGES - the Danish Pig Research Centre, who gave us an update from the latest studies into feeding gilts. The studies that SEGES run are multi-purpose, including finding out how the rearing of gilts influences litter results and longevity. Data from an older study on flushing has also been reviewed and compared with new study results on rearing gilts.
The message from Sønderby Bruun was unequivocal: To produce strong, durable gilts, you have to focus on:
- Feed strength from 100 kg and up to mating
- Feed composition
- Sorting gilts according to condition and size to ensure they are matched in the pens before being transferred to the mating section
- Flushing before mating
Young and heavy!
Not everyone can feed using a mix adapted to gilts. Consequentially, the gilts can gain weight too fast, and put on too much muscle on the body. This strategy does imply considerable risk that the gilts are culled after only one litter.
From when weighing 30-100 kg, we recommend a mix containing around 100 g digestible crude protein and 6 in lysine/FUsv; the feed strength must be 2.9 FUsv/day.
After 100 kg, further reducing the content of lysine can be advantageous – gestation feed with 4.0-4.5 g digestible lysine per FUso is suitable here. With this ratio, the gilts will put on back fat rather than muscle, achieving a durable sow in time.
Sorting and flushing
The gilts are often kept in the batch they were put in when they are to be transferred from quarantine or the gilt section to the mating section. But not all gilts grow uniformly from 30-100 kg.
By sorting them according to size and thickness of back fat when the average weight in the pen is around 100 kg, you can achieve a better flow in both the gilt and mating sections, as the lightest and leanest animals around 100 kg can be allocated a higher feed strength (e.g. 3.5 FUso per day), and a feed with a lower lysine content (3.5-4.0 g digestible lysine per FUso), to get them ready for mating. This also provides the opportunity to have two strategies for how the gilts will be flushed.
Lean gilts should be flushed at 4 weeks. In practice, flushing consists of 3.5 FUso per day with a mix that has a moderate content of protein and amino acids, e.g. a gestation or mating section mixture. Gilts in suitable condition may only need flushing for 5-7 days.
The objective is that a gilt of +210 days has back fat of at least 11-12 mm (and preferably 14-15 mm).
Tips on gilts:
- Take a look at your gilt feed with your feed consultant
- Spend a little time sorting them by size when they have an average weight of 100 kg
- When the gilts are sorted by size, you gain a better overview and flow in both the gilt and mating sections
- The best time for mating is when the gilts are 230-240 days old, and weigh between 140-160 kg
- Age and weight do not always go together for gilts
- Lean – but heavy (typically older gilts) are the most critical in relation to longevity, whilst being light or medium weight and a high back fat thickness are good news in terms of longevity