Gilt management until puberty
The environment a gilt is reared in during her suckling, nursery and finishing stages, as well as during her period as a maiden gilt, can affect her lifetime performance.
Aim to provide an environment that:
- Supports and maintains healthy gilts
- Does not expose gilts to mycotoxins
- Does not compromise growth
Isolation and acclimatisation
- New gilts should be kept in an isolation facility before entering the main unit
- Develop an acclimatisation and vaccination programme with your veterinarian to ensure gilts, both home-bred and purchased, aren’t at risk on entering the sow herd
- The period gilts are kept in isolation will vary, so the following management procedures may occur during this time, or once the gilts have entered the main unit
Stimulation of puberty
Farrowing index, also known as litters/sow/year, tells us the average number of times sows farrow in a year. Puberty is a critical period that should be managed carefully and recorded. Important factors affecting a gilt’s ability to achieve puberty include:
Age: The modern gilt is leaner than previous generations and often reaches puberty later. Do not expose prepubertal gilts to mature boars as they may become accustomed to the boar stimulus and subsequently have an extended period to puberty. Start boar stimulation when the youngest gilt in the group is 180 days of age.
Space: You should provide at least 1.5 m2, but preferably 2 m2, per gilt.
Air quality: Should be good, with little evidence of ammonia.
Light: Provide 14–16 hours of good quality light (at least 50 lux).
Table 1 shows the different degrees of boar contact typically used. The boar should be at least 10 months old and express a high libido. Using boars in rotation will increase the impact of boar contact.
- For best results, combine moving, mixing and initiation of boar contact simultaneously, using gilts at least 180 days of age
- Check for oestrus at least once a day with a boar
- Mark pubertal gilts and record dates of heats; the group will often show a synchronised oestrus
- Try to be quiet and considerate around gilts. Full contact is essential to maximise the effectiveness of the boar stimuli. Discuss with your vet the pros and cons of running a vasectomised boar with the gilts
Table 1. Options for boar contact
|Type of contact||Frequency||Time||Efficacy (where 1 is good and 4 is poor)|
|Full||Twice a day||At least 10 minutes||1|
|Full||Once a day||At least 20 minutes||2|
|Adjacent pen||All day||Constant||3|
|Aerial, visual, vocal||All day||Constant||4 (no stimulation)|
Recommended management at puberty
- Record pubertal gilts’ ID using existing tag/spray mark
- Change spray marker colour every week, for three weeks
- Enter the number of gilts available into projected service week to assist with culling decisions
- Mix into weekly groups, if possible, to simplify their feeding programme
- Distribute projected service dates across paddocks where unsupervised natural service is used
- Identify non-cycling gilts; develop a standard operating procedure for managing anoestrous gilts and set a maximum age at service
- If synchronising gilts, only select those which are cycling to receive the progestogen, as it is not effective on prepubertal gilts