Altrenogest 0.4% oral solution is an efficient tool to regulate estrus in sows batch reproduction activities. It is kind of progestogen progestin analogue which can be fed to pigs to achieve this suppression and thus allow control of the porcine reproductive cycle.

 How is altrenogest used on farms?

An 18 day treatment regimen with Altrenogest 0.4% oral solution will bring your gilts into heat within 3-6 days of completion, thus facilitating heat synchronization and batch management .

How to feed altrenogest 0.4%?

Note 1: Altrenogest can be fed by syringe drench gun or spaying onto feed. To minimise the risk of under-dosing and of wasting product, for 1-2 days prior to the altrenogest dosing regimen individually dose gilts with dextrose water or apple juice to get them used to being dosed; then switch to altrenogest.

In case failed with syringe, we may feed sows by spraying onto feed. However, sows must be put in stall to avoid scrambling for food.

The procedure is putting around 200g feed onto the bunk feeder,spraying 5ml altrenogest onto the feed, adding more feed till the ones with altrenogest was eaten up.

Note 2: scale calibration of syringe drench gun.

Make sure the scale is set up at 5ml by switching the knob before each dosing. After dosing, dropping the residue.

Note 3: Use up at one time after open the package; the rest should be deposited below room temperature avoid light .

Note 4:Wearing protective gloves. Pregnant women or women who suspect they are pregnant should not handle altrenogest.

How to use altrenogest in your farm production cycle

There is a role for altrenogest in all three breeding female classes: sexually mature gilts ,weaned sows and return sows


The classical role of altrenogest has been to synchronise a group of gilts into the breeding programme. Altrenogest results in a pool of gilts ready for breeding on their 2nd observed oestrus at 230-240 days of age and ≥130 kg liveweight. This reduces the need for a large gilt pool with the obvious saving in feed and manpower. However, it is essential to plan and manage your gilt pool to ensure breeding targets are met and that intra-batch variation is minimised to less than 10%.

When should the group of gilts cycle within a batch?

There are two thoughts:

  1. With the sows – to enhance breeding managementThis can reduce the time taken to achieve the mating within a batch. In this case the altrenogest is last given the day before the batch of sows are weaned. For example, if weaning on a Monday, the last altrenogest dose is administered on the Sunday and the gilts and sows will be mated the following Friday and Saturday.
  2. Before the main group of sows – to enhance gilt farrowing management.The gilts are mated 2-3 days before the sows. In this case (with a Monday weaned sow) the last altrenogest dose is administered on the Friday and the gilts mated on Wednesday and Thursday. This provides a number of advantages:
  • The gilts farrow first so more time can be devoted to them
  • They farrow in a cleaner farrowing house
  • The parity 1 piglets are then the oldest at weaning and so not the smallest and weakest!

The parity 1 lactation is slightly longer than the sows allowing for more food to be eaten and a reduction in wean to service interval. This can be especially beneficial in 3-week lactation batch models as parity 1 sows have a reduced farrowing rate and litter size if weaned below 19 days of lactation.(1)

Weaned sows

There are two significant uses of altrenogest in sows: to delay parturition (farrowing); to assist in the development of a batching programme.

  1. To delay parturition. In some pathogen control programmes it may be desirable to both synchronise farrowing and to extend the period without piglets. A case in point is during farm attempts to eliminate Porcine Epidemic Diarrhoea virus (PED). In this case sows are administered altrenogest from day 112 of pregnancy to day 115 (for the main group). On day 115 an injection of PGF is administered to assist parturition.
  2. To assist in the creation of a batching programmes. Many producers around the world want to capitalise on the health and discipline benefits of batching programmes. The use of altrenogest can ensure the success of these programmes. For example, see table 1.(2)

Table 1. Moving from a one-week batch to a 3 or 4-week batch programme using altrenogest

Development of a three week batch programme from a weekly batch programme
Week 1Wean sows and place on altrenogest for 1 weekBatch is created
Week 2Wean sows
Week 3Wean sows one week early
To develop a 4 week batch programme from a weekly batch programme
Week 1Wean sows and place on altrenogest for 2 weeksBatch is created
Week 2Wean sows and place on altrenogest for 1 week
Week 3Wean
Week 4Wean sows one week early

Return sows

Occasionally, and more often with batching programmes, sows may return to oestrus out of sequence. These animals can either be culled or efficiently replaced into the breeding pool by the judicious use of altrenogest. Simply feed altrenogest from 12 days after the out-of-sequence oestrus until 5 days before desired breeding date. This concept can also be adapted for weaned parity 1 sows to create a skip-a-heat concept allowing sows to recover from lactation.(3)