The Department of Agriculture, Environment and Rural Affairs (DAERA) is advising farmers that the replacement gilt is the “foundation” of high performing pig units.
To maximise herd output and profitability replacement gilts need to produce large litters and continue to perform for at least six litters, the department has advised.
According to College of Agriculture, Food and Rural Enterprise (CAFRE) data, gilt output, in terms of numbers born alive, has increased dramatically and is continuing to do so.
As approximately 20% of farrowing’s are from gilts, any improvement in gilt litter size will greatly influence herd output.
Equally important is that good gilt litters are associated with good litter performance in later life.
Local CAFRE pig adviser, Mark Hawe, said that: “Replacement gilts must be prepared to withstand the rigors of breeding life.
“The significant effect that culling gilts or young sows has on herd output and profit is often not appreciated, as it is only when sows reach their third parity that all replacement costs are covered.”
The average replacement rate in the Northern Ireland herd is approximately 45%, meaning that almost half of the sows in the herd are ‘turned over’ each year.
If these culls are gilts or young sows, it is easy to appreciate the damaging affect early culling can have on profitability.
Preparing a gilt from birth
Hawe advised that: “Good preparation starts at birth by maximising colostrum and milk intake to achieve strong healthy pigs at weaning.”
Extra care should be taken with gilt piglets to ensure teats are not damaged, especially if floors are worn.
Front teats can be protected with gaffer tape to ensure all teats are functional at selection.
Replacement gilts are often kept with other pigs during the first and second stage growth periods but ideally, they should be assessed and penned separately from approximately 30kg onwards.
Hawe said: “Arguably feeding is the single most important factor that determines the quality of gilts at service. Replacement gilts should not be fed ad-lib with growing and finishing pigs.”
The advisor said gilts should be reared to achieve a target weight at service, which results in a lower growth rate, giving the reproductive organs, legs and feet time to develop to encourage a long productive life.
Also, a higher level of fat is essential to withstand the rigors of first and subsequent lactations.
The optimum weight for age at service is usually around 150kg at 240 days, but Hawe said that as modern gilts have great growth potential, achieving this target requires restricting feed throughout the growing period.
Having smaller groups of gilts that are penned according to size will help control intake and ensure uniformity at service, he determined.
But Hawe added that growth rates are not simply achieved by restricting the amount of dry sow ration, or worse finisher ration, fed.
Specifically formulated gilt rations are essential to ensure the correct levels of nutrients, minerals and trace elements are available and in the correct proportions to limit growth, strengthen legs and feet whilst optimising body condition for service.
Maiden gilts
Maiden gilts should be kept in stable groups and in the same pen from at least 90kg to first stimulation.
The stockperson should walk through these pens each day, so gilts become familiar with people.
It is essential that gilts are kept in a calm environment at this stage to avoid early onset of heat, so movement of other stock in and out of the house should be kept to a minimum and a boar should never be in this area.
As service is usually at second heat, gilts need to cycle naturally at least once before insemination.
Hawe provided the following advice to encourage the onset of heat:
- Moving them from the ‘calm’ gilt house to the ‘active’ service house;
- Feeding a high energy diet ad-lib;
- Keeping them in a pen beside ‘unfamiliar’ active sow;
- Check for heat twice each day;
- Providing ‘good’ boar exposure to an old boar and ideally full boar contact;
- Moving the boar well away from the gilts when not heat detecting;
- Using boar pheromone sprays during boar contact to help heat detection.
The advisor said the success of gilt preparation can be measured by the spread in time it takes for all gilts in the pen to show signs of heat.
“Extra input into gilts takes extra effort and expense. But as good gilts are the foundation of a productive herd, it is a sound investment,” Hawe added.
