The most productive swine operations have a strong understanding that management of their replacement gilts determines how successful their sow farm will be. From birth to selection to breeding, the way in which replacement gilts are managed plays a crucial role in a gilt's lifetime productivity. In those top-producing herds, proper gilt development has become a high priority and is done well every day. At a time when many variables affecting the bottom line are out of the producer's control, gilt management prior to breeding influences lifetime productivity.
What are realistic expectations for gilt performance in your herd? Two production parameters that are routinely used to measure gilt performance is farrowing rate and total born. You should expect that first-litter gilts have a farrowing rate of at least 94%. The best farms consistently achieve this. Total born can vary some based on genetics, but first-litter total born to be at least more than 14 and many good herds will total born of 15 pigs or more.
Why gilt total born is so important is because we'll often see that the gilts with the highest total born tend to have the highest total born in subsequent parities compared to gilts that have a low total born. Said another way, the best gilts continue to be the best and the poorer performing gilts never catch up over multiple parities. This demonstrates that poorly managed gilts fail to reach genetic potential over their productive lifetime.
What are the best management strategies we see in herds that build the most productive gilt possible?
We often speak about the pillars of gilt management. These are non-negotiable basics of raising gilts that when carried out lead to successful gilt development. These include:
- Adequate boar exposure
- Correct age/size of the gilt
- Pre-breeding stall acclimation
- Skipping one or two heats prior to breeding
- Allowing for flush/ad-lib feeding prior to breeding
- Health stable and vaccinated
To begin with, boar exposure should start around 20 weeks of age. At the time boar exposure starts, gilts are not yet sexually mature. The objective of boar exposure is to stimulate sexual maturity and begin the process of cycling. At 25 weeks of age, with routine boar exposure we expect that the first animals in a group or cohort will begin cycling. Adequate boar exposure and heat detection is critical. This should include daily exposure of gilts to boars as part of the gilt development process.
Gilts need to be of the right age and size at the time of breeding. Each genetic line may vary, but gilts should be at least 30 weeks of age and 300 pounds when breeding occurs. Gilts that enter the herd too young (or old) often fail to stay in the herd through the most productive parities.
For gilts that are planned to be individually housed during gestation, it is recommend that gilts are acclimated to a stall at least 14 days before being inseminated. This allows gilts to become familiar with the stall and acclimated to routine feedings that occur in stall housing.
We know that breeding gilts on the first recorded heat cycle results in lower total born, farrow rate and decreased lifetime performance. Gilts should be bred on the second or third recorded heat cycle to increase performance. In addition, gilts should be allowed ad-lib feed leading up to breeding so that a positive energy balance is maintained and ovulation at the time of breeding is maximized.
Herds should strive to ensure gilts are health stable at the time of breeding and that all vaccines have been completed so that those challenges don't negatively impact cycling and ovulation.
These pillars of gilt management are frequently talked about and really have become common knowledge to swine producers. We still see common pitfalls on-farm that limit these basics from being followed, resulting in a reduction of gilt performance.
One area that is commonly missed is quality boar exposure. This can happen if heat detection is being completed in pens or if farm staff isn't trained in the importance of good boar contact as part of a development program. It's recommended that one boar is used for every 10 to 15 gilts and dedicating adequate time to move boars through pens, check each gilt and document heats. The lack of discipline related to boar exposure and heat detection often leads to less than expected recorded heats and many gilts being inseminated on only the first detected estrus.
Stalls for acclimating gilts in a farm are often a limited commodity. The stalls get used to house other animals and if this is not actively managed, gilts do not get a minimum of 14 days of acclimation prior to breeding.
Full or ad lib feeding gilts can be difficult and messy at times making it easy to overlook. Gilt feed intake prior to breeding has the potential to be high and we often fail to feed as much as the gilt desires to eat. Farms have made this process easier by adding water nipples to the gilt stalls or adding a solid area to allow placement of adequate feed to fulfill gilts' appetite.
The timing of embryo implantation post breeding plays a role in determining when it's OK to move animals. As a rule, you should avoid moving bred animals from a few days post service until 30-day pregnancy check. Likewise, if breeding gilts in a pen setting, they should be housed with animals that were bred at the same time.
From a health standpoint obviously the healthier the animal, the more resources it can put toward reproduction and the more productive she becomes. However, health challenges happen. When they do it's important to consider timing of disease exposure. In general, if a gilt is exposed to a pathogen (porcine reproductive and respiratory syndrome, Mycoplasma, etc.) early enough in the growing phase, it will not be viremic around the time of breeding which will result in less embryonic loss during pregnancy and health stability of the gilt's offspring.
It's important to facilitate timing of exposure with certain pathogens. Timing of vaccine administration is also important. Vaccine administration can result in decreased feed intake. Decreased total born can result if this occurs during or the days prior to breeding. Avoid giving vaccines within 14 days of first service. Vaccines as part of immune stimulation can cause inflammation and a reduction of feed intake, all of which have the potential of reducing ovulation and subsequent total born.
Managing gilts to achieve full genetic potential isn't an easy task. Many herds have figured out that maximizing gilt production takes extra time, resources and the discipline to develop gilts correctly every day. We consistently find that the best performing gilts on the first litter will have the best performance in future parities. Measure gilt performance in your herd. Are they performing like they should? Avoiding common gilt management pitfalls will pay off in the long run.