By Lídia Sbaraini Arend, Female Reproduction Specialist
Gilts are the future of a swine herd. Therefore, they must be inseminated at the right stage and moment to guarantee gestation weight gain and minimize body losses during the first lactation. A correct first insemination will set your gilts up to deliver excellent long-term results in terms of future milk production, reproductive success, and sow longevity.
Lídia Sbaraini Arend is a Female Reproduction Specialist from Topigs Norsvin Global Nutrition and Female Reproduction Services. She provides international technical support on female reproduction across Europe, South Africa, and Asia, and works with her team to develop recommendations and protocols to optimizve health across Europe, South Africa, and Asia. With her team, she also develops recommendations and protocols that eoptimize swine fertility outcomes worldwide. Lidia holds a PhD in Swine Physiology and Reproduction from the University of Illinois Urbana-Champaign.
Crucial factors at first insemination
What are the crucial factors at the first insemination of gilts?
I consider weight at first insemination, physiological age (skipping the first heat), and average daily life gain to be the crucial factors at first insemination. So focus on these and the specific requirements of your gilts’ genetic line to ensure a good start to their production life.
Body condition at insemination
Why does body condition matter when inseminating gilts?
In my opinion, inseminating gilts at their target weight prepares them for success in their first and subsequent lactation and production. Over- or underconditioned gilts can harm production due to the high risk of considerable body weight losses during lactation. The main negative consequences of that during the first lactation are:
1. Suboptimal mammary development, which compromises milk production in the current and future lactations.
2. Suboptimal development of ovarian follicles and embryos after weaning, which could lead to a second parity dip.
Weight is the gold standard!
Which one is the best: caliper or weight?
The caliper can be a practical tool for measuring body condition. However, in my view, it does not correlate well with body weight: you can monitor fat loss, but might fail to detect the loss of protein mass. That means you could overlook actual losses during critical periods, such as lactation.
Identify the most fertile gilts
How does physiological maturity impact?
Body condition and physiological age are equally important. So consider both. Avoid serving during the first heat. It is the least fertile because the reproductive system is still immature. Instead, focus on inseminating during the second or third heat after starting the puberty stimulation program (around 150-170 days of age), once the animal has reached the ideal weight for insemination. Then you will achieve better conception rates and larger litters.
Insemination and gilt development
Does meeting first insemination targets guarantee reproductive success?
No, it does not. Selection begins at birth, continues at gilt selection, and does not end at insemination. Therefore, I strongly recommend you ensure a well-managed weight at insemination and appropriate weight gain during gestation. These measures will promote the growth of both the female and her embryos so they have sufficient body reserves (both fat and protein mass) at first farrowing.
Gilts grow during lactation
Why is weight loss during the first lactation common?
Do not forget that gilts continue to grow during lactation. Therefore, you need to provide sufficient feed intake to meet females’ requirements for maintenance and growth. Doing this will support milk production and promote female reproduction after weaning.
Effective gilt management is not just a detail but a strategic driver of long-term herd performance. Consistent implementation of these basic principles at the barn level can significantly improve productivity across multiple parities, making it a high-return area for management focus.