The impact of recent genetic progress
Over the past decade, genomics has accelerated progress in pig selection, enabling more precise work on key traits such as piglet survival, birth weight and even behavioural aspects. This advancement has radically changed the profile of replacement gilts: today they are leaner animals, grow faster and produce larger litters.
This situation is a direct challenge for technicians and producers: traditional gilt-development parameters are no longer sufficient. Targets for body weight, age at first service, nutrition and management must be adjusted to these new conditions to avoid productivity losses and improve sow longevity on farm.
More liveborn piglets, higher milk demand
One of the major goals of genetic progress has been to reduce the number of piglets born weighing less than 900 grams, as this group has higher lactation mortality and poorer performance throughout finishing. Achieving more uniform litters with better starting weights has an immediate effect: the sow must produce much more milk.
In this context, the modern sow can be considered, practically speaking, a dairy animal. If digestible lysine and energy levels in the diet are not adjusted, loss of condition during lactation compromises reproduction and shortens the productive life of females. According to recent projections, genetic improvement increases digestible lysine requirements by an average of 0.47 g/day per year, of which 0.37 g/day corresponds specifically to the lactation phase.
The challenge of accelerated growth during gilt development
Data show that today’s females gain between 700 and 900 g/day during gilt development. This range, which at first glance may seem favourable, carries significant risks.
- At 700 g/day, there is an opportunity to reduce age at first service without compromising structural development.
- At 900 g/day, by contrast, the likelihood increases that females reach service with excessive body weight and lower body fat, which translates into more leg problems, a higher risk of early culling and reduced longevity in the herd.
The current recommendation is to serve females at 135 to 160 kg at the second oestrus. Exceeding 165 kg at service increases feed costs and raises the risk of reproductive failure and lameness.
Practical strategies for growth control
Controlling intake during gilt development is difficult in group pens, so the most effective tool is designing diets with lower energy density and higher fibre inclusion from 60 kg liveweight onwards. This strategy aims to moderate growth without affecting structure, while also supporting digestive tract development.
Evidence shows that this approach does not reduce productivity per litter, but it does improve retention of females through the fourth parity, with differences of up to +8% in longevity. The most likely mechanism is greater feed intake capacity during lactation, which reduces body condition loss and improves reproductive efficiency.
Minerals, legs and longevity
Accelerated growth also places greater pressure on the musculoskeletal system. Females prioritise growth over mineralisation, which increases the risk of osteochondrosis and leg problems. The technical recommendation is to adjust the diet to provide phosphorus at a level 8% higher than for a finishing pig, along with appropriate calcium ratios, to ensure better bone mineralisation.
This nutritional adjustment, combined with appropriate control of growth rate, is an essential tool for sustaining on-farm longevity.
Towards more efficient replacement
The genomic era offers animals with unprecedented productive potential, but also animals that are more sensitive to management and nutritional errors. Regularly monitoring body weight and daily gain, adjusting diets based on actual prolificacy, and protecting structural development and mineralisation have become fundamental pillars for ensuring productivity and long-term efficiency.
Meet the guest
Dr Jordi C. Montoro is a veterinarian who graduated from the Autonomous University of Barcelona, where he later completed a PhD jointly with Teagasc (Irish Food Agriculture Development Authority) and AFBI (Agri-Food Bioscience Institute, Northern Ireland), specialising in nutrition and management strategies to improve efficiency in finishing animals. During his training, he completed placements at leading institutions such as the Ivars cooperative and Schothorst Feed Research in the Netherlands. He is currently part of PIC’s global nutrition team, with responsibility for Europe, Russia and South Africa, where he combines applied research, international technical support and collaboration with universities, nutrition companies and integrators. His experience brings together genetics, nutrition and management under commercial conditions, offering a key perspective on replacement and longevity of hyper-prolific females in the genomic era.
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