The Impact of Weaning Age on Farrow-to-Finish Production Parameters

By Fiona Tansil, Trouw Nutrition Canada

Weaning age varies from one farm to another. Some might wean at an earlier age depending on the number of sows farrowing each week or due to limitation in the farrowing capacity. On the other hand, some might wean later due to the potential improvement in nursery and grow-finish performance.

This article will discuss the potential impacts of weaning at age 19 and 24 days on growth and production parameters using the cutting-edge Watson model and Scenario software developed by Trouw Nutrition.

Watson is a decision-making tool that can closely predict the production outcomes of weaning at a later age, accounting for various factors such as genotype, environmental condition, feed nutrition, and shipping strategies. By using Watson, we can predict and compare how different weaning ages can affect the average daily gain (ADG), feed intake, and the final exit weight of pigs in nursery or grow finish barns.

close up of brown and pink piglets
    Jodie Aldred photo

Additionally, Watson is able to generate the most optimal feeding budget, which can be adjusted for different production objectives such as improved margin over feed cost or the least cost per kg gain. Meanwhile, Scenario is a financial software to measure and compare the cost of commercial swine production, which accounts for production parameters, feed budget, and cost of operations.

In the nursery barn, increasing weaning age from 19 to 24 days improved entry weight, ADG, feed intake, feed conversion ratio, and exit weight (Main et al., 2004). In addition, increasing weaning age reduced the prevalence of weight loss, belly-nosing (Faccin et al., 2020), and mortality rate (Main et al., 2004). For entry weight to nursery, we predicted a 200 g increase per day for each additional day that the piglet stays in the farrowing unit.

chart comparing product parameters and weaning age
    Comparison of production parameters between weaning at 19 and 24 days in the maternity, nursery, and grow finish units. -Fiona Tansil photo

Watson predicts an ADG difference of 59.52 g between 19 and 24 days wean (Table 1), while published research studies have reported an increase of 65 g/day (Main et al., 2004) and 79 g/day (Faccin et al., 2020) in ADG. Feed-to-gain ratio tends to improve as weaning age increases; Watson predicts a slight improvement from 1.52 to 1.50 for 19- and 24-day weaning, respectively. When pigs are weaned at an older age, they become heavier, bigger, and more robust overall, with a stronger immune system as well. A one per cent reduction in mortality rate from 19 to 24 days weaning age can be expected, while Main et al., 2004 predicted 1.5 per cent decrease in mortality from 18 to 21 days of weaning. Thus, a linear decrease in mortality rate as weaning age increases can be expected in nursery pigs.

In the grow-finish barn, the main advantage of weaning at an older age is the heavier starting weight, improved ADG and earlier days to market.

Based on our experience with producers in Quebec, a saving of $0.16/day/pig is anticipated with shipping pigs earlier to the market. Watson predicts shipping pigs four days earlier, on average, with weaning at 24 compared to 19 days of age. Thus, if a producer has 1,000 finishing pigs, for example, the savings from shipping four days earlier would be $640.

Average daily gain in the grow finish barn has been reported to increase linearly as weaning age increases, which also improves the weight sold per pig weaned. Watson predicts a nine gram/day increase with weaning at 24 compared with 19 days and Main et al., 2004 calculated an 8.7 kg increase in the weight sold per pig weaned from 18 to 21 days of weaning.

In the sow production system, additional lactation feeding cost and the lower number of litters/sow/year need to be considered with increasing weaning age. An additional five days in lactation means the sow requires an estimated 35 kg extra of lactation feed per cycle. This amount is just an estimate and should not be used as an exact prediction as each farm is different.

The number of litters/sow/year also decreases as the sows spend longer in the farrowing unit per cycle. Using Scenario we see a 0.08 unit decrease in the amount of litters/sow/year with five days increase in weaning age. It is also important to evaluate the impact of longer lactation duration on the availability of farrowing space. Some proposed potential solutions are to build supplementary farrowing crates, while keeping the same number of sows or to reduce the number of sows in the existing breeding barn.

Adding supplementary farrowing crates is seen as the preferred solution than reducing the number of sows. However, results vary from one farm to another depending on building infrastructure, equipment cost and other factors. BP


Main, R.G., Dritz, S.S., Tokach, M.D., Goodband, R.D. and Nelssen, J.L., 2004. Increasing weaning age improves pig performance in a multisite production system. Journal of animal science, 82(5), pp.1499-1507.

Faccin, J.E., Laskoski, F., Hernig, L.F., Kummer, R., Lima, G.F., Orlando, U.A., Gonçalves, M.A., Mellagi, A.P.G., Ulguim, R.R. and Bortolozzo, F.P., 2020. Impact of increasing weaning age on pig performance and belly nosing prevalence in a commercial multisite production system. Journal of Animal Science, 98(4), p.skaa031.

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