How to maintain tip-top productivity in gestating sows

Published: 2021-10-27

A well-managed feeding strategy keeps body condition in balance through every reproductive cycle

Keeping sows in good shape from one reproductive cycle to the next is the number one priority to ensure consistent litters of healthy, well-developed piglets. Sows that are too fat, too thin or that fluctuate between the extremes are at risk of compromised performance. It takes careful feed management to get the balance right.

The challenge is that, during the first four to five reproductive cycles, the sow is still growing. During each gestation, her weight increases by an average of 20kg – tempered by the lactation period, when a weight loss of six to nine percent is standard (table 1).

Written by:
Ganna Kirianova
Nutritionist, swine
​+45  2981 0171

* not including litter weight

Table 1. Desired development of body weight following each reproductive cycle

A stable body condition is essential at every stage, from insemination and conception to lactation. That means minimising fluctuations in weight and maintaining back fat thickness at around 14-16 mm. Once farrowing has taken place, body condition must be rapidly restored to prepare the sow for the next cycle.

The link to productivity and life span

Poor management of body condition has severe consequences for sow productivity and lifespan. Table 2 compares the performance of sows of optimum condition with sows that are underweight. The figures speak for themselves. Skinny sows are not only more likely to suffer from shoulder ulcers. The rate of still births at farrowing is substantially higher.

Table 2. Impact of body condition on reproduction. 
Source: ‘Efficient feeding of sows’ presentation by Gunner Sorensen, product manager at
Danish Pig Research Centre (VSP) at the annual VSP congress in 2014 ​

Fat sows, on the other hand, are associated with increased feed costs and are at greater risk of farrowing problems, which may mean they need manual help to give birth. 

Overall feed consumption is also higher in those sows with major weight variations through the cycle. Where weight loss is significant after farrowing, fast recovery is critical to avoid an increase in the number of non-productive days before the sow is ready for the next insemination. 

Table 3. Evaluation of sow body condition by pressing flat hand on hip bone, spine and ribs

Aim for the ideal

The importance of continuous evaluation and regulation of body condition cannot be stressed enough. On the ideal farm, at least 90% of the herd should have the ideal body condition to optimise uterine and foetal development and secure uniform piglet production. 

Efficient feed management throughout the reproductive cycle is key to achieving the best results (table 4). The protein, lysine, phosphorus and calcium in the feed play an important role at each stage (table 5), along with soluble and insoluble fibre and additional vitamins and minerals.

After insemination, the following three to four weeks are crucial to litter size, as it is during this time that eggs attach to the uterus and embryos start to develop. Sows need 2.5 to 4kg of feed a day to obtain sufficient energy to maintain their own weight and support foetal development.  

In the second gestation phase, from 28 to 84 days, feeding levels are typically reduced, depending on an assessment of body condition. Feeding levels are adjusted back up to around 3.5kg for the final three to four weeks before farrowing – contributing to piglet growth and development and priming sow fertility for the next insemination. 

Table 4. Feed guidelines for gestating sows based on body condition. Source: DanBred Feeding Manual

Table 5. Standard recommendation for the nutrient content of feed for gestating sows in a temperate climate zone

The role of climate

Indoor temperatures can also impact feed consumption throughout the cycle. If the temperature is low, the animals’ energy requirements will increase. Around 0.2kg extra feed a day is estimated for every 5°C drop in temperature from a baseline of 20°C. 

A successful feeding strategy, then, both involves regular assessments of the individual sow’s body condition and consideration for the climate zone where production is located. Swift adjustments of the feeding level can make all the difference to achieving a stable result.

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