Feeding lactating sows

Feeding sows correctly throughout lactation is essential for maintaining optimal reproductive performance. Read our information to find out about the nutrient requirements of lactating sows.

During lactation, the primary objectives of nutrition are:

• To maximise the sow’s milk production so as to best support her litter
• To reduce the loss of body reserves

The undersupply of nutrients during lactation has been demonstrated to reduce fertility and embryo survival in subsequent litters. Ensuring that lactating sows have an adequate feeding programme is essential for optimal reproductive performance. This has a considerable effect on returning parity 1 sows in terms of future retention within the herd.

Feed intake

Maintaining and developing the feed intake of sows during lactation can be difficult. It is important to remember that an optimum feed intake during late gestation drives appetite in lactation. Often, sows that are fed ad lib towards the end of gestation will not consume enough during lactation and will subsequently lose condition and milk yield.

It is critical to consider the differences between parities and how this may affect nutrient requirements. Sows have a higher feed intake than gilts; therefore, gilts may need a higher concentration of nutrients. For this reason, it can be beneficial to have two diets on farm: one for parity 1–2 and one for parity 2–3 onwards.

The following table gives typical feed specifications for lactating gilts and sows.

 Table 1. Nutrient specifications for lactating gilts and sows 

¹Amino acids are presented as ratios to standardised ileal digestible lysine

²Digestible phosphorus level is based on diet formulation without the use of phytase. If phytase is being used, then the phosphorus levels must be readjusted. Addition of phytase to the diet is recommended for improved digestibility

³The maximum permitted level of copper in feed for all pigs over 8 weeks post-weaning is 25 mg/kg

Oxidative stress can negatively affect reproductive performance, so it is important that lactating sows’ diets are sufficiently supplemented with antioxidants, including both Vitamin E (Table 1) and selenium.

In addition to the above nutrient recommendations, the following additives may also be considered for lactating sows:

• Phytase

Addition of phytase to lactating sow diets has been shown to increase the nutritional value of feed by increasing the release of phosphorus

• Yeast

Adding yeast (both live and dried) to lactating sow diets has beneficial effects on the intestinal mucosa of both the sow and her litter

• Cereal enzymes

Cereal enzymes such as xylanase, can be included in lactating sow diets to degrade fibre in the feed and enhance nutrient digestibility

• L-carnitine

Research has demonstrated that L-carnitine supplementation during lactation may improve litter performance.

In lactation, the objective should be to maximise feed intake and to meet the considerable milk potential of the sow without utilising her body reserves. Figure 1 shows a typical lactating sow feeding curve. The amount of feed offered during lactation should start low and gradually increase as the sow’s appetite develops.

Figure 1. Example of lactating sow feeding curve

Lactating sows should be fed at least twice a day, but preferably three times a day (or even as much as seven times a day if on automated feed systems) because this has been shown to increase intake by as much as 15%. Ad-lib systems for lactating sows are common, allowing the sow to eat to appetite. During lactation, gilts and sows have different appetites and nutrient requirements, so it can be beneficial to have two diets on farm, one for parity 1–2 and one for parity 2–3 onwards.

During warmer weather, heat stress commonly causes a reduction in sow feed intake. Not only can this affect milk production and therefore the piglets’ growth, but sows weaned in poorer conditions also have longer wean-to-oestrus intervals – particularly first-litter sows. To maintain lactating sow feed intake during the summer months, consider feeding more often – ideally to three or more meals per day – and feed meals during the cooler parts of the day.

A diet with a higher nutrient concentration can also be beneficial when intakes are low to ensure that sows get a greater concentration of nutrients with the reduced feed intake. A temporary measure can also include using a top dress product.

The lactating sow is prone to overheating because she cannot lose heat quickly enough and, as a result, her feed intake will often drop during warmer weather. This effect can be more pronounced in outdoor systems because the sows are exposed to the environment. Outdoor pigs may also have a lower thermoneutral zone because, unlike indoor pigs, they are accustomed to winter temperatures.

Lower feed intake during periods of hot weather can result in reduced milk production. This, in turn, can cause piglet growth rate and weaning weights to decline, which can have a long-term impact on performance. To reduce the effect of high ambient temperatures, prevention is better than cure and you should aim to keep your sows as cool as possible.

Strategies such as ventilation, air cooling, water drips, outdoor siting of arcs, drafts, insulated arcs, wallows and shade should all be considered. In indoor units, using heat mats for the piglets and reducing farrowing house temperature is recommended. Using a higher feed nutrient concentration or a top dress may help but the sow is eating less because she is heat stressed. If the feed is higher in protein, she creates more heat. Any sow condition lost over this period must be regained during the subsequent pregnancy.

Feed is available in several different forms including pellets, meal and rolls. There are benefits of each, and, ultimately, the type of production system and feeding equipment available may dictate choice.

In outdoor systems, sow rolls and nuts may be used. These are beneficial because the sow will forage from the ground, thus helping to increase intake and reduce wastage. Pellets have been widely reported to increase feeding efficiency and feed intake. This may be explained by the finer grist size giving improved availability of nutrients quicker digestion leading to increased intake. 

In the UK, meal is generally a coarse grist product, which increases flowability and reduces blockages and dust. However, feed wastage may be higher.

Water is an essential nutrient for all animals, so ensuring unrestricted access to water is critical. Water intake during lactation is particularly important because it can directly affect milk yield. A flow rate of 10 litres per minute is recommended for nipple drinkers and to ensure sufficient water pressure when more than one sow drinks at the same time. 

Creep feeding is the practice of feeding piglets solid feed during lactation to aid intestinal development and ease the transition from the farrowing house to the nursery house. Creep feeding has various advantages, but to obtain these benefits, the right diets and proper feeding management practices must be used.

• Offer creep feed from seven days of age. Studies have shown that the earlier creep feed is offered, the greater the proportion of piglets that will be eating by weaning
• Offer highly palatable diets with high amounts of milk products (lactose)
• Start with very small amounts from around seven  days of age and replace it at least twice a day. This ensures the creep feed remains fresh and palatable to the piglets
• Giving the creep feed to litters while the sow is eating has been shown to increase creep feed intake
• Consider where the creep feed is offered. Ideally creep should be given on a flat surface to stimulate rooting behaviour and away from heat lamps to prevent deterioration in feed quality
• Piglets should have ad lib access to clean drinking water

This was written in conjunction with ABN, Primary Diets and Premier Nutrition.