12 tips for feeding hyperprolific lactating sows

Supporting the nutritional needs of the hyperprolific sow improves piglet survival rates. Dyoma | Dreamstime.com

Maximizing lactation feed intake in hyperprolific sows enhances future reproductive performance as well as piglet weaning weight and survivability.

The beneficial effects of increased feed intake during lactation on sow reproductive performance are well known. Sows with minimal body fat and protein loss during lactation take less time to return to estrus after weaning. In addition, subsequent litter size tends to be larger, depending on sow condition. For example, for each 10 percent of body fat sows lose during lactation, subsequent litter size is reduced by one piglet. Likewise, each kilogram of body weight sows lose during the previous lactation results in one extra day until conception. The effects of increased feed intake during lactation on litter growth are less well documented (numerically). However, this effect is of paramount importance in systems that place extra value on weaning weight, so it merits further study.

The value of sow milk

Naturally, sow milk is an exceptionally rich source of nutrients for the suckling pig. It contains about 200 g/kg dry matter. On a liquid basis, it contains 55 g/kg protein, 50 g/kg lactose and 80 g/kg fat. Calculated metabolizable energy content is about 5.4 MJ/kg (liquid basis). Assuming that growth in suckling piglets requires approximately 22 MJ ME/kg weight gain and the protein profile in sow milk is ideally balanced, it is estimated that piglets require about 4 kg of milk for each kilogram of body weight gain, based only on energy calculations (22 / 5.4 = 4) for simplicity.

A typical lactation diet based on cereals and proteins of vegetable origin contains about 14 MJ ME/kg. The marginal coefficiency factor of converting feed energy to milk energy is about 70 percent. This implies that each kilogram of the above feed has the potential of yielding 9.8 MJ ME for milk production. If dietary protein quality and quantity do not restrict milk production, a sow should produce approximately 1.8 kg milk (9.8 / 5.4 = 1.8) per kilogram of feed consumed, after deducting enough feed to cover daily maintenance needs.

In reality, when sows eat above maintenance and milk production requirements (rarely), some of the extra energy is diverted to restore or increase body fat and muscle deposits. Thus, the largest response in milk production is anticipated at feed intakes ranging from 4 to 8 kg, with an almost linear response between 5 and 7 kg feed per day. For the purpose of this discussion, we shall assume that only 60 percent of the energy from each kilogram of extra feed consumed is directed toward milk synthesis and yields about 1 kg extra milk (1.8 x 60% = ~ 1). This scenario is more applicable to sows with moderate appetites (5-7 kg/day).

Further, let us assume that a typical sow (nursing a litter of 10 piglets for 21 days) consumes an average of 6 kg feed per day. If daily feed intake increases by 2 kg, she may produce 2 kg extra milk per day. This translates to 0.50 kg extra litter growth per day (2 / 4 = 0.5), and each piglet at weaning would be about 1 kg heavier (0.50 x 21 / 10 = 1). Had the lactation period been 28 days, piglets would be almost 1.5 kg heavier, assuming similar sow feed intake. Heavier pigs at weaning not only require less resource input post-weaning in terms of diets, heating, veterinary interventions, etc., but they also achieve final market weight faster and more efficiently, as each additional kilogram of body weight at weaning reduces time to market weight by about five days.

A sow must consume about 2 to 3 kg of feed per day for her maintenance needs and about 0.5 kg of feed per day, per piglet, for milk production.

So, for each extra kilogram of feed a sow will consume over the course of her lactation, milk yield is expected to increase by at least 1 kg. This is converted to 0.25 kg of piglet gain. The magnitude of response depends on sow condition and base-line feed intake.

How to increase sow feed intake in hyperprolific sows during lactation

1. Feed sows a high-fiber diet or allow ad libitum access to feed during the two weeks before farrowing to allow time for the stomach to expand properly.
2. If you follow a step-feeding program during the first week of lactation, bring sows to ad libitum consumption as soon as possible.
3. Feed lactating sows as often as possible, preferably at three times per day as stomach capacity often limits feed intake when sows are fed only two larger meals.
4. Sows will invariably refuse to eat spoiled feed, so make sure feed troughs are cleaned as needed before adding new feed.
5. Make sure sows have access to plentiful, fresh water or provide water in troughs if water intake is limited. Feed intake and water intake are closely related.
6. Feed high-fat diets to increase nutrient intake and reduce metabolic heat, especially during summer season.
7. Reduce natural fiber in formulations and instead use a chemical laxative for sows prone to constipation. Alternatively, use a concentrated fiber source.
8. Certain in-feed enzymes may enhance nutrient digestibility and increase nutrient intake. They work best for cereals such as wheat and barley.
9. Pelleted feed has reduced volume and allows sows to consume more feed.
10. Quite often an appetizer may enhance feed intake, but the proper appetizer must be located via trial and error as these are farm- and feed-specific applications.
11. Feed sows during the cooler periods of the day (early morning, late evening, and night).
12. Always make sure mycotoxins are as low as possible in lactating sow feed, and, if uncertain, use a wide-spectrum blend of mycotoxin binders.

As a general rule of thumb, a sow must consume about 2 to 3 kg of feed per day for her maintenance needs (depending on age, body weight and condition) and about 0.5 kg of feed per day, per piglet (depending on feed nutrient density), for milk production. For example, a 200 kg sow nursing 10 piglets should consume approximately 6-7 kg feed per day (on average) during a typical 21-day lactation period. In contrast, the same sow nursing 15 piglets requires almost 10 kg feed per day to cope with the increased milk production. This is rather impossible under commercial conditions, hence the need to find ways to enhance feed and nutrient ingestion. If sows consume less feed compared to their needs, then they compensate by first catabolizing body fat (energy deficiency phase) and second by reducing milk production (protein deficiency phase).

Ioannis Mavromichalis, Ph.D., is Nutrition Editor for WATTAgNet and Editor-in-Chief of Pig International.