Summary of current knowledge on sow nutrition in the Scientific literature, January 2015

Summary of current knowledge on sow nutrition in the Scientific literature

Good sow productivity begins with good gilt management. It is recommended that gilts should be served when they have 16-18mm of back fat, are between 220-230 days old, weigh between 130 and 140kg and have reached second or third oestrus. A special gilt diet from approximately 50kg is usually required to achieve these weight and back fat targets. It is also good practice to flush gilts for at least two weeks prior to insemination to increase ovulation rate.

Feeding sows during gestation can involve increased feeding during early and late pregnancy. Indeed, increasing feed allowances (over 3kg) in early gestation can have a beneficial effect on litter sizes. However, it may also have a negative effect on individual piglet growth post birth. Overall, evidence is contradictory on the effect of feed allowance in early gestation, furthermore genetics has largely solved the issue of increasing litter size at this stage. It is recommended that feeding 2.4kg during mid-gestation is sufficient for piglet development and high rates of feeding can actually reduce performance. In theory, feeding 2.5kg is sufficient in late gestation as well and many studies have found no positive impact on litter weight and performance at higher feeding levels.

Adding supplementary fat to sows gestation diets can increase the sow’s energy intake, but there is no consistent effect of additional fat to sow diets on piglet performance. It may however, improve piglet survival, but this may be due to increased gestation length and improved colostrum quality.

Protein content

Protein content is important in gestation diets as most of in utero piglet growth and mammary development is protein. Crude protein should be between 15 and 17% in late gestation to cover the sow’s protein needs for piglet and mammary growth. Lysine levels for gilts should be at least 0.7% in a 2.5kg/day feed allocation and lysine levels for sows should be at least 0.5% in a 3kg/day feed allocation. Supplemental arginine and carnitine (both amino acids) can also improve sow and piglet performance.

Colostrum

Colostrum quality in sows is of utmost importance as colostrum intake is directly correlated to piglet survival. Supplementary fat offered in late gestation may increase fat (energy) content of colostrum, and certain fatty acids (such as supplementary CLA) may also increase immunoglobulins which transfer immunity from the sow to the piglet.

Lactation

During lactation, sows with high feeding levels are able to produce more milk which leads to greater piglet growth and reduces sow body loss. Lactation feed intake is extremely important as intake drives milk yield. To improve intake, the farrowing room temperature needs to accommodate the needs of the sow to stay cool and the needs of the piglet to stay warm. Practical ways to achieve this include directing air flow onto sows, wetting or misting the sows to aid evaporation and using creep-boxes (a covered area for piglets) so that the farrowing house temperature can be reduced. Also, a sow will drink more than 40 liters a day; to help her maintain this, drinkers should have a flow rate of over 2 liters per minute. Lastly, ensure troughs are cleaned thoroughly on a daily basis as mouldy, rancid feed will depress intake.

Adding fat to the lactation diet can reduce mortality and increase growth rate of piglets; however, this can be at the expense of sow body weight. Conjugated Linolenic acid (CLA) at low doses can reduce piglet birth weight, but at 1% inclusion CLA can increase weaning weight. Protein restriction during lactation reduces sow and piglet performance. Studies have found that protein and lysine levels higher than BSAS recommendations (17% and 1% respectively) can improve litter performance and reduce sow weight loss.

In conclusion, a sow can rear 12+ piglets to a good weaning weight if she is given the right fuel (feed!).