Factors that influence colostrum yield and milk production

Litter performance before weaning is mainly influenced by the sow’s colostrum and milk yield. Post weaning growth rate is influenced by the weaning weight, post farrowing mortality rate is influenced by the milk yield of the sow. In the first 2 weeks after birth the piglet is dependent on the sow’s milk for nutrition. Therefore to increase the piglet’s nutritional intake, the sow should produce enough milk.

Sow Colostrum

Colostrum is a form of milk produced by the mammary glands of mammals in late pregnancy and the few days after giving birth (Complete guide to colostrum, 2012). Colostrum is secreted from the udder immediately after farrowing and is a rich source of highly digestible nutrients, which are critical to the survival of the newly born piglet (Pigsite, 2008). Within several hours, the composition of the colostrum changes rapidly to that representing sow milk. The piglet is born with very few antibodies necessary to protect and thrive and relies heavily on the colostrum produced by the sow. The highly intense absorption in the new-born piglet was demonstrated 4 hours after birth and reached the highest intensity between 8 and 12 hours after birth, then tended to decline (Szeky, et al., 1979). Therefore it is of the highest importance that the newly born piglets get to suckle colostrum as soon as possible, to be able to have the maximum benefit from the passive immunity provided by the Sow’s colostrum before absorption declines. The most critical stage of the piglet’s survival is in the first 2 days after birth. The causes of early piglet mortality include reduced vitality due to hypoxia during farrowing, hypothermia and lack of colostrum intake (Malmkvist et al., 2006). Therefore, an early and high intake of colostrum is a major determinant of piglet survival in the first 2 days after birth.

Factors that influence colostrum yield and milk production:

The production of colostrum in sows varies hugely and the factors influencing this are not well known. Alternated colostrum yields can be achieved by reducing the stress before, during and after farrowing as well as ensuring that sows have unrestricted access to fresh drinking water.

Water intake

• Water intake has a large influence on feed intake
• In late gestation water intake can range from 8 - 12 l/day
• At farrowing this may decline to about 6 l/day
• During lactation this may increase to an average of 14 l (range 7-20 l/day)
• Water flow rate should never be lower than 0,6 -1,0 l/min      

Parity

Parity has a slight influence on milk yield with a tendency for a greater production in second- and third parity sows than in first parity or older sows (De Villiers et al., 2007). However, sows that take longer to farrow their 3^rd – 5^th litter of piglets have lower colostrum yields than those who farrowed in less time. Sows that had more stillborn piglets also yielded less colostrum than those who had less (Quensel, 2011). This indicates that the sow may have been in distress at the time of farrowing, and is subsequently producing less colostrum.

Nutrition

Nutrition may have an effect on the production of colostrum by the mammary gland development and through mechanisms controlling colostrum secretion in late gestation. Maintenance of high energy, amino acid and mineral intakes are critical to keep the sow in the herd for a long and economically viable reproductive life. Overfeeding in late gestation has a negative effect on mammary development due to excessive fat disposition in sows (Farmer and Sorsen, 2011).

Temperature

In the current dry summer, sows will be exposed to ambient temperatures above their thermo-neutral zone during the day. This exposure to high ambient temperatures has a negative effect on sow performance during lactation. Reduction in feed intake leads to losses in live weight, excessive loss of back fat depth, changes in natural behaviour, delayed heat cycle and fertility issues. Sows exposed to high ambient temperatures, mobilise their body reserves to support milk production. This in turn results in reduced thyroid activity that causes a reduction in the concentration of the thyroid hormone in the plasma of the lactating sow with a decline in metabolism and milk production (Wung, 1977). However, by increasing the photoperiod from 8 -16 hours light, an increase of milk yield in sows has been noted (Marbry, 1982). This can be translated to an increase of prolactin levels, or an increased suckling frequency in the event of a prolonged photoperiod.

Conclusion

• Colostrum and milk yield is influenced by litter size; birth weight; number of parity; stress before and during farrowing and nutrition
• Colostrum composition in sows may vary
• 20-30% of early piglet mortality is due to lack of adequate nutrition and can be prevented by ensuring the piglets are kept warm and get to suckle immediately after farrowing to ensure maximum absorption of passive immunity provided in colostrum
• Use a separate gilt lactation diet for 1^st parity gilts and thin sows in lactatio
• Feed frequently to individual sow appetite
• Minimize all adverse effects on feed intake
• An increase in average feed intake, can improve piglet weaning weight and may also translate to an increased next litter size

Implications

A profitable pig production enterprise will depend on the management of the sow during gestation and farrowing. Attending to the sow at farrowing, making sure that she is comfortable and paying attention to her behaviour, will ensure that the piglets suckle in the shortest period possible from being born, thus increasing their chances of survival.

Sow nutrition

Sow nutrition during gestation and lactation will have an effect on the litter size as well as the litter weight at farrowing and weaning. The body condition of the sow at weaning influences the duration to post-weaning service, number of services per conception and subsequent litter size. For leaner sows moving into the farrowing house a maximum loss of 2 mm back fat should be sufficient. Fatter sows should have no problem in mobilizing their body reserves to sustain the increasing demand of milk production. Sows weaning either too lean or too fat may very well have prolonged days to service.

Sows fed poorly during lactation produce less milk, wean smaller litters of lower weight and this ultimately leads to the early culling of breeding animals.

References are available on request.

1. 1.   Complete guide to colostrum, 2012
2. 2.   Farmer and Sorsen, 2011
3. 3.   Malmkvist et al., 2006
4. 4.   Marbry, 1982
5. 5.   Pigsite, 2008
6. 6.   Quensel, 2011
7. 7.   Szeky, et al., 1979
8. 8.   Wung, 1977